From: Frank G3YCC (email@example.com)
Having had a beautiful PCB made for the 49er by a friend, I thought I
would have a go at it. Looking at the circuit I though 'that front end
will never cope with European QRM', so I have substituted the simple
circuit with a double tuned front end consisting of two Toko coils and
100p caps top coupled with 8p. There is plenty of room on the PCB for
this mod. Result? No broadcast QRM, well not during the day, night time is
a different story! Still can copy CW, but yes, there is a problem with BC,
as you would expect, but the Rx is much better for the mod. The next thing
to do is add a one transistor audio amp between the FET and the audio amp
(I am using a lm386 not lm380). Will be using toroid chokes in the driver
and pa and have used a toroid in the output pi-tank. I have altered the RX
antenna coupling to the antenna socket, by using my favourite two diodes
back to back across the Toko coil, coupled with a 50p cap to the antenna
socket. None of my mods will mean making the rig any bigger of course, it
is after all a fun rig, but for my own use, I think a few simple additions
will prove worth while. I might box the rig up in a box with nicads, not
sure yet ...
Congrats to the designers of the rig, they certainly started something BIG
for such a SMALL project.
Any other G QRPers having a go at this?
Will pass on the results and any more mods I do, later.
-- Frank G3YCC Ham Radio QRP Web Page: http://homepages.enterprise.net/g3ycc/
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