Article: 94513 of rec.radio.amateur.homebrew From: nospam@nouce.bellatlantic.net Subject: Re: 1N23E vs. Schottkey?? Question Message-ID: References: <112mhh2cegm2nb6@corp.supernews.com> <422ed24e.4199909@News.Individual.NET> <422efd5e$0$31460$5a62ac22@per-qv1-newsreader-01.iinet.net.au> <1110747446.199717.56980@l41g2000cwc.googlegroups.com> Date: Fri, 07 Oct 2005 17:34:13 GMT On Sun, 2 Oct 2005 12:50:45 +0000, John Martin wrote: > >I got a data sheet on 2K25 which is the same as 723. >How do I pass it to you? >dont mind the silly question-I am new to forum and its use. >And while on it may be you can tell me whether 1N23 available in a >glass package and claimed to be Germanium would work just as well as >1N23B available in a ceramic package? >Another confusion-1N23B and with all its various suffixes is claimed to >be Silicon. Could it be that 1N23 is Germanium and the others Silicon? >John >Bill Janssen Wrote: 1N23B is a point contact silicon diode. For the ages that was the closest thing to Shottkey and the diode for microwave. In a lot of old hardware the newer shottkey diodes will easily replace the 1N23 series assuming no mechanical limitations. FYI: the suffix specificied specific sorting of 1n23 for noise, working frequency and threshold voltage. Allison >> hhc314@yahoo.com wrote: >> - >> I'm the youngster -- 1938. >> >> Seems that I'm in the right circle of 'Old Farts' to ask: Has anyone a >> data sheet available on the 723A/B Reflex Klystron? These (along with >> the 1N21 diodes) were used in the AN/APS-3 RADAR and since have found >> use in physics demonstration devices, and to a limited extent ham >> radio >> (with modifications). It is basically a 3-cm or 10-GHZ oscillator. >> >> I have a pin-out, but not a full-blown data sheet. Can anyone help me >> out on this? >> >> Thanks in advance, and 73's. >> >> Harry C. >> >> p.s. Evidently a large number of 723A/Bs were produced by Raytheon, >> but >> in spite of a 15-year employment with the Raytheon Company, I've never >> been able to locate a data sheet. Evidently devices of this type were >> heavily classified during WWII, and consequently most of the >> documentation was classified and eventually, in accordance with >> security instructions, destroyed. >> >> >> - >> Well I might have a Ham Radio Handbook with some data in it but I >> don't >> have a "data sheet". >> I can tell you that about 250 Volts on the shell and minus 75 to 150 >> volts on the repeller will work. >> You have to adjust the repeller voltage to get the maximum power. Also >> the repeller voltage changes >> the frequency. And if you adjust the mechanical frequency then the >> repeller voltage must be changed. >> >> Never never never run the Klystron without the minus repeller voltage >> >> Hope that is useful. >> >> Bill K7NOM Article: 94514 of rec.radio.amateur.homebrew From: James Skalski Subject: wtb 400v rms transformer Message-ID: Date: Fri, 07 Oct 2005 18:51:53 GMT I need a transformer that has 117vac primary and 400v RMS secondary. Jim n2go Article: 94515 of rec.radio.amateur.homebrew From: "Jim" Subject: need 73's article from '98 Date: Sat, 8 Oct 2005 02:40:35 -0400 Message-ID: I need to get 'hold of a copy of an article from the November 1998 issue of 73's magazine. The article is entitled "Build the Fox TTL Foxhunt transmitter". I thought I might be able to find it in a library somewhere, but no luck there. It appears libraries generally don't keep these back issues very long. Does someone have a copy I could get photo copied or scanned and emailed? Thanks Jim jbasi@cfw.com Article: 94516 of rec.radio.amateur.homebrew From: novatech@eskimo.com (Steven Swift) Subject: Re: sig gen plans (FREE offer below) Date: 7 Oct 2005 20:26:24 GMT Message-ID: References: <1128220180.879138.46200@z14g2000cwz.googlegroups.com> <2LV%e.851$Yv6.364@fe06.lga> "xpyttl" writes: >A lot of the modern signal generator projects are based on the Analog >Devices AD9850. Analog Devices actually encourages hams to use their sample >service, so the part itself is no problem. It is relatively simple to >program, so you may choose the microcontroller of your choice, although most >of the projects out there seem to lean toward the PIC. >The challenge could well be the circuit board. The 9850 is only available >in TSSOP so you need a good quality circuit board to attach it to. If your >PCB skills are good this won't be a problem. But if not, you might need to >hunat around for a protoboard or something of that ilk that you can get in >your location. Unfortunately, these tend to be kind of pricey. Back in 1996, one of Novatech's early products was a small DDS board based upon the AD9850. It was later upgraded to the AD9851 to allow higher output frequency. We no longer build this item, but I looked in the back stock area and found that there were hundreds of blank boards left. You can see the schematic at: http://www.novatech-instr.com/Fun/dds6m_sch.pdf and a photo at: http://novatech-instr.com/images/dds6mf.jpg If you want one of these blank boards FREE, send a self-address, stamped ($0.60) envelope to: Novatech Instruments, Inc. attn: DDS6m board P.O. Box 55997 Seattle, WA 98155-0997 and I'll get one out to you. The price is right and might get you over the soldering hump. The discrete parts are 1206, 0805 and 3216. We have a bunch of the key parts (micros, AD9851BRS, etc), but