SR ) writes:
I notice something interesting about this radio. Their are terminal for
6 meters. Throughout the last 10 years when I had scanned the 6 meters
on my scanner, I do not think I had never picked up any hams. (BTW I am
in the New York City area) Yes it is a very short band and it might be
more related to 2 meters, I would think.

So why would Hammarlund go through the effort to add terminals on the
rear of this radio. My only guess is that at the time hams were using
the 6 meters a lot more.

Also, this radio does not seem to pick up much on the 21-21.6 and 28-30
bands.

Different bands have different propagation. The lower bands are lousy in
the day time, and great at night. The higher bands reverse the process.
But also, as the frequency increases the more sporadic the good propagation.
So ten meters, 28-29.7MHz, will be fairly dead much of the time, until
good propagation comes along. The same with 15Meters, 21MHz, though to a
lesser extent, and the moreso on six meters. When conditions are good, then
they can be really good.

If a band is not being used much locally, then you won't hear anything
until conditions are good. And you have to listen quite a bit to hit
the good times. It's like good DX on the FM broadcast band (though since
it's even higher in frequency than 50MHz, it's even less common); when it
happens you can hear stations so far away, but it comes suddenly and
disappears as fast. If you weren't listening to the radio at that time,
and listening to a non-local station, then you might never know that
anything had happened.

Even up to forty years ago, six meters was often the band of choice
for those who used VHF. There was the US Technician license that only
allowed for operation at 50MHz and up (and here in Canada, you could only
use voice with the basic license at 50MHz and up). Since 50MHz was the
lowest band useable by the Technician class licenses, they tended to use it.
Because as uncommon as good propagation was, it was more common than at
2meters. And when conditions were good, you could work fairly good
distances, and with relatively little equipment. Plus, there was a lot of
simple and low power commercial gear manufactured for the band, so the band
did tend to be used for local use. Ironically, when a band is in regular
use it means people are more likely to notice the good propagation, because
they are there already.

So it made a lot of sense to add the 6meter band to a ham-band only receiver.
If nothing else, it was a feature one could boast about over the other
receivers didn't cover the band. People could buy the receiver, and not
need a converter to receive six meters. They could then build or buy a small
and cheap transmitter, and be on the air.

Another good reason for adding is is that the HF ham bands are relatively
small, with the largest of the bunch being the not quite 2MHz of the 10meter
band. All the VHF and UHF bands are larger. The common way to receive
higher bands was to build or buy a converter that translated those
higher bands down to a frequency range your receiver could tune. But with
an HF-only ham band receiver, the biggest slice was about 2MHz. Adding
six meters provided a 4MHz band, which was better, and that provided a band
that did have a wider range. So adding the band gave some VHF coverage,
and set the stage for the reception of higher bands.

I have a reprint copy of the manual. I was reading the part of the SEND
RECEIVE CAL button. And somehow this has something to do with something
called BREAK-IN RELAY. (There is a relay female chassis connector at
the rear.)

Because of this can this radio make some kind of transmission?

No.
Since it's a ham band only receiver, pretty much everyone using it
would be pairing it with a transmitter. The switch was there to
manipulate the receiver so it wouldn't be bothered by the nearby
transmitter, and included a means of controlling the transmitter, in
one simple switch. If the receiver didn't include it, you'd need
a separate switch to take care of switching between receive and
transmit.

Michael