I've just picked up the 3.5MHz VFO (in a nice diecast ally box)
for which I etched the PCB and got working for the first time
in 1986 :-(

Otherwise, having spent too many months designing (AKA procrastinating)
my retro communications RX from the 1960s, time to pick up the reins again!

On Fri, 30 May 2014, gareth wrote:

I've just picked up the 3.5MHz VFO (in a nice diecast ally box)
for which I etched the PCB and got working for the first time
in 1986 :-(

Otherwise, having spent too many months designing (AKA procrastinating)
my retro communications RX from the 1960s, time to pick up the reins again!

That may be because the magazines often put an emphasis on "looking good",
so we pause while trying to figure out the details, rather than jump in
and then have a panel and chassis with endless holes from false starts.

Bill Hoisington, K1CLL wrote endlessly for "73" in the sixties and early
seventies, a lot of half-baked projects, but he was constantly trying
things. He didn't care about how it looked. It helped that most of his
work was done with copper circuit board, just as a surface to solder to,
or make shielding with, etc. We saw the same thing with Frank C. Jones,
every time a new device came out (bipolar, nuvistor, FET), he'd wire up a
bunch of VHF converters (one for each band) using the devices. And then
scrap them when the next new device came along. If a lot of effort is put
into looking good, not only will you take forever, but it will never match
state of the art, because by the time it's finished, something new will
come along.

Jim Kyle once had a very interesting receiver in "73", "the SJS receiver".
Used a low frequency Command set receiver (the one that had the 85KHz IF),
a converter between it and more converters. Built in two or three small
rack panels, there was lots of flexibility there. If he wanted to change
something, he didn't have to scrap it all.

The same could be done nowadays, especially with so much broadbanding.
Build a good IF stage, put it in a box. Then have the detector in a
second box, so you could try different things, including synchronous
detectors and "sideband slicers". Get a good mixer, follow it with any
needed amplifier, and a roofing filter, and put that in a box. You can
always come back and rearrange things. But, you can get that going on a
hamband with some simple VFO (in a separate box), working your way up to
something fancier when time, money or experience allows. SInce the mixer
is broadband, the filtering is separate, allowing for endless
experimentation, or multiple paths. Have a relatively simple filter for
all bands, then a much better front end filter for your favorite band, or
if you're using this with a VHF converter, a wideband passband type filter
would be best, so you don't need to returne it as you tune the VHF band.

With DC control of switching and levels, you don't have to arrange the
front panel to handle a fancy bandswitch that needs the wafers close to
the tuned circuits being switched. The volume and RF gain controls don't
have to be close to the circuitry if they are controlling DC, and you can
lay them out for where on the front panel you want them.

Michael

"Michael Black" wrote in message
xample.org...
On Fri, 30 May 2014, gareth wrote:

I've just picked up the 3.5MHz VFO (in a nice diecast ally box)
for which I etched the PCB and got working for the first time
in 1986 :-(

Otherwise, having spent too many months designing (AKA procrastinating)
my retro communications RX from the 1960s, time to pick up the reins
again!

That may be because the magazines often put an emphasis on "looking good",
so we pause while trying to figure out the details, rather than jump in
and then have a panel and chassis with endless holes from false starts.

rest of very interesting reply snipped

I think that could be (I know it is!) part of my problem; I am inspired by
the
Eddystone EA12 and want it to look like that.

Your comment about separate boxes is a good one, and from an experimental
point of view, I had considered making the RF preselector in a separate box,
so that it could be used as a station accessory for whatever RXs came later.