Re: [AMRadio] FW: Homebrew receiver
The Squires Sanders SS-1R and SS-IBS both used a pair of 7360s. I never had a 1R, but I never thought the IBS worked noticeably better than any other relatively high end radio with more conventional vacuum tube mixer circuitry like the NC400 or the 51J4. And the thing was harder to align correctly as well (maybe that's why I wan't impressed = never got it right:) Scott --- StripMime Report -- processed MIME parts --- multipart/alternative text/plain (text body -- kept) text/html The reason this message is shown is because the post was in HTML or had an attachment. Attachments are not allowed. To learn how to post in Plain-Text go to: http://www.expita.com/nomime.html ---
RE: [AMRadio] FW: Homebrew receiver
It does not have the same looks as a 75A4, but those are going for about $1000.00, then you have to hack it up to install other filters and audio Not really. My outboard filter box runs miniature coax to a 9-pin plug, that plugs into one of the filter slots on the rx. The only mod I had to make was to clip one lead on the 100 pf resonating cap on the "hot" side. I just pushed it aside, so if I ever wanted to put the rx back to stock condx, it would be very simple to re-solder that lead. The filters in the box use their own variable resonating caps, so each filter can be peaked for optimum performance. As I recall, I had to run an AGC lead so that the AGC functions normally with the outboard filters. I could return the rx to stock in less than hour if I so desired. As for the audio mods, I simply bridged .1 caps across the existing .01 caps, without removing them. It would be a simple matter to remove the .1's, since I didn't follow the Collins practice of "making a firm mechanical connection before applying solder". I swear they must have tied some of the component leads into square knots on the solder lugs before applying solder. But, I don't know why anyone would want to un-do the audio modification that makes the rx sound decent on AM. I pick audio off the grid lead to the final audio amp before the 6AQ5. I recall it is a 12AT7 (or is it a 12AU7?). I use another 9-pin plug that replaces the tube. I have an outboard cathode follower in a small box to couple the audio to the external amp and avoid loss of high frequency response because of cable capacitance. The cathode follower gets its power entirely from the circuitry that originally fed power to the audio stage. This mod can be reversed simply by unplugging the coupling device and plugging the tube back in. I bought my 75A4's back in the early 1980's when they were dirt cheap. I paid $100 for one (with all 3 stock filters) and $200 for the other (with only the SSB filter). With a little fixing up, both receivers work FB OM. Don K4KYV _ Fretting that your Hotmail account may expire because you forgot to sign in enough? Get Hotmail Extra Storage today! http://join.msn.com/?PAGE=features/es
Re: [AMRadio] FW: Homebrew receiver
Brett, you should do a photoessay on the building of this dream receiver. Dave, W3ST Secretary to the Collins Radio Association Publisher of the Collins Journal www.collinsra.com - Original Message - From: "Brett Gazdzinski" <[EMAIL PROTECTED]> To: Sent: Monday, November 03, 2003 8:34 AM Subject: RE: [AMRadio] FW: Homebrew receiver > The ARRL handbook went with those like crazy, in the 1960's. > I don't think I have any 7360 tubes. I did not look hard > for them in the junk box. I DID look in the antique electronic supply > catalog, > and they wanted about $50.00 each I think! > > I should look in the junk box, since I may have some of these tubes, > I got a BUNCH of industrial tubes with numbers out of some old > sat com military stuff, many 7 and 9 pin tubes, the very nice > black tube shields, and even a bunch of those big triodes(6sa7?). > > I cant say just how quiet those tubes are, since I never used one. > Anyone know of a receiver that actually uses a 7360 as a mixer??? > > > In the first home brew receiver I built, I used a 6SA7, but unlike other > designs, it used a tube with three grids, injecting the antenna > signal into the control grid, the LO into the