pa2a.org


Share Thread:  
The fence wire as a telephone line
#1
Field telephones has already been discussed in another thread. This thread has focus on the connections between the phones.

The field telephone thread is here: http://www.pa2a.org/thread-field-phones-use-diagnosis?

Especially in dry areas this has been a tradition to do. What is needed for a usable telephone connection between e.g. to field (or other hand crank-) -telephones?

An electric connection made as a wire isolated from ground, and ground as return, or even better 2 wires, end even better, 2 wires twisted with some revolutions, the more, the better. (They used one revolution pr 4 poles in the old days, we use the same pr fraction of an inch today to carry data on the line) The to wires need to not have contact to each other.

What is a reasonable resistance in the loop? Hard to tell but a pair of awg # 20 will give a nice and stable connection for at least 10 miles.

Back to the fence wire. The steel wire used in a fence works well for pretty long distances, as long as the wooden poles are dry. If you want it to work well in rain, you have to put it on insulators, as one for electric fences, the neck of a bottle or other kinds glass or plastic doing that job. Just remember the sun might be tough to some kinds of plastics.

Now you have one wire from A to B, and you may use the grounds current carrying capacity as the other wire. This has some drawbacks, as high resistance, you may get noise from other things sending current trough ground, and in some cases it is possible to tap your signal. (not likely, but possible).

What makes a good ground connection? Metallic structures going in to the ground, as all kinds of metal pipes. A metal rod driven into moist soil. The army used metal rods in the latrine for easy connections. Your fantasy is the limit, but be careful with the grounding of the mains.

dsk
dsk, proud to be a member of pa2a.org since Feb 2016.
Reply
#2
The next is you do not only have it from A to B .. You may connect many telephones in parallel on the same line. Here are field telephones of the older types not as suitable as the newer ones, because of the way they are designed. Old civilian hand crank telephones are better, or TA-43 or later among field telephones copes well with e.g. 6 phones on the same line.
You just have to have a system of ring signals, a number of short and long rings, as in the Morse alphabet. And you need a ring off signal to clarify the end of conversation, usually a long ring.


dsk
dsk, proud to be a member of pa2a.org since Feb 2016.
Reply
#3
This is getting me curious as to what we could do with our newfangled polypropylene and stainless steel woven fence rope and tape. (Lots of people are getting rid of the high-tensile steel around horses.)
gascolator, proud to be a member of pa2a.org since Nov 2012.
Reply
#4
That is an important issue, any wire usable for an an electric fence will do for a limited distance, The better insulated and the higher current carrying capacity, the better. Never tested those new products.

dsk
dsk, proud to be a member of pa2a.org since Feb 2016.
Reply
#5
I think you just answered my question. PolyRope and especially PolyTape wires are quite fine, perhaps on the order of #64. Great for high voltage, but any appreciable current is going to fry them. Then you have neither fence nor phone.

Probably could develop a high-voltage/low-current variant that would work, but the cost would exceed that of a set of BaoFeng radios.
gascolator, proud to be a member of pa2a.org since Nov 2012.
Reply
#6
gascolator;173479 Wrote:I think you just answered my question. PolyRope and especially PolyTape wires are quite fine, perhaps on the order of #64. Great for high voltage, but any appreciable current is going to fry them. Then you have neither fence nor phone.

Probably could develop a high-voltage/low-current variant that would work, but the cost would exceed that of a set of BaoFeng radios.

You hit it in the center Wink A lo-cost electric fiber rope ha a resistance of approx 2.15 ohms pr meter (=yd) equals a copper wire of AWG #38 A triple galvanized steel wire ø=2.5mm has 0.3 ohms pr meter or equals a copper wire of AWG #20

Still it is hope DeLaval BW Polyband BW40 has a resistance of has 0.08 ohms pr m equals awg #24, this should do the job for quite a distance.

I had to look this up, and it seems like they recommend steel wire for fixed fences, and the other stuff where the fences are of more temporarily character. But of course a good salesman sells what he want, and it is definitely quite a job to make a good fence.
dsk, proud to be a member of pa2a.org since Feb 2016.
Reply
#7
dsk;173481 Wrote:
gascolator;173479 Wrote:I think you just answered my question. PolyRope and especially PolyTape wires are quite fine, perhaps on the order of #64. Great for high voltage, but any appreciable current is going to fry them. Then you have neither fence nor phone.

Probably could develop a high-voltage/low-current variant that would work, but the cost would exceed that of a set of BaoFeng radios.

You hit it in the center Wink A lo-cost electric fiber rope ha a resistance of approx 2.15 ohms pr meter (=yd) equals a copper wire of AWG #38 A triple galvanized steel wire ø=2.5mm has 0.3 ohms pr meter or equals a copper wire of AWG #20

Still it is hope DeLaval BW Polyband BW40 has a resistance of has 0.08 ohms pr m equals awg #24, this should do the job for quite a distance.

I had to look this up, and it seems like they recommend steel wire for fixed fences, and the other stuff where the fences are of more temporarily character. But of course a good salesman sells what he want, and it is definitely quite a job to make a good fence.

We don't use much of the fine, cheap, stuff. Mostly the 1/4", and the tape for gates. Works great. Even at the end of a 2000' run, with only a single ground-stake, the smallest Zareba solar charger has it kicking between 2000-3000 volts, depending upon how damp the soil is and how good my ugly, long, knots are.
gascolator, proud to be a member of pa2a.org since Nov 2012.
Reply
#8
I'll guess it will work fine as a phone line at 2000'
Of-course not at the same time as the fence generator is working.
When having a field telephone in each end, and a good ground return the current will be at maximum when ringing, you may reach 10 millamps (0.01 amp) at the most, so that will be no problem.

By experience, horses who knows it as an electric fence, will not try again, so you may have it un-powered for days.
Cattle or pigs are tougher (or more stupid?) those fences needs to have more juice, always.

I guess that's a commonly known experience.

dsk
dsk, proud to be a member of pa2a.org since Feb 2016.
Reply






Possibly Related Threads...
Thread Author Replies Views Last Post
  Interested in a German wwii field telephone? dsk 1 385 10-22-2017, 04:11 PM
Last Post: dsk
  An old rotary telephone as a field telephone? dsk 1 414 03-13-2016, 11:09 AM
Last Post: dsk



Users browsing this thread: 1 Guest(s)

Software by MyBB, © 2002-2015 MyBB Group.
Template by Modogodo Design.