we'd have to come up with a price for that. Steve. -- Steven D. Swift, novatech@eskimo.com, http://www.novatech-instr.com NOVATECH INSTRUMENTS, INC. P.O. Box 55997 206.301.8986, fax 206.363.4367 Seattle, Washington 98155 USA Article: 94517 of rec.radio.amateur.homebrew From: James Skalski Subject: need millen bandswitch Message-ID: Date: Fri, 07 Oct 2005 21:01:26 GMT I have a millen 51001 one pole 6 position bandswitch but I need an extra pole. Anyone have one of these switches that I can gang together? It is a 60 degrees. If you have any other 2 gang bandswitch that would also work. Something like a radio switch 86 or 88. Article: 94518 of rec.radio.amateur.homebrew From: "amdxjunk" References: Subject: Re: wtb 400v rms transformer Date: Fri, 7 Oct 2005 21:04:44 -0500 Message-ID: <7109f$43472936$18d64e3c$22669@KNOLOGY.NET> Don't know your application, but a couple of 120v to 240v transformers, with the primaries paralleled and secondaries in series would be close. Mike K. "James Skalski" wrote in message news:dtz1f.68$Iq3.55@trndny01... > I need a transformer that has 117vac primary and 400v RMS secondary. > > Jim n2go Article: 94521 of rec.radio.amateur.homebrew From: James Skalski Subject: 4cx800a hf amplifier? Message-ID: Date: Sat, 08 Oct 2005 16:58:54 GMT anyone used a pair of these for an hf amplifier? did you run them at 2500Vdc? I saw one site that ran them at 4000V. Any links or articles describing the tank circuit? or parameters that were sucessfully used in your amplifier? anyone know what capacitors and inductors are used in the qro 2500 amplifier? Jim n2go Article: 94522 of rec.radio.amateur.homebrew From: Conrad Poos Subject: Re: The weekly F.AQ References: <1128783838.470837.91170@f14g2000cwb.googlegroups.com> Message-ID: <0yT1f.94968$RW.65052@fe2.news.blueyonder.co.uk> Date: Sat, 08 Oct 2005 17:42:20 GMT Polymath wrote: > What is Ham Radio? Aha....the CBer returns. Welcome back good buddy! --------------- The following posts are by Gareth Alun Evans, aka 'Airy R Bean', aka 'Polymath': _Sep 6 1997, 8:00 am_ As the result of holding a CB licence, I have recently received a consultative document about the future of CB Radio in this country, which suggests that serious consideration is being given to legalising AM and SSB on 27 Mhz. -- 72's etc _Sep 6 1998, 8:00 am_ A group of us in Wiltshire have just equipped from Tandy, standard Midland 40 channel rigs. All work fairly well, range about 1/2 mile, less if in trees. Get your aerials somewhere else, the Tandy ones are too rigid and break easily. Most farmer's wholesalers have them. New rig about £60, second hand about £20. Don't forget your CB licence @ £15 pa. As a radio ham, I was very sceptical at first (CB=Children's Broadcasting, etc) But once we got them, they are indispensable. With all the backchat besides the useful conversations, it makes it seem as though everybody in the convoy is in one vehicle and makes for a much more enjoyable day out. _Sep 19 1998, 8:00 am_ 73 de Gareth G4SDW (Also licensed CB), ------------------------ Google is your friend :) Poos -- vy 73 de Conrad Poos "Ich bin ein radio amateur" Article: 94523 of rec.radio.amateur.homebrew From: Frank Turner-Smith G3VKI Subject: Re: The weekly F.AQ References: <1128783838.470837.91170@f14g2000cwb.googlegroups.com> Message-ID: Date: Sat, 08 Oct 2005 17:51:12 GMT Poxy mouth wrote: > What is Ham Radio? > Staying long Beanie? I hope not. Don't let us make you late back to the nut house. ...(_!_)... Article: 94524 of rec.radio.amateur.homebrew From: John Woodgate Subject: Re: epoxy instead of solder? Date: Sat, 8 Oct 2005 19:16:06 +0100 Message-ID: <1GD3m6TmzASDFwAT@jmwa.demon.co.uk> References: I read in sci.electronics.design that TRABEM wrote (in ) about 'epoxy instead of solder?', on Sat, 8 Oct 2005: >He's sensing me samples of both types although the spec's aren't >available due to translation problems (the stuff is imported, and no >English translation of the spec sheets exists). What language(s) is it in? -- Regards, John Woodgate, OOO - Own Opinions Only. If everything has been designed, a god designed evolution by natural selection. http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk Article: 94525 of rec.radio.amateur.homebrew From: John Wilkinson Subject: Ceramic filters and IF transformers Date: Sat, 8 Oct 2005 22:58:47 +0100 Message-ID: <1d5lb2htukmhs.19vdy8t2sdukq$.dlg@40tude.net> Hi, I am trying to design a 455KHz IF stage. I would like to use a 455KHz 7KHz BW ceramic filter. Looking at the Murata data, they suggest that an additional IFT is used to reduce the spurious responses. Has anyone used such a scheme? Does it mean connecting the IFT directly to the output of the filter? Do I really need to worry about the spurious resonses? Collins mechanical filters seem to have the same problem, but do these also usually have an IFT as well? Thanks, John. Article: 94526 of rec.radio.amateur.homebrew From: "Richard H." Subject: Re: epoxy instead of solder? References: <1128617993.936210.242550@g14g2000cwa.googlegroups.com> Message-ID: Date: Sat, 08 Oct 2005 21:50:25 -0700 TRABEM wrote: > He's sensing me samples of both types although the spec's aren't > available due to translation problems (the stuff is imported, and no > English translation of the spec sheets exists). Hopefully they've taken the time to write / translate / send you