On 07/02/2013 09:33 AM, Michael Black wrote:
On Tue, 2 Jul 2013, Channel Jumper wrote:


'Michael Black[_2_ Wrote:
;806491']On Mon, 1 Jul 2013, wrote:
-
My restored, aligned GPR-90 is coming home tomorrow - excite to try the

beast on my long wire antenna! Will report later, maybe post a video.
-
I paid $20 for mine at a garage sale last August. I didn't get out to
the
garage sales early, so by the 1pm or so I expected to find little. I
turn
down a street where a sale had been advertised, and a couple of houses
away I could see a shortwave receiver, I couldn't tell what brand or
model, but clearly it was a classic. I get close, it's a TMC GPR-90. I

figure it will be way over my price range, but I ask and they say "$20".

I say "I expected three or four hundred" and they still said "$20". It

was too good a price to ignore. So I haul it home on foot and bus, the

other plans for the day cancelled.

And it sits there, other things in the way. The rectifier tube is loose

in the base, so I have dig out that box of tubes and hope I have one.
And
the fuseholder is missing, the piece that screws in with the fuse. That

may have come off on the trip home. So until I find those pieces, it's

not even getting turned on.

I don't know if it will need much work. Physically it's in great shape,

maybe a bit of rust on the bottom. No case, but that doesn't bother
me.

I assune that if I'd not come along at that point, it would have been
tossed. There have been garage sales at that house before, but this
time
it was younger people, relatively so, and I guess they were the kids
clearing out the hosue. When I did a search when I got home, I found an

earlier ad from the same area offering a GPR-90, so it had to be them.
They tried at $100 and had no luck, so I was the last call I suspect.

I've been going to garage sales since about 1990. And I never saw
shortwave receivers until one rummage sale in 2006, a Grundig Satellite

500. I find one about every year now, some just average analog
portables
with a band or two, but some digitally tuned and fairly high grade, and
I
pay almost nothing. I even got a Grundig mini 300 for 2.00, right after

getting a Sony SW-1 for ten dollars. The mini is an odd thing, single
conversion and analog tuning, and not a great receiver, but it has a
frequency counter so no need to fuss with dials. By making it extremely

complicated, the unit becomes much simpler. It's probably as bad as my

hallicracters S-120A I got in 1971, except with the frequency counter
dial, I can actually tune to a specific frequency. The GPR-90 is the
only
tube receiver in the bunch. I would have expected to find a cheap
receiver like the Hallicrafters S-38 or even a Radio Shack DX-150 long
before finding a GPR-90.

Michael
The Generations change.

The old people dies and the young people thinks that they see dollar
signs and that you can get rich off a old broken piece of junk.

When they realize that there is almost no one interested in it, they
either sell it for what they can get out of it, or they throw it in the
garbage.

The dumpsters at some hamfests are full of unwanted boat anchors.

Well you should have been around forty years ago, when the stuff was
really unwanted. It was tubes, it was am only, and nobody wanted it,
which made it cheap. Endless stuff that is now expensive passed around
for little or nothing. And that attritiion helps to make the current
equipment more expensive, since supply has gone down as demand goes up.

Beauty is in the eye of the beholder.
Not much call for a AM radio - not much to listen to anymore.

The GPR-90 was a mid-range receiver, not up there with the R388 but
better than a lot of stuff. It's not an "AM radio", it's a shortwave
receiver. And like so many of that era, it lacks a product detector but
you can use it for SSB by turning down the RF gain, turning up the audio
gain.

But if you can find a general coverage receiver that does the Amateur HF
bands, there is still a lot to listen to when the bands are open.

Hook it up and enjoy.

If you do not have a amateur radio license, get one.

If you can fix a old radio, I'm sure you can study and pass a couple of
35 question, multiple guess tests...

You are clueless. You haven't noticed me posting in other newsgroups?

I'm sure by your CB handle I've been licensed longer than you, since
June of 1872, and the test was a lot harder here in Canada since it
wasn't aimed at the beginner.

Michael

You forgot to turn on the BFO. BFO level is frequently too low for
demodding SSB hence the need to reduce RF gain.

dave wrote:
You forgot to turn on the BFO. BFO level is frequently too low for
demodding SSB hence the need to reduce RF gain.

Yep, easy to see from the jpeg that there's a BFO present.

I seem to remember having to repair an old KnightKit
tube radio that worked OK otherwise - bad capacitor in
the BFO. Person I bought it from didn't know what one
was so he wouldn't have had any reason to know it wasn't
working when he owned it.

On Tue, 2 Jul 2013, dave wrote:


You forgot to turn on the BFO. BFO level is frequently too low for demodding
SSB hence the need to reduce RF gain.

No I didn't. It should be a given that you need the BFO. I was making
the point that it's one of those radios of the time that didn't have a
product detector, so you had to do what all the books said to do. A few
years later, most receivers did have product detectors. Indeed, the
GPR-90 came along right at the cusp, so you could get an external unit
that added a product detector (and I think some extra selectivity) and
some really fine tuning. The receiver has the an IF output jack on the
back, even has a jack for feeding audio back into the receiver (though the
TMC adapter had a built in audio amplifier). Other receivers had similar
units. The R388 and the R390 didn't have product detectors, though they
are considered some of the best receivers from the time (and perhaps for
all time).

