http://www.universal-radio.com/catal.../0175filt.html
has some filter replacement tips.

Crystal filters at 455Khz are quite easy to find on the used market
($10 to $20) or new for about $80 or so.

You will get quite a few suggestions for filter bandwidths, but keep in
mind that narrow bandwidth makes for a dull signal since it chops off
the high frequencies. You would need one for AM BCB or shortwave, then
one for sideband. Around 2.4Khz for sideband is good. For BCB, maybe
6Khz.

The used crystal filters generally come on daughter boards. The odds
are the daughter board won't fit your radio. [I don't have a R75, so I
don't know how it is arranged inside.] However, there seems to be a
standard pinout for crystal filters. It may be the Icom has an open
area on the PCB to install the optional filters, or do a swap.

Some filters can be found here, but you should check to see if Kiwa
upgraded your filters.

http://www.gigaparts.com/store.php?a...FLT&type=radio

Lenny wrote:
As the subject says, I'm looking for ways to hear the weak ones that are
getting drowned
out by the strong ones in the same frequency area.
I'm using a Kiwa modified R-75 with an Antenna Supermarket Eavesdropper
antenna.
I've tried every control on the Icom. With some stations, I can tune them
so that I can understand
the voices. Others, I'm not so lucky.
Am I at the limits of what the R-75 can do?
Are there any other mods I can make to it, within reason, to improve it?
The radio does great with pulling in hams, the utility stations I've tried,
stronger World Broadcast stations, and even some of the
weaker World Broadcast stations. But if there's a weak station next to a
stronger one, no dice.
Does it take a better receiver, such as the Drake R8B to isolate out the
weaker stations?
What is the property of the receiver that lets this happen?
Is it extremely sharp cutoffs on the filters?
Please explain?
Thanks for any light you can shed on this question.
Lenny