Has anyone built a radio or other projects ? Feel free to share ! Or maybe you have some info on a Ham project that others may be interested in trying.
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Homebrew Projects
- Thread starter Sonwatcher
- Start date
Haven't 'built' much lately...
Repair work is a different story altogether. I have a table piled with fix-it projects; a few for fellow hams from the area.
On the design front: I'm currently working on a synthesizer replacement for the old 7-line Drake series along with an interface which will allow a Kenwood R5000 and a TS440S to be run together in master/slave configuration - like the TR7/R7 twins. Doing this requires polling both radios via their communications ports - seeing if the operating frequency of the 'master' has changed - then setting the 'slave' accordingly.
Obviously, implementing such control was easier with the older gear - one merely had to utilize existing the VFO (and possibly, HET osc) signals.
I've got an FR101D kicking around the shack and may design a solid-state replacement for its VFD-based digital display. The Noritake tubes Yaesu used in their counters are getting to be quite scarce - and while mine works FB, I would rather get a working circuit put together before it's needed.
Repair work is a different story altogether. I have a table piled with fix-it projects; a few for fellow hams from the area.
On the design front: I'm currently working on a synthesizer replacement for the old 7-line Drake series along with an interface which will allow a Kenwood R5000 and a TS440S to be run together in master/slave configuration - like the TR7/R7 twins. Doing this requires polling both radios via their communications ports - seeing if the operating frequency of the 'master' has changed - then setting the 'slave' accordingly.
Obviously, implementing such control was easier with the older gear - one merely had to utilize existing the VFO (and possibly, HET osc) signals.
I've got an FR101D kicking around the shack and may design a solid-state replacement for its VFD-based digital display. The Noritake tubes Yaesu used in their counters are getting to be quite scarce - and while mine works FB, I would rather get a working circuit put together before it's needed.
Way cool! Two of my favorite toys to play with, frequency synthesizers and digital displays.
As for the Drake Seven line, are you thinking PLL, DDS, or some of each? Played with a couple of AD985x demo boards, but I haven't tried buidling anything with smt parts.
We've built a couple hundred, total one-band PLL synthesizers, mostly to fit Browning transmitters, but the chip we use is getting long in the tooth, and harder to find. Gotta figure it's time to go with a more modern serial-data input PLL chip. Got any favorites in that dept? Still using a MC145106 with a 74HC164 latch feeding its parallel divisor inputs. Clunky, but reliable. Until you go shopping for a hundred of them.
I'm still waiting for someone out there to perfect the idea the Glenn slider was meant to meet. A 'universal' frequency controller that would take the place of the quartz crystal in nearly anything. Emphasis on "nearly". The Glenn came up short on performance in many, many ways. Still thinking that a 150 MHz VCO (like Mini-Circuits) mixed with a 100 MHz crystal would do the job, using the difference frequency to deliver 1 to 50 MHz. The limitations of the 1976-era 'offset' counter in the Glenn made it unsuitable for radios with an inverted frequency relationship. But with a one-chip computer running the "counter" display, it would be no big deal.
Tricky part would be stability and FM noise. But that's the weak link in the chain with the Glenn. Noisy and unstable.
Wonder if you've ever checked out Almost All Digital Electronics. Neil has worked out some clever frequency-display designs.
I played with a variation on the setup he uses, a PIC cpu that gets your input frequency fed right to its 'external clock' input. Microchip published an application note years ago, showing a clever way to keep it down to two chips, plus the display. I added a second input and arithmetic to add or subtract them with the intent of putting it into the Cobra 2000GTL, and come up with an outright replacement for the original counter module. Hooked it to my Tuirbo for a while. It worked on a Cobra 148GTl, too. Never did put it into a Cobra 2000. The way I drove the 7 display digits didn't work out all that well. Wasn't very bright, and had a slight flicker to it. Decided the LED display had to go back to the drawing board. Never got off of it.
It did have one feature that I've never used. Figured it would be cool to put on an old Browning Mark III receiver. The internal arithmetic had a jumper-selectable option to subtract 455 kHz from the two measured input frequencies. Never got around to putting LED digits on it small enough to replace the "On The Air" window on the speaker grille. Would never have been able to sell it for enough to matter, but it would probably qualify for bragging rights, if nobody beat me to it.
On the other hand, converting a Maco 300 to use a Russki GU-74B tube is still on the back burner. That's the one that Svetlana calls the "4CX800". That tube and the socket together cost less than two M2057 tubes. Odds are the Maco will see the light of day before putting a counter in place of the "On The Air" light will. Good ideas are cheap and plentiful. The time and money to work them out properly just isn't.
73
As for the Drake Seven line, are you thinking PLL, DDS, or some of each? Played with a couple of AD985x demo boards, but I haven't tried buidling anything with smt parts.
We've built a couple hundred, total one-band PLL synthesizers, mostly to fit Browning transmitters, but the chip we use is getting long in the tooth, and harder to find. Gotta figure it's time to go with a more modern serial-data input PLL chip. Got any favorites in that dept? Still using a MC145106 with a 74HC164 latch feeding its parallel divisor inputs. Clunky, but reliable. Until you go shopping for a hundred of them.
I'm still waiting for someone out there to perfect the idea the Glenn slider was meant to meet. A 'universal' frequency controller that would take the place of the quartz crystal in nearly anything. Emphasis on "nearly". The Glenn came up short on performance in many, many ways. Still thinking that a 150 MHz VCO (like Mini-Circuits) mixed with a 100 MHz crystal would do the job, using the difference frequency to deliver 1 to 50 MHz. The limitations of the 1976-era 'offset' counter in the Glenn made it unsuitable for radios with an inverted frequency relationship. But with a one-chip computer running the "counter" display, it would be no big deal.
