Do you think splicing 100' of wire onto a GTO exit wand would work?


I bought too short of a driveway-gate exit wand (GTO FM139 = 50 feet); I
need 150 feet.
Nobody told me (so I'm saying it here), one really needs about 150 feet if
they want the driveway gate to be open by the time the moving mass of metal
(i.e., automobile) reaches the gate. Lesson learned.
Researching the web, it appears GTO sells three wands:
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FM139 = 50 feet wired (about $180)
- FM140 = 100 feet wired (about $200)
- FM141 = 150 feet wired (about $225)
The instructions say you can not splice additional lengths
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Calling
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technical support at 800-543-4283, they say there is
no difference between the wands or the wire other than the length BUT if I
splice in a wire, it won't work.
The technical support guy was very helpful. He said the reason it won't
work is that the "sensitivity of the magnetic field" changes with the
splice.
I don't understand why (if I make a good splice) but maybe there is
something about magnetic fields I don't understand that you can elucidate
for me? The wire is 5 conductor 16awg multi-strand shielded.
What is it about a splice that destroys the magnetic field?
Reply to
Elmo
One thing is shielding of the splice...
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Then other than that, the wire length might have a certain *total* resistance or *total* capacitance and this is adjusted for at the wand or at the adjustment for the wand.
This principal might be along the lines of adjusting a CB antenna like it says here (length of the antenna matters)...
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"Elmo" wrote in message
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)
Reply to
Bill
On the face of it, this is a pile of manure.
It's possible (as someone else said) that the system might be calibrated for specific cable lengths, and it might be difficult to splice the wire in such a way as to maintain the desired electrical characteristics. But an amateur antenna system has at least two "splices" in it -- one at the transmitter, the other at the antenna -- and it works fine.
If the folks running the company are "nice" people, they should take back the too-short cable -- even though it's been used -- and give you full credit towards a cable of the right length.
Reply to
William Sommerwerck
First thing, how do you get IN ????
Second thing, try an additional 5-10 feet and see if there is something other than ??
Whats the connector look like ??
greg
Reply to
GregS
Add the required number/severity of speed bumps to force the drivers to slow down to whatever speed works for the 50 foot wand.
Reply to
DerbyDad03
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or.pdf
They didn't say they couldn't get any but that the gate didn't open fast enough for the speed they were driving. Obviously one solution might be to go a little slower.
Reply to
George
This is for exit only. I asked how do they get in, thinking any decent gate will have a remote control. Go through same procedure as to get in, push button. !!!! That RF is a usefull thing !!! Remote control !!! A magnetic sensor is usefull to prevent closing the gate and hitting car.
greg
Reply to
GregS
I know that when my girlfriend got spliced, it destroyed our magnetic field.
Seriously, I'm a 3 or 4 out of 10 on electronics knowledge, not even a skilled amateur, but this reminds me of "No user-serviceable parts inside". It depends on who the user is. I even saw that on a Black & Decker tire pump, on the plug for the cigarette lighter. I drilled out the rivets, replaced a burned-out fuse, and it's worked fine for 10 years now.
The product you write about seems intended for corporations and rich people. I'll bet it's a way to squeeze another 150 dollars out of you.
(They won't exchange what you bought for the longer one because you buried yours already and it's dirty?)
Oh, yeah, the technician might even believe what he told you even if I'm right.
It would be easier to do a nice splice if you offset the individual splices an inch or so from each other.
To the other people here, any reason he can't use one sheet of alimumim foil to shield everything all at once.
If you're burying it when you're done, silicone tape, I think it's called, is even better than heat-shrink tubing and doesn't slip on, it wraps on. Stretch it to 2 or 3 times its length, then wrap while streched and within a few days it merges into one big probably waterproof blob. Hard to find though.
Reply to
mm
On Mon, 01 Feb 2010 19:47:16 GMT, snipped-for-privacy@zekfrivolous.com (GregS) wrote:
Could be like the gate at a corporate site I occasionally visit - for entry, you speak to a guard and show ID via a TV camera and the guard opens the gate. A device like the one in this thread is used to allow people to exit the gate.
John
Reply to
news
There is a keypad to get in, and a remote. Both work fine for the owner of the house, but not for guests. Guests enter via the outside-the-gate intercom keypad. But the gate closes 25 seconds after being opened. When guests leave, the exit wand triggers the gate to open.
