Article: 97653 of rec.radio.amateur.homebrew From: John Laczik Subject: ferrite toroids and capacitors for antenna tuner Date: Tue, 13 Jun 2006 10:26:58 +0100 Message-ID: Which types of ferrite toroids and capacitors would be recommended for an antenna tuner that is to be used 1.5 MHz - 30 MHz (possibly up to 50 MHz)? Max. transmit power is 100 ~ 150 W. Ideally I would prefer components that are available from either RS (rswww.com) or Farnell (uk.farnell.com). Farnell do toroids from N27, N30, 3C85, 3R1, 4C65, 3E5 and 3E25 materials; which ones are suitable for broadband HF power applications? For the capacitors, would any of the surface mount types be suitable? Thanks, John Article: 97654 of rec.radio.amateur.homebrew From: Roy Lewallen Subject: Re: ferrite toroids and capacitors for antenna tuner Date: Tue, 13 Jun 2006 02:49:29 -0700 Message-ID: <128t2hc3mngue17@corp.supernews.com> References: Exactly what "broadband HF power application" do you have in mind? A single transformer or balun covering the whole band? Capacitors are usually avoided in broadband applications. How will you be using them? Are you a licensed amateur? Roy Lewallen, W7EL John Laczik wrote: > Which types of ferrite toroids and capacitors would be recommended > for an antenna tuner that is to be used 1.5 MHz - 30 MHz (possibly > up to 50 MHz)? Max. transmit power is 100 ~ 150 W. > > Ideally I would prefer components that are available from either > RS (rswww.com) or Farnell (uk.farnell.com). > > Farnell do toroids from N27, N30, 3C85, 3R1, 4C65, 3E5 and 3E25 > materials; which ones are suitable for broadband HF power applications? > > For the capacitors, would any of the surface mount types be suitable? > > Thanks, > > John Article: 97655 of rec.radio.amateur.homebrew From: John Laczik Subject: Re: ferrite toroids and capacitors for antenna tuner Date: Tue, 13 Jun 2006 15:01:53 +0100 Message-ID: References: <128t2hc3mngue17@corp.supernews.com> Roy, > Exactly what "broadband HF power application" do you have in mind? Sorry, I should have been more precise. What I wrote referred to an antenna tuner that covers the various ham/marine bands in the 1.5 MHz to 50 MHz range, i.e inductors and capacitors that are suitable for use in this 'broad' frequency range. Also, the antenna tuner probably will have a balun in it, which would not be tuned and hence would be broadband. > Are you a licensed amateur? Yes. > How will you be using them? I am trying to set up a rig on a boat, and one of the options is to make a remote controlled antenna tuner for RX, and up to ~100W TX, instead of using one of the rather expensive commercial units. The antenna/tuner will be used to receive marine weather transmissions, and for CW QSOs on the ham bands. Thanks, John, HA5PG/MM Article: 97656 of rec.radio.amateur.homebrew From: "AAA RF Products" Subject: FS: SMA Cable Assemblies, $9.90 each, made in USA Message-ID: Date: Tue, 13 Jun 2006 09:31:20 -0700 Any 10 SMA Male to SMA Male cable assemblies for $99.00 RG-58C/U or RG-223/U Mix & match any 10 Length available: 12", 18", 24", 30", 36", 48", 60", 72", 84", & 96" High quality & made in USA Please email sales@AAARFProducts.com or call 949 481 3154 (San Clemente, CA, USA) AAA RF Products 946 Calle Amanecer, suite E San Clemente, CA 92673 Article: 97657 of rec.radio.amateur.homebrew From: "Steve N." Subject: Re: FCC tutorial on looking up schematic/info using ID number Date: Tue, 13 Jun 2006 13:36:38 -0500 Message-ID: References: <1149865881.746342.289440@h76g2000cwa.googlegroups.com> <1149885762.986782.203720@u72g2000cwu.googlegroups.com> Manufacturers can pay the FCC to keep various documents from public view. When they are available, you can see them. If you can't see / download them, then they are confidental. 73, Steve, K9DCI "John" wrote in message news:LKGdnQrXgdnIXBHZnZ2dnUVZ_tCdnZ2d@comcast.com... > Looks like I picked a poor example. > The schematic is permanently confidential. > Click on the word "Detail" for the second entry. > Click on the "mail slot icon" for any of the > documents to display the document. > If you click on the word "Summary", it will > show which documents are "Permanently Confidential" in the > column of the same name. > > "n4aeq" wrote in message > news:1149885762.986782.203720@u72g2000cwu.googlegroups.com... > > Thanks John, i can get it to display a list of documents that are in > > .pdf but i there is no > > way to click or open the docs. They just show the list of docs, > > pitcures & other, does this mean i need to do something else? Is a > > login required before the link will be active? > > > > John wrote: > >> "John" wrote in message > >> news:rM-dnTtr1L2MKhTZnZ2dnUVZ_tmdnZ2d@comcast.com... > >> > > >> > "n4aeq" wrote in message > >> > news:1149865881.746342.289440@h76g2000cwa.googlegroups.com... > >> >> Im trying to lookup schematics/info the FCCs website: > >> >> > >> >> https://gullfoss2.fcc.gov/prod/oet/cf/eas/reports/GenericSearch.cfm > >> >> > >> >> I have the website but havent had much luck looking anything up using > >> >> fcc id #, sense this > >> >> is my first attempt then maybe theirs something im doing wrong on the > >> >> search page. Alot > >> >> of people seem to use the site for schematics and other good > >> >> information, seems like > >> >> it would great for the ham/experimenter. Any help getting started at > >> >> looking up information > >> >> on the fcc website would be appreciated. > >> >> > >> > https://gullfoss2.fcc.gov/prod/oet/cf/eas/reports/GenericSearch.cfm > >> > > >> > > >> I hit transmit too soon. > >> Note that the FCC ID is entered in pieces, the first 3 characters in the > >> first block, and all of the rest in the second block. That is all that > >> you > >> have to enter. Try PY3WG511-F as an example. There are lots of > >> documents available. > > > > Article: 97658 of rec.radio.amateur.homebrew From: Roy Lewallen Subject: Re: ferrite toroids and capacitors for antenna tuner Date: Tue, 13 Jun 2006 12:55:43 -0700 Message-ID: <128u626p48l6sde@corp.supernews.com> References: <128t2hc3mngue17@corp.supernews.com> Thanks for the clarification. The core requirements for a broadband application like a broadband transformer or balun are much different than for a narrowband (high Q) application like an inductor in a matching network. I wouldn't use ferrites at all for the inductor cores, but powdered iron -- type 6 except perhaps below 3.5 MHz where type 2 might be slightly better. For fixed capacitors I'd stick to NPO (C0G) ceramic for Q and stability. Roy Lewallen, W7EL John Laczik wrote: > Roy, > >> Exactly what "broadband HF power application" do you have in mind? > > Sorry, I should have been more precise. What I wrote referred to > an antenna tuner that covers the various ham/marine bands in the > 1.5 MHz to 50 MHz range, i.e inductors and capacitors that are > suitable for use in this 'broad' frequency range. Also, the antenna > tuner probably will have a balun in it, which would not be tuned > and hence would be broadband. > >> Are you a licensed amateur? > > Yes. > >> How will you be using them? > > I am trying to set up a rig on a boat, and one of the options is to > make a remote controlled antenna tuner for RX, and up to ~100W TX, > instead of using one of the rather expensive commercial units. The > antenna/tuner will be used to receive marine weather transmissions, > and for CW QSOs on the ham bands. > > Thanks, > > John, HA5PG/MM > Article: 97659 of rec.radio.amateur.homebrew From: Allodoxaphobia Subject: Re: Tektronix FG501A drift question Date: 14 Jun 2006 16:17:22 GMT Message-ID: References: