If it is still felt in some quarters taht the future of amateur radio
lies in sweeping youngsters in off the streets, then a reversion
to AM would do the trick, so that they can listen in with simple equipment.

"gareth" wrote in message
...
If it is still felt in some quarters taht the future of amateur radio
lies in sweeping youngsters in off the streets, then a reversion
to AM would do the trick, so that they can listen in with simple
equipment.



worked for me in '66....

On Wed, 20 Jan 2016, gareth wrote:

If it is still felt in some quarters taht the future of amateur radio
lies in sweeping youngsters in off the streets, then a reversion
to AM would do the trick, so that they can listen in with simple equipment.

But a lot of not expensive digitally tuned portable shortwave radios can
receive SSB and CW well.

I paid close to a hundred dollars in the summer of 1971 for a
Hallicrafters S-120A (it was the transistorized model), the cheapest
shortwave receiver I could get locally. It was awful, lots of backlash on
the tuning, not that it mattered since the ham bands were tiny places on
the dial and calibration pretty much didn't exist. It overloaded badly
from tv and FM stations, and putting a filter ahead likely wouldn't help
since the receiver wasn't particularly shielded.

And it didn't receive SSB. So yes, I could tune in the few ham using AM,
I think they are still there since some of them were young at the time.

ONly with time did I come to realize that the BFO was too weak compare to
the incoming signal, so I added a potentiometer betweent he antenna and
the receiver to act as an attenuator. Then I could receive SSB, it's no
wonder I'd previously described SSB as "being distorted". But by the time
the signals were weak enough for the BFO to work, relativley few signals
got through.

When I got a Grundig YB-400 a few years back, it was about the same price
(and I got a free windup radio as a bonus), and it does receive SSB fine.
The dial is a whole lot better too, as is selectivity.

That Grundig, despite being a far better receiver, cost a whole lot less
than that Hallicrafters. Money is easier to come by now.

Regen receivers can apparently receive SSB (I use "apparently" sicne I've
never tried it, but when they go into oscillate, it's about the same as a
direct conversion receiver).

One could build a direct conversion receiver, indeed in the late sixties
and early seventies, those took over from regens (and even simple
superhets) for the beginner.

A simple superhet is probably easier to build now than in the past.
Ladder filters have taken a significant role in homebrewing, and thus a
decent filter is much cheaper than if you had to buy a KVG filter forty
years ago. Having a crystal filter in the HF range means image rejection
is so much easier You have to fuss about making the VFO stable.

The one advantage of AM is that it may be easier to build a low power AM
transmitter than an SSB transmitter, though now that everyone wants a VFO,
it may not. But you don't need the conversions if you build an AM
transmitter like they used to be built. On the other hand, that's when
DSB with a suppressed carrier stepped in. Most of the ease of AM, but no
carrier. Since everyone has an SSB receiver, the fact that two sidebands
are sent doesn't mean a thing, the extra one is stripped off in the
receiver. Not efficient use of the spectrum, but it does get a
transmitter going fast.

Of course, here in Canada none of this is relevant, since the entry level
license doesn't allow for building of transmitters.

Michael

"Michael Black" wrote in message
news:alpine.LNX.2.02.1601201350360.31828@darkstar. example.org...
The one advantage of AM is that it may be easier to build a low power AM
transmitter than an SSB transmitter, though now that everyone wants a VFO,
it may not.

Sorry, don't follow that logic!
On the other hand, that's when DSB with a suppressed carrier stepped in.

Actually, most of those who TX DSBSC do NOT have the appropriate
means of receiving it, for, unless you cheat by chopping off one of the
sidebands
(not to be confused with sidetone, STC) you need a injection oscillator
tightly phase locked to the original carrier, for a 90 degrees phase error
will result
in a received signal strength of zero!

In rec.radio.amateur.equipment gareth wrote:
If it is still felt in some quarters taht the future of amateur radio
lies in sweeping youngsters in off the streets, then a reversion
to AM would do the trick, so that they can listen in with simple equipment.

The future is certainly not in overweight, geriatric men.


--
Jim Pennino

"gareth" wrote in message
...
"Michael Black" wrote in message
news:alpine.LNX.2.02.1601201350360.31828@darkstar. example.org...
The one advantage of AM is that it may be easier to build a low power AM
transmitter than an SSB transmitter, though now that everyone wants a
VFO, it may not.

Sorry, don't follow that logic!
On the other hand, that's when DSB with a suppressed carrier stepped in.

Actually, most of those who TX DSBSC do NOT have the appropriate
means of receiving it, for, unless you cheat by chopping off one of the
sidebands
(not to be confused with sidetone, STC) you need a injection oscillator
tightly phase locked to the original carrier, for a 90 degrees phase error
will result
in a received signal strength of zero!



Oops, phrased that badly, for it has nowt to do with the received signal
strength, but
the demodulated audio will disappear.

On Wed, 20 Jan 2016, gareth wrote:

"Michael Black" wrote in message
news:alpine.LNX.2.02.1601201350360.31828@darkstar. example.org...
The one advantage of AM is that it may be easier to build a low power AM
transmitter than an SSB transmitter, though now that everyone wants a VFO,
it may not.

Sorry, don't follow that logic!

In the old days, you'd run a VFO at 80 or 40metres, and multiply up, all
the HF bands being 3.5MHz. But that multiplied the drift of the VFO, and
for each higher band, the segment of the dial that covered that band got
smaller the higher up you got. And with the WARC bands, you need other
frequencies.

If multiplying the VFO is no longer so great, then heterodyning the VFO is
the way to go, and once you have that, adding a balanced modulator and a
filter to get SSB is only incrementally more difficult.



On the other hand, that's when DSB with a suppressed carrier stepped in.

Actually, most of those who TX DSBSC do NOT have the appropriate
means of receiving it, for, unless you cheat by chopping off one of the
sidebands
(not to be confused with sidetone, STC) you need a injection oscillator
tightly phase locked to the original carrier, for a 90 degrees phase error
will result
in a received signal strength of zero!

I dont' see that. Receivers are so much better now, it may be finicky
about tuning but you should be able to knock the unwanted sideband off the
side of the filter.

That was exactly how it was done in the fifties and sixties when DSBsc got
a lot of promition, often by the modification of an AM transmitter so the
output stage became a high level balanced modulator. Most people would
never know you were sending DSBsc unless you told them, since SSB
receivers had become increasingly the norm, so they thought it was just
another SSB signal.

Synchronous detection was described in "CQ" about 1957, I think it wsa
someone from GE who wrote the article, and while some built them through
the years, they were never common. It wasn't until the Sony 2010 came
along in the eighties that synchronous detection became a 'big thing".

Long before phase comes into play, if you don't have the carrier in the
right place between sidebands, you really can't understand what's going
on, since if the BFO is in the wrong place, each sideband is translated to
a different spot in audio. So they clash with each other. That's why one
can live with a mistuned BFO on SSB, it simply sounds low or high pitched.

Michael

On 20/01/2016 15:42, gareth wrote:

If it is still felt in some quarters taht the future of amateur
radio lies in sweeping youngsters in off the streets, then a
reversion to AM would do the trick, so that they can listen in with
simple equipment.

DSB, easy peasy.



--
Extend ****s law - make 'em wear a cheat sheet 24/7

"Fred Roberts" wrote in message
...
On 20/01/2016 15:42, gareth wrote:

If it is still felt in some quarters taht the future of amateur
radio lies in sweeping youngsters in off the streets, then a
reversion to AM would do the trick, so that they can listen in with
simple equipment.

DSB, easy peasy.


No good - no carrier