[ARC5] DF-ing.

[J. Forster]

On your last comment, a dual channel rexceiver would be needed as you say.

-John

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


> On 3 Jul 2013 at 9:42, J. Forster wrote:
>
>> OK. In fact, then, when properly nulled, the loop is in the worst
>> possible orientation for actually receiving the signal.
>
> Correct.
>
>> This is done
>> to make the servo problem easier, since the phase of the loop signal
>> reverses about 180 degrees as the loop turns through the null
>> position, and this can easily be turned into a servo error signal to
>> drive the loop to null.
>
> Again, correct.
>
>> Maybe, operationally, you don't need to actually hear the station you
>> are locked onto.
>
> Yes. Absolutely.
>
>> Use a peak-seeking servo. This is done by slightly dithering the
>> azimuth of the loop, and then using a phase sensative detector on the
>> output, with a reference 90 deg. shifted from the dither. This is
>> Pound Locking.
>>
>> Something like this was used in the conical scan of the SCR-584 RADAR.
>>
>> Another possible design would be a second loop at right angles, used
>> to actually receive the signal.
>
> Yes, and this was done quite early on. I cannot remember the military
> nomenclature of a unit I only recently read about that worked just exactly
> this
> way. As I remember it, the receiver used was unique in that it had two
> parallel RF/IF channels, one for each "loop" then combined them in the
> output. It used, as I remember it, a cross-needle "meter" for output
> indication.
>
> Ken W7EKB
>
>