[600MRG] 735 mods

[Dave Riley]

More 735 mods ++


And you can transvert to/from those frequencies
> send-receive signals sound at least as good as you would expect the
> IC735 to sound on 40 meters except use 10mhz. and a mixer for the
> IF and we can spend another message thread on that choice...

That sounds like an excellent idea!_I mean the thread._

Accurate 10 mhz. is so easy to receive now a days... Or even a cheap rubidium osc. on e-bay
But a diciplined oscillator via GPS is devine and el-cheapo...  Will cite adds later..
And you can get stable, accurate 10 mhz. too all the way up to Jackman, Paul ;-) So there is half the transverter...

Ken sez;_I had considered a transverter too. I just thought it was very 
interesting that a "modern" transceiver could be effectively modified to 
cover 630 meters. _

Nawww, too much work, I'm retired and lazy now so cheap and easy is the focus...
Why spend big bux instead of depleting the junk pile?? I am straight lining this one down to 20 years of re-junk...
That 735 final winding does great from 160-10m but it really hates working @ 630m and hogging a lot of wasted current...
The spurs and remixed products make me go dizzy, no thanks... Clean is gooder..


If I'd had a IC-735 around that wasn't being used on HF, I probably
> would have 'ruined' it in a heartbeat. That would have been the most
> cost effective way to get on.
OY, easy big fella...  The junk pile is the key, Grasshopper, trust me...
> With a little help to keep it within budget I build a really cheap
> transmit converter. But since a good stable 10 MHz oscillator isn't
> happening here for some time,
Need new thread for this one, Hon Ed. sez my sidekick, Hashtafisti 
Scratchie!!!

>   I'm using a signal generator that I
> would prefer not to leave running for so many hours. So even now, if
> I had a 735 that wasn't needed for HF I'd dig into the little
> bugger... ;-)
>
>
> Got $9 in the budget?https://www.mouser.com/Passive-Components/Frequency-Control-Timing-Devices/Oscillators/_/N-7jdfi?P=1z0woad
> just add 3.3 to 5V , a cap and a filter if you like...
> Those Ic735 mods mostly seem to extend the PA capability downward in frequency.Not sure what shorting the transistor in receive section? was about but? those were my initial impressions.
> The LPF might need some tweaking for 630M. I think going all the way down to 2200 meters is too much of stretch, though.I might try before and after tests with a spectrum analyzer to see what happens when I get time to do it.
> Since the target frequency is below 160M, why would harmonics be much of an issue with the 160M LPF?Add a 630M section in series with the 160M LPF?
My first dive in to that direction was to use the IC-706 on 10mhz... 
Removed the B+ RED lead to the final and VOILA!! just the right level to 
direct feed a DBM...
But take an old rig like a Johnson Viking Challenger, Heathkit AT-1 or 
something, then you have 80% of the job done for you already...
Run the 735 at about 5-10 watts in to the cathode of the original final, 
put high class GPS 10 mhz on to the grid and you got a 20 watt output 
630 or 220, ahh what the hell 4000m also.. With new coil and cap in the 
final, then just waiting for a LP filter, several examples here, not a 
problem... Need junk??
Plug in coils or band switching??? Or hard wired per band??

Then you can take it from SAQ ( 17.2kcs. rx ) all the way up to 4000m, 
2200,. 630m and to light, almost... At light frequencies it is even 
easier...
The 735 stays happy nice, and the re-employed junk is very proud of you...

More input soon, N1BUG is beating me up with the TA sigs lately... I 
guess it is time to re-commission the KW1 PA... I'll show em!!!

Doncha just LOVE it??   73s from TinkerHam Dave @ aa1a


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/600mrg/attachments/20180126/927988cf/attachment.html>