[time-nuts] Dead 5065A - Some comments - Some questions... (III)

[paul swed]

Magnus agree on the bandwidth tripling. I thought the A3 generated 90 MHz.
I was thinking the PLL at 90 MHz with a small power amplifier to drive the
multiplier.
I did see the pictures of the modernized A3 so thats a great answer.
Ultimately my concern has been the SRD multiplier. There is some real magic
going on in that unit as has been mentioned on time-nuts. If the diode goes
there are no replacements accept for another unit.
Regards
Paul.

On Thu, Aug 27, 2020 at 8:19 AM Magnus Danielson <magnus at rubidium.se> wrote:

> Hi Paul,
>
> On 2020-08-26 17:11, paul swed wrote:
> > Ulf I was thinking the 137 Hz was injected differently. But yes its a
> > varicap on the 5 Mhz signal. Still that same effect can be accomplished
> in
> > the PLL feedback loop. I would simply go try these things but can not
> hack
> > my one and only 5065. Its working just fine.
> Arn't you curious about making it work finer? :)
> > A question
> > The 137 is injected at 5Mhz isn't it multiplied to a FM swing of 2466 Hz
> at
> > 90 MHz? Granted close in sidebands would still contain 137 Hz.
>
> No, the modulation frequency would still be the same, but the modulation
> width scale up as the carrier scales up. Thus, the frequency deviation
> scales up.
>
> As you are a ham, I will make you recall the old days. In the old days
> as people aimed to reach the 70 cm band, they used their 2 m equipment
> and trippled the frequency. This makes the 144 MHz go to 432 MHz, the 25
> kHz deviation go to 75 kHz deviation and the modulated voice stays the
> same pitch as it had on 144 MHz and does not pitch up about 1.5 octaves.
>
> Cheers,
> Magnus
>
>
>
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