One more bit of information on the design that may clear up some points.
I relayed this to a couple of other hams earlier in email conversations and
thought you all here would benefit from the knowledge.
On receive, in the 599 and RX366, signal comes in, goes through the AM
broadcast filter, which does prevent the STRONG stations from coming in on
any "path" after that. It won't get rid of them, it just attenuates them to
a point where they won't interfere with ham bands.
After that, if you go to a band, the rx path is switched to a filter that
blocks out EVERYTHING but that band. Meaning, if you select 40, it will
block (as much as it can) 10, 12, etc., generally, it blocks other bands
and out of band signals from coming through.
Now, if you go out of the band, the receive path goes to the general
coverage path that lets everything come through, without any attenuation.
This is the same path for between bands and outside of bands including the
AM Broadcast and SWL sections.
But, the FIRST thing that EVERYTHING goes through, is the AM Broadcast band
"attenuation".
AM stations can be so strong and if they are nearby, they can cause
problems on about every band, even using a band pass filter, that is why we
add this "blocker" to the front. It attenuates the signals to the point
that they aren't a nuisance to the band paths in the preselector. But it
isn't removed enough so that it isn't usable to listen to 930AM.
So, on the RX366, listening to SWL stations is not a problem, the path goes
through the AM broadcast filter, then to the open barn door path, so, any
signal from any other area outside of the AM broadcast can be tuned to, and
can also affect the SWL area. If you have a neighbor running 1500w on 40 or
12 or another "ham band", you may hear distortion from him listening to SWL
at 9mhz. But if you are on 12, you shouldn't hear him distort your 40.
And no, none of these filters are perfect, if you have Mr butthead next
door to you running 2400w illegally, well, all bets are off, or even 1500w
on your block, you may still hear something, but it should be minimal.
On the original sub receiver, there is no broadcast band filter, which
means it can affect the ham bands. This is a huge advantage of the original
sub receiver over the RX366 in that broadcast band signals are not
attenuated at all and can be heard at full fidelity. This is also a huge
disadvantage of the original sub receiver in that strong AM stations leak
into the ham bands and cause various issues degrading receive performance.
To quantify the differences, compare the Jupiter receiver tests with the
Eagle receiver tests. Granted, the original receiver (jupiter hardware)
does give a bit better performance due to the DSPs, but generically it is a
good yardstick for it.
Thanks, and 73,
John Henry, KI4JPL
TEN-TEC Engineering
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