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Re: [CQ-Contest] Icom 746 as contesting rig

Subject: Re: [CQ-Contest] Icom 746 as contesting rig
From: Jan Erik Holm <sm2ekm@telia.com>
Date: Tue, 25 Jul 2006 08:12:09 +0200
List-post: <mailto:cq-contest@contesting.com>
Yes in many cases our receivers these days are far too sensetive,
i e too low noise floor, usually on the low bands it´s not needed
at all.
Fixing things with a RX front end attenuator is IMO smart, forexample
if you attenutae RX with 6 dB that will give your RX 12 dB increased
IMDDR3 performance, that´s why a small attenuation will make a
big impact.

However in some radios, forexample FT-1000D, before you get to the
step attenuator you first turn off the preamp, IMO that is very
stupid since you just lose too much RX sensistiity, in the FT-1000D
you first lose 20 dB before you get to the attenutor and that is
far too much.

In my FT-1000D´s I have "hard wired" the preamp so it never turns
off and the switch just operates the 6 12 18 dB RX front end
attenuator steps.

In case someone is interested this is how to do:

On RF Unit board, locate connector J1003, Ground Pin 1 (green wire),
can be done with a 1 inch pice of wire to the case of the band
pass filter shielding, solder directly to the J1003 Pin 1 pin.

73 Jim SM2EKM
-----------------

Larry Schimelpfenig wrote:

> 
> I found that the receiver was prone to IMD on the lower bands with really 
> big signals present. While Quack suggested that one turn the RF gain down, I 
> found that a few db of attenuation nicely took care of the problem. Beyond 
> that issue I found the 746 to be a great contesting rig. While I used the 
> 746 in the NAQPs, Sprints, Sweepstakes etc from home, I was operating the dx 
> 
> 73 de Larry K7SV


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