07-03-2020, 05:25 PM
You guys hit with the capacitance on the strap.
I've been through several windings on the osc.
and det. coils to experiment, and could struggle
to get a 'decent' sound, it was unstable, esp.
volume wise. I went with 32g on the oscillator
last night, still something not right. This morning
I removed the air cap and switched the osc. connection
to the other side with the brass washer, and then screwed
the strap back with the insulated washer.
A real pain. All back together and what a difference,
everything changed, sound much smoother, can hear exactly
what the trimmers are doing and can push up the
volume with stability. Still don't know what hooking up
the other way was doing, but the chassis hole lines up
with the right side screw, should have been a clue.
Probably all my windings would have been acceptable, a forgiving radio,
just find the IF you end up with. I used plain old
Pen Gear Matte Finish invisible (scotch) tape wrapped
to the thickness of the original celluloid with 32G wrap
on top for the RF osc. coupling. Is it heterodyning the original way, no, but acceptable.
It does a strange thing, after around 5 minutes of playing is suddenly dies, and have to tune several KHZ down
to get it back, and the sound is not quite as loud and good, maybe a tube, the 27 is getting weak. It's a fun twiddle machine.
I've been through several windings on the osc.
and det. coils to experiment, and could struggle
to get a 'decent' sound, it was unstable, esp.
volume wise. I went with 32g on the oscillator
last night, still something not right. This morning
I removed the air cap and switched the osc. connection
to the other side with the brass washer, and then screwed
the strap back with the insulated washer.
A real pain. All back together and what a difference,
everything changed, sound much smoother, can hear exactly
what the trimmers are doing and can push up the
volume with stability. Still don't know what hooking up
the other way was doing, but the chassis hole lines up
with the right side screw, should have been a clue.
Probably all my windings would have been acceptable, a forgiving radio,
just find the IF you end up with. I used plain old
Pen Gear Matte Finish invisible (scotch) tape wrapped
to the thickness of the original celluloid with 32G wrap
on top for the RF osc. coupling. Is it heterodyning the original way, no, but acceptable.
It does a strange thing, after around 5 minutes of playing is suddenly dies, and have to tune several KHZ down
to get it back, and the sound is not quite as loud and good, maybe a tube, the 27 is getting weak. It's a fun twiddle machine.
