[ARC5] [MRCA] Vintage test equipment?

[Rob Flory]

I use a Navy-marked Measurements 80 signal generator which has a calibrated
output and variable attenuator.

RF

On Thu, Apr 10, 2014 at 10:09 AM, D. Platt <jeepp at comcast.net> wrote:

> In reviewing the alignment procedures and maintenance practices, etc. for
> the SCR-274-N and ARC-5 equipment, I'm curious what test equipment they
> (the military) had at the time and, in fact, used for the aforementioned?
> I know that the early scopes were present, although not "calibrated" as we
> know it today.  I also know the BC-221 and LM were readily available, of
> course.  Also, fairly accurate voltage measuring equipment, to include, I
> believe, VTVMs (which would provide high impedance measurements).  I
> suppose that the standard 20k/v multimeters would obviously have been
> available.  Finally, signal generators, too.  The thing is, accuracy and
> precision is my real question.  I don't think that the military had quite
> the PMEL functions available today.  How good were the test sets out in the
> field?  Boiling it all down, I read the procedure in the maintenance
> manuals for the above radio sets, in particular the receivers and their
> alignment and test.  *If I'm interpreting things correctly*, the
> procedure for measuring receiver bandwidth was one where, instead of
> setting up a reference on the desired frequency and moving a calibrated
> signal generator up and down or sweeping the bandpass, they (Navy and Army)
> used a method whereby the signal generator was set on frequency and the
> receiver was tuned above and below the set frequency (or was it the
> reverse?)  Anyway, by increasing the signal generator levels in discrete
> steps up to values representing from 6db (2x) to +60db (1000x) from the
> reference, the receiver (or generator?) was off-tuned until receiver output
> was seen to drop to the original set level.  Of course, the method does
> work, no question, and by using fairly accurate (and measurable at the
> time) high levels, the results could be considered good.
>
> Does this seem reasonable to all of you?  Again, other then the LM and the
> BC-221, what other "standard" RF and measurement test gear was in use from
> '42 thru '45?
>
> Inquiring minds ask.......
>
> Jeep K3HVG
>
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