[222mhz] FW: Synthacoder 509 info

[Dr. Gerald N. Johnson]

On Fri, 2007-09-28 at 11:16 +0000, BSoltoff at comcast.net wrote:
> Synthacoder 509.  Does this ring a bell with anyone.  It is a 220-MHz synthesizer intended to be used with a Midland 13-509 on 220.  I've acquired one from eBay, but it is sans manual.  It was made by a company called Engineering Specialties, in Oxnard, CA some years ago.  The company appears to be defunct.
> 
> I'd appreciate a lead on a manual (or a copy), or any words about use and operation.  The web doesn't seem to have any info available for this model. The only reference I've found is from an old JPL ham club bulletin
> 
> Tnx, K3IUV, Bert
> _______________________________________________
I'm thinking 73 magazine, but I can't put a year on it. At least the
13-509 was documented there with a few mods.

Without seeing the synthacoder, I expect its not wildly different from
other add on synthesizers of the era. Mix the VCO with a crystal
oscillator down to a TTL programmable counter, 4046 phase detector, one
op amp to control the VCO, BCD thumb wheels to set the frequency. A bit
of logic to select wheel bank A or bank B for R/T simplex or split. RX
LO in the 45 MHz range, TX in the 8, 9, or 12 MHz range.

Unless its a multiple layer board, it shouldn't take days to scratch out
a complete schematic. Probably its single sided which makes that easier.

73, Jerry, K0CQ