[Boatanchors] Making Stable Inductors for 2 MHz

[J. Forster]

>
>
> This is an interesting problem.   One possibility that could get around
> some of the stability and keying issues (slow oscillator starting times,
> etc. ) would be to let the oscillator (or oscillators) run continuously,
> and send the output through a gating circuit that could be set to
> provide the appropriate 30 to 40 microsecond "on" times together with
> the needed "off" period for the demonstration signal.

The pulse needs to be shaped in amplitude. That gets more complicated.

> It would even be
> possible to combine the gates with zero-crossing detectors to provide
> "perfect" outputs, that is to say free from transients caused by
> starting or stopping at some arbitrary part of the waveform.

But, since the carrier and timing are not synced, such a scheme introduces
jitter.


>  This
> technique should work with either crystal controlled or free running
> oscillators.  If necessary, more than one gate "in series" could be used
> to ensure sufficient isolation, that is to say a 120 dB or better
> reduction from full output.    As I said, and interesting problem, the
> solution to which could provide several hours of entertainment with a
> prototyping board and a box-full of parts on the workshop bench.

Yes. I have a nice keyed Colpitts working already. My only concern
remainng is the long term inductor stability.

Best,

-John

=============

> And yes, I too remember the LORAN pulsing in and around the 160 meter
> band, and the joy I felt when I finally found a receiver that had a
> noise blanker good enough to make if go away.  The first instance came
> with a HQ-170 with the optional noise blanker, which  knocked the noise
> down from S9+40 db to maybe S3, which made it possible to carry on a
> QSO.  Later on, I got a Drake R-4C.  It's blanker made the LORAN just
> plain go away.  It was nothing short of amazing.
>
>
> - Jim, KL7CC
>
>
>
> Drew P. wrote:
>> John wrote:
>>
>> (snipped)
>>
>> "I'm working on a LORAN-A simulator for the DAS-1 on the MASSACHUSETTS
>> and
>> have a design question.
>>
>> (snip)
>>
>> 'm now looking at building a stable, keyed oscillator in the above
>> frequency range. My intention is to use a SS Hartley or Colpitts."
>>
>> (snip)