suppressor grid. > > Most designs I looked at had 4 grids when separate injection was used, > and would be in the very noisy category. > > This circuit was based on the Scott SLRM receiver I have. > > Mixer noise seems very very low on the homebrew, lowest of any > receiver I have ever tried. > I am not sure how important the noise figure is on 80 and 40 meters, > on higher bands, I know its important, but I don't go up there. > > On comparison to very weak signals on a very clear quiet band, > the homebrew will copy someone who is VERY weak, but give clear > copy, on the R390a, I might not even be able to tell there is a signal > there! > > I have not compared the homebrew directly to the Scott or the SX17, > but they have bandwidth problems, going quite wide at 60 db down. > That will likely add noise. > > For homebrew #2, I went with a 6ah6 in circuit design b in the handbook > (1961?), control grid gets the antenna signal, the LO is injected > into the cathode, suppressor grid is grounded, screen grid has > screen voltage on it. > Its supposed to be quiet. > I can also inject both signals into the control grid, I may try > both designs to see which works best. > > The receiver is moving along well, all the metal is cut, drilled, > punched, and I will paint the chassis on this receiver. > > The B+W coil stock arrived, the filters arrived, this receiver will > have selectable bandwidth, 4.5Khz and 5.5Khz. > > The LO coil (B+W coil stock) is mounted in a small metal box along > with the band switch (shorts out some of the coil) along with > the 40 meter tune cap, to adjust the 40 meter frequency, so I can > set it up like homebrew #1, switching between 160, 80 and 40 meters > has the receiver go to 1880, 3880, and 7290 when I change bands. > > The coil has been tested in the LO circuit for calibration... > > I broke down and bought a dremel tool, easy to make square holes > for things like relays, power cord plug in (with filter), digital > frequency display, etc. > > I need to find a good aluminum primer for painting the chassis. > > Brett > N2DTS > > > > > -Original Message- > > From: [EMAIL PROTECTED] > > [mailto:[EMAIL PROTECTED] Behalf Of Donald Chester > > Sent: Sunday, November 02, 2003 11:02 AM > > To: amradio@mailman.qth.net > > Subject: RE: [AMRadio] FW: Homebrew receiver > > > > > > > > >I am not sure how much the RF amp adds to the noise level. > > >A well designed rf amp section can actually reduce noise levels. > > >Noise mostly comes from mixers, and overall tube counts. > > >All mixers add some noise, some designs are much better than others, > > >and the more there are, the more noise you get. > > > > > >I used single conversion, with a quiet mixer setup, and > > >used two tuned circuits of very high Q in the input, > > >along with resonant dipole antennas for 80 and 40 meters, > > >so I don't get any images or other problems, as signals > > >out of band are attenuated very much before making it to > > >the mixer. > > > > I think the best mixer designed ever developed used the 7360 > > or similar beam > > deflection tube. I'd like other opinions on the subject, if > > anyone thinks > > there is anything else that actually surpasses the > > performance of these > > tubes in mixer service? > > > > Don K4KYV > > > > _ > > See when your friends are online with MSN Messenger 6.0. > > Download it now > > FREE! http://msnmessenger-download.com > > > > ___ > > AMRadio mailing list > > AMRadio@mailman.qth.net > > http://mailman.qth.net/mailman/listinfo/amradio > > ___ > AMRadio mailing list > AMRadio@mailman.qth.net > http://mailman.qth.net/ma
Re: [AMRadio] Homebrew 1929 Superheterodyne Receiver: UPDATE
