Need some general guidance... Need to communicate over about 30 miles of 19 awg wire pair. Will a pair of cheap butt sets do this. If so, are there any recommendations or pit falls. Radio isn't an option as both facilities are below ground.

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Mark

Just having butt sets won't allow you to talk, you need talk battery. You could put in a cheap used system that would allow you to call back and forth, Viking also makes various devices that may work also. Although I don't know your specific application, how do you know when to listen for the other person??, or will one person just sit and wait for the other person to come on the line??

Thanks for the reply! This is a temp setup for testing a monitoring circuit on a different pair. It would only be used during this test. Both ends would know about when the other is going to be there. One end of the communication would be an electical engineer and the other a technican with limited electronics knowledge. Speed and ease of use would be the keys to this soulution. Cost would also be a consideration, but ten units under 2-3k$ would likly be a deal maker.

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Mark

30miles is a long way to push battery. What would probably work if you can find them is 22 volt drycell batteries like telco uses. Put a battery on each end. On one end run the ring side of your pair to the battery, +or-, for sake of arguement say - put one lead of your butt set on + and the other lead to tip. On other end run tip side of pair to - of batt and butt set lead to + and to ring of pair. Should give you enough current to talk.

If you could find some old, magneto based phones the army used to use....

simple solution..get 2 cell phones and be done with it.

Because of the location of the poster and distance, I assumed that wasn't an option. Being out here in the sticks also, I know cell coverage is spotty at best.

I used a tone generator set in continuity mode ,put in series with your Butt set Tip lead, that would provide enough batt. to carry on a conversation, don't remember the distance though? Its been a while.

Worth a try.

Rick

Butt sets and a power supply should work for you. We used to use our toners in series with or test sets between IDFs a lot (before cell phones) as RICK suggests. That wont be enough juice over your 30 miles though.

Looking on the bright side, you ARE working with 19awg wire. And, 30 miles of 19awg has the same resistance as about 9.5 miles of 24awg (now it doesn't sound all that far ).

I think I would try talk battery from an old 1A2 power supply. I haven't used one for years. There used to be several manufacturers that made them. Elgin is the brand we used the most.

Good Luck!

We used a test set at the central office that would test pair gain/loss on a dry pair. It also could send talk-battery on a long loop to communicate with tech on other end. Can not remeber the brand, but it was used for central office applications to remote sites.

Worked like a champ. We had squak box at central office end and tech on other end used there buttset.

Good Luck!!

If you can find them at a Army Surplus, the cheapest and easiest to use is a couple of the Army's field phones (TA-312). No other equipment is needed. You have one at each end with 2 D cell batteries in each. The handset is "push to talk". And to call the other station, you turn the crank on the side, which sends ringing voltage down the line.

Here's what they look like:
https://www.myinsulators.com/commokid/telephones/ta43pt_9.jpg

The way we did this in the past is with
a -48 DC power plant, Lorraine comes to mind. We used this on the talk pair testing long haul fiber. This might work on 19 gauge.

Good Luck

Chris

Pull the battery out of your truck and put it in series in the ckt. The worst that could happen is you drain the battery and are stuck there.

I once "rescued" an old manual set from an abandoned railroad line 'way out in the swamps. There was a battery box with it that held two 6 volt lantern batteries.

Bear in mind, current, rather than voltage is what makes phones happy, so if you can get around 20 milliamps at the far end, you'll be fine.

I'd say, get a couple of those lantern batteries, connect them either in series or parallel, and see what works.

jsaxe

If you connect two buttsets in series with a 48V battery you can talk if both buttsets are in talk. If ether buttset is in monitor the other buttset cannot generate voice. With both buttsets left in talk the battery will run down. If you connect two buttsets in parallel with one battery at one end the buttset on the same end as the battery will have all of the line current and the buttset on the far end cannot be herd. You will need an inductor in series with the battery to keep the voice signal from shunting out thru the battery. If you have two batteries with inductors one on each end then each buttset can be heard. Leave the buttsets in monitor when not talking and the batteries will last longer. This circuit has no signaling. The Viking DLE-200B Ringdown circuit provides signaling but spec says it will only work up to 2.6 miles on 24AWG. This would be about 10 miles on 19AWG. There you have it.

All
On behalf of the USAF, thanks for the advise. You'd think being in the military, we'd have some old field phones around and know how to do this, but everyone has gone radio and sat. We also thought about going to a surplus and buying some, but that just didn’t seam right, buying them back! Based on the posts, we've set up a test line with about 4k resistance and have tried everything from 9 volt battery to a 48 volt power supply. As one might assume, as the voltage goes up, so did our volume. I suspect it was more a function of the amount of current. It was the best at 48 volts. I found an article that indicated as long as you have 20mamp, you can communicate. We will have one chance to test on the real lines before we have to use this solution and any other thoughts you all have would be appreciated!
Thanks again,
Mark

Mark, If you have two pairs then you can connect the transmitter of one handset to the reciever of another handset in series with a powersupply.

In the old days of cow pastures, installers would talk over barbed wire; conect one lead to the wire and stick the other one into the ground, no power source needed.

Mark, most of the responses have been from ex-military guys. What these boys learned was before the "techo" age. Look up an old master sgt. in your area. I'm sure there's a few around and your command sergeant major might help in this area. The old boys might like to help! Considering I'm a card carrying retiree, I,m always on call!

you could try what we call the parkway test set.. i belive the model number is pl-259. it is a tone generation set, a test set.. and it also has a talk circuit that runs off of 9vdc..

many splice and cable installation techs use this to communicate thru manholes while splicing.. you can run tone and talk at the same time..

you can attach a standard butt set (but it has to be a modern one with dual speaker phone setup) or you can use a headset with microphone..

not sure where you'll find one on the open market.. but they work great in the field for our techs..

depending on your wire guage you should be fine on the basic 9vdc..

the only thing you might want in addition is a separate circuit to run a buzzer as this system does not ring from one end to the other.. ..

Redtail has the definitive test. All you need is a 48 volt DC power supply with one lead to your buttset and the other lead to one of the pairs and the person on the other end with their buttset clipped on the wires and the returning pair to the power supply.

The Tellabs 8001 24/48 VDC power supply (I can loan you one if you pay the shipping) is a couple amps and if you can't do it with that in 48 VDC mode, then the talk path over 30 miles is a pretty much hopeless cause.

Of course, you could just get four charged car batteries and skip the Tellabs. DC drops off a lot more than AC over distance, which is why we have AC power lines.

Hey folks, if they didn't figure this one out it's way too late now.