But with that level of receiver, turning down RF gain wasn't a real issue.
I had no problem receiving SSB, even on six meters, on the SP-600 I had
forty years ago.

ON the other hand, that Hallicrafters S-120A (the transistorized model)
that I got in the summer of 1971 had a horribly weak BFO, so by the time
I'd attenuated the incoming signal (a pot between the antenna and the
receiver), there weren't many signals left strong enough to receive.

On 07/11/2013 09:38 AM, Michael Black wrote:
On Tue, 2 Jul 2013, dave wrote:


You forgot to turn on the BFO. BFO level is frequently too low for
demodding SSB hence the need to reduce RF gain.

No I didn't. It should be a given that you need the BFO. I was making
the point that it's one of those radios of the time that didn't have a
product detector, so you had to do what all the books said to do. A few
years later, most receivers did have product detectors. Indeed, the
GPR-90 came along right at the cusp, so you could get an external unit
that added a product detector (and I think some extra selectivity) and
some really fine tuning. The receiver has the an IF output jack on the
back, even has a jack for feeding audio back into the receiver (though
the TMC adapter had a built in audio amplifier). Other receivers had
similar units. The R388 and the R390 didn't have product detectors,
though they are considered some of the best receivers from the time (and
perhaps for all time).

But with that level of receiver, turning down RF gain wasn't a real
issue. I had no problem receiving SSB, even on six meters, on the SP-600
I had forty years ago.

ON the other hand, that Hallicrafters S-120A (the transistorized model)
that I got in the summer of 1971 had a horribly weak BFO, so by the time
I'd attenuated the incoming signal (a pot between the antenna and the
receiver), there weren't many signals left strong enough to receive.


I've had a couple R-390As. I used to leave them on 11175 upper with RF
gain low, carrier sliced off with 2 or 4 KC mechanical filter by
slightly tuning off center, BFO on about 1200 cycles. It was dead quiet
unless someone spoke, like dolby FM. It would stay perfectly tuned for
days, with the ovens off.

I can't afford electricity to waste on old radios.

dave wrote:

On 07/11/2013 09:38 AM, Michael Black wrote:
On Tue, 2 Jul 2013, dave wrote:


You forgot to turn on the BFO. BFO level is frequently too low for
demodding SSB hence the need to reduce RF gain.

No I didn't. It should be a given that you need the BFO. I was making
the point that it's one of those radios of the time that didn't have a
product detector, so you had to do what all the books said to do. A few
years later, most receivers did have product detectors. Indeed, the
GPR-90 came along right at the cusp, so you could get an external unit
that added a product detector (and I think some extra selectivity) and
some really fine tuning. The receiver has the an IF output jack on the
back, even has a jack for feeding audio back into the receiver (though
the TMC adapter had a built in audio amplifier). Other receivers had
similar units. The R388 and the R390 didn't have product detectors,
though they are considered some of the best receivers from the time (and
perhaps for all time).

But with that level of receiver, turning down RF gain wasn't a real
issue. I had no problem receiving SSB, even on six meters, on the SP-600
I had forty years ago.

ON the other hand, that Hallicrafters S-120A (the transistorized model)
that I got in the summer of 1971 had a horribly weak BFO, so by the time
I'd attenuated the incoming signal (a pot between the antenna and the
receiver), there weren't many signals left strong enough to receive.


I've had a couple R-390As. I used to leave them on 11175 upper with RF
gain low, carrier sliced off with 2 or 4 KC mechanical filter by
slightly tuning off center, BFO on about 1200 cycles. It was dead quiet
unless someone spoke, like dolby FM. It would stay perfectly tuned for
days, with the ovens off.

I can't afford electricity to waste on old radios.

Yeah, after all, your pal, Boy Barry, said that under his plan, electricity
costs would necessarily skyrocket.

You're both f00kin clown 'tards!

On Thursday, July 11, 2013 5:48:55 PM UTC-5, dxAce wrote:
dave wrote:



On 07/11/2013 09:38 AM, Michael Black wrote:

On Tue, 2 Jul 2013, dave wrote:





You forgot to turn on the BFO. BFO level is frequently too low for

demodding SSB hence the need to reduce RF gain.



No I didn't. It should be a given that you need the BFO. I was making

the point that it's one of those radios of the time that didn't have a

product detector, so you had to do what all the books said to do. A few

years later, most receivers did have product detectors. Indeed, the

GPR-90 came along right at the cusp, so you could get an external unit

that added a product detector (and I think some extra selectivity) and

some really fine tuning. The receiver has the an IF output jack on the

back, even has a jack for feeding audio back into the receiver (though

the TMC adapter had a built in audio amplifier). Other receivers had

similar units. The R388 and the R390 didn't have product detectors,

though they are considered some of the best receivers from the time (and

perhaps for all time).



