[JRC] Narrow CW filters for the NRD-525 (and other receivers)

[Philip Atchley]

Hello.
I just completed a lot of research looking for a "narrow" CW filter for the
NRD-525 and corresponding with various suppliers etc.  Putting out "wants"
on the reflectors got no offers of filters.

Here's what I found available. Prices are US Dollars and don't include
shipping.

1.  InRad #306 & #719 125 Hz filter (and other bandwidths) $155.00 USD.
2.  New 300Hz JRC filter from Universal Radio $139.95 USD (YES, they still
have them available).
3.  New Collins 300 Hz "Mechanical filter on PC Board for JRC radios from
Sherwood Engineering.   $129.00 USD.
4.  New 400 Hz Xtal filter on board for JRC from Sherwood Engineering
$129.00.

For those who don't know, Sherwood Engineering is a respected firm for
receiver updates, mods etc.  From what they told me, Nearly any filter is
better than the 300 Hz filters that JRC manufacture for their receivers (due
to poor shape factors.)  They suggested that for my listening habits that
the 300 Hz Collins Mechanical was probably the best choice.  The 125 Hz
filters available elsewhere would give better selectivity but the increased
"Ringing" may cover up many weak signals (I've used one in a R-71A and they
do ring). To use 'most' aftermarket filters on the JRC NRD-525,  there is a
small mod that needs to be done to the IF board in the form of adding
coupling capacitors (this was done by someone to install the Kenwood Trio
filter that is presently in my radio).  So far as I can see this is the ONLY
advantage to using the Factory JRC filter!!

So, to make a long story short, today I ordered the Collins 300 Hz
mechanical filter for my receiver (If it's a Collins filter, you KNOW it's
good).



73 de Phil, KO6BB

DX begins at the noise floor!
k06bb@elite.net
Merced, Central California
37.18N  120.29W  CM97sh