[UK-CONTEST] Fwd: CC April CW TX Bandwidth

Bob Henderson bob at 5b4agn.net
Wed Apr 15 01:15:08 PDT 2009


---------- Forwarded message ----------
From: Bob Henderson <bob.5b4agn at gmail.com>
Date: 2009/4/15
Subject: Re: [UK-CONTEST] CC April CW TX Bandwidth
To: g3wvg at btinternet.com


Two cents from Cyprus.........

I've done the Inrad mod once and the W8JI mod on several MPs.  Both are
essentially the same.  The difference being that while the W8JI mod provides
for the value of critical components to be selected on test, the Inrad
approach has simplified the mod to use predetermined nominal values.  The
SOT approach provides a solution which better compensates foir manufacturing
tolerances in YOUR MP.  Hence superior click suppression is available via
this route.  That said, the Inrad mod does provide a very useful
improvement.  Even using Tom Rauch's approach I have encountered variations
in outcome, ranging from very useful to highly impressive.

FWIW

Bob, 5B4AGN



2009/4/15 <g3wvg at btinternet.com>


> Hi All ..
>
> For what it's worth I did the INRAD mod on my old FT1000MP (but not using
> their kit). I think it's a bit easier to do than the W8JI mod but with, I
> believe, similar results.  It's very well detailed in the link below.
>
> http://www.va3cr.net/Mods/Material/Inrad%20key%20click%20mod%202.pdf
>
> 73 Ian G3WVG
>
>
>
>
> -----Original Message-----
> From: uk-contest-bounces at contesting.com
> [mailto:uk-contest-bounces at contesting.com] On Behalf Of Andy Cook, G4PIQ
> Sent: 14 April 2009 19:47
> To: uk-contest at contesting.com
> Subject: Re: [UK-CONTEST] CC April CW TX Bandwidth
>
> Sorry to come late to this discussion - was tied up over the weekend. I
> think the other reason that Clive might well have got away without a key
> click mod in the circumstances of operating +/- 10 kHz is that key clicks
> are probably not the dominant problem here - phase noise, broadband Tx
> noise
> and blocking dynamic range, are and the MP is pretty good in those
> respects.
>
>
> Key clicks become a real problem at much closer spacings like 500 Hz or 1
> kHz spacing but from moderate signals rather than just really huge ones. In
> theory in CW you can make decent use of really narrow filters and this
> should make CW contesting much less congested and more pleasant than SSB
> contesting. Well - that's only half true right now. Some signals are very
> clean and you can operate say 300 Hz away from them with no issues, but
> that's not the case if the other operator is using an un-modified FT1000MP.
> The clicks from these stations in CW contests cause just as much
> frustration
> as QRM from adjacent SSB QSOs in SSB contests.
>
> I've only modified the MPs I use in contests in the last 3 years or so. It
> took me getting really irritated at the number of QSOs that other people's
> clicks were busting for me to realise that anyone operating CW with an MP
> and a moderate station really must do the mods. They are simple to do and
> make a huge difference.
>
> There are those folks who say - I don't want to do that because it means
> that others can operate much closer to me. I don't buy that as an
> acceptable
> answer - it's like the use of 6 kHz filters on SSB transmit, or
> intentionally over-driving your amplifier or pushing it out of class AB,
> using the grid current warning LED in a grid drive tetrode amp as the the
> 'on' light.... The more people that we can persuade to fix the problem by
> peer pressure the less trouble we all will have
>
> 73,
>
> Andy, G4PIQ
>
> -----Original Message-----
> From: uk-contest-bounces at contesting.com
> [mailto:uk-contest-bounces at contesting.com] On Behalf Of Ian White GM3SEK
> Sent: 11 April 2009 19:42
> To: uk-contest at contesting.com
> Subject: Re: [UK-CONTEST] CC April CW TX Bandwidth
>
>
> Clive Whelan wrote:
>
> >> There does seem to be some variability between individual rigs, but
> >> even the best of them are clicky and the worst are downright
> >> horrible.
> >
> >Well myself and GW3RIH must have been very lucky in getting a couple of
> >good 1000MPs then, because we lived 500 yards apart and both ran 400w,
> >me using an Alpha 78 and Wes using a TL922, and we could operate within
> >10kHz of each other on 14Mhz , without insurmountable problems
> >problems. You don't suppose that could have been because we didn't
> >overdrive the amplifiers do you? ;-)
> >
>
> No, the problem is definitely with the transceivers themselves.
>
> However, if you were using your amplifiers at the 400W level, the
> transceiver output power would have been only about 20-25W. That might
> have helped to reduce the levels of key clicks, though it wouldn't have
> been directly due to the reduction in power - more likely the effect it
> might have had on the ALC dynamics.
>
> Nobody has really got to the bottom of why it happens... least of all
> Yaesu.
>
>
> --
>
> 73 from Ian GM3SEK
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