[INRAD] Icom roofing filter status?

[Charlie Mazoch Jr.]

Hi Jim:
  George is having a board built for the Icom roofing filters. You're 
probably right about the Yaesu board working. All it does is add a bit 
of amplification. The only thing I plan on adding is a switching setup 
so the original filter can be used for FM or AM. Depending on the rigs 
popularity, ease of modification and number of inquiries George may 
order roofing filters. He likes to keep his mods using the "KISS" method 
for most hams. A lot of people get nervous around SMT and expensive 
rigs.  I did the second IF cascade filter mod on a FT-980 using his 
FT-920 setup and it does help a lot. The trick is keeping adjacent 
signals out of the first IF by using narrow roofing filters with several 
poles instead of the 20 Khz 2 pole OEM filters. Once there they put the 
screws to a receivers AGC. I downloaded the Icom 751A service manual 
from www.dk.mods/.  I did a bandpass filter diode switches mod on my 
Kenwood TS-2000 a couple of years ago which  is posted there. It has 
been looked at over 12 thousand times which indicates a lot of 
disappointed amateurs. The rig in OEM configuration has the worse 
receiver for internally generated noise I've ever heard.     73's  
Charlie    W5VIN

W7RY wrote:

> Thanks Charlie.
>
> Oh well... it was a try. I may contact George and see if I can get him 
> to order one on 70.4515. I think I would need an additional amplifier 
> though. Perhaps the one that is used on the 1000MP amplifier board 
> would work.
>
>  
>
> I'll break out the manual and take a look.
>
>  
>
> 73
>
> Jim W7RY
>
>  
>
>  
>
>  
>

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