Pictures man...we need PICTURES!!! At 07:37 AM 11/03/2003 -0500, you wrote: Well, the receiver metal work is ALL DONE---the receiver paint work is ALL DONE(at last!)...and this past weekend I wired the filaments & the primary AC wiring... I'm on night shift for the next two weeks, & I'm quite confident that I can get everything completed by the middle of the month: that'll leave me a good two weeks to get the thing (hopefully!) trouble-shot & operational, well in advance of the Bruce Kelley 1929 QSO Party... Boy, a project of this magnitude sure does take time...! Thus far, I figure I put in AT LEAST a GOOD WEEK drawing the schematic/laying out the parts (on paper) & planning the thing, TWO weeks doing all the metal work (drilling holes for sockets, screws, transformers, tie bars, AD NAUSEUM!), and ANOTHER good week doing the priming/painting---a WHOLE MONTH, & the darned thing is only now getting its first whiffs of rosen & solder... I must say, though, thus far, it's a pretty-looking thing: those white National & Millen ceramic sockets sure are FB nestled-in atop the flat black painted chassis top... A good supply of 224's/224A's has been steadily arriving at the door, c/o eBay... I can hardly wait to hear those push-pull 245's swing into action! Hopefully this monster will PLAY as good as it LOOKS! Hi Hi. Will keep you posted... ~73!~ Eddy VE3CUI - VE3XZ ___ AMRadio mailing list AMRadio@mailman.qth.net http://mailman.qth.net/mailman/listinfo/amradio [EMAIL PROTECTED] Because of problems with the "ARRL.NET" forwarding system and Earthlink, I have abandoned that service. Please REMOVE "[EMAIL PROTECTED]" from your address book and replace with "[EMAIL PROTECTED]" Thank You! (I'll stop posting this signature at the end of October!)
RE: [AMRadio] FW: Homebrew receiver
Well, sure, if you do something about the bandwidth choices, and the audio. Instead of paying what they are going for now, I think its much better to get a 75s1 for around $200.00/$300.00 and installing a kiwa filter in place of the back to back IF cans, and doing something about the audio, an internal IC chip running 5 watts, or an external audio amp, or even a sub board with a pair of push pull output tubes like 6aq5,s or something. Its much cheaper, smaller, just as stable and accurate. It does not have the same looks as a 75A4, but those are going for about $1000.00, then you have to hack it up to install other filters and audio If you have a 455Khz IF, Kiwa makes a filter board with two filters, switched in circuit by diodes. A very small switch is all that is needed, or you can use your own switch/spare contacts on an existing switch. Other receivers can be great, if they have a 455Khz IF, the r388, all the 75a receivers, the 75s receivers, other old receivers that have a 455Khz IF can have two choices of mechanical filter like bandwidth at low cost. Almost all receivers really benefit from a hi fidelity audio amp with big speaker. If you have a lot of receivers, it makes a lot of sense to go with ONE good amp and ONE big speaker. Makes it easy to record off the air, takes up less space, sounds really good, and saves loads of space. My Scott has a built in speaker, small but good sounding, and I do have a separate speaker hooked up to the SX17 for that great push pull output sound, but cant say they sound better than the Marantz amp. Brett N2DTS > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of Donald Chester > Sent: Sunday, November 02, 2003 11:15 AM > To: amradio@mailman.qth.net > Subject: RE: [AMRadio] FW: Homebrew receiver > > > > >My favorite style was the Collins 75a series > > I use a 75A4, which is often bashed by the AM folks, but I > find it to be > about the best receiver I have ever tried. If I find a truly > superior > receiver to the A4, I'll retire mine and change over to that. > > The main deficiency of the A4 is the audio. I use an > outboard AF amp (an > old 50's vintage 10w hi-fi amplifier using a pair of 6V6's in > pushpull). I > changed the .01 mfd coupling caps in the low level audio > stages of the > receiver to 0.1. Actually, I just bridged the .1's across > the originals, to > minimise melted plastic insulation on the wiring in the > receiver. I pulled > out the original 6AQ5 to save unnecessary drain on the power > supply and to > reduce heat generation. I also clipped out a couple of 510 > pf mica caps > that were added in later models to attenuate the high > frequency response. > From the diode detector to the audio output, the frequncy > response is now > almost flat from 30~ to about 5000~. > > On one of my A4's I added an outboard box with additional mechanical > filters. The stock 3 selectivities is not enough if you want > cw, ssb plus > optimum AM under a variety of band condx. > > Don K4KYV > > _ > Want to check if your PC is virus-infected? Get a FREE > computer virus scan > online from McAfee. > http://clinic.mcafee.com/clinic/ibuy/campaign.asp?cid=3963 > > ___ > AMRadio mailing list > AMRadio@mailman.qth.net > http://mailman.qth.net/mailman/listinfo/amradio
