Article: 94259 of rec.radio.amateur.homebrew From: "John A" Subject: Re: HP 8558B Analyser Problem - Help Needed Date: Thu, 1 Sep 2005 10:16:45 +0100 Message-ID: References: Hi Frank, I've done something just as easy - I unscrewed the LO input to the first mixer but left it close enough to couple in some LO. Problem fixed, but gain - of course - well down. Then I reinstated the first mixer LO and did the same thing with the third mixer LO - with the same result. If my brain is working this means that AN, if not THE, overload is occurring beyond the third mixer. I still thing the first mixer may be the area to work on, though. Any thoughts? KBO, as Churchill used to say! Thanks, John "Frank" wrote in message news:wPMPe.213249$HI.190788@edtnps84... > > "John A" wrote in message > news:deihdb$m2g$1@news8.svr.pol.co.uk... > > See > > > > http://homepage.eircom.net/~ei9gq/spec2.jpg > > > > > > for a screen shot. > > Assume the center is a zero frequency. Looks suspiciously like LO IF > overload to me. Try a 10 dB pad in the mixer output -- should be easy to > get at. As you mentioned there may be a mixer balance problem. I thought > the HP8558B used to plug in a HP141T display, but found a pic on the web, > and it appears to be a later generation. I have occasionally seen the > results of transmitting directly into those old spectrum analyzers, and in > the 70s, it was $1,000 for the attenuator, and $1,000 for the mixer. Sure > hope you don't have that kind of problem. > > Regards, > > Frank > > Article: 94260 of rec.radio.amateur.homebrew From: "John A" Subject: Help finding equivalent diodes needed Date: Thu, 1 Sep 2005 11:54:45 +0100 Message-ID: I've an HP 8558B Spectrum Analyser with dud diodes in its first mixer (one shows 0.33v forward, high resistance reverse, the other 11 ohms either way around) The official part 08558-20095 and its replacement 08558-60152 have long become obsolete. Can anyone suggest a substitute? The application is in a low power balanced mixer mixing input signals in the range 0 to 1500MHz with a Local Oscillator tuning from 2050MHz to 3550MHz to produce a signal passing through a 5000MHz low-pass filter to a 2050MHz bandpass filter. The present diodes are small glass wire-ended diodes about 4mm long and about 1mm diameter. Many thanks in advance. John Article: 94261 of rec.radio.amateur.homebrew Message-ID: <43170CA7.DC07AEED@earthlink.net> From: "Michael A. Terrell" Subject: Re: Help finding equivalent diodes needed References: Date: Thu, 01 Sep 2005 14:13:56 GMT John A wrote: > > I've an HP 8558B Spectrum Analyser with dud diodes in its first mixer (one > shows 0.33v forward, high resistance reverse, the other 11 ohms either way > around) > > The official part 08558-20095 and its replacement 08558-60152 have long > become obsolete. Can anyone suggest a substitute? The application is in a > low power balanced mixer mixing input signals in the range 0 to 1500MHz with > a Local Oscillator tuning from 2050MHz to 3550MHz to produce a signal > passing through a 5000MHz low-pass filter to a 2050MHz bandpass filter. The > present diodes are small glass wire-ended diodes about 4mm long and about > 1mm diameter. > > Many thanks in advance. > > John Can you replace the mixer with something from Mini-circuits? http://www.minicircuits.com/ -- Link to my "Computers for disabled Veterans" project website deleted after threats were telephoned to my church. Michael A. Terrell Central Florida Article: 94262 of rec.radio.amateur.homebrew From: Eamon Skelton Subject: Re: Help finding equivalent diodes needed Message-ID: References: Date: Thu, 01 Sep 2005 17:02:17 +0000 On Thu, 01 Sep 2005 11:54:45 +0100, John A wrote: > The present diodes are small glass wire-ended diodes about 4mm long and > about 1mm diameter. Hello John, I have a UHF mixer in my junkbox. It has a pair of of glass Schottky diodes about the same size as yours. I think they are HP 8000 series. I know that they work well on 23CM. Picture here: http://homepage.eircom.net/~ei9gq/diode.jpg They are yours if you want them. 73, Ed. EI9GQ. -- linux-2.6.13 Remove 'X' to reply by e-mail. Article: 94263 of rec.radio.amateur.homebrew From: "EL84" Subject: Re: What Is Ham Radio?.....A Weekly F.A.Q. Date: Thu, 1 Sep 2005 19:15:17 +0100 Message-ID: <3noupoF2lsp0U1@individual.net> References: <1125598298.766344.4330@g14g2000cwa.googlegroups.com> "Polymath" wrote in message news:1125598298.766344.4330@g14g2000cwa.googlegroups.com... > What is Ham Radio? Yawn, same record, needle stuck Article: 94264 of rec.radio.amateur.homebrew Date: Thu, 01 Sep 2005 19:18:43 +0100 From: Somebody Subject: Re: What Is Ham Radio?.....A Weekly F.A.Q. References: <1125598298.766344.4330@g14g2000cwa.googlegroups.com> <3noupoF2lsp0U1@individual.net> Message-ID: <43174605$0$97098$ed2619ec@ptn-nntp-reader03.plus.net> EL84 wrote: > "Polymath" wrote in message > news:1125598298.766344.4330@g14g2000cwa.googlegroups.com... > >>What is Ham Radio? > > Yawn, same record, needle stuck > > It's a waste of time, it hasn't really changed things has it? Tiresome though. Article: 94265 of rec.radio.amateur.homebrew From: "Joe L." Subject: zener in HP 6111A D.C. power supply Date: Thu, 01 Sep 2005 17:19:00 -0500 Message-ID: Hi. I'm repairing a H.P. 6111A D.C. power supply and need to replace a shorted diode. It is CR32. If anyone out there has the service manual, could you please tell me what this part is? It seems to be marked GE1-3.2Z so it's not a stretch to think that it's a 3.2V zener, but I'd like to know for sure. Thanks. -- Joe Article: 94267 of rec.radio.amateur.homebrew From: Russ Subject: Re: Help finding equivalent diodes needed Message-ID: References: Date: Fri, 02 Sep 2005 01:46:57 GMT On Thu, 01 Sep 2005 17:02:17 +0000, Eamon Skelton wrote: >On Thu, 01 Sep 2005 11:54:45 +0100, John A wrote: > > >> The present diodes are small glass wire-ended diodes about 4mm long and >> about 1mm diameter. > >Hello John, > >I have a UHF mixer in my junkbox. It has a pair of of glass >Schottky diodes about the same size as yours. I think they >are HP 8000 series. I know that they work well on 23CM. >Picture here: http://homepage.eircom.net/~ei9gq/diode.jpg > > >They are yours if you want them. > >73, Ed. EI9GQ. Ed, could you contact me off-list please. I have a couple of questions to ask. My e-mail follows in suitable munged-up fashion. r c n i x o n (at) m*i*n*d*s*p*r*i*n*g (dot) c&o&m Just remove the obvious characters. Thanks, Russ - kf4wxd Article: 94268 of rec.radio.amateur.homebrew From: Eamon Skelton Subject: Re: Help finding equivalent diodes needed Message-ID: References: Date: Fri, 02 Sep 2005 08:12:03 +0000 On Fri, 02 Sep 2005 01:46:57 +0000, Russ wrote: > Ed, could you contact me off-list please. I have a couple of questions to > ask. My e-mail follows in suitable munged-up fashion. > > r c n i x o n (at) m*i*n*d*s*p*r*i*n*g (dot) c&o&m Hello Russ, Thats the most munging I have ever seen in an e-mail address. Remove the leading X from my From: address. User: nospam Domain: oceanfree.net 73, Ed. EI9GQ. -- linux-2.6.13 Remove 'X' to reply by e-mail. Article: 94269 of rec.radio.amateur.homebrew From: "Ralph Mowery" References: <1125645575.256209.260480@g47g2000cwa.googlegroups.com> Subject: Re: RF-circuit board Message-ID: <83XRe.5841$FW1.5430@newsread3.news.atl.earthlink.net> Date: Fri, 02 Sep 2005 11:53:40 GMT "Fero" wrote in message news:1125645575.256209.260480@g47g2000cwa.googlegroups.com... > Hi > what is the difference between RF-circuit board ( high frequency ) and > non-RF-circuit board ? > What happen when I use non-RF-circuit board for 900 MHz frequency ? > > Thanks > > Fero > The differance is the material the copper is on. It can cause the tuned circuits to be differant and it may be so lossey the material will burn if the power is high enough. Article: 94270 of rec.radio.amateur.homebrew From: "Rob Gibson" Subject: Re: What Is Ham Radio?.....A Weekly F.A.Q. Date: Fri, 2 Sep 2005 19:07:19 +0000 (UTC) Message-ID: References: <1125598298.766344.4330@g14g2000cwa.googlegroups.com> <1125608281.462511.212590@g43g2000cwa.googlegroups.com> wrote in message news:1125608281.462511.212590@g43g2000cwa.googlegroups.com... > Polymath, Any chance of going back to the hole you live in and give us > all a break as your weekly whinge is BORING !!!!! > You don't have to read it, it's not