Cool stuff. Way cool.

Just trying to sort out the bandswitching from the pictures:

Antenna input is switched to one of six bandpass+optional RF amp
boards. It looks like the antenna switching is by the black relays in
the back?

Eight bands, six band boards, a couple of the bands must be close
enough together that they utilize a common board? Or maybe the IF *is*
one of the bands...

There appears to be a preselector knob on the front, how does this go
into the bandpass/RF amp boards.

The output from the RF band boards is then brought to some sort of
combiner board that I cannot make out anything but a bunch of SMA jacks
on. Is there switching there too, or (because of power switching to
the RF boards) is this just a simple combiner?

And that Eddystone dial is to die for. Oh, man.

Tim.

"Tim Shoppa" wrote in message
oups.com...
Cool stuff. Way cool.

Just trying to sort out the bandswitching from the pictures:

Antenna input is switched to one of six bandpass+optional RF amp
boards. It looks like the antenna switching is by the black relays in
the back?

Eight bands, six band boards, a couple of the bands must be close
enough together that they utilize a common board? Or maybe the IF *is*
one of the bands...

There appears to be a preselector knob on the front, how does this go
into the bandpass/RF amp boards.

The output from the RF band boards is then brought to some sort of
combiner board that I cannot make out anything but a bunch of SMA jacks
on. Is there switching there too, or (because of power switching to
the RF boards) is this just a simple combiner?

And that Eddystone dial is to die for. Oh, man.

Tim.
Hi Tim,
An excellent job of sleuthing- I never could have done that.The RX is
essentially an 80M RX with xtal controlled converters for the other bands.
You are correct, the rear board switches the antenna to one of 6 front end
BP+LP filters- 10M 28-28.5 and 28.5-29 share a filter and 80M is bypassed
through this section directly into the preselector (which works on 3.5-4MHz
only). The board along the power supply side switches the filter outputs
into the 1st mixer. A relay on the output of the 1st mixer selects either
its output ( 3.5- 4MHz) or the 80M signal directly from the antenna. This
signal then goes to the preselector- which is a very sharp tunable BP.
The relay board on top of the chassis toward the rear selects the
appropriate L.O. and routes B+ through the coax to the L.O. 160M and 49M
share the same L.O. but different input filters.

Again, brilliant work on your part.

Dale W4OP

Dale, that receiver is among the best homebrew rigs that I have seen
in 45 years! Incredible job!

Ted KX4OM

On Wed, 23 Mar 2005 22:08:37 GMT, "Dale Parfitt"
wrote:

I had posted this elsewhere, and it has created some interesting feedback.
Based on Wes W7ZOI's Preogressive RX from the late 1980's. A wonderfully
balanced design to which I added some bells and whistles I like in a
receiver.
These are some shots of my almost finished 1980's theme HF receiver.
All stainless hardware, teflon wiring. Rock stable VFO, homebrew xtal
filters ( 5/2/5/0.5), selectable and defeatable AGC, notch filter, tone
control, QSK input,built in front end BP filters for each band, preselector,
AM/USB/LSB/CW.
Enjoy:
http://www.parelectronics.com/pics/W7ZOI11%20copy.jpg

http://www.parelectronics.com/pics/w7zoi13jpg.jpg

http://www.parelectronics.com/pics/w7zoi14.jpg

http://www.parelectronics.com/pics/w7zoi15.jpg

Dale W4OP
for PAR Electronics, Inc.