an MSDS for it... Richard Article: 94527 of rec.radio.amateur.homebrew From: "deBaser" References: <1128850649.830901.238850@g14g2000cwa.googlegroups.com> Subject: Re: "What is Ham Radio?" - The Daily F.A.Q. Date: Sun, 9 Oct 2005 11:48:12 +0100 Message-ID: <1128854784.10243.0@echo.uk.clara.net> "Polymath" wrote in message news:1128850649.830901.238850@g14g2000cwa.googlegroups.com... > What is Ham Radio? > Why do you always repeat this stuff Gareth? You need to move on. You are living in the past. deBaser Article: 94528 of rec.radio.amateur.homebrew From: Spike Subject: Re: "What is Ham Radio?" - The Daily F.A.Q. Date: Sun, 09 Oct 2005 12:23:49 +0100 Message-ID: References: <1128850649.830901.238850@g14g2000cwa.googlegroups.com> <1128854784.10243.0@echo.uk.clara.net> deBaser wrote: > >"Polymouth" wrote: > >> What is Ham Radio? >> > > >Why do you always repeat this stuff? >You need to move on. You are living in the past. > Many questions have been raised by the technical and other postings made in the past by Polymouth and other - similar-sounding, probably sock-puppets - proponents of 'ham radio'. They have meant that the errors so made have had to be corrected, sometimes in a long thread, or spread over several threads, or merely involving a considerable spread in time. Should anyone require enlightenment, a Frequently Posed Responses (FPR) is appended. New items added. This is Version V. It replaces all other Versions. [ ] In the UK, no repeat no licence of any kind is necessary to specify, design, construct, modify, repair, own, or (under some circumstances) test an Amateur transmitter. [ ] A pass in a current examination for a UK Amateur Licence qualifies the successful candidate for the issue of a UK Licence. Holders of the appropriate levels of licence are permitted to operate transmitting equipment that is not subject to a formal approvals procedure, and to carry out technical investigations. A qualification for a Licence, or the Licence itself, is not, repeat not, a qualification to specify, design, construct, modify, repair, or own transmitting equipment. See above. [ ] Before sunrise on Friday, September 1st, 1939, Germany attacked Poland at 4:45am, when the Battleship "Schleswig-Holstein", on a so-called goodwill visit, opened fire on the Polish naval depot and garrison at Westeplatte. World War II had begun. An hour later, first German units crossed the Polish border. Britain entered the war two days later. She did not repeat not start WWII. [ ] Because the 'dimensions' of both sides of the Radar Range Equation need a term having the units of square metres in order to balance, references to ratios of these terms expressed in terms of decibels does not repeat not imply that they are in themselves a ratio of powers. [ ] FM can be demodulated by an AM receiver using the 'Slope Detection' method. Placing an NBFM signal entirely within a channel in a channelised AM receiver is not repeat not Slope Detection. [ ] A company's Returns Policy is not repeat not an admission that it deliberately produces shoddy goods, no matter how well wrapped at the time of purchase. [ ] An IP Address in the headers of one's posts is not repeat not Secret Information. [ ] An exemplary driver is not repeat not one who makes an obscene gesture to show that the other driver is an idiot. [ ] An exemplary driver is not repeat not one who repeats an obscene gesture to confirm that the other driver is an idiot. [ ] XRC is not repeat not a suitable method of differentiating between the 80 percent of metals that have FCC crystal structure. [ ] Millimetre-waves are not repeat not generated by 'nuclear emissions'. [ ] The length of the day on this planet is not repeat not 23H20. [ ] A spring/damper model is not repeat not a mechanical analogue of a capacitor/inductor. [ ] Dehumidifiers do not repeat not work by absorbing heat. [ ] Gas Company piping is not repeat not blue in colour. [ ] 1 deciBel is not repeat not equal to 10 Bels. from Aero Spike Article: 94529 of rec.radio.amateur.homebrew Message-ID: <43495192.1B02D2E0@softhome.net> From: Paul Jaeger Subject: Re: 4cx800a hf amplifier? References: Date: Sun, 09 Oct 2005 10:21:22 -0700 Here's one example: http://images.tentec.com/radio/pdf/417_manual.pdf Paul James Skalski wrote: > > anyone used a pair of these for an hf amplifier? did you run them at > 2500Vdc? I saw one site that ran them at 4000V. > Any links or articles describing the tank circuit? or parameters that > were sucessfully used in your amplifier? anyone know what capacitors and > inductors are used in the qro 2500 amplifier? > > Jim n2go Article: 94530 of rec.radio.amateur.homebrew From: fmmck@aol.com (Fred McKenzie) Subject: Re: OT: CQ Serenade Date: Sun, 09 Oct 2005 15:02:19 -0400 Message-ID: References: In article , "Johnson" wrote: > a link posted on the French usenet group fr.rec.radio.amateur "CQ Serenade" > http://www.von-info.ch/hb9afo/histoire/NON-CQ_cq_serenade_fr.mp3 You may also enjoy http://www.von-info.ch/hb9afo/histoire/cw-rythm.mp3 73, Fred, K4DII Article: 94531 of rec.radio.amateur.homebrew From: "Dale Parfitt" References: <1128937320.824585.306480@g44g2000cwa.googlegroups.com> Subject: Re: EMTECH Kit Users...Opinions? Ideas? Message-ID: Date: Mon, 10 Oct 2005 18:55:09 GMT wrote in message news:1128937320.824585.306480@g44g2000cwa.googlegroups.com... > Greetings One and