compulsory. Article: 94272 of rec.radio.amateur.homebrew From: "Pete KE9OA" References: Subject: Re: Help finding equivalent diodes needed Message-ID: Date: Fri, 02 Sep 2005 20:23:36 GMT Hey John, An HP1N5711 diode should do the trick. I sent a few to a fellow in Canada some months back that had a blown 1st mixer in his 8558. I have about 150 on hand and I would also be glad to send a few your way. Pete "Eamon Skelton" wrote in message news:pan.2005.09.02.08.12.03.355088@oceanfree.net... > On Fri, 02 Sep 2005 01:46:57 +0000, Russ wrote: > > >> Ed, could you contact me off-list please. I have a couple of questions >> to >> ask. My e-mail follows in suitable munged-up fashion. >> >> r c n i x o n (at) m*i*n*d*s*p*r*i*n*g (dot) c&o&m > > Hello Russ, > > Thats the most munging I have ever seen in an > e-mail address. Remove the leading X from my From: > address. User: nospam Domain: oceanfree.net > > 73, Ed. EI9GQ. > > -- > linux-2.6.13 > Remove 'X' to reply by e-mail. > Article: 94273 of rec.radio.amateur.homebrew From: "Pasi" Subject: oscillator problem: pulling crystal abt 500 Hz in LT2S SSB Electronics -transverter Date: Sat, 3 Sep 2005 11:02:02 +0300 Message-ID: I have SSB Electronics transverter LT2S. Its 116 MHz crystal oscillator is about 500 Hz off the frequency eg. running somewhere 116 000, 500 kHz. How could this be tuned to pulled 116 MHz? Or is even impossible/too hard to do? See picture http://www.g1ogy.com/projects/LT2S/page13.jpg The oscillator is T1/Q1 I am talking about. Any ideas, any help? 73 Pasi, oh2pt, tuomi@sci.fi Article: 94274 of rec.radio.amateur.homebrew From: Eamon Skelton Subject: Re: oscillator problem: pulling crystal abt 500 Hz in LT2S SSB Electronics -transverter Message-ID: References: Date: Sat, 03 Sep 2005 10:09:47 +0000 On Sat, 03 Sep 2005 11:02:02 +0300, Pasi wrote: > The oscillator is T1/Q1 I am talking about. Any ideas, any help? > > 73 Pasi, oh2pt, tuomi@sci.fi What happens if you adjust L7? 73, Ed. EI9GQ. -- linux-2.6.13 Remove 'X' to reply by e-mail. Article: 94275 of rec.radio.amateur.homebrew From: "nn" Subject: Re: oscillator problem: pulling crystal abt 500 Hz in LT2S SSB Electronics -transverter Date: Sat, 3 Sep 2005 15:06:22 +0300 Message-ID: References: "Eamon Skelton" wrote in message news:pan.2005.09.03.10.09.47.235287@oceanfree.net... > What happens if you adjust L7? > > 73, Ed. EI9GQ. I haven't touched it. But as far as I understand its there to avoid oscillation to disturb regulation process insuide L09. So it should have nothing to do with the crystal "pushing". (Let me know if I am totally wrong... :) Pasi, oh2pt Article: 94276 of rec.radio.amateur.homebrew From: fmmck@aol.com (Fred McKenzie) Subject: Re: oscillator problem: pulling crystal abt 500 Hz in LT2S SSB Electronics -transverter Date: Sat, 03 Sep 2005 14:00:47 -0400 Message-ID: References: In article , "nn" wrote: > "Eamon Skelton" wrote in message > news:pan.2005.09.03.10.09.47.235287@oceanfree.net... > > What happens if you adjust L7? > > > > 73, Ed. EI9GQ. > > I haven't touched it. But as far as I understand its there to avoid > oscillation > to disturb regulation process insuide L09. So it should have nothing > to do with the crystal "pushing". (Let me know if I am totally wrong... :) Pasi- The 1 microfarad capacitor prevents the regulator from oscillating. L7 would normally be adjusted for maximum output from the oscillator stage, but may also have an effect on frequency. Since it is all you have to adjust, I suggest you adjust it. I believe the crystal is connected in a series-resonant configuration, which is less affected by circuit values. The only recourse may be to purchase a new crystal. 