Synchronize pocket-size devices

[Bill Overton]

I would like to synchronize the output frequency and phase
relationship of several _battery powered_ signal generators at remote
locations. There are no interconnecting wires or line-of-sight.

Is there any possible way to achieve this?

Bill Overton

 

[Paul Keinanen]

Sync to the AC line from ambient pickup?

The obvious problem is the +/-120 degree phase shift problem depending
of which phase you are picking up from the three phase network.

As far as I understand, the US does not have a synchronous AC network.
In continental Europe, most countries are in the UCTE synchronous
network, however, the ex. CIS IPS, the Scandinavian NORDEL and the UK
systems are not synchronous and are floating freely from each other.

Or use some available RF, like a TV station?

In countries, in which there still is an analog service, it would be
quite easy to lock into horizontal/vertical synch signal. An analog
satellite broadcaster would be interesting (if you find one). Perhaps
the best chance would be in the C-band (4 GHz).

WWV? GPS? How about one of those cheap WWVH
watches/clocks?

WWV in the US, Rugby (60 kHz) or Mayflingen (77.5 kHz) would be a good
source in Europe.

GPS would no doubt be the best solution.

Do your own RF transmitter/receivers?

Day/Night with photocells? That would be a slow loop.

If you program the equation of time into your device, you could use a
very narrow slit to let the sun rays into the photocell, when the sun
passes the meridian. Since the sun is about 0.5' wide, so it takes
about 2 minutes to pass a that wide slit, this will significantly
reduce the loop time constant required.

 

[Joerg]

In the old days TV sync of remote locations was obtained by phase comparing
at the studio, and sending a signal via the national FM radio stations,
the remote side detected that signal, the signal steered the remote oscillator until
phase lock was achieved in the studio (so they could use trick effects).
Of course, due to the propagation speed of EM waves, you can only synchronise
all oscillators in phase at ONE point.
Think about it.

Wasn't it here in the group? Someone posted a patent where the inventor
claimed to have made an RF path or some sort of wunder-antenna where the
path is faster than the speed of light, and it sailed past the examiners.

 

[Joerg]

I would like to synchronize the output frequency and phase
relationship of several _battery powered_ signal generators at remote
locations. There are no interconnecting wires or line-of-sight.

Is there any possible way to achieve this?

You'd have to put some numbers behind that. Output frequency in kHz or
MHz? How many miles is "remote"? How big a battery, battery runtime
requirements, etc.?

 

[Bill Overton]

Many thanks for the replies.

If I just needed to output audio frequencies from the remote devices,
I suppose I could use a CB base station or wireless PA to transmit a
continuous tone.

That would be an off-the-shelf solution.

For anything higher I could use a frequency multiplier.

How does that sound?

Bill Overton

 

[Martin Brown]

I would like to synchronize the output frequency and phase
relationship of several _battery powered_ signal generators at remote
locations. There are no interconnecting wires or line-of-sight.

Is there any possible way to achieve this?

Phase lock them to MSF Rugby, DCF77 or whatever other broadcast time
signal is available in your area. You might have to correct them for
geometrical distance from the transmitter depending on the accuracy you
require.

Regards,
Martin Brown