All, > > I am considering the EMTECH single band QRP kits, especially the > 40 and 15 meter kits, with perhaps the 30m too. > > Was wondering... > > (1) Are there any kind of "users" groups for the rigs? > > (2) Do the rigs have any popular "mods" published? > > Direct replies to k4yz@aol.com would be appreciated, but will > check back here also. > > 73 es TNX in advance > > Steve, K4YZ > Hi Steve, I got frustrated with their site ( dial up here). All I could find was the boards for the rigs at $80 each. They show them in a cabinet, but darned if I could find the cabinets. Anyway, I would really consider the Elecraft K-1 or KX-1 kits as an alternative with lots more features/perfomance than these rigs. Dale W4OP Article: 94532 of rec.radio.amateur.homebrew From: John Wilkinson Subject: Receiver bandwidth Date: Mon, 10 Oct 2005 20:48:51 +0100 Message-ID: <18f19hicdgfnd$.7gnt1gih8f2b$.dlg@40tude.net> Hi, I have bought a 45MHz crystal filter with a bandwidth of +/-10KHz, according to the spec. Now does this mean a real bandwidth of 20KHz? If so when a receiver states a bandwidth of 7KHz, is that +/-7KHz, ie 14KHz? If I am designing a good communications receiver from 6KHz-30MHz to receive AM, SSB and CW and want 2 good filters, what are the bandwidths I should consider? Thanks, John. Article: 94533 of rec.radio.amateur.homebrew From: "Dale Parfitt" References: <1128937320.824585.306480@g44g2000cwa.googlegroups.com> <1128977207.030986.117310@g47g2000cwa.googlegroups.com> Subject: Re: EMTECH Kit Users...Opinions? Ideas? Message-ID: Date: Mon, 10 Oct 2005 21:04:17 GMT > Hey Dale.... > > I e-mailed them some time ago and they said they weren't going to > market the cabinets any longer...You'd think they could at least change > the site to day so, eh? > > And in researching it a bit more, I see they once offered that > add-in AF filter, but now only make reference to it as a "Handbook" > project. > > I was leaning to the EMTECH kits from reviews I read in HAMBREW in > the 90's (96? 97?) It's on the website too... But in any case, I > liked the appearance of the rig and the extra power was nice too... > > I'd love the Elecraft kits myself too...especially the K2, however > justifying the almost $400 expenditure to Mrs K4YZ would be a bit > problematic! > > 73 > > Steve, K4YZ Hi Steve, Current pricing on the K1 is $289 for the 2 band rig and $359 for the 4 bander. I have built the K2 7 or 8 years back- worked right off and a fabulous rig. You won't be disappointed with a K1. The Sierra is also a contender- but can get pricey. Another great radio is the Dave Benson's Small Wonder Labs line: http://www.eham.net/reviews/detail/187 Talented designer and great support. 73, Dale W4OP > Article: 94534 of rec.radio.amateur.homebrew From: nospam@nouce.bellatlantic.net Subject: Re: Receiver bandwidth Message-ID: <13nlk1pum427n8anfbgm1eualjkfvpcque@4ax.com> References: <18f19hicdgfnd$.7gnt1gih8f2b$.dlg@40tude.net> Date: Mon, 10 Oct 2005 21:36:04 GMT On Mon, 10 Oct 2005 20:48:51 +0100, John Wilkinson wrote: >Hi, >I have bought a 45MHz crystal filter with a bandwidth of +/-10KHz, >according to the spec. >Now does this mean a real bandwidth of 20KHz? Likely the case. Some spec total bandwidth other specify 6db edge as distance from the filter center frequency. >If so when a receiver states a bandwidth of 7KHz, is that +/-7KHz, ie >14KHz? If they didn't put the +/- there then its 7khz total. >If I am designing a good communications receiver from 6KHz-30MHz to receive >AM, SSB and CW and want 2 good filters, what are the bandwidths I should >consider? AM wide 12-16khz Am narrow 6-10khz SSB anywhere from 2-3khz with many around 2.4khz wide Any wider than 3khz will be poor in crowded bands. I happen to prefer 2.1 to 2.3khz. CW I've seen 1.4khz all the way down to 200hz most consider 400-600hz adaquate. In all cases the skirt selectivity usually bandwitdth measured from the 6 to 60db points are important indicators of filter quality and any value of 2 or less is good enough and 1.4 would be excellent. The idea is you'd ike to be able to put the offending signal outside the bandpass and well attenuated. What some builders do for CW is use the CW filter and use an peaked audio filter to narrow the audio band pass. Not quite as effective but often cheaper. Allison KB1GMX Article: 94535 of rec.radio.amateur.homebrew From: "Dale Parfitt" References: <18f19hicdgfnd$.7gnt1gih8f2b$.dlg@40tude.net> <13nlk1pum427n8anfbgm1eualjkfvpcque@4ax.com> Subject: Re: Receiver bandwidth Message-ID: <7ZC2f.28413$q81.1812@trnddc06> Date: Mon, 10 Oct 2005 23:39:47 GMT wrote in message news:13nlk1pum427n8anfbgm1eualjkfvpcque@4ax.com... > On Mon, 10 Oct 2005 20:48:51 +0100, John Wilkinson > wrote: > >>Hi, >>I have bought a 45MHz crystal filter with a bandwidth of +/-10KHz, >>according to the spec. >>Now does this mean a real bandwidth of 20KHz? > > Likely the case. Some spec total bandwidth other specify 6db edge > as distance from the filter center frequency. > >>If so when a receiver states a bandwidth of 7KHz, is that +/-7KHz, ie >>14KHz? > > If they didn't put the +/- there then its 7khz total. > >>If I am designing a good communications receiver from 6KHz-30MHz to >>receive >>AM, SSB and CW and want 2 good filters, what are the bandwidths I should >>consider? > > AM wide 12-16khz > Am narrow 6-10khz > > SSB anywhere from 2-3khz with many