73, Fred, K4DII Article: 94277 of rec.radio.amateur.homebrew From: Roy Lewallen Subject: Re: Old Fashioned SS QRP CW TX ? Date: Sat, 03 Sep 2005 16:52:51 -0700 Message-ID: <11hkdqlo3gedg87@corp.supernews.com> References: <1125755868.846171.213790@g47g2000cwa.googlegroups.com> SpamHog wrote: > . . . > I could sure dream up a circuit, but I wonder where to look for > inspiration. I know e.g. no solid state professional transmitters of > such ilk... > > 1960's solid state tactical radios perhaps? > > Ideas anyone? _Experimental Methods in RF Design_, available from the ARRL. Or its predecessor _Solid State Design for the Radio Amateur_. The latter book is out of print, but you might be able to find a used copy. Roy Lewallen, W7EL Article: 94278 of rec.radio.amateur.homebrew From: "Pasi" Subject: Re: oscillator problem: pulling crystal abt 500 Hz in LT2S SSB Electronics -transverter Date: Sun, 4 Sep 2005 13:16:10 +0300 Message-ID: References: Frank and Fred, Thank you for your help. I will try L7 first (and then trimmer of pair of twisted wires). Let's see what happens. I need counter to borrow first.. I will be back. 73 Pasi, oh2pt Article: 94279 of rec.radio.amateur.homebrew From: Eamon Skelton Subject: Re: oscillator problem: pulling crystal abt 500 Hz in LT2S SSB Electronics -transverter Message-ID: References: Date: Sun, 04 Sep 2005 11:00:05 +0000 On Sat, 03 Sep 2005 15:06:22 +0300, nn wrote: > "Eamon Skelton" wrote in message > news:pan.2005.09.03.10.09.47.235287@oceanfree.net... >> What happens if you adjust L7? >> >> 73, Ed. EI9GQ. > > I haven't touched it. But as far as I understand its there to avoid > oscillation > to disturb regulation process insuide L09. So it should have nothing to do > with the crystal "pushing". (Let me know if I am totally wrong... :) > > Pasi, oh2pt It looks like a fairly low inductance which resonates with the 12pf, 68pf and other capacitances in the oscillator to form a 116MHz tuned circuit. Try adjusting it to see if it will pull the oscillator to the correct frequency. If you turn it too far, it will reduce the L.O. output or stop it >from running. If you are not happy with the result, you can always put it back where it was. If all else fails, you could try putting a variable capacitor or inductor in series with the crystal. 73, Ed. EI9GQ -- linux-2.6.13 Remove 'X' to reply by e-mail. Article: 94280 of rec.radio.amateur.homebrew From: "Pasi" Subject: Re: oscillator problem: pulling crystal abt 500 Hz in LT2S SSB Electronics -transverter Date: Sun, 4 Sep 2005 14:09:14 +0300 Message-ID: References: "Eamon Skelton" wrote in message news:pan.2005.09.04.11.00.05.346076@oceanfree.net... > a 116MHz tuned circuit. Try adjusting it to see if it will > pull the oscillator to the correct frequency. If you turn > it too far, it will reduce the L.O. output or stop it > from running. If you are not happy with the result, you > can always put it back where it was. > > If all else fails, you could try putting a variable capacitor > or inductor in series with the crystal. > > 73, Ed. EI9GQ Ed, What is the best way to know the value before i touch it? Should I measure the voltage after this coil - or how? And most probably there is RF-voltmeter needed? Pasi Article: 94281 of rec.radio.amateur.homebrew From: Eamon Skelton Subject: Re: oscillator problem: pulling crystal abt 500 Hz in LT2S SSB Electronics -transverter Message-ID: References: Date: Sun, 04 Sep 2005 14:05:28 +0000 On Sun, 04 Sep 2005 14:09:14 +0300, Pasi wrote: > What is the best way to know the value before i touch it? Should I measure > the voltage after this coil - or how? And most probably there is > RF-voltmeter needed? > > Pasi It would be very difficult if not impossible to find the exact inductance of L7 while it is in circuit. Just count the number of degrees of rotation you make to the tuning slug. You could mark the slug and former with white paint or tipex before you start. If you don't have a VHF frequency counter, you could use a 2M beacon as a frequency reference. Most of the 2M beacons audible from here are correct to within +/- 200Hz. GB3MCB is usually within 100Hz. Even a very good crystal oscillator is unlikely to be stable to less than 1 ppm, so there is little point in trying to get an error of less than 100Hz. 73, Ed. EI9GQ. -- linux-2.6.13 Remove 'X' to reply by e-mail. Article: 94282 of rec.radio.amateur.homebrew From: "Pasi" Subject: Re: oscillator problem: pulling crystal abt 500 Hz in LT2S SSB Electronics -transverter Date: Sun, 4 Sep 2005 22:37:20 +0300 Message-ID: References: Hi everyone, Transverter is now on correct frequency. LO was tunable through this L7. And it is still oscillating after