[TowerTalk] Fwd: The details of wiring a homebrew AZ/EL rotator
hanslg at aol.com
Sat Jan 25 22:14:43 EST 2014
If i understand it right: You use the shield as one conductor for your sensor, which need three wires. The only way, what I see, is that you make sure the sensor is NOT connected to anything, that is, the sensor is "floating" in relation to everything else in the rotator. You should left the shield connected only to the sensor. That will give the best isolation to the surrounding. You have to make sure that the "DC" controlling the motor does NOT contain a lot of signals generating EMI on your sensor signal. You may have to place two LP filter at the controller, cleaning up the DC, motor drive power.
A last advice: Place a shield around your sensor and connect the cable shield to that shield/screen. That should keep you UHF and VHF signals out.
Good luck and let us know how it worked out.
Best 73 de,
Hans - N2JFS
From: Lizeth Norman <normanlizeth at gmail.com>
To: Nate Bargmann <n0nb at n0nb.us>
Cc: towertalk <towertalk at contesting.com>
Sent: Sat, Jan 25, 2014 1:22 pm
Subject: Re: [TowerTalk] The details of wiring a homebrew AZ/EL rotator
The rotator is complely homebrew. Cables carry various DC signals. One
cable carries 2 motor poles (4 wires), the other carries a 3 wire sensor
set with ground and +5Vdc (total 5 wires)
On Sat, Jan 25, 2014 at 1:02 PM, Nate Bargmann <n0nb at n0nb.us> wrote:
> * On 2014 25 Jan 11:16 -0600, Lizeth Norman wrote:
> > I have double shielded 18Ga 4 twisted pair wire.
> > When I terminate the wire, what do I do with the braid shield. There will
> > be 40W UHF or 50W VHF max around, so the idea of protecting my sensor's
> > ttl) wiring is something I'm concerned about.
> Ordinarily I would think that grounding one end would be the correct
> thing to do. As I've not done what you're doing on a tower, I would
> consider bonding it to the tower ground at the bottom where it breaks
> away to the shack and not bond it to ground at either of the terminating
> ends. It seems that would drain off lightning static and any stray
> transmitted energy.
> Does the controller manufacturer offer any suggestions?
> 73, de Nate >>
> "The optimist proclaims that we live in the best of all
> possible worlds. The pessimist fears this is true."
> Ham radio, Linux, bikes, and more: http://www.n0nb.us
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