On Tue, 13 Jun 2006 22:01:22 -0500, Gudmundur wrote: > Hi folks, > > I have a Tek function generator model FG501A and the D.C. offset in > the 'fixed' or 'non-variable' position seems real drifty with > temperature changes. Probably a wider audience for this: sci.electronics.repair Jonesy -- Marvin L Jones | jonz | W3DHJ | linux 38.24N 104.55W | @ config.com | Jonesy | OS/2 *** Killfiling google posts: Article: 97660 of rec.radio.amateur.homebrew Message-ID: <449036A6.DE5356F7@earthlink.net> From: "Michael A. Terrell" Subject: Re: Tektronix FG501A drift question References: Date: Wed, 14 Jun 2006 16:18:26 GMT Gudmundur wrote: > > Hi folks, > > I have a Tek function generator model FG501A and the D.C. offset in > the 'fixed' or 'non-variable' position seems real drifty with > temperature changes. I thought my unit was bad when I noticed it was > offset nearly .5 volts at startup then drifting toward 0 offset after > extended warmup, that was until I discovered the unit where I work > was even worse than mine at about 1.5 volts of offset. The offset > can be adjusted to zero for some exact given temperature, but geez > guys, change the temperature about 10 degrees and the offset changes > about .25 volts. > > Anyone ever run into this? Seems kinda crappy compared to most Tek stuff. > Do the two units I can lay my hands on have a shot compensating > component? Other than d.c. offset drift the unit works perfect. > > Thanks. news:sci.electronics.equipment might be of more help. -- Service to my country? Been there, Done that, and I've got my DD214 to prove it. Member of DAV #85. Michael A. Terrell Central Florida Article: 97661 of rec.radio.amateur.homebrew From: John Wilkinson Subject: Re: 44.545MHz LO References: Date: Thu, 15 Jun 2006 19:37:15 +0100 Message-ID: On Mon, 12 Jun 2006 08:23:33 +0100, John Wilkinson wrote: > Hi, > I need a good second LO at 44.545MHz. > I have a few crystals that I bought, that are say they are 44.545MHz, but > are really 44.548MHz. I tried pulling the frquency somewhat, but to no > great avail. > I have read that overtone crystals are hard to pull. > > Does anyone know where I can get good quality crystals at this frequency? > > Or how I may combine some easily available crystal frequencies to get > either 44.545MHz or 45.455MHz? > > Best regards, > John. Hi, I would like to thank Joe, W3JDR and Tim Wescott for thier help. I made a common base colpits oscillator, as per the ARRL handbook, with a 2N3904, and got it working at 45.455MHz...Great. That's a lesson learnt. Best regards, John Article: 97662 of rec.radio.amateur.homebrew From: fmmck@aol.com (Fred McKenzie) Subject: Re: Weller Tech Sheets Date: Wed, 14 Jun 2006 14:59:59 -0400 Message-ID: References: In article , "g. beat" <@> wrote: > I have been slowly scanning my collection of Weller Tech Sheets and posting > these on BAMA. w9gb- Do you by any chance have a Fluke collection as well? I'm looking for an instruction sheet for installing the 1300 MHz prescaler, Option 72XXA-331K, into the Fluke 7260A or 7261A counters. It is Fluke Stock Number 546087. Fluke no longer had any record of it when I checked. BAMA has the 7261A manual, but not this instruction sheet. Thanks. Fred, K4DII Article: 97663 of rec.radio.amateur.homebrew Subject: ** FLEA at MIT ** Sunday June 18th Cambridge MA From: w1gsl@mit.edu (Steven L. Finberg) Date: 15 Jun 2006 01:00:27 GMT Message-ID: <4490b12b$0$570$b45e6eb0@senator-bedfellow.mit.edu> This comming Sunday... +++ Now even more Buyers Parking !!! Thanks to TKT we have use of their new parking lot across Albany St from the SWAPFEST !!! !! ** More Buyers PARKING is available ** for details see http://web.mit.edu/w1gsl/Public/flyer *** !!!! In our Traditional GARAGE and the adjacent lot !!!! **** so come rain or shine or super heat the Flea is on !!! ********* $1 buyers discount with hardcopy of this notice ******** COMPUTERS - ELECTRONICS - HAM RADIO - COMPUTERS - ELECTRONICS - HAM RADIO FLEA all SUMMER at MIT Sunday June 18yh 2006 9AM-2PM Come to the city for a great flea - plenty of free parking. MIT's electronics and ham radio flea will take place on the third Sunday of each month this summer, April thru October. There is tailgate space for over 600 sellers and free, off-street parking for >2000 cars! Buyers admission is $5 (you get $1 off if you're lucky enough to have a copy of our ad) and sellers spaces are $20 for the first and $15 for each additional at the gate. The flea will be held at the corner of Albany and Main streets in Cambridge; right in the Kendall Square area from 9AM to 2PM, with sellers set-up time starting at 7AM. SEASON PASS + Advance Seller Discount A sellers discount season pass is available which offers a 30% discount. By prepaying you get a discount and earlier admission. See the registration form. *** Attention Sellers *** Prepaid vendors.. Season Pass or monthly, will be admitted FIRST. Separate lines will form prior to gate opening for prepaid and nonprepaid vendors !! RAIN or SHINE !! Have no fear of rain, a covered well illuminated tailgate area is available for all sellers (6'8" clearance). Talk-in: 145.23- (PL 88.5) W1BOS/R and W1XM/R-449.725/444.725 (PL 114.8/2A). Sponsors: MIT Electronics Research Society MIT UHF Repeater Association (W1XM) MIT Radio Society (W1MX) Harvard Wireless Club (W1AF) For more info / advanced reservations 617 253 3776 ********** $1 buyers discount with hard copy of this notice ************ <<<<<<<<<<<<<<<<<<<<<<<< cut here >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Mail the coupon below by the 5th of the month to be a Prepaid Vendor. FLEA at MIT 2006 Rates SELLERS To use your prepaid spaces the named vendor MUST be present. Rates include one admission per space. Season Pass $99 First Space includes all 7 2006 meets $70 each additional Space Must be received by April 16th Advance $17 First space $12 Additional Spaces Must be received by the 5th of the month. Gate Admission $20 First Space $15 Additional Spaces Admission is after the prepaid vendors Early Bird Buyer -Admission after the prepaid vendor line is admitted. ~ 7:15AM ** You may not sell. ** $15 per person at the gate. ****************************** cut here ******************************* FLEA at MIT 2006 Advance Space Application ____April ____May ____June ____ July ____Aug ___Sept ____Oct @ $17 for the first each month + $12 each additional ____ Season Pass @$99 _____ Additional Season Spaces @$70 Name ________________________ Call __________ $ Included______ Address ________________________ Phone __________ Make Check to The MIT Radio Society City ____________________ State _______ Zip _______ PO Box 397082 Cambridge MA 02139 E-mail _____________________________________________ ******************************************************************************* Steve Finberg W1GSL w1gsl@mit.edu PO Box 82 MIT Br Cambridge MA 02139-7082 617 258 3754 ******************************************************************************* Article: 97665 of rec.radio.amateur.homebrew Date: Thu, 15 Jun 2006 19:24:38 +1000 From: Daniel Subject: Re: FA KEITHLEY 610C ELECTROMETER, PICO AMMETER COULOMB METER Plus References: <8659g.23076$mX1.20976@newsfe2-gui.ntli.net> <-5GdndVPALJIOfrZnZ2dnUVZ_vqdnZ2d@comcast.com> <0rhl629t40if5hih8t7hm85gn5s5h44qei@4ax.com> Message-ID: <44911a16$0$3650$88260bb3@free.teranews.com> Ross Mac wrote: > "Roy L. Fuchs" wrote in message > news:gtg172letiechtlciahvlssjq2nal7lbqj@4ax.com... >> On Sun, 21 May 2006 11:24:16 -0400, "Ross Mac" >> Gave us: >> >>> "Roy L. Fuchs" wrote in message >>> news:0rhl629t40if5hih8t7hm85gn5s5h44qei@4ax.com... >>>> On