the pull :) I was very pessimistic that this L7 would affect on freq. Thank you for your advice. Btw, I have to say that this German piece of electronic has really good quolity inside the box. 73 Pasi, oh2pt "Eamon Skelton" wrote in message news:pan.2005.09.04.14.05.28.367430@oceanfree.net... > On Sun, 04 Sep 2005 14:09:14 +0300, Pasi wrote: > > >> What is the best way to know the value before i touch it? Should I >> measure >> the voltage after this coil - or how? And most probably there is >> RF-voltmeter needed? >> >> Pasi > > It would be very difficult if not impossible to find the > exact inductance of L7 while it is in circuit. > > Just count the number of degrees of rotation you make > to the tuning slug. You could mark the slug and former > with white paint or tipex before you start. If you don't have a > VHF frequency counter, you could use a 2M beacon as a frequency reference. > Most of the 2M beacons audible from here are correct to within +/- 200Hz. > GB3MCB is usually within 100Hz. > > Even a very good crystal oscillator is unlikely to > be stable to less than 1 ppm, so there is little > point in trying to get an error of less than 100Hz. > > 73, Ed. EI9GQ. > > > -- > linux-2.6.13 > Remove 'X' to reply by e-mail. > Article: 94283 of rec.radio.amateur.homebrew From: "Phil" References: <1125755868.846171.213790@g47g2000cwa.googlegroups.com> Subject: Re: Old Fashioned SS QRP CW TX ? Message-ID: Date: Sun, 04 Sep 2005 21:41:49 GMT "SpamHog" wrote in message news:1125755868.846171.213790@g47g2000cwa.googlegroups.com... > I'd like to build myself a small SS QRP CW TX with a broad transmit > frequency range (say 3-10 or 5-15 MHz), and clean output. Something I > could use now on the current ham bands with a CW-capable digital > portable RX, but could forget in a cupboard and use anywhere else if > the need / right arises in n year's time. > > Hardwired band limits may look reassuring from a legal standpoint, yet > almost all commercial radios DO let you get into trouble, frequency > wise, so what the heck... + you don't know what the future has in > store. > > I figure it would be plenty to put together the following: > > - always on VFO > > - a couple of quasi-linear _tuned_ (!) amp stages > built around a 3-section variable capacitor > > - no bandswitching, no plug in tuning coils > or HRO-style coil drawers > > - always-on buffer > > - power keying on PA > > - electronic QSK > > - switched receive-mode VFO-offset cap, > patched it into QSK, > to kick it way off the operating frequency > ( and off the _amp_chain_passband_ as well ! ) > & fully kill output + avoid any issues > in isofrequency operation > > - pi network, PA current meter. > > I'd draw the line this side of DDS, with huff-puff to be perhaps added > at a later stage, but I'm open to convincing. > > I could sure dream up a circuit, but I wonder where to look for > inspiration. I know e.g. no solid state professional transmitters of > such ilk... > > 1960's solid state tactical radios perhaps? > > Ideas anyone? > Hello, Try to get hold of an HW8, an old Heathkit QRP CW Transceiver. Lots of modifications and/or extensions can be found on the internet. Use an old RC4 (Drake) for listening. With some effort, you can let those two rigs transceive. Plenty of projects around that idea! Have fun. Article: 94284 of rec.radio.amateur.homebrew From: "Phil" References: <1125755868.846171.213790@g47g2000cwa.googlegroups.com> <1125938742.272074.326510@g14g2000cwa.googlegroups.com> Subject: Re: Old Fashioned SS QRP CW TX ? Message-ID: Date: Mon, 05 Sep 2005 21:31:27 GMT "SpamHog" wrote in message news:1125938742.272074.326510@g14g2000cwa.googlegroups.com... >I was poring over a HW-9 schematic already. > > Very cool, cept it's anything but broad range: doubler/tripler, mixers, > LOs, all sorts of acrobatics that cut down the number of components but > make the whole more inflexible. > > Right now I am thinking about using: > > - a signal generator > > - 1 driver and 2 or 3 massively derated finals in parallel, all AB > class or so, with broadband RF transformers, i/o at 50 ohm or so > > - perhaps a bit of negative feedback > > - putting all the filtering