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[CQ-Contest] Popping/Thumping IC-7410 during ARRL DX CW

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Subject: [CQ-Contest] Popping/Thumping IC-7410 during ARRL DX CW
From: "Mike" <ve9aa@nbnet.nb.ca>
Date: Tue, 19 Feb 2013 19:32:54 -0400
List-post: <cq-contest@contesting.com">mailto:cq-contest@contesting.com>
I know there are a great bunch of CONTESTERS on here. If this

does not fit this forum, I bow my head in shame....if anyone knows the 7410
(or

Ic-7600/9100) pse email me directly if this is not forum proper.

I don't know where else to post to find CW

contesters as good as you all.

Mike VE9AA

---------------------------------

> 

> This was the first contest outing for my 'new-to-me' 7410...and I did 33
hrs

in the ARRL DX CW during crowded band condx using low, wire ground-planes on
all bands.

> One thing that stood out to me was that the rx seemed like it was thumping

when stations got close to me. Just like if I had the NB on. (but I didn't).
I

even tried turning the NB on and off, to make sure it wasn't somehow
activated

and just not displaying that it was activated.

> Nope...a bit worse with the NB on.

> 

> My old radios the past 10-12 yrs were a IC-746 (original) (fully filtered)
and

before that an IC-736.

> 

> So, what gives? I tried using a narrow filter setting when needed (250Hz)
and

also at times, 450-500Hz....these were crowded bands !

> I tried hard vs. soft with no real perceptible difference.

> 

> Also, there was another lesser condition that almost seemed like a delay
on

the receiver coming back instantly to full steam on RX. I would transmit and
then when the

pileup answered me, it seemed like the first character or two of the
stations

calling, were attenuated until the RX fully "recovered" (if that makes

sense)....I think this was more an audio issue than a signal issue as I
watched

the "s-meter". (someone emailed me directly and suggested my amp clicking
when I went to RX was pumping the AGC..

Maybe that's possible? I use an old MLA2500 and the T/R relay is not quiet,
nor 100% 'clean'.

> 

> I am more concerned about the thumping sound than anything else. 33 hours
of

that was hard on my head.

> 

> The only time it didn't sound bad was when I was on a less crowded band
(like

10m Sunday afternoon, I found a slot high up in the band) or when 40m first

opened to EU around 3pm local and there were virtually no USA/VE's on 40.

> 

> Any insight wise from 7410/7600/9100 CW users?

 

>Forgot to say, I tried fast and medium AGC (no real difference) and also
the

radio has both roofing filters installed. I think they way the previous
owner

had it configured (and I haven't changed it) was when I was on 450-500Hz
filter,

the 6k was inline and if I was on the 250Hz filter, the 3k was inline. I
never

ran @ 2.4Khz as that would be insane in a very busy CW contest situation.

 

I didn't use any other "features" like NB, NR or whatever.

 

I tried narrowing the PBT "a little" at times but wasn't much better.

 

So far, my old 736 or 746 act more civilized deep in the trenches of an

extremely busy band....where I am the happiest, I might add.

 

Any late model ICOM contesters on this forum ??

 

73 es tnx, Mike VE9AA dit dit

 

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