Mon, 15 May 2006 19:42:38 -0400, "Ross Mac" >>>> Gave us: >>>> >>>>> "Roy L. Fuchs" wrote in message >>>>> news:gvof629spp34fho2k68kvv340b0memcg0r@4ax.com... >>>>>> On Sun, 14 May 2006 17:44:51 -0400, "Ross Mac" >>>>>> Gave us: >>>>>> >>>>>>> "Roy L. Fuchs" wrote in message >>>>>>> news:l70f62pu6h880c700hb0lghjn9moindili@4ax.com... >>>>>>>> On Fri, 12 May 2006 19:12:04 GMT, Gave us: >>>>>>>> >>>>>>>>> FA KEITHLEY >>>>>>>> You posted to only ONE correct group. The posts in the rest of the >>>>>>>> groups are all SPAM, asshole. >>>>>>> Wrong again Dimbulb...do your homework..... >>>>>>> >>>>>> Not in school, you stupid fucktard. >>>>> Oh...you must be...you use schoolyard lingo! >>>> You wouldn't know. You're just an old alzheimeristic twit. >>>> >>>>> That's the best you can do Hey Dimbulb? >>>> My worst is two orders of magnitude better than your best. >>>> >>>>> Wrong and wrong again....what else is new.... >>>> You should stop talking about yourself. >>>> >>>>> Big on mouth and small on brains..... >>>>> >>>> You're an idiot. That is quite succinct. >>>> >>>> This is a text forum, you retarded bastard. There are no mouths >>>> here, dumbfuck. >>> The typical moronic response expected from the likes of you >>> Darkmatter..... >>> >> You're an idiot. > > You resemble that remark.... > Friends at play.....eh! Daniel -- Posted via a free Usenet account from http://www.teranews.com Article: 97668 of rec.radio.amateur.homebrew From: Roy Lewallen Subject: Re: 800W output filters Date: Thu, 15 Jun 2006 12:42:54 -0700 Message-ID: <1293e242pv6po6c@corp.supernews.com> References: <1150318703.539417.171210@f6g2000cwb.googlegroups.com> <1150375339.271112.198340@i40g2000cwc.googlegroups.com> <1150399367.816664.222490@h76g2000cwa.googlegroups.com> American Technical Ceramics (ATC) makes capacitors specifically for high power, low loss RF applications. You might see if you can get some of their products. My guess is that you'll find ordinary NPO ceramics to be good enough if you use multilayer ones, rather than disks, of decent physical size. The critical spec is the ESR if you can get it for candidate ceramics. I don't, however, have personal experience at running them at this power level. Roy Lewallen, W7EL Article: 97669 of rec.radio.amateur.homebrew From: Robert Baer Subject: Re: FA KEITHLEY 610C ELECTROMETER, PICO AMMETER COULOMB METER Plus References: <8659g.23076$mX1.20976@newsfe2-gui.ntli.net> <-5GdndVPALJIOfrZnZ2dnUVZ_vqdnZ2d@comcast.com> <0rhl629t40if5hih8t7hm85gn5s5h44qei@4ax.com> <44911a16$0$3650$88260bb3@free.teranews.com> Message-ID: <4tkkg.6269$lf4.1851@newsread1.news.pas.earthlink.net> Date: Thu, 15 Jun 2006 21:40:16 GMT Meanwhile, what is happening with that poor neglected Kiethley 610C? Article: 97670 of rec.radio.amateur.homebrew Date: Fri, 16 Jun 2006 06:47:03 +0200 From: Dexxsterlab Subject: FT-817 FT-857 FT-897 KEYPAD Message-ID: <449237bf$0$16926$4fafbaef@reader4.news.tin.it> http://www.dexxsterlab.com/kp8x7/kp8x7e.pdf http://www.qsl.net/it9xxs Article: 97671 of rec.radio.amateur.homebrew From: Paul Keinanen Subject: Re: Looking for DC over coax injector design Message-ID: <154592da0jfq3uc10br2p1l61ct4dfb8dt@4ax.com> References: <1150450858.458876.257340@i40g2000cwc.googlegroups.com> Date: Fri, 16 Jun 2006 14:55:09 +0300 On 16 Jun 2006 02:40:58 -0700, "zorton" wrote: >While poking at it with my brother in law the idea of using plexiglass >to see inside was brought up. Of course all this box will do is >provide a junction for the RF and ground and house my lighting >arrestor. However, it wouldn't be like me to not install some blinky >lights! > >Here's the idea. Since the lightning arrestor will pass DC except when >it's shorted to ground I was thinking of putting 12 volts up past the >arrestor and lighting up a green led or something. That way all I have >to do is look at the box to know that the arrestor isn't shorted to >ground. If you put DC injection somewhere between the arrestor and your rig and feed power to the DC injector from any convenient mains outlet, this may cause a lot of harm. Assume that the lightning will cause some high voltage peaks in the mains that will propagate through the DC injector and destroy the input stages of your rig. If the overvoltage is really large, the lightning arrestor will limit the amplitude _at_the_arrestor_, but if the injector is close your rig, your rig will receive a higher voltage than the arrestor turn on voltage, due to the cable voltage loss between the injector and arrestor. You will also need a separator in the arrestor box to separate RF and the LED DC current from each other, otherwise, the LED will rectify your transmitted RF current and cause a lot of harmonics, which will radiate through the antenna. Note also that the separator filter inductances in the arrestor box might interact with the lightning pulse and might even generate larger voltages than otherwise. But to your actual question, for HF+6m any LC filter circuit should be doable, as long as you keep an eye on stray inductances and capacitances. On VHF/UHF a single band injector/separator could be done from open/closed quarter/half wave stubs. Paul OH3LWR Article: 97672 of rec.radio.amateur.homebrew From: "Steve N." Subject: Re: Looking for DC over coax injector design Date: Fri, 16 Jun 2006 13:48:03 -0500 Message-ID: References: <1150450858.458876.257340@i40g2000cwc.googlegroups.com> <154592da0jfq3uc10br2p1l61ct4dfb8dt@4ax.com> "Paul Keinanen" wrote in message news:154592da0jfq3uc10br2p1l61ct4dfb8dt@4ax.com... > On 16 Jun 2006 02:40:58 -0700, "zorton" wrote: > > >While poking at it with my brother in law the idea of using plexiglass > >to see inside was brought up. Of course all this box will do is > >provide a junction for the RF and ground and house my lighting > >arrestor. However, it wouldn't be like me to not install some blinky > >lights! > > > >Here's the idea. Since the lightning arrestor will pass DC except when > >it's shorted to ground I was thinking of putting 12 volts up past the > >arrestor and lighting up a green led or something. That way all I have > >to do is look at the box to know that the arrestor isn't shorted to > >ground. > > If you put DC injection somewhere between the arrestor and your rig > and feed power to the DC injector from any convenient mains outlet, > this may cause a lot of harm. > > Assume that the lightning will cause some high voltage peaks in the > mains that will propagate through the DC injector and destroy the > input stages of your rig. If the overvoltage is really large, the > lightning arrestor will limit the amplitude _at_the_arrestor_, but if > the injector is close your rig, your rig will receive a higher voltage > than the arrestor turn on voltage, due to the cable voltage loss > between the injector and arrestor. > > You will also need a separator in the arrestor box to separate RF and > the LED DC current from each other, otherwise, the LED will rectify > your transmitted RF current and cause a lot of harmonics, which will > radiate through the antenna. > > Note also that the separator filter inductances in the arrestor box > might interact with the lightning pulse and might even generate larger > voltages than otherwise. > > But to your actual question, for HF+6m any LC filter circuit should be > doable, as long as you keep an eye on stray inductances and > capacitances. > > On VHF/UHF a single band injector/separator could be done from > open/closed quarter/half wave stubs. > > Paul OH3LWR Justin, Wow! Paul really has concerns. Some I don't quite understand. The rig is