"COLIN LAMB" wrote in message
nk.net...
The PRO-310 is a gorgeous receiver. Unfortunately, it has
a case built inside a case and is very difficult to work
on. On the broadcast band, it is single conversion, which
presents a problem for images.

There were two different color models and they were too
expensive to manufacture. They are certainly collector's
items.

Colin K7FM
Well, lots of receivers are single conversion on the
broadcast band and do not have image problems. It seems to
me that the PRO-310 did have some problems, something to do
with the gain structure I think. It got fixed but they were
simply too expensive to compete at the time. For about the
same price one could buy a 75A4, which is arguably a better
ham receiver and could buy RX such as the GPR-90 for less
money.
It would be interesting to know the story behind the
PRO-310, it was beautiful, worked well, but just missed the
mark.


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Richard Knoppow
Los Angeles, CA, USA




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Posted via a free Usenet account from http://www.teranews.com

It missed the mark in its day but today they're scarce and quite
collectible. I recall reading the review back in 56 when I was in high
school and have been after one ever since. this is the second one I've
ever seen. Kinda like if there was only one dandelion everyone would
like to have in their lawn.

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73
Hank WD5JFR

"Richard Knoppow" wrote in message
.. .

"COLIN LAMB" wrote in message
nk.net...
The PRO-310 is a gorgeous receiver. Unfortunately, it has a case
built inside a case and is very difficult to work on. On the
broadcast band, it is single conversion, which presents a problem for
images.

There were two different color models and they were too expensive to
manufacture. They are certainly collector's items.

Colin K7FM
Well, lots of receivers are single conversion on the broadcast band
and do not have image problems. It seems to me that the PRO-310 did
have some problems, something to do with the gain structure I think.
It got fixed but they were simply too expensive to compete at the
time. For about the same price one could buy a 75A4, which is arguably
a better ham receiver and could buy RX such as the GPR-90 for less
money.
It would be interesting to know the story behind the PRO-310, it was
beautiful, worked well, but just missed the mark.


--
---
Richard Knoppow
Los Angeles, CA, USA



--
Posted via a free Usenet account from http://www.teranews.com

"Well, lots of receivers are single conversion on the
broadcast band and do not have image problems."

Well, that is true, but what I left out was that the if is 50 kHz. It is
the only radio to my knowledge that runs 50 kHz ifs with single conversion.

The bandspread tuning is quite unique. There was supposed to be a run of
1,000 - but I bet less than 100 are still around. Maybe the other 900 are
still in a warehouse and will show up on the surplus market one of these
days - ha.

I have one.

Colin K7FM

"COLIN LAMB" wrote in message
ink.net...
"Well, lots of receivers are single conversion on the
broadcast band and do not have image problems."

Well, that is true, but what I left out was that the if is
50 kHz. It is the only radio to my knowledge that runs 50
kHz ifs with single conversion.

The bandspread tuning is quite unique. There was supposed
to be a run of 1,000 - but I bet less than 100 are still
around. Maybe the other 900 are still in a warehouse and
will show up on the surplus market one of these days - ha.

I have one.

Colin K7FM
50Khz, I will have to look at the schematics. I knew
there was a low frequency IF involved in order to get sharp
selectivity using conventional components. 50khz _would_ be
likely to have problems with images.


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Richard Knoppow
Los Angeles, CA, USA




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Posted via a free Usenet account from http://www.teranews.com

It is dual conversion at some point, but not the lowest band.

Colin K7FM

It's single conversion on the two lower bands below 2.2 Mc, IF is 52Kc
on those single conversion and 1802 Kc with double conversion on the 4
upper covering up to 35.53 Mc. Hey an expensive Q5er!

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73
Hank WD5JFR

"COLIN LAMB" wrote in message
ink.net...
It is dual conversion at some point, but not the lowest band.

Colin K7FM

"Henry Kolesnik" wrote in
message
et...
It's single conversion on the two lower bands below 2.2
Mc, IF is 52Kc on those single conversion and 1802 Kc
with double conversion on the 4 upper covering up to 35.53
Mc. Hey an expensive Q5er!

--

73
Hank WD5JFR

"COLIN LAMB" wrote in message
ink.net...
It is dual conversion at some point, but not the lowest
band.

Colin K7FM


It seems to me that Hallicrafters did the same thing with
a couple of their receivers. BTW, I _thought_ there was a
PRO-310 handbook on the web and that I had it. Evidently its
not so. I found some advertising and nothing more.


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Richard Knoppow
Los Angeles, CA, USA




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Posted via a free Usenet account from http://www.teranews.com