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.
nomadradio said: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.
nomadradio said: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.
nomadradio said: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.
nomadradio said: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.
nomadradio said:Tricky part would be stability and FM noise. But that's the weak link in the chain with the Glenn. Noisy and unstable.
nomadradio said:Wonder if you've ever checked out Almost All Digital Electronics. Neil has worked out some clever frequency-display designs.
nomadradio said: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.
nomadradio said: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.
nomadradio said: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.
nomadradio said: