Re: hw9 experience needed


From: Stan Goldstein, N6ULU (
Date: Sun Jun 04 1995 - 13:51:57 EDT

Hi Dr Rick, I haven't played with my 9 too much yet , but here is
my thought on the matter of filtering.

It seems to me that the front end has none ! And in any situation
where there are adjacent signals, serious distortion occurs to the
point of not being able to copy at all.

Because the audio already has a narrow filter and doesn't help at
all in those situations, I conclude that any additional audio filter-
ing will not help. ( If you achieve any degree of success with audio
filtering, please let me know .)

I have been looking for ways to improve the IF filter and come up with
the following alternatives

1 KB1MJ, Paul , Paul put together a filter kit some years ago which
  consisted of matched crystal filters and either a change or an
  additional IF amp to compensate for insertion loss and impedance
  This kit , at $ 28, was in my opinion "The way to go".
  ( Was it you who told me you had one of these kits but didnt want
  sell it ? )

2 The IF frequency is 8.807 Mhz, the same as some Kenwood rigs.
  There are several mods out to use a Kenwood filter with an additional
  (or 2 ) stage of IF amplification , to make up for the insertion loss.

  The problem with this is the cost of the Kenwood filters. A bit over
  $ 100. I haven't found a used one for a fair price yet.
  International Filters, make a direct substitute ( I think they
  claim steeper skirts ). I haven't checked their prices yet, but expect
  them to close to Kenwood.

If any one has a kb1mj filter kit they are not going to use, please
let me buy it from you.



72.25 (I still use high power when I need it)
Stan Goldstein , N6ULU

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