at the end, such as 3 tank circuits with > 3-section VC + pi network; doing so would possibly simplify the > mechanics of providing effective shielding. > I have no idea in what the HW-9 differs from the HW-8 in the transmitter stages. I know the receiver of the HW-9 is more elaborate than the direct reception of the HW-8. I do not feel comfortable with broadband signal generators in transmitters since they tend to be noisy and jittery. To some extend, it could work on FM, but I doubt the results will be worth anything in SSB. Signal generators produce also lots of spurious; filtering at the end stage will be a real challenge. I still have the intention to use the "inj." output of a Drake R4B, mixed with the output of an x-tal oscillator (somewhere around 6 MHz, I don't remember exactly) to send on the frequency the R4B listens on. With some fiddling, you could find in every receiver a frequency to mix with a fixed oscillator to get the same effect. The resulting signal will need filtering before any amplification, so much for your wish to go broadband! On the other hand, filtering over a broad band at the end stage is OK only if you intend to use a dummy load at all times (HI). A real antenna will not present the required impedance over the entire frequency range to the output of your filter. The garbage you intended to filter will only be partially taken care of. So you see, quite a challenge! Article: 94285 of rec.radio.amateur.homebrew From: Jim Thompson Subject: Re: PLL troubleshooting experience Message-ID: References: Date: Mon, 05 Sep 2005 17:25:11 -0700 On Mon, 5 Sep 2005 17:01:03 -0700, John Miles wrote: >This page grew out of the need to keep track of the debugging process on >a synthesizer (sub)project that I recently volunteered to help with. > >http://www.speakeasy.org/~jmiles1/ke5fx/ssa/lo1.html > >Thought I'd post a link to it in case anyone else runs into similar >problems. At the very least, it shows how easy it is to overlook the >obvious when you're fooling with this stuff. > >-- jm > >------------------------------------------------------ >http://www.qsl.net/ke5fx >Note: My E-mail address has been altered to avoid spam >------------------------------------------------------ Fun, isn't it ?:-) I actually made a hybrid 300MHz IF strip that looked a lot like your lash-up, with soldered-on barriers between sections. Except with notches for the screened interconnect feed-throughs. ...Jim Thompson -- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | | http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food. Article: 94286 of rec.radio.amateur.homebrew From: "Mike Kulyk" Subject: WTT Bearcat 155XL Desktop Scanner/FOR Broken Winchester 94 rifle Message-ID: Date: Mon, 5 Sep 2005 20:36:00 -0400 I have a good working Bearcat 16 channel scanner. I have it working on 2 meter and 440 mhz. Great for office or to listen to fire calls ETC.. I am looking for a BROKEN,,, RATTY MESSED up Winchester Lever gun. Model 94 would be great.. PARTS gun.. I am looking for a winter project.. Mike WB2GLW Article: 94287 of rec.radio.amateur.homebrew From: "Peter Barbella" Subject: Old Part Needed Message-ID: Date: Tue, 06 Sep 2005 02:04:27 GMT Hello all, I'm restoring a 50s vintage EICO 720 transmitter. I'm in need of a 50 k potentiometer rated at 4 watts (or above) that is NOT wirewound. The old part looks like a thin ribbon-like piece of resisitive material bent into a circle and placed inside the pot case. The spring loaded center contact appears to be in good shape, but the ribbon is fractured (microscopically) in two locations along its length. I have been unable to find a replacement for this part at any of the large parts supply houses. Does anyone know of a source? Regards, Peter Barbella KB1LZH Article: 94288 of rec.radio.amateur.homebrew From: Jim Adney Subject: Re: Old Part Needed Date: Mon, 05 Sep 2005 21:42:32 -0500 Message-ID: References: On Tue, 06 Sep 2005 02:04:27 GMT "Peter Barbella" wrote: >I'm restoring a 50s vintage EICO 720 transmitter. I'm in need of a 50 k >potentiometer rated at 4 watts (or above) that is NOT wirewound. > >The old part looks like a thin ribbon-like piece of resisitive