[INRAD] Roofing filter excess gain.

[Anders Janis SM4RNA]

Once again Inrad has shown their honesty and desire to improve our radios. I can think of quite a few companies that not would have released this information by them self. Once again I am impressed.

I have not notised any problems since I installed the roofingfilter. Unfortunately the B-PLL on the PLL brokedown just days after I installed the roofingfilter and it took more than 6 weeks until my radio was ok again. The noice level seem to have increased som during  the time the radio was broken. As the amount of electric devices increases by the day I am not conviced that the increase in nice level is due to increased gain in the receiver. But I can not be sure. Looking forwards to see the comments from others that have installed the roofing filter that not had the radio on repair for 6 weeks.

de Anders SM4RNA

----- Original Message ----- 
From: "George Cutsogeorge" <w2vjn at rosenet.net>
To: "Inrad List" <list at inrad.net>
Sent: Thursday, April 06, 2006 5:37 PM
Subject: [INRAD] Roofing filter excess gain.


> The amplifier gain associated with the FT 1000MP/MV roofing filters has 
> proven to be correct for that radio and that filter.  The filters for the 
> IC-775/765 radios are coming through with less insertion loss, so the 
> amplifier gain may be a bit high.  I don't have any lab data on this as the 
> borrowed IC 775 is long gone.  The filters I am presently experimenting with 
> for the TS-930 also have less loss and the amplifier will be changed for 
> these radios.  If you feel the gain is too high in your radio for some 
> reason, it can be reduced by changing two resistors.  Both must be changed 
> in order to keep the impedance match correct.
> 
> Gain        R5        R6
> 9dB        12        220
> 6             15       150
> 4             18       120
> 
> Please send me some feedback on any changes made and the effects on 
> performance.
> 
> 73,
> George, W2VJN 
> 
> 
> 
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