[Andrew2]

Originally Posted by Damien VK3RX

I had a 545 at one point, but can't say I noticed that AM problem. Maybe I had a later build. The DSP is quite good, given the age of the technology. I only ever use it lightly to take the edge off noise anyway.

The 545 is a very pretty radio, if we can use that term

Another one I regret selling ...

And a pix of the mess inside the 515's Kokusai filters, before repacking with some cotton wool.

OK Damien
I've got into one of my 'I must find this just to satisfy myself' moods. I haven't found JW's 545 review yet, but I did come across this:

Date: Sat, 12 May 2001 11:15:32 -0600
From: Rob & Terri Sherwood <rob@sherweng.com
Subject: Re: Prem-Rx: RE: Great prem-rx posts
A comment on the JRC 545. When it first came out, likely a pre-production unit that I tested for
Passport, the garbage that one heard tuning around a clean test signal in the plus / minus 20 kHz range
was staggering. There were hundreds of tweets and multiple hets, and an AGC that was going nuts. (By
the way, the test generator was at that time an HP 8640A, a very clean cavity tuned oscillator divided
by N to produce the HF test signal.) If the test signal was over 50 dB above the noise floor of the radio,
the garbage from the DSP was so bad I wondered how JRC could contemplate shipping the product.
After giving them a heads up, they modified something in the DSP to limit the stop-band signal so that
its artifacts were different. I am not saying significantly better, but different. Instead of hundreds of
tweets, the stopband garbage just became noise to a larger extent. To help this mess, we typically
replace the DSP protection filter at 455 kHz with an 8 kHz filter instead of the 18 kHz filter that comes
stock. Does this help plus/minus 4 kHz? No. But it does provide 40 dB additional rejection at plus /
minus 5 kHz, and does help when having to cope with an adjacent-channel signal that is stronger than
the desired signal by 50 dB or more.

As you say, later units may have been given some attention in this area. BTW, I recall an article in Radcom about re-furbing the Kokusai filters, very interesting.