material bent >into a circle and placed inside the pot case. The spring loaded center >contact appears to be in good shape, but the ribbon is fractured >(microscopically) in two locations along its length. > >I have been unable to find a replacement for this part at any of the large >parts supply houses. Is there any hint of who the original maker might have been? What's the overall diameter of the pot? - ----------------------------------------------- Jim Adney jadney@vwtype3.org Madison, WI 53711 USA ----------------------------------------------- Article: 94289 of rec.radio.amateur.homebrew Message-ID: <431D6114.5CB09B27@earthlink.net> From: "Michael A. Terrell" Subject: Re: The Perfect Ham Store? References: <1125008389.118793.289820@g14g2000cwa.googlegroups.com> <1125081915.412415.325230@g44g2000cwa.googlegroups.com> <2s2dnZ2dnZ24ZZfxnZ2dnVgGkt6dnZ2dRVnyqZ2dnZ0@pipex.net> Date: Tue, 06 Sep 2005 09:27:32 GMT Highland Ham wrote: > > Surplus people in the USA like 'Surplus of Nebraska ' and 'Peter Dahl' seem > rather expensive. 'Peter Dahl' makes custom transformers, so you can't expect "Cheap" if you want it to last. -- ? Michael A. Terrell Central Florida Article: 94290 of rec.radio.amateur.homebrew Message-ID: <431D9267.A43F077B@wilbur.com> From: wilbur Subject: Re: Old Part Needed References: Date: Tue, 06 Sep 2005 12:58:15 GMT http://www.surplussales.com/ Article: 94291 of rec.radio.amateur.homebrew Message-ID: <431D92AF.D5DC237B@wilbur.com> From: wilbur Subject: Re: The Perfect Ham Store? References: <1125008389.118793.289820@g14g2000cwa.googlegroups.com> <1125081915.412415.325230@g44g2000cwa.googlegroups.com> <2s2dnZ2dnZ24ZZfxnZ2dnVgGkt6dnZ2dRVnyqZ2dnZ0@pipex.net> <431D6114.5CB09B27@earthlink.net> Date: Tue, 06 Sep 2005 12:59:34 GMT old saying, you gets what you pay for ! http://www.allelectronics.com (surplus stuff, good quality items, low shipping) Article: 94292 of rec.radio.amateur.homebrew From: "John W3AYT" Subject: F.S. AEA PK-232MBX Message-ID: Date: Tue, 06 Sep 2005 16:37:48 GMT forsale AEA pk-232mbx interface. have all manuals, cables and copy of software. unit not working and I don't have time to mess with it. asking $50 here in Phila., Pa. will ship if you pay shipping. John -- John Haberkern w3ayt@arrl.net Article: 94293 of rec.radio.amateur.homebrew From: "Andrew Mitz" Subject: Re: beeswax in an oscillator compartment References: <8Nadnf27areq6ULcRVn-tg@comcast.com> Message-ID: Date: Tue, 06 Sep 2005 20:59:57 GMT Beeswax is exceptionally good for protection from an ionic environment (salt water, human body). Rick Karlquist N6RK wrote: > In 1975, I worked for a marine radio company called Konel. > I worked on their first synthesized radio, which I inherited > from another designer. The original design had a VCO that > was quite microphonic. We didn't even bother with beeswax, > we potted itin Red Glyptol. Even that wasn't good enough > for two reasons. The speaker was in the same box and the > sailors would turn it up so you could hear the radio over > the engine noise. Also, the 10,000 HP engines on tug boats > produced a lot of vibration which got into the VCO. > I designed a VCO with an inductor printed on the PC board, > and that did the trick. A few months later, Konel went > out of business and few if any radios were produced. > > Rick N6RK > > > "Larry Gagnon" wrote in message > news:pan.2004.12.15.21.21.27.858623@fakeuniserve.com... > > I posted a few days ago about repairing a VHF marine radio. > > Thankfully I solved my problem, locating three cold solder joints > > in the VCO, which entailed removing metal shields and all the > > beeswax that coated all the components. That was character building > > work! > > > > I gather the beeswax is to ensure rigid components to maintain > > stability of the oscillator? Any other reasons for it? Is it > > necessary for me to remelt the old wax and spread it around as > > before, or can I get away with just reshielding the VCO? > > > > Any suggestions appreciated. > > > > Larry VE7EA > > > > -- > > ******************************** > > to reply via email remove "fake" > > Microsoft will soon release their newest product: a vacuum