[1000mp] Mk V Field, strange behaviour!

[Dean Fewkes]

Andy,

I have operated 2 Fields and they both did this. The problem was worse when
the rigs were cold and just turned on. The problem is that some RF is still
present when the rig switches to receive and that triggers the AGC. I think
that this is common on most fields in the CW mode and I do not believe that
is has been associated with any failures. On my own Field, the problem went
away when I installed the roofing filter and the Inrad key click mod. I did
the mods at the same time so I cannot say which one corrected the problem.

Dean Fewkes
KG7MZ


----- Original Message ----- 
From: "Andy Hamon" <andyh at cwgsy.net>
To: <1000mp at mailman.qth.net>
Sent: Sunday, April 10, 2005 1:23 PM
Subject: [1000mp] Mk V Field, strange behaviour!


> Can anyone shed some light on a problem I have with my MkV Field???
> As I am on my second Field in six months and both behaved the same, is it
a
> design "issue" or am I unlucky to have had two Duds?
>
> Here's the situation:
>
> When I use CW, 90% of the time, the S meter fires across to 60 over 9 when
> the radio switches from TX to RX. Not a lot of fun if I am using full
> break-in.
> After various discussions with Yaesu, the message seemed to be "that is
just
> the way it is".
>
> As a "lab" test I hooked up a dummy load and pressed the MOX switch
without
> sending any code. No CW and no power out on the meter. When I  pressed the
> MOX switch again the radio went back to receive and the S meter showed S9,
> dropping to zero over time, typically half a second with fast AGC and two
to
> three seconds on slow AGC. On slow AGC the background noise seemed a bit
> attenuated immediately the radio switched to RX and came back to full
> strength as the S meter dropped to zero.
>
> I even tried a full CPU reset, but all that did was to give me half an
> hour's work setting the radio up again!
>
> Any idea what is going on and if there is a mod to fix it?????
>
> I have spoken to various users of the Field who say the Inrad roofing
filter
> did wonders for the clicks & pops etc. I have one but have not fitted it
in
> case I get the Yaesu line " the problem has been created by modifying the
> radio, warranty void".
>
> Can anyone help.
>
> Incidentally, if the AGC is switched OFF the problem does not exist, but
> strong signals sound BAD (as you would expect) and on SSB the problem does
> not exist.
>
> Thanks
>
> Andy, GU4WTN
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