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Reduced RTK Range?
I’m using a Topcon Legacy E for a base and a Topcon Hiper+ for a rover (with a Pacific Crest PDl 4535 radio). My range has recently dropped to less than a 1/4 mile. Any ideas why or how to troubleshoot?
For more details:
About 2 weeks ago, I tied a 1/4 corner 3000′ from one of my control points (base set-up). The next time I was set up on that same control point, I tried to re-tie the 1/4 corner; but lost radio contact at about 1400′. I had to set another control point and “leap-frog” my way down to the 1/4 corner. I don’t know what my range was before; but it’s definitely much less now. Using amplified power on the radio doesn’t increase my range significantly. I’m pretty sure it’s not environmental, since I didn’t have any trouble the first time. -
12 Replies
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Antenna connections. I had a similar experience and found the antenna on the base was the culprit.
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Agree antenna, antenna cable, antenna mount are the first three things to check. Next would be battery – we’ve found that we get much better, more consistent performance from batteries that are made for the long, slow discharge / recharge cycle. I recommend a 12v gel cell with at least a 17Ah capacity that’s made for a golf cart or wheelchair (ours are made for Hoveround chairs) or something similar. Car and truck batteries are the worst things you can possibly use for your radio.
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Thanks. I’ll check my connections. There is a coaxial-to-BNC adapter between the radio and antenna. I’ll take a look at that.
Lee D. What’s wrong with the truck battery? I have a 12 volt 9Ah sealed battery that I use for the base. It’s only 2 years old and seems to work fine. I did try my truck battery though, for testing.
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Agreed. On my Hiper system the radio issues that needed to be checked were:
Broken base antenna wire.
Broken rubber duck
Radio board on Hiper (contacts loose)
Radio board on Hiper replaced.If you are looking for an old base & Hiper setup I probably have one we could part with.
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I was going to say almost all the same things as posted above. Bad wire, connections, or related item.
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Kevin – We started really seeing a problem when we changed from PDLs to TDLs when the 12.5KHz narrow banding was mandated. Car and truck batteries are designed to have that one big surge to start the motor; what we found was that they couldn’t deliver the continuous amperage to push the transmitter. I’ve seen several instances where a TDL was on and the transmit light was flashing but there was literally nothing coming out the antenna. Pacific Crest has a white paper available on this.
The side benefit of changing was that the gel batteries are smaller and much lighter, which the field crews appreciate.
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tovio1037,
I’d love to have another GPS setup just like this one.
However, I’m saving my money for a used Robotic system. I’m not really a “GPS” Guy. I was just able to piece together a GPS system. It’s handy for commercial work (which I try to avoid); but, I prefer to use GPS for control and tie everything Robotically.
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Thanks for all your help. I found a short in this cable for my Base Radio antenna.
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The cable appears to be in good cosmetic condition. How did you find the short, and in what part of the cable is it?
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I tested for continuity with an ohm meter (set to beep). My brother held one test lead on the center of one end. I did the same on the other end. Moving the wire broke continuity. I think it’s right at the base. It doesn’t quite feel right; but, we didn’t test it any further. I have a new cable on the way.
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Good thing you caught that – that will fry your radio in short order.
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KevinFoshee, post: 353283, member: 8314 wrote: Moving the wire broke continuity
[Pedantic]That’s an open circuit, not a short. A short would mean continuity between center and shield.[/pedantic]
That’s a stress point where it isn’t surprising that it eventually broke. If Jim Frame or I had that problem, we would of course disassemble it to see if we could fix it.
Glad you figured it out, anyway.
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