connected to the antenna anyway, so if lightning zaps it, a well done DC injector shouldn't make things any worse that it already is. My opinion is that if you get a hit bad enough to go from the mains, into the injector and into the rig, you'll have lots of damage from other pathec as well, so this probably won't be the worst, ot even the only thing to zap the rig. Where you inject the DC into the line, you have an RF choke. Appropriate attention to both RF and arc-over considerations should minimize this as a "damage-to-the-rig". The capacitor used to block the DC from the rig, must be minimum size needed (for the lowest band you'll use) so it passes the least amount of lightning-induced spike. I don't see any serious Gotchas, but then, I don't know your capability / technical level, but two RF choke and and two caps is all it takes, while you observe all the "normal" RF care required for a box through-which you are routing RF...short leads, proper connections to the arrestor and all that. The lightning arrestor, obviously can't be a DC short to ground or you need the cap on the rig side and take the DC off on the rig side of the arrestor. If the arrestor passes DC, you can pick off the DC on the antenna side. On the "DC" side of the choke, you should also have another bypass cap to keep RF off the LED and out of the 12 V power source. I think the most important thing in this whole situation, is to do the arrestor correctly. A good installation is fairly complex and the closet to the ideal the more protection you'll get. THE DC part should be pretty standars practice. Short leads where ther need to be. Big gaps where any high voltage can be. Super-duper ground for the arrestor. Proper RF practices. 73, Steve, K9DCI Drive he neighbors nuts with these blinking lights in the back yard! You could even rectify the RF and then the little blinkey lights'll blink with your SSB or CW... Later Dude. Article: 97673 of rec.radio.amateur.homebrew From: "Jim GM4DHJ" References: <1150485745.993044.253690@f6g2000cwb.googlegroups.com> <1150487681.183895.82230@c74g2000cwc.googlegroups.com> Subject: Re: Think you might be interested? Then here's your FAQ! Message-ID: Date: Fri, 16 Jun 2006 20:18:51 GMT Me too...I also...... Article: 97674 of rec.radio.amateur.homebrew From: "Mr_JŪ" References: <1150485745.993044.253690@f6g2000cwb.googlegroups.com> <1150487681.183895.82230@c74g2000cwc.googlegroups.com> Subject: Re: Think you might be interested? Then here's your FAQ! Message-ID: <2QEkg.87180$wl.13166@text.news.blueyonder.co.uk> Date: Fri, 16 Jun 2006 20:50:06 GMT "Chaney" wrote in message news:1150487681.183895.82230@c74g2000cwc.googlegroups.com... > Welcome back...I for one have missed your humour... > Oh theres a shock. Article: 97675 of rec.radio.amateur.homebrew From: Roy Lewallen Subject: Re: Looking for DC over coax injector design Date: Fri, 16 Jun 2006 14:56:15 -0700 Message-ID: <1296a7vdtshs4cb@corp.supernews.com> References: <1150450858.458876.257340@i40g2000cwc.googlegroups.com> <154592da0jfq3uc10br2p1l61ct4dfb8dt@4ax.com> Steve N. wrote: > . . . > Drive he neighbors nuts with these blinking lights in the back yard! > > You could even rectify the RF and then the little blinkey lights'll blink > with your SSB or CW... Long ago my Elmer told me a story of a local ham who got the bright (pun intended) idea of putting a large neon bulb at the top of his vertical antenna. Not long afterward, his neighbor knocked on the door complaining of TVI. "How do you know it's me that's causing the interference?" the ham asked. "Because," said the neighbor, "every time that light on the top of the antenna blinks, my TV goes crazy." The next night the ham was seen in the back yard with a BB gun shooting out the neon bulb. Roy Lewallen, W7EL Article: 97676 of rec.radio.amateur.homebrew From: "Theo" References: <1150485745.993044.253690@f6g2000cwb.googlegroups.com> Subject: Re: Think you might be interested? Then here's your FAQ! Message-ID: Date: Fri, 16 Jun 2006 22:05:11 GMT Oh not again! Is it his turn again to use the family brain cell??! Article: 97677 of rec.radio.amateur.homebrew Message-ID: <44934FDC.8060204@fuse.net> Date: Fri, 16 Jun 2006 20:42:04 -0400 From: jawod Subject: Re: Think you might be interested? Then here's your FAQ! References: <1150485745.993044.253690@f6g2000cwb.googlegroups.com> Brian's Conscience wrote: > A necessary preface..... > > (It is becoming increasingly difficult to fly the flag for > decency and for civilised behaviour in Radio Hammery. Even > the Usenet newsgroups dedicated to the cause have degenerated > into a hotbed of abusive onslaughts by those who ought to know > better; the Nugatory Numpties who boast of an interest > exceeding 10, 20, 30, 40 or even 50 years and yet who have > proved themselves incapable of even meeting the trivial exam > standards set for 6-year-olds. However, there still exists > the fundamental basis on which Ham Radio is based, and > that will never die. This FAQ ("What Is Ham Radio?") will > be regularly published and will not be shouted or bullied > down. It is important that those of a technical bent, who > are the natural seed-corn of Radio Hammery and who > gravitate towards us to be the real novitiate, can > still find us, (and know that we are still here), their fellows.) > > -----ooooo----- > > So,.....What is Ham Radio? > > Ham Radio is a technical pursuit for those who > are interested in the science of radio wave > propagation and who are also interested in the > way that their radios function. It has a long-standing > tradition of providing a source of engineers who > are born naturals. > > Ham Radio awakens in its aficionados a whole-life > fascination with all things technical and gives > an all-abiding curiosity to improve one's scientific > knowledge. It's a great swimming pool, please dive in! > > This excitement causes a wish to share the experience > with ones fellow man, and shows itself in the > gentlemanly traditions of Ham Radio. > > Radio Hams are in a unique privileged position in that > they can construct and operate their own equipment! No-one > else has this privilege. Users, such as broadcasters, > the po lice and armed farces, CBers and mobile phone > users have to purchase ready-made gear. Manufacturers > are not licensed to operate their gear. Radio Hams > are qualified to design, build and then > operate their own pieces of equipment. They do this > with gusto, and also repair and modify their own > equipment. This is a privilege well worth the effort > to gain, and one to be jealously guarded. > > The excitement that drives a Radio Ham starts with > relatively simple technologies at first, perhaps making > his own Wimshurst machine and primary cells. Small pieces > of test equipment follow, possibly multimeters and signal > generators. Then comes receivers and transmitters. It is with > the latter that communication with like-minded technically > motivated people takes off. The scope for technical > development grows with the years > and now encompasses DSP and DDS. There is also a great deal > of excitement in the areas of computer programming to > be learnt and applied. > > The technical excitement motivates Radio Hams to compete > with each other to determine who has designed and manufactured > the best-quality station. This competitiveness is found in DXing, > competitions and fox-hunts. > > -----OOOOO---- > > However, beware! A Ham Radio licence is such a > desirable thing to have that there are large > numbers of people who wish to be thought of > as Radio Hams when, in fact, they are nothing > of the kind! Usually such people are a > variation of the CB Radio hobbyist; they buy their > radios off the shelf and send them back to be > repaired; they are not interested in technical discussion > and sneer at those who are; they have no idea how > their radios work inside and have no wish to find out; > they are free with rather silly personal insults. > > These CB types engage in the competitive activities > with their Cheque-Book-purchased off-the-shelf radios > in a forlorn effort to prove that they are Radio Hams. > > No _REAL_ Radio Hams are deceived by such people! > > -----ooooo----- > > One infallible way to disambiguate the CB Radio Hobbyist > from the _REAL_ Radio Ham is to solicit their view of the > difference between CB Radio and Ham Radio. A Radio Ham will > perceive Ham Radio to be a technical pursuit and will > perceive CB Radio to be a social communications facility > no different in essence to a land-line telephone or a > GSM mobile in the hands of a 6-year-old. Thus a Radio Ham > could also hold a CB licence safe in the knowledge that > such a licence says no more about him than having a land-line > telephone, whilst continuing to regard Ham Radio as a separate > technical pursuit. > > A CB Radio hobbyist, on the other hand, sees no difference between > a Ham Radio licence and a CB Radio licence. To him, they are > sisters-under-the-skin. Wrongly, the CB Radio Hobbyist then > tries to classify himself as the equal of the Radio > Ham when, in fact, he is nothing of the kind. > > Ham Radio is not CB Radio and has no common ground with it! > Ham Radio is _THE_ technical pursuit for gentlemen; CB Radio > is the operating hobby for those who buy their rigs and > equipment off the shelf. > Your definition of ham radio describes probably less than 20% of currently operating hams. Social communication is the heart of ham radio. Maybe technical saavy is the soul. (Newsgroups would necessarily be the colon... and I don't mean ":") > -----ooooo----- > > If you are the sort of person who is motivated by > a technical interest in how things work; if you took apart > malfunctioning clocks, toasters and the like and put them > right despite never having seen them working, then > a Ham Radio licence is your traditional route! There has > never been a shortage of such people, and those who gravitate > towards such an interest have always been welcomed into > our shacks and their interests fostered. There is not today, > nor has there ever been, a need to go out and encourage > and press children, children who have never expressed an > interest in Ham Radio, to come into our shacks. Such an > activity should cause eyebrows to be raised - what > normal well-adjusted adults seek the social acquaintance > of children?! > > -----ooooo----- > > Please remember that this FAQ is a _POSITIVE EXHORTATION_ > to you to exert yourselves to join our fraternity! (If you find > otherwise, then perhaps you are already classing yourself in the > mediocre groups of those who are criticised in the FAQ and from > whom we _MUST_ dissociate? If so - it's never too late for > a re-taxonomisation on your part - there's nothing elitist about > us, and we welcome all those who are prepared to put themselves > out in order to join our ranks!) > NO, it's not elitist AT ALL to "disambiguate" (is that a word?) between REAL hams and the rest of the freaks and losers that "pose" as hams. What bullshit. It's a very big tent and there's room for all. Article: 97678 of rec.radio.amateur.homebrew From: Frank Turner-Smith G3VKI Subject: Re: Think you might be interested? Then here's your FAQ! References: <1150485745.993044.253690@f6g2000cwb.googlegroups.com> Message-ID: Date: Sat, 17 Jun 2006 02:07:43 GMT on 16/06/2006 20:22 The Chippenham village idiot said the following: > A necessary preface..... > YAWN! I knew it was too good to be true. Article: 97679 of rec.radio.amateur.homebrew From: mc.puttd@hammer.down.bro Subject: Re: Think you might be interested? Then here's your FAQ! Date: Sat, 17 Jun 2006 11:47:30 +0100 Message-ID: On 17 Jun 2006 03:33:08 -0700, "Brian's Conscience" wrote: >I'd not even read this group since 17th? March? April? >let alone contributed to it and have been engaged on >other projects, primarily preparing my first anthology >of poetry for publication. Coming soon to a remaindered book-stall near you. The Ballad of Reading Jail - Pt 2. Article: 97680 of rec.radio.amateur.homebrew From: "W3JDR" References: <1gcsk57ynooj.1g7beguan3iw1$.dlg@40tude.net> Subject: Re: Noise in first IF Message-ID: Date: Sat, 17 Jun 2006 11:32:36 GMT John, My comments are below your text snippets: > I have for the time being disonnected the first mixer, and am able to feed > in a 45MHz signal straight into the firts IF amp if I wish.> > Now if I look at the output of the second IF with a spectrum analyser, > with > the power off to the first IF, but with the 2nd LO running, I can wind up > the second IF's gain, and the noise floor goes up, which I guess is > expected, but there are no peaks at 455KHz. This would be expected, as there is nothing to bandlimit the output of the high-gain 455 KHz IF, so you're seeing its broadband input noise amplified by its gain. > > If I connect the power to the first IF, and then wind the gain of the > second IF up, I get a noisy peak at 455KHz, that varies in aplitude with > the gain. The input to the first IF has a dummy load. This is also to be expected, as the input noise of the first IF is amplified by its gain, then bandlimited before amplifying in the second IF. > > The second LO is a crystal oscillator, see my previous questions regarding > this. > > The question is, should I expect to see a peak, I dont think so. > What could be causing this? The first IF is in a double sided PCB > enclosure. > > I hope someone can help as this is driving me nuts.... Don't go nuts - it sounds normal. It would be a lot easier to say if everything truly is normal if you could supply some numeric data - fortunately you have a signal generator and a spectrum analyzer. I suggest that you put a signal into the first mixer and observe the output of the last IF on your spectrum analyzer. What input signal level does it take to get 10 dB output signal-to-noise ratio. What level does it take to get the same result feeding a signal into the first IF chain, then the second IF chain, etc ??. Don't worry so much about gain during these tests, just the signal-to-noise ratios. BTW, make sure the analyzer's resolution bandwidth is approximately the same as the receiver's IF bandwidth for these tests, otherwise you'll have to apply a noise bandwidth correction). Good luck Joe W3JDR Article: 97681 of rec.radio.amateur.homebrew From: "Tool of the Walrus" References: <1150485745.993044.253690@f6g2000cwb.googlegroups.com> Subject: Re: Think you might be interested? Then here's your FAQ! Date: Sat, 17 Jun 2006 07:56:06 -0400 Message-ID: <3447$4493edbf$d1cc41f6$31491@snip.allthenewsgroups.com> And if you think that was easy folks, then it's easier to pull a fig from the anus of a donkey.... :) - - - - - - - "The people who are regarded as moral luminaries are those who forego ordinary pleasures themselves and find compensation in interfering with the pleasures of others." - Bertrand Russell Article: 97682 of rec.radio.amateur.homebrew From: "Ken Ward" References: <1150485745.993044.253690@f6g2000cwb.googlegroups.com> <3447$4493edbf$d1cc41f6$31491@snip.allthenewsgroups.com> Subject: Re: Think you might be interested? Then here's your FAQ! Message-ID: Date: Sat, 17 Jun 2006 12:16:40 GMT "Tool of