I understand why you feel that way about it..........I didn't realize that
it was that good of a design. I like that MW preselector control. I was
really surprised to find silver mica caps in the front end. They didn't
skimp on this one.
Of course, the big question might be "how does it compare to the Lowe
receivers?"
Very similar in operation. It appears that most of the modern receiver
designs have about the same sensitivity; the differences would be in
overload performance.

Pete

"BDK" wrote in message
...
In article ,
says...
I picked up this receiver today. Some fellow traded it even up with a
friend
of mine for an R4C. I traded a Takahashi FS-78 Flourite refractor for it.
If
the JRC unit was working properly, it would have been a good deal, but I
thought, "what the heck?"
When I put it on my test bench, it could barely hear a 60% modulated 10uV
signal...........not good.
I did download a schematic from a Dutch website and saw that the 1st
mixer
uses U310 JFETs. No big deal, right?
When I removed the shield from the mixer assembly, I discovered that
instead
of the U310s, a Siliconix E431 dual JFET is used. This is a very high IP3
mixer, capable of +20 to +30dBm in a properly designed circuit.
I bought a batch of them several years ago from, you guessed
it....................the Rockwell-Collins surplus store.
I replaced the defective component and now the receiver is hearing
signals
all the way down to .1uV, which is typical of any of the modern day
receivers that use this topology.
I have been looking for one of these receivers for a few years; it's
ironic
that about the only way that you can get ahold of them is if they are in
need of repair. It wasn't too bad..........about an hour or so for the
repair.
Now I see why people don't want to sell these receivers. Good
quality......................even the roofing filter appears to be a 6 or
8-pole unit. This one's a keeper!

Pete




I've had mine since late 85. All of my other ones will probably go away
sooner or later, but unless my 515 dies and I can't get it fixed, it
will be here when I'm carted off...never to return...

BDK