"Antonio Vernucci" ) writes:
I heard of a local guy who was using a Q-multiplier in conjunction with the
Mosley CM-1 receiver. It seems that Mosley never built Q-multipliers. so he
probably adapted a device of another manufacturer.

I searched Google, but I could not find any reference to which Q-multiplier
would be suitable for the CM-1.

Does anyone have experience with using a Q-multiplier with the CM-1, and knows
how it should be connected to the radio?

Thanks & 73

Tony I0JX.


There's nothing special about a Q-Multiplier. It's a single stage
regenerative amplifier added in parallel to the receiver's existing
IF, and as you turn up the regeneration the single coil that it
has gets quite selective (but, it's not a particularly sharp curve).

You'd attach it to the plate side of the mixer tube, and either power
it with it's own power supply or grab some power from the receiver. There'd
be an on/off control, and a regeneration control. Some got fancy,
and provided a notch function.

Assuming the Mosley uses a 455KHz IF, then pretty much any Q-Multiplier
will work. And the construction articles and manuals would all include
some general detail about attaching it to a receiver.

Most were based at 455KHz, because that's where most IFs were. And of
course, those receivers that had a lower IF were in less need of a bit
of oomph in the selectivity department, while except for things like
BC-348s with 910KHz IFs, any receiver with a higher IF would likely
not benefit from a Q-Multiplier (because the center frequency was
high enough that even with regeneration a single coil was too broad,
and also receivers with higher IFs tended to start with decent
crystal filters).

Michael VE2BVW

There's nothing special about a Q-Multiplier. It's a single stage
regenerative amplifier added in parallel to the receiver's existing
IF, and as you turn up the regeneration the single coil that it
has gets quite selective (but, it's not a particularly sharp curve).

You'd attach it to the plate side of the mixer tube, and either power
it with it's own power supply or grab some power from the receiver. There'd
be an on/off control, and a regeneration control. Some got fancy,
and provided a notch function.

Assuming the Mosley uses a 455KHz IF, then pretty much any Q-Multiplier
will work. And the construction articles and manuals would all include
some general detail about attaching it to a receiver.

Most were based at 455KHz, because that's where most IFs were. And of
course, those receivers that had a lower IF were in less need of a bit
of oomph in the selectivity department, while except for things like
BC-348s with 910KHz IFs, any receiver with a higher IF would likely
not benefit from a Q-Multiplier (because the center frequency was
high enough that even with regeneration a single coil was too broad,
and also receivers with higher IFs tended to start with decent
crystal filters).

I have a Q-multiplier both in my Drake 2B (external) and in my Hammarlund HQ-110
(internal).

Anyway when one connects an external Q-multiplier to a receiver, perhaps
something has to be changed. For instance the connection cable capacitance may
cause a non-recoverable detuning of the IF transformer, or other problems. That
is why I was looking for someone who had a direct experience in connecting an
external Q-multiplier just on the CM-1, to know whether he had any problem with
that.

73

Tony I0JX