around 2.4khz wide Any wider > than 3khz will be poor in crowded bands. I happen to prefer 2.1 to > 2.3khz. > > CW I've seen 1.4khz all the way down to 200hz most consider > 400-600hz adaquate. > > In all cases the skirt selectivity usually bandwitdth measured from > the 6 to 60db points are important indicators of filter quality and > any value of 2 or less is good enough and 1.4 would be excellent. > The idea is you'd ike to be able to put the offending signal outside > the bandpass and well attenuated. > > What some builders do for CW is use the CW filter and use an peaked > audio filter to narrow the audio band pass. Not quite as effective > but often cheaper. > > > Allison > KB1GMX > Allison's advice is right on the mark. I recently built an amateur only band HF receiver and chose 6/2.5/0.5 for the three modes. I think what Allison meant to say about the peaked audio filter was to use it in conjunction with the SSB filter for CW selectivity. 73, Dale W4OP Article: 94536 of rec.radio.amateur.homebrew From: Ken Scharf Subject: Re: Receiver bandwidth .. dayton filter find! References: <18f19hicdgfnd$.7gnt1gih8f2b$.dlg@40tude.net> <13nlk1pum427n8anfbgm1eualjkfvpcque@4ax.com> Message-ID: Date: Mon, 10 Oct 2005 20:20:05 -0400 nospam@nouce.bellatlantic.net wrote: > On Mon, 10 Oct 2005 20:48:51 +0100, John Wilkinson > wrote: > > >>Hi, >>I have bought a 45MHz crystal filter with a bandwidth of +/-10KHz, >>according to the spec. >>Now does this mean a real bandwidth of 20KHz? > > > Likely the case. Some spec total bandwidth other specify 6db edge > as distance from the filter center frequency. > > >>If so when a receiver states a bandwidth of 7KHz, is that +/-7KHz, ie >>14KHz? > > > If they didn't put the +/- there then its 7khz total. > > >>If I am designing a good communications receiver from 6KHz-30MHz to receive >>AM, SSB and CW and want 2 good filters, what are the bandwidths I should >>consider? > > > AM wide 12-16khz > Am narrow 6-10khz > > SSB anywhere from 2-3khz with many around 2.4khz wide Any wider > than 3khz will be poor in crowded bands. I happen to prefer 2.1 to > 2.3khz. > > CW I've seen 1.4khz all the way down to 200hz most consider > 400-600hz adaquate. > > In all cases the skirt selectivity usually bandwitdth measured from > the 6 to 60db points are important indicators of filter quality and > any value of 2 or less is good enough and 1.4 would be excellent. > The idea is you'd ike to be able to put the offending signal outside > the bandpass and well attenuated. > > What some builders do for CW is use the CW filter and use an peaked > audio filter to narrow the audio band pass. Not quite as effective > but often cheaper. > > > Allison > KB1GMX > That 45mhz would make a good 'roofing' filter to use ahead of a 455khz if filter. Normally using a first if of 45mhz and a second if of 455khz would result in 'second order' images leaking in, but with a good roofing filter ahead of the second mixer the problem is solved. Some years ago, I bought a bunch of 9mhz if filters at the Dayton Hamvention. They are 3.2khz BW (at the 6db points) filters made by CF Networks for the Gonset Sidewinder transciever. I think this was a vhf rig, which would account for the wider bandwidth. However, these are 8 pole filters, with a shape factor of 1.08 @ 15db down (rises to 1.23 @ 45db down). With this shape factor, these filters probably have similar rejection of off frequency qrm as would a 2.4khz filter with a 2.0 shape factor. Since I have a bunch of them, I could use 2 or even 3 of them in the IF stage (one after the mixer, one before the detector, and one between stages). This would decrease the apparent shape factor even more. The nominal carier frequencies for these filters were 8998.0 khz and 9001.7 khz. With the 3.2khz bandwidth this put the cariers 250hz outside the stated bandwidth (-15db point for these filters). I wonder just how these filters would actually work out in a rig today. That 3.2khz bandwidth DOES seem a bit wide, but the crazy shape factor seems to make it worthwhile to try. Article: 94537 of rec.radio.amateur.homebrew From: "Bill" Subject: Wanted: KAM All-Mode EPROM Message-ID: Date: Tue, 11 Oct 2005 01:40:40 -0230 I recently was given an older KAM All-Mode TNC. It only has version 3.06 firmware. I was hoping to find a version 5 or later EPROM. Does anyone have an EPROM to sell me or can tell me where to get the bin file to burn my own EPROM. I have talked to Kantronics and they told me they no longer support this TNC. Thanks. Bill Article: 94538 of rec.radio.amateur.homebrew From: nospam@nouce.bellatlantic.net Subject: Re: Receiver bandwidth .. dayton filter find! Message-ID: <3g9nk15317t4fkiobq0h8i36vvg9s6arre@4ax.com> References: <18f19hicdgfnd$.7gnt1gih8f2b$.dlg@40tude.net> <13nlk1pum427n8anfbgm1eualjkfvpcque@4ax.com> Date: Tue, 11 Oct 2005 11:56:14 GMT For VHF 3.2 would likely work well enough except if there is a sporatic E opening and people tend to pile up. Then it's really wide! For filters I use microprocessor crystals in the ladder configuration. With the correct shunt C and 4-8 crystals you can make a very fine crystal filter with bandwisths from 2-400hz to as wide as you may want. The design process is documented elsewhere (see EMRFD and the handbook as well as internet). I build for 6 and 2m and have built very nice ladder filters this way. Also