the Walrus" wrote in message news:3447$4493edbf$d1cc41f6$31491@snip.allthenewsgroups.com... Eh? Article: 97683 of rec.radio.amateur.homebrew From: "Chaney" References: <1150485745.993044.253690@f6g2000cwb.googlegroups.com> <1150487681.183895.82230@c74g2000cwc.googlegroups.com> <2QEkg.87180$wl.13166@text.news.blueyonder.co.uk> Subject: Re: Think you might be interested? Then here's your FAQ! Message-ID: Date: Sat, 17 Jun 2006 13:05:45 GMT That I'm not an *rs* licker...that I have a mind of my own and don't have to follow the status quo to feel a part of something... Run along...your "friends" are waiting... -- Chaney Chaney's World www.chaney.i12.com "Mr_JŪ" wrote in message news:2QEkg.87180$wl.13166@text.news.blueyonder.co.uk... > > >> > Oh theres a shock. > > Article: 97684 of rec.radio.amateur.homebrew From: Ken Scharf Subject: Re: Tube failure mode: gassy? References: <1150512910.810581.47510@c74g2000cwc.googlegroups.com> <449372F9.FCD4EC92@hotmail.com> <1150548130.837876.81650@f6g2000cwb.googlegroups.com> Message-ID: Date: Sat, 17 Jun 2006 10:35:58 -0400 shoppa@trailing-edge.com wrote: > Pooh Bear wrote: > >>shoppa@trailing-edge.com wrote: >> >> >>>Is this classic "gassy" tube failure? Towards the end it seemed to be >>>slightly more blueish on the top. >> >>What condition was the getter in ? > > > Dark metallic. Not whitish, not even on the edges. > > Just warmed it up again, and looked for interelement shorts. No shorts, > just lots of grid and plate current when negative grid bias and B+ is > applied, it seems to "run away" in fact (after 5-10 seconds of bias/B+ > the currents start taking off steeply). No oscillations/parasitics on > the scope. > > I actually have another GE 807 that's been in my junk box for many > years (presumed "junk"), and it has a similar getter and similar excess > currents (actually worse). > > One thing I want to eliminate as a possibility is that something in my > homebrew amp did this tube in after just a few dozen hours of service: > 390V on the plate, 255V regulated on the screen, about -23V on the grid > to give 38mA idle current, all following the classical AB1 parameters > in the 40's vintage tube manuals. This is MUCH relaxed compared to > typical ham transmitter usage I've done with 807/6L6GC/6146's in the > past (which is 700 to 750V B+, 80 or 90mA plate, class C so substantial > grid current, etc.) but that was ICAS. > > Tim. > swap the tubes around and see if the problem moves with the tube or stays in the socket. But I bet it's the tube. The getter only absorbs oxygen. However other gasses can be outgassed from the metals in the tube and cause problems perhaps. Article: 97685 of rec.radio.amateur.homebrew From: flipper Subject: Re: Tube failure mode: gassy? Date: Sat, 17 Jun 2006 10:07:09 -0500 Message-ID: References: <1150512910.810581.47510@c74g2000cwc.googlegroups.com> <449372F9.FCD4EC92@hotmail.com> <1150548130.837876.81650@f6g2000cwb.googlegroups.com> On 17 Jun 2006 05:42:10 -0700, shoppa@trailing-edge.com wrote: >Pooh Bear wrote: >> shoppa@trailing-edge.com wrote: >> >> > Is this classic "gassy" tube failure? Towards the end it seemed to be >> > slightly more blueish on the top. >> >> What condition was the getter in ? > >Dark metallic. Not whitish, not even on the edges. > >Just warmed it up again, and looked for interelement shorts. No shorts, >just lots of grid and plate current when negative grid bias and B+ is >applied, it seems to "run away" in fact (after 5-10 seconds of bias/B+ >the currents start taking off steeply). No oscillations/parasitics on >the scope. > >I actually have another GE 807 that's been in my junk box for many >years (presumed "junk"), and it has a similar getter and similar excess >currents (actually worse). > >One thing I want to eliminate as a possibility is that something in my >homebrew amp did this tube in after just a few dozen hours of service: >390V on the plate, 255V regulated on the screen, about -23V on the grid >to give 38mA idle current, all following the classical AB1 parameters >in the 40's vintage tube manuals. This is MUCH relaxed compared to >typical ham transmitter usage I've done with 807/6L6GC/6146's in the >past (which is 700 to 750V B+, 80 or 90mA plate, class C so substantial >grid current, etc.) but that was ICAS. I've got a 6EM7 that does the same thing and it's visual appearance is perfect as well so I doubt it's your circuit. Ironically, it turned out to be fortuitous in my case because I was testing a circuit design intended to force PP current balance and that tube was a great test subject. Dern thing works even though it would run away on it's own. >Tim. Article: 97686 of rec.radio.amateur.homebrew From: Frank Turner-Smith G3VKI Subject: Re: Think you might be interested? Then here's your FAQ! References: <1150485745.993044.253690@f6g2000cwb.googlegroups.com> <1150487681.183895.82230@c74g2000cwc.googlegroups.com> <1150540388.497835.138790@f6g2000cwb.googlegroups.com> Message-ID: Date: Sat, 17 Jun 2006 23:31:23 GMT on 17/06/2006 11:33 The Chippenham Village Idiot said the following: > You are very kind. However, I shan't stay long > (Cue chorus from the very Childish Broadcasters (CBers) > criticised in the article) becaue I never intended to call > in yesterday. So you admit to being unable to control your own actions. > I'd not even read this group since 17th? March? April? Now you're trying to kid us you can read? > let alone contributed to it CONTRIBUTED? BWWWAHAHAHAHAHAHAHAHAHAHAHA! and have been engaged on > other projects, primarily preparing my first anthology > of poetry for publication. We've seen examples of your 'poetry', Beanie. Don't give up the day job (if you have one). I had some time on my hands yesterday, and that probably led to something else all over your hands. > had a quick look, with a microscope? < remaining crap snipped > FOAD, TWAT. ...(_!_)... Article: 97687 of rec.radio.amateur.homebrew From: nospam@nouce.bellatlantic.net Subject: Re: Tube failure mode: gassy? Message-ID: References: <1150512910.810581.47510@c74g2000cwc.googlegroups.com> <449372F9.FCD4EC92@hotmail.com> <1150548130.837876.81650@f6g2000cwb.googlegroups.com> <449431FF.1080703@invalid.invalid> <1150564803.188626.193430@g10g2000cwb.googlegroups.com> Date: Sun, 18 Jun 2006 00:27:26 GMT On 17 Jun 2006 10:20:03 -0700, shoppa@trailing-edge.com wrote: >Doug Smith W9WI wrote: >> semi-dumb question: where are you measuring the bias voltage? (directly >> at the tube, or on the other side of the grid resistor?) >> >> I'm wondering if a bad coupling cap is causing the bias at the tube to >> drift towards 0v or even positive. > >Well, I WANT the bias to be circa -20V or -25V. There's a negative >supply and some pots which form a stiff voltage divider and supplies >grid bias through a 100K resistor. > >On the "bad" tube grid current is so high that it does indeed drift up >to 0V in a minute or so. Yeah, I know, there's not supposed to be grid >current until the grid goes positive. I suspect this is the root of the >problem. > >The coupling capacitors are indeed good and moving the tube around it >follows the tube. > >Tim. Tim, Thats a classic gassy tube. One possible source is small cracks around the tube pins as it gets hot there and often there is limited air circulation. I've been 30 years since I've seen a 807 modulator (acutally 4 in parallel push pull) and I've had the honor of watching them do interesting things back when they were easily found at $2.50 each. Allison Article: 97688 of rec.radio.amateur.homebrew From: "Jimbo's old machine......" References: <1150485745.993044.253690@f6g2000cwb.googlegroups.com> <1150487681.183895.82230@c74g2000cwc.googlegroups.com> <1150540388.497835.138790@f6g2000cwb.googlegroups.com> Subject: Re: Think you might be interested? Then here's your FAQ! Message-ID: Date: Sun, 18 Jun 2006 07:23:58 GMT > let alone contributed to it and have been engaged on > other projects, primarily preparing my first anthology > of poetry for publication. I had some time on my hands yesterday, Ah ha!.....no doubt about Ladies from various parts of the Country........ Article: 97689 of rec.radio.amateur.homebrew From: "Jimbo's old machine......" References: <1150485745.993044.253690@f6g2000cwb.googlegroups.com> <1150487681.183895.82230@c74g2000cwc.googlegroups.com> <1150540388.497835.138790@f6g2000cwb.googlegroups.com> Subject: Re: Think you might be interested? Then here's your FAQ! Message-ID: Date: Sun, 18 Jun 2006 07:25:10 GMT Straw in the wind.....straw in the wind.....fly fly fly Article: 97690 of rec.radio.amateur.homebrew From: MAc Subject: mc3362 and xtal filter termination Date: Sun, 18 Jun 2006 14:29:20 +0200 Message-ID: Hi All I'm trying to use TQF9-02 (similar to xf9b)(impedance 500ohm) filter in receiver on MC3362. In original project there was homebrew filter connected to pins 17,19 MC3362 via capacitors 220pf. Have you any ideas for proper termination of Xfilter? MAc Article: 97691 of rec.radio.amateur.homebrew From: David Subject: Re: A Complex Metaphysical Conundrum... References: <1150641495.634423.169620@h76g2000cwa.googlegroups.com> <1150642068.135448.47400@y41g2000cwy.googlegroups.com> Message-ID: <44956c8b@news.wineasy.se> Date: 18 Jun 2006 17:08:59 +0200 AndyS wrote: > paul@burridge8333.fsbusiness.co.uk wrote: >> Hi all, >> I once believed that UHF(and beyond) RF electronics was the most >> technically challenging hobby there is. Period. >> However, I've since read about some chap who claims his principal >> 'hobby' is Quantum Mechanics! This fellow is in prison somewhere in the >> UK and all his 'work' is *entirely* theoretical (obviously - given the >> confined circumstances) and consists of the academic pursuit of the >> subject alone including heaps of serious number-crunching and >> formidably cryptic calculus. >> The complex, metaphysical conundrum that arises from this is: can QM >> (highly theoretical even if you actually work hands-on with particle >> accelerators) ever be accurately described as a 'hobby?' >> What does the Panel think? >> p. > > Andy writes: > > I think that talking incessantly about a subject that one can't > prove by demonstration shows an inferiority complex. The dude is > afraid to argue a subject whose results can be proven.... > Quantum mechanics is a science - you don't *prove* anything. You make theories to explain data obtained by experiment, and verify the predictions of these theories with more experiments. Anyone looking for a subject whose results can be proven should stick to maths (another good choice for people stuck in prison!). But as a science, QM is solid (if somewhat difficult) - just because the guy in prison can't personally verify any predictions he comes up with, doesn't mean they can't be verified by others. After all, much of the theory is developed by people at universities, not just the more "practical" scientists working with particle accelerators and the like. > Just like arguing Catholicism versus Buddha --- an interesting > way , for some, to waste their time. But no way to be proven > wrong....... > > If the fellow's mind was as good as the fellow seems to think > it is , himself, he wouldn't be afraid to approach subjects where > he could be shown in error..... > Given that you apparently know nothing about quantum mechanics, what subjects were you thinking of? > I bet the SOB has never changed the oil in his own truck.....I bet > if he tried, he would mess it up..... > So what? Is that some sort of red-neck test of manhood? > > Andy in Eureka, Texas > Article: 97692 of rec.radio.amateur.homebrew From: "Jim GM4DHJ" References: <1150485745.993044.253690@f6g2000cwb.googlegroups.com> <1150487681.183895.82230@c74g2000cwc.googlegroups.com> <1150540388.497835.138790@f6g2000cwb.googlegroups.com> <1150642752.277529.179330@g10g2000cwb.googlegroups.com> Subject: Re: Think you might be interested? Then here's your FAQ! Message-ID: Date: Sun, 18 Jun 2006 15:15:46 GMT "The Conscience" wrote in message news:1150642752.277529.179330@g10g2000cwb.googlegroups.com... >3 have been published in The Petersfield Post, 1 > in The Wiltshire Gazette And Herald, 1 on the > www.adoptabeach web site (But was removed, presumably > because Charmouth beach was scavenged clean), 1 > was on display in the church porch at St.Enodoc's, > trebetheric. A number have been published on Usenet. > > Some are, indeed, about ladies - 2 of those in The Petersfield > Post, for example. In response to one of them, the daughter > (now in her 90's) of the lady I wrote about contacted me > to say that her family were very pleased with the publicity. very... good sounds like more fun than Amateur radio these days........I'll stick to..."There was a young lady from......." Article: 97693 of rec.radio.amateur.homebrew From: Bill Janssen Subject: Re: Tube failure mode: gassy? References: <1150512910.810581.47510@c74g2000cwc.googlegroups.com> <449372F9.FCD4EC92@hotmail.com> <1150548130.837876.81650@f6g2000cwb.googlegroups.com> <449431FF.1080703@invalid.invalid> <1150564803.188626.193430@g10g2000cwb.googlegroups.com> Message-ID: Date: Sun, 18 Jun 2006 15:29:24 GMT This is a multi-part message in MIME format. --------------000600030907060803090203 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit nospam@nouce.bellatlantic.net wrote: >On 17 Jun 2006 10:20:03 -0700, shoppa@trailing-edge.com wrote: > > > >>Doug Smith W9WI wrote: >> >> >>>semi-dumb question: where are you measuring the bias voltage? (directly >>>at the tube, or on the other side of the grid resistor?) >>> >>>I'm wondering if a bad coupling cap is causing the bias at the tube to >>>drift towards 0v or even positive. >>> >>> >>Well, I WANT the bias to be circa -20V or -25V. There's a negative >>supply and some pots which form a stiff voltage divider and supplies >>grid bias through a 100K resistor. >> >>On the "bad" tube grid current is so high that it does indeed drift up >>to 0V in a minute or so. Yeah, I know, there's not supposed to be grid >>current until the grid goes positive. I suspect this is the root of the >>problem. >> >>The coupling capacitors are indeed good and moving the tube around it >>follows the tube. >> >>Tim. >> >> > >Tim, > >Thats a classic gassy tube. One possible source is small cracks >around the tube pins as it gets hot there and often there is limited >air circulation. > >I've been 30 years since I've seen a 807 modulator (acutally 4 in >parallel push pull) and I've had the honor of watching them do >interesting things back when they were easily found at $2.50 each. > >Allison > > > I have used tubes with the "gassy problem. I got the tubes free because of the problem. I used the tubes in my transmitter by biasing the tube with a very stiff bias supply. I used a choke coil to get the bias to the grid. They were 829 tubes and were used on two meters. Bill K7NOM --------------000600030907060803090203 Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit nospam@nouce.bellatlantic.net wrote: 
On 17 Jun 2006 10:20:03 -0700, shoppa@trailing-edge.com wrote:

  
Doug Smith W9WI wrote:
    
semi-dumb question: where are you measuring the bias voltage?  (directly
at the tube, or on the other side of the grid resistor?)

