[Today’s run: 2 miles]
I’ve gotten connected to an email reflector about the HBR receivers and I see there is a lot of good information.
I’ve been asked to make some pictures available so that people can see what it looks like. This blog post will be a repository for that info.
Underside Left
Underside Right
Bandswitch – front end
My posts to eham.net (link to eham.net discussion) contains links to some of the same pictures and my description of what I think the tubes are doing:
Thanks for all the advice. This thing has some indications
of having worked (dial calibration marks, etc.) but
also has loose ends. So it may have been an unsatisfactory
attempt. Makes an interesting puzzle!Tube line up and signal path (as far as I can tell so far)
(underside, part 1 http://w0ep.us/radio_stuff/unkown_rx/GEDC0205.JPG )
Slug tuned coils selected by bandswitch along with a
one-section air variable (about 1 in. dia, knob labelled “antenna”)
It appears that some coils are not attached.6au6
More bandswitched coils. Some small air-variables in this
neighborhood but they are not connected to anything!6cs6
nearby is a 6ak5 and some slug tuned
coils also bandswitched. I believe this is the LO.Single section air-variable cap on the top deck, a bit larger
in dia. (1.25″ ?) and about 2 inches long (20 plates?)
which is attached to gear drive and main tuning.IF can
6be6
IF can
1330 and 8340 crystals attached to
a switch marked for USB/LSB nearby
is a 6ak5IF can
6cb6
IF can
(underside part 2 http://w0ep.us/radio_stuff/unkown_rx/GEDC0206.JPG )
6t8
output to headphones
audio xfmr (I think it is not even connected)
6aq5
In the neighborhood of the 6t8 is a 6c4 and a
1’x1′ can shaped thing. from that collection comes the
BFO signal, loosely coupled by wire twisted in
near that last IF can.6au6 with a 100 kHz crystal which appears
to inject calibrator signal into the front end.Tubes left over that I don’t yet know the function of: 12au7, 6ak5
And there is a 5y3gt rectifier tube.
(topside http://w0ep.us/radio_stuff/unkown_rx/GEDC0213.JPG )
The front panel is nicely painted with factory-type lettering.
(front http://w0ep.us/radio_stuff/unkown_rx/GEDC0218.JPG )
Controls on the front —
knobs look like from a xxxxBC-348xxxx (correction, BC-312),
arrows and sometimes word printed on knobs
(left to right)ANTENNA
SIDEBAND (upper/lower) (knob says “crystal” and has an arrow)
Band switch (80M 40M 20M 15M 10M)
R.F. GAIN
A.V.C. (switch: up-HIGH/down-LOW)
C.W. OSC (switch: up-ON / down-no marking)
AUDIO (integral power on/off switch)
PITCH
CALIBRATE (switch: no markings)
SQUELCH (integral switch)
PHONES (jack)
DIAL/SET (little knob up near the dial which shifts
the rotating thing a bit left or right)There is an s-meter in the upper left which is a Triplet meter
with pencil marks “s-9”, “+20”, “+40” on the meter dial.Main tuning knob is in the center. slide-rule dial with single,
narrow window and a turning mechanism actuated by the band switch
(mechanism is disconnected due to dial cord break). Paper
cover on the turned cylinder has pencil marks with ham-band
type numbers.I will try to get some pictures. (added picture links to this post)
Injecting a signal in the antenna I can follow it through the
coils and bandswitch. It gets lost near the sideband switch.
But I’m not sure if I have the main tuning set correctly to receive.
I’ll have to work on that some more.With phones plugged in, I can get some sound if I
max the audio gain. I’m thinking it is self oscillation.
Otherwise, no static or shoosh noise at all.I don’t know for sure that the tubes are in the right sockets,
but this is where I found them. All tubes tested ok in
my ancient and dodgy tube tester. All tubes have bayonet-type
shields except rectifier.
A later post on eham (after discovering that the tube in the socket for the LO was incorrect)
I found a 6C4 in my tube collection and gave that a try.
It works!Three settings of the bandswitch seem to work.
With those settings the LO produces:Low — High || +1415 1st IF
12639 — 12926 || 14054 — 14341
2234 — 2601 || 3649 — 4016
5767 — 5976 || 7172 — 7391