Tricky part would be stability and FM noise. But that's the weak link in the chain with the Glenn. Noisy and unstable.
Wonder if you've ever checked out Almost All Digital Electronics. Neil has worked out some clever frequency-display designs.
I played with a variation on the setup he uses, a PIC cpu that gets your input frequency fed right to its 'external clock' input. Microchip published an application note years ago, showing a clever way to keep it down to two chips, plus the display. I added a second input and arithmetic to add or subtract them with the intent of putting it into the Cobra 2000GTL, and come up with an outright replacement for the original counter module. Hooked it to my Tuirbo for a while. It worked on a Cobra 148GTl, too. Never did put it into a Cobra 2000. The way I drove the 7 display digits didn't work out all that well. Wasn't very bright, and had a slight flicker to it. Decided the LED display had to go back to the drawing board. Never got off of it.
It did have one feature that I've never used. Figured it would be cool to put on an old Browning Mark III receiver. The internal arithmetic had a jumper-selectable option to subtract 455 kHz from the two measured input frequencies. Never got around to putting LED digits on it small enough to replace the "On The Air" window on the speaker grille. Would never have been able to sell it for enough to matter, but it would probably qualify for bragging rights, if nobody beat me to it.
On the other hand, converting a Maco 300 to use a Russki GU-74B tube is still on the back burner. That's the one that Svetlana calls the "4CX800". That tube and the socket together cost less than two M2057 tubes. Odds are the Maco will see the light of day before putting a counter in place of the "On The Air" light will. Good ideas are cheap and plentiful. The time and money to work them out properly just isn't.
73
Sorry for the dropout - had to don another hat the past few days; one of painter. Was prepping and shooting a set of saddlebags and trunk for my wife's motorcycle...and am glad THAT job is finished! :x
DDS, with control done via BASIC Stamp or PIC. I'm using an AD985-based board which is distributed by the NJQRP Club.
I would seriously consider an ASIC-based solution...any of the AD- devices would probably work well for what you're attempting to do.
Especially where heat is concerned - those things got WARM!
You could also use an LMO approach - where your low-frequency reference is phase-locked to a source much higher in frequency. Would be simple to invert the output frequency relative to the reference...
Filter...filter...filter. I'm figthing this very problem on an old Cubic Astro D. It uses a 4046 as its loop detector...I get a fundamental and two spurs down ~20dB at roughly 3 KHz either side of 'center'. Am fairly sure it's a filtering problem...and getting to the components thereof requires digging away chucks of potting material. A job best left for winter.
I've seen a few of his designs posted but didn't know he had a site. Thankya for the linky.
Shift-register the display data and increase the refresh interval. I've often wondered when someone was going to do that trick for some of the older rigs. Not a lot of good equipment being made these days - but I suppose that the market has dried up somewhat.
I can list a ton of those...the 7-line PTO replacements will undoubtedly be among them. Still - if it serves to keep interest in the old gear alive...
Agreed. I just removed a 3x 813 amp from Ye Olde Shaque and am going to cannibalize it for parts...for a 3x 3-500 or similar. I have a couple of Kenwoord TS-820S lineups and figure that it'll end up connected to one of those; in the junk box are a number of Kenwood knobs and other trim pieces which could be used to make the thing 'match'.
There are two transverters (502, 506) connected to one of the -820 combos. A pair of amps for 6 and 2M - each using a 3CX800 - is on tap some time down the road.
Building another scooter for my XYL (after she managed to get t-boned on her old one in early May) has chewed up a large part of my summer. On the positive side, she DID pass her Tech test @ Dayton.
And to you.
nomadradio said:
DDS, with control done via BASIC Stamp or PIC. I'm using an AD985-based board which is distributed by the NJQRP Club.
nomadradio said:
I would seriously consider an ASIC-based solution...any of the AD- devices would probably work well for what you're attempting to do.
nomadradio said:
Especially where heat is concerned - those things got WARM!
nomadradio said:
You could also use an LMO approach - where your low-frequency reference is phase-locked to a source much higher in frequency. Would be simple to invert the output frequency relative to the reference...
nomadradio said:
Filter...filter...filter. I'm figthing this very problem on an old Cubic Astro D. It uses a 4046 as its loop detector...I get a fundamental and two spurs down ~20dB at roughly 3 KHz either side of 'center'. Am fairly sure it's a filtering problem...and getting to the components thereof requires digging away chucks of potting material. A job best left for winter.
nomadradio said:
I've seen a few of his designs posted but didn't know he had a site. Thankya for the linky.
nomadradio said:
Shift-register the display data and increase the refresh interval. I've often wondered when someone was going to do that trick for some of the older rigs. Not a lot of good equipment being made these days - but I suppose that the market has dried up somewhat.
nomadradio said:
I can list a ton of those...the 7-line PTO replacements will undoubtedly be among them. Still - if it serves to keep interest in the old gear alive...
nomadradio said:
Agreed. I just removed a 3x 813 amp from Ye Olde Shaque and am going to cannibalize it for parts...for a 3x 3-500 or similar. I have a couple of Kenwoord TS-820S lineups and figure that it'll end up connected to one of those; in the junk box are a number of Kenwood knobs and other trim pieces which could be used to make the thing 'match'.
There are two transverters (502, 506) connected to one of the -820 combos. A pair of amps for 6 and 2M - each using a 3CX800 - is on tap some time down the road.
Building another scooter for my XYL (after she managed to get t-boned on her old one in early May) has chewed up a large part of my summer. On the positive side, she DID pass her Tech test @ Dayton.
nomadradio said:
And to you.