Understand, well I was surprised in my findings.
I did get the same result on two radios.
However being an engineer I have to belive what
my own measurements tells me.
What might be interesting is to know what PIN
diodes you did use, also it would have been
interesting with measurements before and after
the PIN diode change.
Different PIN diodes will give different result
on different frequencies.
This will show up when you measure with and without
the INRAD 4 kHz roofing filter, what I mean is
the filter will work differently with different
PIN diodes, atleast this is what I did find out
and I´m not sure I can explain it.
My understanding is that it has to do with the diodes
"carrier life time" however I´m no expert in this and
I´m trying to study up on it.
I suppose this will get too technical for the contest-list
so I better drop it maybe.
73 Jim SM2EKM
--------------------------------------------------------------
Jeff Stai wrote:
> At 12:35 AM 7/24/2006, Jan Erik Holm wrote:
>
>>However personaly I´m not sure buying a INRAD roofing filter
>>for the 1000D is well spent money.
>>With the mods below an INRAD roofing filter does not seem
>>to give any IMDDR3 increase at all.
>>However, on a 1000D with no bandpassfilter diode mod an INRAD
>>roofing filter gives a substantial IMDDR3 increase, around 15dBm.
>>This is the mods I´m talking about.
>>1. W8JI noise blanker mod
>>2. Replace bandpass filter switch diodes, forexample per Yaesu
>> service bulletin TB-93201
>
>
> I have two 1000Ds that have these mods, and I added the roofing filter to
> each when it became available. The difference is like night and day. Nearby
> station interference is greatly reduced.
>
> 73! - jeff wk6i
>
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