On Mar 5, 3:09�pm, Dave Heil wrote:
wrote:
On Mar 3, 8:23pm, Dave Heil wrote:
I find it impressive that Hallicrafters made so many different
receiver models in so few years (say, 1945-1960).

Loads and loads. �Most were variations on a common theme
with styling
changes though octal tubes might have been replaced by loctals or miniat
ure 7 or 9 pin types.

Hallicrafters never went for loctals in a big way; they were used only
where there was no other choice at the time. Your variations-on-a-
theme idea is correct; notice how similar the SX-42 and SX-62 are on
the inside.


The 'A-4 was the best of the period. �The models with the Collins
vernier tuning knob were the best of the best.

IMHO Collins made a design mistake by putting such a fast tuning rate
(100 kc. per knob turn) on the 75A-4. The reduction knob fixed that.

A few years ago, a small company began manufacturing a reduction knob
for the 75A-4, machined out of solid brass. Functional and
attractive.

The 75A-4 is the first receiver I know of that included passband
tuning as a standard feature.

I think you're right. �My 75A-3 came with a Universal Service
(predecessor to today's Universal Radio) PTO mod which plugs
into the
NBFM socket. �The Collins winged emblem was removed, a hole
drilled in
the spot and a long 1/4" shaft from the PBT box ran through the
hole.
An engraved plate was mounted on the panel and the shaft was
fitted with a miniature knob.

How did it provide PBT? The 75A-4 PBT is entirely mechanical; it works
by rotating the PTO and the BFO controls simultaneously, but so that
their frequencies move in opposite directions. The linearity of both
oscillators is such that the received carrier frequency does not move.

�A mod for the AGC time constant was also added. �The
thing is nearly the equal to a 75A-4.

NICE!

That was
followed by the light gray, low profile styling of the KWM-2/2A and
S-Line in the late fifties.

Which changed the game completely.

Everybody began jumping on that band wagon. �
Heathkit came up with the
"poor man's S-Line"; Drake introduced the 1-A, 2-A and 2-B and
TR-3;
Swan introduced monoband and multiband transceivers;
Hallicrafters and
National also began producing smaller, lighter separates and
transceivers.

IIRC the 1-A predated the S-line and KWM-2. It was a revolutionary
design; small, light and compact at a time when even inexpensive
receivers were big and heavy. Note the tiny, taller-than-it-is-wide
front panel and the very deep chassis. The 1-A had passband tuning
too, but it was implemented by having a tunable LC filter at the last
IF. The 2-A and 2-B are excellent receivers for their price and
complexity, and are prized today. But they were a dead end in one way:
there was no matching transmitter that could transceive with them.

What the KWM-2 and S-line did was to make "transceiving" popular.

The KWM-1 and a few other rigs like the legendary Cosmophone (the
first true full-featured HF amateur transceiver) had been the first
manufactured amateur HF rigs to use the same tunable oscillator to
control both the transmitter and receiver, but they did not achieve
wide popularity.

Indeed, a homebrew 40 meter *CW* transceiver built around a surplus
BC-453 was described in a 1954 QST, probably the first published use
of the idea in amateur radio. It even had full QSK. But it was ahead
of its time.

The KWM-2 and S-line took transceiving to another level. Not only were
they smaller and lighter than their predecessors, they had relatively
few controls. They made SSB more popular with hams by reducing the
cost and size and eliminating the job of zerobeating the transmitter.
Tune an SSB station correctly and the transmitter was automatically on
the right frequency.

Add to this the grounded-grid linear amplifier and things really
changed. High power 'phone became not only less expensive but a lot
smaller and lighter. Transceivers and matched-pair separates became
the new paradigm in HF ham gear; AM wasn't part of that.

Compare the Heathkit line of 1964-65 with what they were selling just
5 years earlier for just one example.

IMHO what turned the tide were two now-classic HF rigs:
the Yaesu
FT-101 and the Kenwood TS-520.

I'd toss in the Yaesu tube-type rigs such as the
FTDX-560 and 570.

Well, sort of. They had QC problems and were really competition for
the likes of Swan, who did the same lots-of-watts-from-sweep-tubes
game.

They did offer extras but you should look at the TS-520's receiver
specs. �They're dismal. �

But you have to ask "compared to what?" Plus they were almost all
"solid state", which was a selling point even if performance suffered.


Consider the TS-520S, for example.
It did the usual 80-10 meter SSB
job pretty well. But it also gave a choice of AGC fast/slow/off, an
optional narrow CW filter that was pretty good, RIT/XIT,
160 meters
and WWV/JJY, fan-cooled finals, plus a built-in AC
power supply.

Yep. �It served pretty well as an everyman's rig and
would have been
much better if the receiver section had been better design.

Agreed, but for the time and price it was decent enough. Point is,
it opened the door.