since microprocessor crystals in the range of 4-20mhz are dirt cheap it's also a help. Also the higher the frequency the less likely dual conversion is required to avoid images and allows the selectivity to be closer to the antenna (better overload performance). My latest 6m rig uses 12mhz crystals, 8 of them for a 2.3khz bandwidth at 6db and 3.9khz at 60db with symetrical skirts. Allison KB!GMX On Mon, 10 Oct 2005 20:20:05 -0400, Ken Scharf wrote: >nospam@nouce.bellatlantic.net wrote: >> On Mon, 10 Oct 2005 20:48:51 +0100, John Wilkinson >> wrote: >> >> >>>Hi, >>>I have bought a 45MHz crystal filter with a bandwidth of +/-10KHz, >>>according to the spec. >>>Now does this mean a real bandwidth of 20KHz? >> >> >> Likely the case. Some spec total bandwidth other specify 6db edge >> as distance from the filter center frequency. >> >> >>>If so when a receiver states a bandwidth of 7KHz, is that +/-7KHz, ie >>>14KHz? >> >> >> If they didn't put the +/- there then its 7khz total. >> >> >>>If I am designing a good communications receiver from 6KHz-30MHz to receive >>>AM, SSB and CW and want 2 good filters, what are the bandwidths I should >>>consider? >> >> >> AM wide 12-16khz >> Am narrow 6-10khz >> >> SSB anywhere from 2-3khz with many around 2.4khz wide Any wider >> than 3khz will be poor in crowded bands. I happen to prefer 2.1 to >> 2.3khz. >> >> CW I've seen 1.4khz all the way down to 200hz most consider >> 400-600hz adaquate. >> >> In all cases the skirt selectivity usually bandwitdth measured from >> the 6 to 60db points are important indicators of filter quality and >> any value of 2 or less is good enough and 1.4 would be excellent. >> The idea is you'd ike to be able to put the offending signal outside >> the bandpass and well attenuated. >> >> What some builders do for CW is use the CW filter and use an peaked >> audio filter to narrow the audio band pass. Not quite as effective >> but often cheaper. >> >> >> Allison >> KB1GMX >> >That 45mhz would make a good 'roofing' filter to use ahead of a 455khz >if filter. Normally using a first if of 45mhz and a second if of 455khz >would result in 'second order' images leaking in, but with a >good roofing filter ahead of the second mixer the problem is solved. > >Some years ago, I bought a bunch of 9mhz if filters at the Dayton >Hamvention. They are 3.2khz BW (at the 6db points) filters made by >CF Networks for the Gonset Sidewinder transciever. I think this was >a vhf rig, which would account for the wider bandwidth. However, these >are 8 pole filters, with a shape factor of 1.08 @ 15db down (rises >to 1.23 @ 45db down). With this shape factor, these filters probably >have similar rejection of off frequency qrm as would a 2.4khz filter >with a 2.0 shape factor. Since I have a bunch of them, I could use >2 or even 3 of them in the IF stage (one after the mixer, one before >the detector, and one between stages). This would decrease the >apparent shape factor even more. The nominal carier frequencies for >these filters were 8998.0 khz and 9001.7 khz. With the 3.2khz >bandwidth this put the cariers 250hz outside the stated bandwidth >(-15db point for these filters). > >I wonder just how these filters would actually work out in a rig >today. That 3.2khz bandwidth DOES seem a bit wide, but the crazy >shape factor seems to make it worthwhile to try. Article: 94539 of rec.radio.amateur.homebrew From: "William E. Sabin" References: <18f19hicdgfnd$.7gnt1gih8f2b$.dlg@40tude.net> <13nlk1pum427n8anfbgm1eualjkfvpcque@4ax.com> <1129035650.566963.227640@f14g2000cwb.googlegroups.com> Subject: Re: Receiver bandwidth Message-ID: Date: Tue, 11 Oct 2005 13:28:02 GMT "Tim Shoppa" wrote in message news:1129035650.566963.227640@f14g2000cwb.googlegroups.com... >> AM wide 12-16khz >> Am narrow 6-10khz > > Maybe it's my aging male ears but I've never heard an AM transmission > where a >10kHz filter was needed or even desirable. Whenever I switch > on the wider filter I just hear more hiss and static, and no more > fidelity. In my homebrew receiver (see QRZ.COM), for SSB reception using headphones, I toggle-switch in a modified audio response increase in the upper range of speech frequencies, 3 dB at 3000 Hz. This greatly improves speech intelligibility at low audio volume, and this saves my aging ears from overload, especially when listening to weak signals. It is important to protect hearing, at any age. Bill W0IYH Article: 94540 of rec.radio.amateur.homebrew From: nospam@nouce.bellatlantic.net Subject: Re: Receiver bandwidth Message-ID: References: <18f19hicdgfnd$.7gnt1gih8f2b$.dlg@40tude.net> <13nlk1pum427n8anfbgm1eualjkfvpcque@4ax.com> <1129035650.566963.227640@f14g2000cwb.googlegroups.com> Date: Tue, 11 Oct 2005 13:39:10 GMT On 11 Oct 2005 06:00:50 -0700, "Tim Shoppa" wrote: >> AM wide 12-16khz >> Am narrow 6-10khz > >Maybe it's my aging male ears but I've never heard an AM transmission >where a >10kHz filter was needed or even desirable. Whenever I switch >on the wider filter I just hear more hiss and static, and no more >fidelity. > >I can hear a small difference between 6kHz, 8kHz, and 10kHz with local >AM BCB stations. My preference has always been to abhor hiss so I tend >to go towards the narrower side. I don't think my ears are as >sensitive to hiss as when I was younger but it still bothers me >especially with extended listening. That is because most