[600MRG] IC735 mods...an alternative

[John Langridge]

>It's not readily apparent to me that the mod to extend the range down to
630M  would render it useless on any of the bands.

I took that Dave had some insight into the performance on other band with
this mod.  If I had a 735 on the shelf, I would probably do the mod to
evaluate it but if it was my only rig I might be a bit more dubious...

73,

jl

On Fri, Jan 26, 2018 at 9:57 AM, J Mcvey <ac2eu at yahoo.com> wrote:

> Ok nobody needs the "drive of shame" and harmonic suppression is certainly
> important.
> I was thinking along the lines of how this 630M mod would "ruin the radio".
> It's not readily apparent to me that the mod to extend the range down to
> 630M  would render it useless on any of the bands.
> Am I missing something?
>
>
> On Friday, January 26, 2018 10:48 AM, Neil Klagge <w0yse at msn.com> wrote:
>
>
> I too have taken that drive around The neighborhood to listen to my second
> harmonic on 950 kHz. Adding 1750 pF across one of the inductors in the LPF
> of my GW3UEP amplifier squashed the harmonic down to almost nothing.
>
> Neil, w0yse
>
> Sent from Neil's iPhone
>
> On Jan 26, 2018, at 07:41, John Langridge <kb5njd at gmail.com> wrote:
>
> >Since the target frequency is below 160M, why would harmonics be much of
> an issue with the 160M LPF?
>
>
> Second harmonic of 475 is 950, which is in use in many BC markets...
> 473's third harmonic is right around 1420...
>
> Many of us have taken the drive of shame where we activate our stations on
> WSPR or CW and still hear our signals on 950 kHz many miles away.  Never a
> good thing.  Adding one of the W1VD-designed filters made it where I
> couldn't hear myself sitting in my drive way.
>
> 73,
>
> John
>
>
> On Fri, Jan 26, 2018 at 9:32 AM, J Mcvey via 600MRG <
> 600mrg at mailman.qth.net> wrote:
>
> Got $9 in the budget?
> https://www.mouser.com/ Passive-Components/Frequency-
> Control-Timing-Devices/ Oscillators/_/N-7jdfi?P= 1z0woad
>
> <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?
>
>
> On Friday, January 26, 2018 7:53 AM, N1BUG <paul at n1bug.com> wrote:
>
>
> >> Why ruin a perfectly good radio???
>
> 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.
>
> 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, 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... ;-)
>
> 73,
> Paul N1BUG
>
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