I'm wondering if a bad coupling cap is causing the bias at the tube to
drift towards 0v or even positive.
      
Well, I WANT the bias to be circa -20V or -25V. There's a negative
supply and some pots which form a stiff voltage divider and supplies
grid bias through a 100K resistor.

On the "bad" tube grid current is so high that it does indeed drift up
to 0V in a minute or so. Yeah, I know, there's not supposed to be grid
current until the grid goes positive. I suspect this is the root of the
problem.

The coupling capacitors are indeed good and moving the tube around it
follows the tube.

Tim.
    

Tim,

Thats a classic gassy tube.  One possible source is small cracks
around the tube pins as it gets hot there and often there is limited
air circulation.

I've been 30 years since I've seen a 807 modulator (acutally 4 in
parallel push pull) and I've had the honor of watching them do 
interesting things back when they were easily found  at $2.50 each.

Allison
I have used tubes with the "gassy problem. I got the tubes free because of the problem.
I  used the tubes in my transmitter by biasing the tube with a very stiff bias supply. I used
a choke coil to get the bias to the grid. They were 829 tubes and were used on two meters.

Bill K7NOM
--------------000600030907060803090203-- Article: 97694 of rec.radio.amateur.homebrew From: "Jim GM4DHJ" References: <1150485745.993044.253690@f6g2000cwb.googlegroups.com> <1150487681.183895.82230@c74g2000cwc.googlegroups.com> <1150540388.497835.138790@f6g2000cwb.googlegroups.com> <1150642752.277529.179330@g10g2000cwb.googlegroups.com> <1150644195.945506.14010@u72g2000cwu.googlegroups.com> Subject: Re: Think you might be interested? Then here's your FAQ! Message-ID: <6Nelg.21024$n13.12238@newsfe2-win.ntli.net> Date: Sun, 18 Jun 2006 16:01:06 GMT "The Conscience" wrote in message news:1150644195.945506.14010@u72g2000cwu.googlegroups.com... > The ones that appeal to me are those where you'd > think that a rhyme would be impossible, such as... > > There was a young lady from Exeter, > So pretty, that men craned their necks at her. > Indeed, one was so brave > As to take out, and wave, > The distinguishing mark of his sex at her. Tee hee! ......I like that........ Article: 97695 of rec.radio.amateur.homebrew From: MAc Subject: Re: mc3362 and xtal filter termination Date: Sun, 18 Jun 2006 18:15:32 +0200 Message-ID: References: <1150641782.494039.108680@g10g2000cwb.googlegroups.com> I only found (app note), that filter should be 330ohm Article: 97696 of rec.radio.amateur.homebrew Message-ID: <44958929.72F04037@turneraudio.com.au> From: Patrick Turner Subject: Re: Tube failure mode: gassy? References: <1150512910.810581.47510@c74g2000cwc.googlegroups.com> Date: Sun, 18 Jun 2006 17:12:01 GMT shoppa@trailing-edge.com wrote: > OK, I'm trying to understand the failure of a 807 beam tetrode in a > homebrew push-pull audio amp. > > Tubes are GE, about 45 years old, bought as new old stock several weeks > ago. > > Being run with 400V on the plate and 255V on the screens. > > Both behaved very nicely for a few weeks in my amp, and plate current > at idle followed the curves in the books just fine. They were > well-balanced. > > But tonight under some listening stress the B+ fuse blew. > > Turning the bias (supplied from a bias supply through a 100K resistor) > down to -40V, the good tube is drawing a small amount of plate current > while the other draws 40mA after warmup and current goes up and up and > up until it hits 100mA or so and I turn the amp off before blowing > another fuse. Check the grid current and as the bad tube warms up grid > current is increasing and increasing as well, to the point where the > -40V is being entirely dropped in the 100K resistor (I guess that means > about half a mA of grid current). > > The tube with high current always had some violet-blue spots that > danced on the top but they were on the glass and mica so I figured that > was normal but now I don't know. There was also this strange orange > spot that was on a mica insulator there too. > > Is this classic "gassy" tube failure? Towards the end it seemed to be > slightly more blueish on the top. The violet - orange colouring only ever occurs as a tube dies from gas intake. Normally the tubes should have a slight "royal blue" low level flurescence usually visible in darkness. the bright blue flickering is the end for the tube; its only good for the bin unless you salvage the tube base plug for a multi wire plug. After turn on with the output tubes in you should measure the voltage across each bias resistor >from supply to grid pin. Usually the gassy tube draws grid current at idle with the grid becoming positive with respect to the bias supply. Just what has caused the gasiness in anyone's guess but to test the coupling caps remove the output tubes and measure dc voltage across the biasing resistors to the output tubes. There should be less than a mV after leaving the amp on for an hour. Using 807 from WW2 NOS could be dodgy since gas leaks could occur; not enough to turn the getters white or even slightly brown edged but enough to cause rapid failure well before the usual 5,000 hrs you should get from a hi-fi output tube. But then I have just repaired an ARC VT100 and out of 8 brand new Ei 6DJ8 there were two which were quite faulty because one of the twin triodes in each tube became gradually saturated and fully turned on for no reason other than they had been poorly manufactured in Yugoslavia. Nice gold lettering on the outside, crummy work inside. > > I've burnt up/blown up a lot of 6146 and other variant beam tetrodes > over the years but now I'm trying to get some understanding of what's > happening :-). > > Will a certain chunk of NOS 807's simply be this way from age? Youse takes your chances with ancient 807. They usually were renowned for their ruggedness but heck, anything ancient must surely be less reliable than had it been made yesterday to the same spec. Would you fly in a NOS Mustang P51 that was NOS? Not me, that's fo sure. Maybe I got 20 x 807, I dunno their history, and I ain't got around to using any; maybe I never will.... Patrick Turner. > > > Tim.