[1000mp] Roofing filter observation, A=B test

[Jim W7RY]

I too noticed the same great performance. I did operate in the ARRL RTTY 
Roundup contest last weekend and listening on the bands with a pair of 
125Hz filters centered at 2200 Hz was a pleasure to listen to without all 
the noise.


My MK-V did not have the INRAD 70 MHz IF mod installed. To get the same 
s-meter reading with a calibrated signal generator after installation of 
the roofing filter I had to turn down the IF gain to about 9. I think I 
finally setteled on a setting of 10. Originally it was set at 13.

I you listening to a quite band... I would highly recommend it!

73
Jim W7RY

At 08:30 AM 1/14/2005, =?iso-8859-4?B?VPVubm8gVuRoaw==?= wrote:
>Just a quick note on my roofing filter observations:
>
>I have two MPs both so far with IF mods. All filters in and mostly 
>identical in all measurements.
>
>So I had the opprotunity to install roofing filter into one instead of IF 
>mod and do A=B testing.
>
>1. I did not notice signal strength change. I think I have both set to 12 
>in 9.x menu and they were still identical.
>2. I did not find any strong enough signals close enough to cause any 3rd 
>order IMD products so I did not see any difference in signal clarity, 
>cutting splatters or anyhing like this. I guess I have to wait for contest 
>for that.
>3. What I did notice for sure was remarkable HISS REDUCTION. The backround 
>noise was constantly about 1-2 S-units lower on all bands. Quite 
>remarkable. The receiver is more quiet. What actually seems like an 
>ordinary band noise was noticably lower.
>
>I am satisfied:)
>
>73
>tonno
>es5tv
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