AM broadcast station use brick wall filters at around 4-5khz. Use to be a time back in the analog days the roll off was both higher and gentler. Of course the Beach Boys surf music was current then. I also listed two AM filters for that reason. Completeness only. Though some of the 75M AM window folks (3885khz) insist that a wide filter is useful. >I am told that the 16kc wide filter on my R-390A was used largely for >when multiple channels were being multiplexed (e.g. multi-RTTY or >multi-voice channels). That may be but AM used ot be much better fidelity at one time. Allison KB!GMX Article: 94541 of rec.radio.amateur.homebrew From: "Heytubeguy" Subject: FA: JENNINGS FixVac Caps 250,2000pf + mo Message-ID: Date: Tue, 11 Oct 2005 18:59:27 GMT Jennings 250 pf & 2000 pf fixed vacuum capacitors + more 'stuff' too: see at : http://search.ebay.com/_W0QQfgtpZ1QQfrppZ25QQsassZheytubeguy Tnx and check back often, heytubeguy Article: 94542 of rec.radio.amateur.homebrew From: "Jeff" Subject: Choice of iron powder toriod? Message-ID: Date: Wed, 12 Oct 2005 10:47:56 +1300 Hi, Im confused regarding the choice of iron powder toroid for a 7Mhz high pass filter. I need to use a small size (T68) toroid. For the freq range, some reference texts say T68-2 is the one, others say T68-6" grade. I see differing "best Q range" specs for the 6 grade.....2-30Mhz......10-50Mhz...etc. Have similar need for 20Mhz LPF, but assume "6" is really the choice there. Any suggestions as to the relative differences and reasons to choose between grades 2 and 6 for the HPF in T68 size? Thanks, JEFF Article: 94543 of rec.radio.amateur.homebrew From: "Joe L." Subject: Re: Choice of iron powder toriod? References: Date: Tue, 11 Oct 2005 17:50:17 -0500 Message-ID: In article , "Jeff" wrote: > Im confused regarding the choice of iron powder toroid for a 7Mhz high pass > filter. I need to use a small size (T68) toroid. For the freq range, some > reference texts say T68-2 is the one, others say T68-6" grade. I see > differing "best Q range" specs for the 6 > grade.....2-30Mhz......10-50Mhz...etc. > Have similar need for 20Mhz LPF, but assume "6" is really the choice there. > Any suggestions as to the relative differences and reasons to choose between > grades 2 and 6 for the HPF in T68 size? > Either grade 2 or 6 should work fine at 7 and 14 MHz. The Al values differ somewhat, so the number of turns to get a given inductance will be a little higher for grade 6 than grade 2. You only need to confirm that the number of turns required will actually fit on your T68-size core. For a given number of turns, the unloaded Q does peak at one frequency but is still quite good on either side of that frequency. Unless you have some real need to achieve the highest possible Q for a given inductance at the frequency of interest, I wouldn't worry too much about it. Wind the toroids, build the filter, and see how it works out! -- Joe Article: 94544 of rec.radio.amateur.homebrew Message-ID: <434C4682.57DE7D69@hotmail.com> Date: Wed, 12 Oct 2005 00:10:58 +0100 From: Pooh Bear Subject: Re: Choice of iron powder toriod? References: Jeff wrote: > Hi, > Im confused regarding the choice of iron powder toroid for a 7Mhz high pass > filter. I need to use a small size (T68) toroid. For the freq range, some > reference texts say T68-2 is the one, others say T68-6" grade. I see > differing "best Q range" specs for the 6 > grade.....2-30Mhz......10-50Mhz...etc. > Have similar need for 20Mhz LPF, but assume "6" is really the choice there. > Any suggestions as to the relative differences and reasons to choose between > grades 2 and 6 for the HPF in T68 size? Having just been playing with Micrometals cores myself, I gather that -2 is indeed the 'best' for higher frequencies. The local distributor says it's stocked in greater depth too. Have you also looked at Magnetics Inc and Arnold ? Graham Article: 94545 of rec.radio.amateur.homebrew From: Joerg Subject: Re: Choice of iron powder toriod? References: Message-ID: <7%X2f.873$Zv5.374@newssvr25.news.prodigy.net> Date: Tue, 11 Oct 2005 23:35:31 GMT Hello Jeff, wrote: > Hi, > Im confused regarding the choice of iron powder toroid for a 7Mhz high pass > filter. I need to use a small size (T68) toroid. For the freq range, some > reference texts say T68-2 is the one, others say T68-6" grade. I see > differing "best Q range" specs for the 6 > grade.....2-30Mhz......10-50Mhz...etc. > Have similar need for 20Mhz LPF, but assume "6" is really the choice there. > Any suggestions as to the relative differences and reasons to choose between > grades 2 and 6 for the HPF in T68 size? Not that this is an exact science but typically I switch from #2 to #6 around 10MHz. But I never design with high Q because that can be a pain in production. Regards, Joerg http://www.analogconsultants.com Article: 94546 of rec.radio.amateur.homebrew From: bg998@FreeNet.Carleton.CA (Martin Potter) Subject: Re: Receiver bandwidth Date: 12 Oct 2005 01:45:36 GMT Message-ID: References: <18f19hicdgfnd$.7gnt1gih8f2b$.dlg@40tude.net> John Wilkinson (johnwilkinson@clara.co.uk) writes: > > If I am designing a good communications receiver from 6KHz-30MHz to receive > AM, SSB and CW and want 2 good filters, what are the bandwidths I should > consider? > John, if you really want to listen to CW and FSK signals in the VLF band (8-30 kHz) then you will find a 