Standard RX design?

[gareth]

At the GQRP rally in Sherborne, Dorset, I picked up the chassis for a valved
radio
for the princely sum of £10, intending to raid it for its component parts,
especially
the dial drive and the s-meter.

However, on close inspection back in the shack it seems too good to be
a breakdown unit, and the reason for my enquiry is to determne whether it
is an example of a standard home brew design published some time in the
past?

It appears to be an 80m RX with a 455kHz IF, with a half-lattice Xtal
filter,
together with an Xtal controlled converter to cover the (pre-WARC) HF
bands.

So any clues anyone?

It is so well made, in terms of the accuracy of drilling apparent in the
aluminium
(aluminum for the Yanks) chassis that whoever did make it, I feel that I'd
be
treading on his grave by disassembling it.

It is about 40 years old from the Mullard "piece of toffee" polyester
capacitors in it.

[Michael Black]

Post by gareth
At the GQRP rally in Sherborne, Dorset, I picked up the chassis for a
valved radio for the princely sum of ?10, intending to raid it for its
component parts, especially the dial drive and the s-meter.
However, on close inspection back in the shack it seems too good to be
a breakdown unit, and the reason for my enquiry is to determne whether it
is an example of a standard home brew design published some time in the
past?
It appears to be an 80m RX with a 455kHz IF, with a half-lattice Xtal
filter, together with an Xtal controlled converter to cover the
(pre-WARC) HF bands.
So any clues anyone?
It is so well made, in terms of the accuracy of drilling apparent in the
aluminium (aluminum for the Yanks) chassis that whoever did make it, I
feel that I'd be treading on his grave by disassembling it.
It is about 40 years old from the Mullard "piece of toffee" polyester
capacitors in it.

That's not that good a description, it could be anything from a
construction project in one of the magazines, or something someone picked
and choosed from other circuits.

It doesn't even seem that distinctive to location, it just as easily
sounds like something out of QST as something from the UK. A good builder
makes substitutions, so having a Mullard capacitor in there doesn't have
to reflect some specific article in a magazine.

There was a whole period when many a receiver in QST was in the form of a
single conversion receiver tuning one band, with a converter ahead of it.
I'm not sure if that was common in the UK or not. It went on quite a
while, though in 1971 the receiver in the ARRL Handbook tuned 10metres,
with an upconverter for the lower bands. Useful for adding VHF converters
because of the wider band, but it helped that they converte 28MHz down to
a 9MHz IF where there was a KVG filter.

What's the IF frequency? If it's not 455KHz, then that might be some
lead. There were some construction articles that used higher IFs, but not
that common (and once commercial crystal filters became available, that
sort of thing tended to disappear, until everyone started building ladder
filters).

Michael

[gareth]

Post by Michael Black

Post by gareth
It appears to be an 80m RX with a 455kHz IF, with a half-lattice Xtal
filter,

What's the IF frequency?

[Michael Black]

Post by Michael Black

Post by gareth
It appears to be an 80m RX with a 455kHz IF, with a half-lattice Xtal
filter,

What's the IF frequency?

I did see that, I guess I was attaching the "it appears" to the IF
frequency.

Michael