RE: [AMRadio] Homebrew 1929 Superheterodyne Receiver: UPDATE
Eddy, What are you building? Yes, my designs take about a month of looking in every book and at every receiver diagram I have, another month or more going through all the parts I have to get nice ones that will work well, another month laying out parts, moving things around, changing the odd bit, then moving things around again. The holes, once things are finalized are quite quick, I did them all over the weekend, the chassis and the front panel. Painting and labeling the controls is always a giant pain in the butt. Brett N2DTS > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of Eddy Swynar > Sent: Monday, November 03, 2003 7:38 AM > To: Amradio@mailman.qth.net; [EMAIL PROTECTED]; > [EMAIL PROTECTED] > Subject: [AMRadio] Homebrew 1929 Superheterodyne Receiver: UPDATE > > > Well, the receiver metal work is ALL DONE---the receiver > paint work is ALL > DONE(at last!)...and this past weekend I wired the filaments & the > primary AC wiring... > > I'm on night shift for the next two weeks, & I'm quite > confident that I can > get everything completed by the middle of the month: that'll > leave me a good > two weeks to get the thing (hopefully!) trouble-shot & > operational, well in > advance of the Bruce Kelley 1929 QSO Party... > > Boy, a project of this magnitude sure does take time...! Thus > far, I figure > I put in AT LEAST a GOOD WEEK drawing the schematic/laying > out the parts (on > paper) & planning the thing, TWO weeks doing all the metal > work (drilling > holes for sockets, screws, transformers, tie bars, AD > NAUSEUM!), and ANOTHER > good week doing the priming/painting---a WHOLE MONTH, & the > darned thing is > only now getting its first whiffs of rosen & solder... > > I must say, though, thus far, it's a pretty-looking thing: those white > National & Millen ceramic sockets sure are FB nestled-in atop > the flat black > painted chassis top... > > A good supply of 224's/224A's has been steadily arriving at > the door, c/o > eBay... > > I can hardly wait to hear those push-pull 245's swing into > action! Hopefully > this monster will PLAY as good as it LOOKS! Hi Hi. > > Will keep you posted... > > ~73!~ Eddy VE3CUI - VE3XZ > > ___ > AMRadio mailing list > AMRadio@mailman.qth.net > http://mailman.qth.net/mailman/listinfo/amradio
RE: [AMRadio] FW: Homebrew receiver
The ARRL handbook went with those like crazy, in the 1960's. I don't think I have any 7360 tubes. I did not look hard for them in the junk box. I DID look in the antique electronic supply catalog, and they wanted about $50.00 each I think! I should look in the junk box, since I may have some of these tubes, I got a BUNCH of industrial tubes with numbers out of some old sat com military stuff, many 7 and 9 pin tubes, the very nice black tube shields, and even a bunch of those big triodes(6sa7?). I cant say just how quiet those tubes are, since I never used one. Anyone know of a receiver that actually uses a 7360 as a mixer??? In the first home brew receiver I built, I used a 6SA7, but unlike other designs, it used a tube with three grids, injecting the antenna signal into the control grid, the LO into the suppressor grid. Most designs I looked at had 4 grids when separate injection was used, and would be in the very noisy category. This circuit was based on the Scott SLRM receiver I have. Mixer noise seems very very low on the homebrew, lowest of any receiver I have ever tried. I am not sure how important the noise figure is on 80 and 40 meters, on higher bands, I know its important, but I don't go up there. On comparison to very weak signals on a very clear quiet band, the homebrew will copy someone who is VERY weak, but