Ward Rehkopf wrote:
Have just purchased a Mackay 3010C - need replacement tuning strip or
directions on how to make one. snip

Hi,
Congratulations on the 3010C. Sorry, I can't help on the tuning strip,
I think they are made of unobtainium. It's like a woven fiberglass,
with sprocket holes on one side, with the frequency calibration
printed on it. It is back lit, so you can read the frequency.
The tuning strip unspools from one roll, and is taken up
on another roll, like an old style typewriter ribbon.
I understand the earliest 3010 tuning strips were film, like the Racal
RA-17 receiver.

One hint: when you get your 3010C and have it standing on its side
for access to the chassis bottom, you shouldn't turn
the main tuning knob.

Turning it can cause the tuning strip to ride off its sprockets,
and may have caused the original tuning strip to become damaged.
The damage is generally widened sprocket holes in the tuning strip,
which leads to dial backlash.

There is some dial backlash even with a good tuning strip,
so you "fine tune" SSB with the variable BFO.
The tuning rate is about 100kc per revolution.

Another hint: I was unhappy with the sound of the SSB audio
on mine, a muffled Donald Duck sound accompanied the audio.
C.W. signals didn't sound crisp, either.
I noticed that if I backed off the IF gain, the audio cleared up.
It turned out to be 455kc IF energy getting to the audio preamp,
fixed by adding a disc capacitor from grid
to cathode of the audio preamp.

Another hint: the 3010C uses the same type of mechanical filters
as the Collins 75A-4. It came with a 3.1kc filter installed,
and an empty socket where a 500Hz c.w. filter could be added.
Even with no mechanical filters installed, a 6kc wide
crystal filter is built in, and adds its skirt selectivity
to whatever mechanical filter is in use.

Another hint: if your VFO seems to jump about 18kc in calibration,
look at the 6U8A VFO premixer tube. A 6U8A crystal oscillator
caused the jump, only resolved by changing 6U8A tubes.
The bad 6U8A seemed to change from overtone oscillation to fundamental
mode oscillation whenever it wanted to.

The 3010C has an unusual rf amplifier tube, an Amperex 7788
very high transconductance pentode. They are expensive,
sought after by vacuum tube audio men.

QST reviewed the 3010 receiver in April 1967.
Electric Radio magazine reviewed it in Feb 1997.

Mackay Marine was a division of ITT.

73,
Ed Knobloch