100 Hz filter very useful. ... Martin VE3OAT Article: 94547 of rec.radio.amateur.homebrew From: Carl Domanico Subject: For Sale Message-ID: Date: Wed, 12 Oct 2005 07:29:10 GMT Hi I have for sale two Comet/NCG Meters : 1) NCG-3000 118 mHz-530 MHz SWR / Wattmeter 5-20-200 Watts Bought New in Box for $ 110.00...Item is in mint condition. Make offer 1) Comet CMX-3 140 mHz - 525 MHz SWR / Wattmeter 20-50-200 watt Is remotable...Paid $ 170.00 New In Box Item is in Mint condition. Make offer... Thanks Carl N2MFW Article: 94548 of rec.radio.amateur.homebrew From: "William E. Sabin" References: Subject: Re: Choice of iron powder toriod? Message-ID: Date: Wed, 12 Oct 2005 12:22:51 GMT Get a copy of Amidon's catalog which gives detailed suggestions for powdered iron and ferrite materials, based on many years of experience. www.amidoncorp.com Bill W0IYH "Jeff" wrote in message news:drW2f.17270$iM2.1412876@news.xtra.co.nz... > Hi, > Im confused regarding the choice of iron powder toroid for a 7Mhz high > pass > filter. I need to use a small size (T68) toroid. For the freq range, some > reference texts say T68-2 is the one, others say T68-6" grade. I see > differing "best Q range" specs for the 6 > grade.....2-30Mhz......10-50Mhz...etc. > Have similar need for 20Mhz LPF, but assume "6" is really the choice > there. > Any suggestions as to the relative differences and reasons to choose > between > grades 2 and 6 for the HPF in T68 size? > Thanks, > JEFF > > Article: 94549 of rec.radio.amateur.homebrew From: "Paul M0EME" Subject: Wanted PL519 valves Date: Wed, 12 Oct 2005 16:52:48 -0000 Message-ID: <434d3f61_1@mk-nntp-2.news.uk.tiscali.com> I need 4 PL519 valves for a 400w HF amp, has anyone got any for sale?????? Also 4 valve bases.... -- Thanks and 73's de Paul M0EME 432MHz EME 4 times FO19, FT847, MGF1302, 100 Watts at feed, Spectran. Initials 432MHz #2 CW #4 JT65 http://myweb.tiscali.co.uk/m0eme Article: 94550 of rec.radio.amateur.homebrew From: Clint Sharp Subject: Re: Wanted PL519 valves Date: Wed, 12 Oct 2005 19:17:45 +0100 Message-ID: <8RsiW2CJNVTDFwZE@clintsmc.demon.co.uk> References: <434d3f61_1@mk-nntp-2.news.uk.tiscali.com> In message <434d3f61_1@mk-nntp-2.news.uk.tiscali.com>, Paul M0EME writes >I need 4 PL519 valves for a 400w HF amp, has anyone got any for sale?????? >Also 4 valve bases.... > You might want to try JPG electronics in Chesterfield? They might be able to help, alternatively drive around and watch out for the scruffiest looking TV repair shops you can find and ask in there. -- Clint Sharp Article: 94551 of rec.radio.amateur.homebrew From: "Jeff" References: Subject: Re: Choice of iron powder toriod? Message-ID: Date: Thu, 13 Oct 2005 10:01:05 +1300 Thanks for all the suggestions. Ive got some Amidon T68-6 toroids to wind up, and will test the completed filter on a spectrum analyser next week. JEFF "Jeff" wrote in message news:drW2f.17270$iM2.1412876@news.xtra.co.nz... > Hi, > Im confused regarding the choice of iron powder toroid for a 7Mhz high pass > filter. I need to use a small size (T68) toroid. For the freq range, some > reference texts say T68-2 is the one, others say T68-6" grade. I see > differing "best Q range" specs for the 6 > grade.....2-30Mhz......10-50Mhz...etc. > Have similar need for 20Mhz LPF, but assume "6" is really the choice there. > Any suggestions as to the relative differences and reasons to choose between > grades 2 and 6 for the HPF in T68 size? > Thanks, > JEFF > > Article: 94552 of rec.radio.amateur.homebrew From: "Asimov" Subject: Pulsing LEDs for higher efficiency Message-ID: References: <2-idnQXJaNeGAdDeRVn-rg@comcast.com> Date: Thu, 13 Oct 2005 04:11:04 GMT "Tom Coates" bravely wrote to "All" (12 Oct 05 19:28:03) --- on the heady topic of "Pulsing LEDs for higher efficiency" TC> From: "Tom Coates" TC> Xref: core-easynews rec.radio.amateur.homebrew:88233 TC> I want to build some emergency lighting equipment using LEDs and 12V. TC> A friend told me that it is possible to get more light per Watt by TC> pulsing the LED to instantaneous levels well above its average ratings. TC> Is this true, if you include power consumed in the pulsing circuit? TC> If it is, can anyone suggest a simple and cheap circuit and the TC> appropriate operating values? TC> The reason for the 12V requirement is that I'm also working on a solar TC> charger for my transceiver batteries and want to use the same charger TC> for the lighting batteries. TC> Suggestions would be appreciated. TC> Tom, N3IJ This pulsed drive technique is supposed to take advantage of the human vision's persistance. If the led is driven brighter for a long enough time the eye will perceive it as being brighter than if using the equivalent average continuous current. Visual persistance is approximately 10 milli-seconds, and if the repetition rate is faster than this then the led will seem to be on all the time. The same technique is used with multiplexed digital displays. One problem with pulsed led drive is that it generates rfi due to the rapidly switching voltage levels. Unless care is taken with risetime, wire lengths, decoupling, and shielding, then the gain in efficiency is a doubtful tradeoff for the simplicity of direct dc drive. It depends on the application. If you want really bright flashes then use a xenon strobe tube. A*s*i*m*o*v ... Neurotoxin Lite! Tastes great... Less drooling...