cleaner. > > It will be their only product which doesn't suck. > > Article: 94294 of rec.radio.amateur.homebrew From: "AAA RF Products" Subject: FS: Coax Connectors, Adapters, & Bulk Cable Message-ID: Date: Tue, 6 Sep 2005 21:01:51 -0700 Please email sales@aaarfproducts.com for our new catalog or visit www.aaarfproducts.com Article: 94295 of rec.radio.amateur.homebrew Message-ID: <431E9412.10505@killspam.internode.on.net> Date: Wed, 07 Sep 2005 17:17:38 +1000 From: Alan Peake Subject: Re: beeswax in an oscillator compartment References: <8Nadnf27areq6ULcRVn-tg@comcast.com> <1126070196.869170.150400@g49g2000cwa.googlegroups.com> > I consider this to be the definitive reason why beeswax is a better > potting material for VCO's. > > What more do you want? - its cheap, readily available, easy to use, > recyclable, easy to get out for equipment maintenance, smells ok when > melted (better than modern chemicals) - need I say more? > > Andrew VK3BFA Andrew, do you know what the thermal conductivity of beeswax is? Alan Article: 94296 of rec.radio.amateur.homebrew From: "B.Binggeli" Subject: Re: beeswax in an oscillator compartment Date: Wed, 07 Sep 2005 10:03:46 +0200 Message-ID: References: <8Nadnf27areq6ULcRVn-tg@comcast.com> <1126070196.869170.150400@g49g2000cwa.googlegroups.com> <431E9412.10505@killspam.internode.on.net> Alan Peake schrieb: > >> I consider this to be the definitive reason why beeswax is a better >> potting material for VCO's. >> >> What more do you want? - its cheap, readily available, easy to use, >> recyclable, easy to get out for equipment maintenance, smells ok when >> melted (better than modern chemicals) - need I say more? >> >> Andrew VK3BFA > > Andrew, do you know what the thermal conductivity of beeswax is? > Alan > http://www.fao.org/docrep/w0076e/w0076e12.htm Bruno Article: 94297 of rec.radio.amateur.homebrew From: Roy Lewallen Subject: Re: RF-circuit board Date: Wed, 07 Sep 2005 02:40:30 -0700 Message-ID: <11htdciemstjs69@corp.supernews.com> References: <1125645575.256209.260480@g47g2000cwa.googlegroups.com> <1125690035.759489.188140@g14g2000cwa.googlegroups.com> <1125835645.355237.20020@z14g2000cwz.googlegroups.com> <1125942615.521449.254260@g44g2000cwa.googlegroups.com> <1126078729.380780.132680@g49g2000cwa.googlegroups.com> Fero wrote: > Hi Tom, > > I have got one more question : could this RF-4 material be used for > frequency up to 2,4 GHz too ? ( blue toot ) > Namely, Nordic offers chips for this frequency, too. > > Thanks a lot. > > Fero I used ordinary FR-4 for a 6 GHz pulsed oscillator in a commercial product, and the last I heard it was working fine in mass production. But it's used only in a dry environment, and doesn't have any high Q networks or filters. If your design can tolerate relatively high loss and a moderate dielectric constant (about 5) that varies with temperature and humidity, FR-4 is fine. If it can't, you should consider Rogers PTFE board products or something similar. Roy Lewallen, W7EL Article: 94298 of rec.radio.amateur.homebrew From: Yukio YANO Subject: Re: beeswax in an oscillator compartment References: <8Nadnf27areq6ULcRVn-tg@comcast.com> Message-ID: Date: Wed, 07 Sep 2005 15:34:45 GMT Andrew Mitz wrote: >>"Larry Gagnon" wrote in message >>news:pan.2004.12.15.21.21.27.858623@fakeuniserve.com... >> >>>I gather the beeswax is to ensure rigid components to maintain >>>stability of the oscillator? Any other reasons for it? Is it >>>necessary for me to remelt the old wax and spread it around as >>>before, or can I get away with just reshielding the VCO? >>> >>>Any suggestions appreciated. >>> >>>Larry VE7EA > I have repaired a number of Epoxy Potted VCO modules by simply resoldering ALL of the PCB board connections ! The source of the problem is difference in the Coefficient of Expansion between the Epoxy potting compound and the PCB and the solder connections. Close inspection (under a microscope) will show that the joints in question have been fractured by repeated thermal cycling. Hand resoldering, rather than the original Wave-Soldering will produce a much stronger bond between the component leads and the PC board and reduce the problem. Yukio YANO VE5YS