[Argonaut_USERS_Group] Argonaut Retro..a work in progress.

[Earl Andrews]

Well at least one chap expressed some interest ..so I guess there would be a small market for the Argonaut Retro. Actually..it is a work in progress already!..there will be at least one around..the one I make for myself out of the junker 509 I have.
- The 509 had an interesting rx front end circuit with those 
two tunable coils. We were warned not to twiddle with them..because they are/require alignment using a sweep generator. Well ..Im not even going to bother with that circuitry with my argonaut retro. 
More modern radios use fixed front end filters..ie the INDEX one (I have one of these radios).
Ive already built a new front end filter prototype based on fixed (that is fixed but adjustable with trimmer caps).
I aligned the filters (torroid wound coils and trimmers) with my autek rf analyser. 50 ohms input and output from the filters. 
Bandswitching will be accomplished by a front panel switch ..of course..Im thinking of diode switching..1n914 small sig diodes. 
For the actual RF amplifier stage..Id like to get away from the dg mosfet and use something a little more modern and with a little bit more gain..an MMIC with a slightly variable voltage to adjust/cut off the gain. Lots of gain and low noise to pull in weak sigs whenever possible. 
Id like to have the MMIC in a socket..possible a tiny daugher card header..in case the ic would be damaged somehow. Easy to replace or experimaent with.
There would be a good filter before the mmic and some fixed filter after the mmic. Ive fiddled with some prototypes on the bench so far.
-The transmit driver stage would have fixed filtering as well.
I dont think diode switching would be possible with the power level involved (id have to work that out).
two simple transistors in the tx driver stage like the 509.
- for the mixer..both rvr and tx..id like to keep it as simple as possible. The gilbert cell mixer (ne602 or 1496) like the 515 has (parts would have to be availabe).
As for mass production of the Argonaut Retro. Well..that is something that Ill have to "wait and see" how the prototype turns out.
It would be fun to have a small basement shop with manufactures about 25 or so a year. Fun to toss around in my mind anyways. Another option ..would be to just have a repair shop and repair/align with test jigs for the cct boards ect. 
To everyone..have a safe and happy new year. 72 Earl VE3AB