Reply to
Elmo
There is no connector. Each of the four 16 AWG multi-stranded wires arrives from the factory stripped of about 1/4 inch at the ends and tinned solid.
We just screw those four wires plus the shield into connections on the gate opener motherboard.
Reply to
Elmo
Yes. The "typical" gate setup is:
1a. Owner approaches gate and flips remote control to get in. 1b. Utility truck approaches gate and pushed their logged 4-digit combo on the digital keypad to get in (whether or not someone is home) 1c. Guest arrives and has to press the intercom button and can only be let in if someone inside the house provides them access. Guest then pushes a button on the keypad to open the gate.
2. In all cases above, the gate closes 25 seconds after it was opened.
3. In all cases above, when the owner/utility/guest leaves, the gate automatically opens for them via the exit want magnetic field disturbance sensor.
At least that's how my gate is set up. Some are set up to open via cellphone but mine isn't fancy.
Reply to
Elmo
I suppose it's too late to exchange the exit wand.
Yep. For good reason. The contraption belches RF somewhere between 20Khz and 150Khz and is similar to the vehicle detectors used for traffic signal control. The mass of the vehicle detunes the coil resulting in an increase in oscillator gate(?) current. In other words, the whole mess, including the cable, is part of a resonant circuit.
If you were able to rip apart the tube, you'll probably find an iron core, with a zillion turns of wires wrapped around it. There will also be a tuning capacitor, which is the key problem. Each length of cable will have a different tuning capacitor, where the difference in lengths is roughly equal to the difference in capacitance. These differences are compensated by the internal tuning cap. If you're lucky, they may have jumpers inside to select different cable lengths. If the designer is really cool, the capacitor might be inside the controller.
You might be able to get some clues if there are any patent numbers of FCC ID numbers on the devices. I couldn't find anything registered to "Gates That Open".
They may be right. 100ft of untwisted parallel cheezy wire is good for about 500pf or so. That's quite a bit and will seriously affect the resonant frequency of the wand. However, if the support droid is telling the truth, then there should be a jumper or adjustment inside the controller box for different lengths of cable. The manuals are useless. So, you get to rip it open. Learn By Destroying(tm).
Baloney. Well, maybe 50% baloney. The resonant frequency will change, and therefore, so will the sensitivity.
It's not the splice. It's the added capacitance wrecking the resonance.
Nope.
Reply to
Jeff Liebermann
On Mon, 01 Feb 2010 23:08:04 -0800, Jeff Liebermann wrote:
Ok, I lied. It's not the added capacitance. It's the added inductance of the 100ft of feed cable. The destructions for a different type of loop at:
show an inductance of 0.22 microhenries per foot for the connecting cable (presumably the same cable for both types of loops). That's quite a bit of added inductance. I'm guessing, but it looks like the target value for the loop and cable feed is about 100 microhenries.
Either way, adding the 100ft of cable is not going to work.
Reply to
Jeff Liebermann
On Mon, 01 Feb 2010 23:21:31 -0800, Jeff Liebermann wrote:
Looks like the oscillation frequency is dependent on the loop inductance. I (wrongly) assumed it was a fixed frequency (to make the FCC happy). That means you could probably extend the cable feed and all that will happen is that the oscillation frequency will be drastically lowered. I don't know if that's going to cause a problem with whatever they use for a detector, but it just might work. However, if the new lower frequency causes airplanes to fall out of sky, I suggest you instead purchase the correct exit sensor.
Reply to
Jeff Liebermann
The simple answer is just try it! What do you loose, a few minutes of time?
That said, just make sure your splice is absolutely waterproof. 3M makes underground splice kits that may work (used primarily for telco work).
Reply to
PeterD
I have to find the 4-wire multi-stranded shielded cable first ... but I will try the splice kit at the same time if I can find that also.
This morning I called GTO technical support again at 800-543-1236 and spoke this time with a woman with a southern accent who told me a splice could be done, but she said the problem is that it will eventually break. And, since it will be underground, I won't know where it is and I'll be calling technical support who won't know that it was spliced while they troubleshoot.
When I asked "but CAN it be spliced?", she confirmed there is no difference in the wand itself between the longer lengths of wire as the sensitivity adjustments are done on the gate control board itself.
I'll look for that 3M waterproof splice kit. I think I'll need a low-voltage splice kit. According to this web site, the voltage is 8 to 32 VAC or 8 to 26 VDC with a miniscule current of 1.5ma.
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Reply to
Elmo

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