�The
Japanese were not the only ones with this problem. �
Heath's early solid
state receiver, the HW-303 was an absolute clunker in this regard.

I think you mean the SB-303. And yes it was - very sensitive but at
the cost of dynamic range.

Hammarlund made one valiant effort to stave off the JA's with the
introduction of the solid state HQ-215. �I have one of those and
it is a
pretty darned good receiver. �It has an edgewise drum dial
with 1 KC
readout, has fixed, selectable USB/LSB and a variable BFO for
CW. �It
has a preselector in the front end, offers AUX band
positions and places
for three Collins mechanical filters. �The mixing scheme is the
same as
the S-Line and it has the same 200 KC band segments. �There are
input/output ports on the rear panel so that the receiver can be
slaved
to a 32S-whatever transmitter for transceive use. �I think it was
first
offered about 1967.

Correct on all counts. It was meant to be a solid-state 75S-3. But
never quite got there. Hallicrafters made the almost-all-solid-state
FPM-300 transceiver a few years later, too.

Its drum dial inspired the Southgate Type 4 (receiver) and Type 7
(transceiver) dials. But they use all-gear-drive.

It should be remembered that there were some colossal also-rans in
that period, too. B&W made their 6100 transmitter with its multiknob
mixing synthesizer, obviously inspired by commercial/military sets
like the R-1051. Stable but poorly adapted to amateur HF operation.

The legendary Squires Sanders SS-1R was poised to give Collins a good
run for the money, but without a matching transmitter, not many hams
were going to spend S-line-level dollars for it.

Some folks criticized amateurs for being "slow" to use solid-state HF
rigs, but there was a reason for caution. More than one early SS rig
had come to grief, like the Hallicrafters FPM-200 of the early 1960s
and the EF Johnson Avenger transceiver, of which only about a dozen
were made. Avenger was a decent rig but cost so much to make that EFJ
never produced more, knowing they wouldn't sell. EFJ never again made
an amateur HF transceiver, and was soon not making HF ham gear at all.

Central Electronics pioneered the no-tune transmitter (with all
tubes!) back in the late 1950s, and was poised to market a matching
receiver (the 100-R) which was reportedly as good or better than the
75S-3. But the company was bought for some patents and other contracts
and was soon out of the amateur market. The sole 100-R prototype
survives to this day.

OTOH, Southgate Radio is still building rigs after 40+ years...

Not just price but price/performance/features combo.
For example, try
to think of a US-made HF amateur transceiver that
had the following:

- 100 watt output class
- 6146 finals, not sweep tubes
- Sharp CW filter
- RIT/XIT
- AGC off/slow/fast

That's quite a number of preconditions.

Not really, IMHO, and they're pretty basic things, easily implemented
with 1960s technology.

�I don't think there were any.

Exactly.

The Heath SB-102 comes close. �

Not really. It doesn't have RIT/XIT, and you can't easily add it.
Can't turn off the AGC nor adjust its time constant either.

The Drake TR-4CW comes close (6JB6's).

Only if you get the model that had both RIT and the sharp filter,
which was only produced for a short time. Blink and you missed it.
Plus check the price of a TR4-CW with power supply and speaker. Ouch!

By comparison, the TS-520S had all of that and more, even if the rx
wasn't as good.

Digi-Key got its start about the same time as Ten Tec - 1968
or so.
Their name comes from the fact that the company got
started by selling
digital ICs (RTL!) in small quantities to hams so they could build
solid-state Morse Code keyers. Then they just kept
growing, 'but the
name stayed.

They've done phenomenally well. �Many of the old line distributors

are just plain gone.

Newark and Allied are still around.

Nor are they overly ornate. They are functional and
attractive just as they are.

Agreed. �I've often wondered if any of the modern gear will be
functional/repairable in forty or fifty years. �My guess is that i
t will
not.

I think it will be, but in different ways:

The first way will be the renovators, who make a few good rigs from a
pile of problem sets. This is already starting to happen; look on ebay
for "TS-940" and you will see lots of parts for sale.

The second way will be the rebuilders, who will make replacement PCBs
using parts available then. A much harder go at first, but given the
automation possibilities now, who knows what the future could do.

Look up the stuff made by
one of my Elmers, master homebrewer W2LYH.
(several QST articles).

I know a few guys who still operate the W6TC HBR series of
receivers that they or others constructed. �

There are folks still building HBRs today, from scratch.

But with all due respect to those designs, do check out W2LYH's
designs, such as the 23 tube receiver or the ultrastable Frankling
VFO. His construction is an art in itself; no ornamentation needed.

I often wonder what happened to his rig. I don't think I want to know.

I also of quite a number of quality
homebrew linear amps which are still put on the air on a regular
basis.

Yep. Also a number of SB-200s, SB-220s, L-4s and similar amps are
pounding out the watts today, often with upgrades and modernizations.

73 de Jim, N2EY