[Drake] R4C Filter loss/mode independent of bandwidth selection

Sun, 28 Sep 2003 05:52:47 +0700

Hi Scott,

Ref your first question.
I have noticed the same thing with my 500Hz filter but put it down to a
bad filter. I initially thought it might be alignment but swapping it
out with another filter from a friends R4C showed a big difference, his
filter barely affected signal strength when a signal was properly tuned.
My filter in his radio showed the same high loss. I also notice that
with my receiver both the 1.5KHz and 500Hz filters move the S meter zero
point considerably.

Hopefully some wise owl will step in here an enlighten us both. I have
previously dismantled one of the xtal filters in a TR4C and resoldered
connections to cure an intermittent. Wonder if there might be something
I can do with this one.

73's
Martin, HS0ZED

-----Original Message-----
From: [email protected] [mailto:[email protected]]
On Behalf Of [email protected]
Sent: 28 September 2003 05:40
To: [email protected]
Subject: [Drake] R4C Filter loss/mode independent of bandwidth selection

1) Can anyone tell me about what the typical R4C 500 cycle filter loss
is 
compared to the stock SSB filter?  I haven't measured with anything
accurate, but 
the peak drops from about 20 over S9 to about S9 when switching to the
500 
cycle filter, and wondered if that's typical or excessive - the filter
otherwise 
performs well; and

2) Is there a mod for making mode and bandwidth selection independent -
I've 
got an early R4C and would like to have multiple AM bandwidths
available.

Thanks, Scott

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