But with that level of receiver, turning down RF gain wasn't a real

issue. I had no problem receiving SSB, even on six meters, on the SP-600

I had forty years ago.



ON the other hand, that Hallicrafters S-120A (the transistorized model)

that I got in the summer of 1971 had a horribly weak BFO, so by the time

I'd attenuated the incoming signal (a pot between the antenna and the

receiver), there weren't many signals left strong enough to receive.





I've had a couple R-390As. I used to leave them on 11175 upper with RF

gain low, carrier sliced off with 2 or 4 KC mechanical filter by

slightly tuning off center, BFO on about 1200 cycles. It was dead quiet

unless someone spoke, like dolby FM. It would stay perfectly tuned for

days, with the ovens off.



I can't afford electricity to waste on old radios.



Yeah, after all, your pal, Boy Barry, said that under his plan, electricity

costs would necessarily skyrocket.



You're both f00kin clown 'tards!

Back on that sauce again, Tonto?

On Thursday, July 11, 2013 12:41:11 PM UTC-4, dave wrote:
On 07/11/2013 09:38 AM, Michael Black wrote:

On Tue, 2 Jul 2013, dave wrote:





You forgot to turn on the BFO. BFO level is frequently too low for

demodding SSB hence the need to reduce RF gain.



No I didn't. It should be a given that you need the BFO. I was making

the point that it's one of those radios of the time that didn't have a

product detector, so you had to do what all the books said to do. A few

years later, most receivers did have product detectors. Indeed, the

GPR-90 came along right at the cusp, so you could get an external unit

that added a product detector (and I think some extra selectivity) and

some really fine tuning. The receiver has the an IF output jack on the

back, even has a jack for feeding audio back into the receiver (though

the TMC adapter had a built in audio amplifier). Other receivers had

similar units. The R388 and the R390 didn't have product detectors,

though they are considered some of the best receivers from the time (and

perhaps for all time).



But with that level of receiver, turning down RF gain wasn't a real

issue. I had no problem receiving SSB, even on six meters, on the SP-600

I had forty years ago.



ON the other hand, that Hallicrafters S-120A (the transistorized model)

that I got in the summer of 1971 had a horribly weak BFO, so by the time

I'd attenuated the incoming signal (a pot between the antenna and the

receiver), there weren't many signals left strong enough to receive.





I've had a couple R-390As. I used to leave them on 11175 upper with RF

gain low, carrier sliced off with 2 or 4 KC mechanical filter by

slightly tuning off center, BFO on about 1200 cycles. It was dead quiet

unless someone spoke, like dolby FM. It would stay perfectly tuned for

days, with the ovens off.



I can't afford electricity to waste on old radios.

My R-390(not A)got drowned in seawater last year, during the storm called Sandy . Now I don't know what to do with it...

On Fri, 12 Jul 2013, wrote:


My R-390(not A)got drowned in seawater last year, during
the storm called Sandy . Now I don't know what to do with it...

It's kind of late now. You should have carefuly rinsed it out at the
time, getting into all the crevices, then let it dry carefully, usually by
putting it in the oven at a very low temperature for some hours.

Every so often the ham magazines would run articles about what to do with
equipment that fell into even salt water. I think Glen Zook did a piece in
CQ in the early seventies, that did deal with something as complicated as
the R390.

I once dragged home a stereo receiver that I found in a bank of snow, it
was suffering from some minor salt damage due to salt used for melting
ice. I rinsed it carefully and then popped it in the oven, and that got
rid of the salt, it ran for years.

Michael

On 07/12/2013 04:53 AM, Michael Black wrote:
On Fri, 12 Jul 2013, wrote:


My R-390(not A)got drowned in seawater last year, during the storm
called Sandy . Now I don't know what to do with it...

It's kind of late now. You should have carefuly rinsed it out at the
time, getting into all the crevices, then let it dry carefully, usually
by putting it in the oven at a very low temperature for some hours.

Every so often the ham magazines would run articles about what to do
with equipment that fell into even salt water. I think Glen Zook did a
piece in CQ in the early seventies, that did deal with something as
complicated as the R390.

I once dragged home a stereo receiver that I found in a bank of snow, it
was suffering from some minor salt damage due to salt used for melting
ice. I rinsed it carefully and then popped it in the oven, and that got
rid of the salt, it ran for years.

Michael

I'd like to see the oven an R-390A will fit in...

Run it with filaments only, for a couple days, if you need artificial
heat. Don't turn off "Standby" until you are sure it is dry. Use a dim
bulb tester to prevent damaging current surge. Stay alert.

On 07/12/2013 12:42 AM, wrote:
On Thursday, July 11, 2013 12:41:11 PM UTC-4, dave wrote:


I can't afford electricity to waste on old radios.

My R-390(not A)got drowned in seawater last year, during the storm called Sandy . Now I don't know what to do with it...


Wash it out really good with fresh water, then blow it out with your
leaf blower. Let it bake in the sun.

The K3 is a better radio and uses a Watt or two on receive (0.77 Amperes
at 14VDC actually). It satisfies my high performance Jones, without
dominating my life. I really like the way the 51J3 looks.