give clear copy, on the R390a, I might not even be able to tell there is a signal there! I have not compared the homebrew directly to the Scott or the SX17, but they have bandwidth problems, going quite wide at 60 db down. That will likely add noise. For homebrew #2, I went with a 6ah6 in circuit design b in the handbook (1961?), control grid gets the antenna signal, the LO is injected into the cathode, suppressor grid is grounded, screen grid has screen voltage on it. Its supposed to be quiet. I can also inject both signals into the control grid, I may try both designs to see which works best. The receiver is moving along well, all the metal is cut, drilled, punched, and I will paint the chassis on this receiver. The B+W coil stock arrived, the filters arrived, this receiver will have selectable bandwidth, 4.5Khz and 5.5Khz. The LO coil (B+W coil stock) is mounted in a small metal box along with the band switch (shorts out some of the coil) along with the 40 meter tune cap, to adjust the 40 meter frequency, so I can set it up like homebrew #1, switching between 160, 80 and 40 meters has the receiver go to 1880, 3880, and 7290 when I change bands. The coil has been tested in the LO circuit for calibration... I broke down and bought a dremel tool, easy to make square holes for things like relays, power cord plug in (with filter), digital frequency display, etc. I need to find a good aluminum primer for painting the chassis. Brett N2DTS > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of Donald Chester > Sent: Sunday, November 02, 2003 11:02 AM > To: amradio@mailman.qth.net > Subject: RE: [AMRadio] FW: Homebrew receiver > > > > >I am not sure how much the RF amp adds to the noise level. > >A well designed rf amp section can actually reduce noise levels. > >Noise mostly comes from mixers, and overall tube counts. > >All mixers add some noise, some designs are much better than others, > >and the more there are, the more noise you get. > > > >I used single conversion, with a quiet mixer setup, and > >used two tuned circuits of very high Q in the input, > >along with resonant dipole antennas for 80 and 40 meters, > >so I don't get any images or other problems, as signals > >out of band are attenuated very much before making it to > >the mixer. > > I think the best mixer designed ever developed used the 7360 > or similar beam > deflection tube. I'd like other opinions on the subject, if > anyone thinks > there is anything else that actually surpasses the > performance of these > tubes in mixer service? > > Don K4KYV > > _ > See when your friends are online with MSN Messenger 6.0. > Download it now > FREE! http://msnmessenger-download.com > > ___ > AMRadio mailing list > AMRadio@mailman.qth.net > http://mailman.qth.net/mailman/listinfo/amradio
[AMRadio] Homebrew 1929 Superheterodyne Receiver: UPDATE
Well, the receiver metal work is ALL DONE---the receiver paint work is ALL DONE(at last!)...and this past weekend I wired the filaments & the primary AC wiring... I'm on night shift for the next two weeks, & I'm quite confident that I can get everything completed by the middle of the month: that'll leave me a good two weeks to get the thing (hopefully!) trouble-shot & operational, well in advance of the Bruce Kelley 1929 QSO Party... Boy, a project of this magnitude sure does take time...! Thus far, I figure I put in AT LEAST a GOOD WEEK drawing the schematic/laying out the parts (on paper) & planning the thing, TWO weeks doing all the metal work (drilling holes for sockets, screws, transformers, tie bars, AD NAUSEUM!), and ANOTHER good week doing the priming/painting---a WHOLE MONTH, & the darned thing is only now getting its first whiffs of rosen & solder... I must say, though, thus far, it's a pretty-looking thing: those white National & Millen ceramic sockets sure are FB nestled-in atop the flat black painted chassis top... A good supply of 224's/224A's has been steadily arriving at the door, c/o eBay... I can hardly wait to hear those push-pull 245's swing into action! Hopefully this monster will PLAY as good as it LOOKS! Hi Hi. Will keep you posted... ~73!~ Eddy VE3CUI - VE3XZ
