[time-nuts] Remote GPS Oscillator Steering

Chris Albertson albertson.chris at gmail.com
Thu Apr 18 13:22:37 EDT 2013


On Thu, Apr 18, 2013 at 4:23 AM, Iain Young <iain at g7iii.net> wrote:

>
> Oh I know it can handle it, I was trying to avoid a nice 10MHz signal
> on an unshielded conductor smack on the Amateur Radio 30m band :) It's
> more RF here than Time/Frequency, and if I can avoid clashes, so much
> the better...


A transformer coupled signal is going to be well balanced and not radiate.
 You don't need more than a few millivolts

If you are worried about a 10Mhz sine wave, then you need to be very much
more worried about what Ethernet does.  Those sharp edged pulses have
harmonics all other the RF spectrum.  But no problem because they are
transformer couple and the wire is very tightly twisted.    Why not try an
experiment?  Place an RF transformer in a diecast box and make and a 50 ohm
load in a second box.  Connect the boxes with 100 feet of cable.  Put 1 mW
of 10MHz into the  transformer and then measure leakage from the mid span
of the cable.  Turn up the power until either you can detect some or the
transformer fails.   The trick is to use good quality transformers on each
end so the signal really is well balanced.   I salvage the transformers for
old Ethernet cards.

-- 

Chris Albertson
Redondo Beach, California


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