I operate the latest R8s unit, and it seems to me that the internal antenna is weak, since i cannot lock radio signal in small distances. Either that or theres some jamming or signal interference. Do you think an upgrade to an external radio/antenna could fix, improve the situation? Should i start considering such an option
The first step should be to find someone with a radio scanner to see if the channel frequency is already in use in your area, or to change your frequency setting to see if the symptoms change.
How far is "even in small distances" ?
I have had instances where radio only works for about 100m from the base.?ÿ This was using an external PDL 35w radio when the base antenna cable had come detached (unplugged) from the radio.?ÿ ?ÿSo check your base antenna is not faulty.
If you are you working in heavily timbered areas and?ÿtransmitting at 12.5khz spacing, radio signal will wash out quickly once you loose line of sight.?ÿ ?ÿIf you have access to a Trimble external antenna, would be worth trying the shorter 0db rated tip configuration as this should work better in undulating terrain.?ÿ
I have tried swapping out antennas on the R8 rover for ones with different ratings and length etc and find that the standard R8 rover antennas work pretty well even at long ranges.?ÿ ?ÿ
I have an SPS881 and SPS882 rover both with 450-470 RX/TX radios.?ÿ I tested these units alongside an R8-3 and find that the R8-3 radios provide significantly better reception at longer ranges.?ÿ The SPS radios lose signal strength after a few kilometers while the R8-3 is still showing 100%.?ÿ ?ÿApparently not all radios fitted to the trimble R8 range are "equal", some are better than others.?ÿ
As a "last resort" option, I swapped out the original SPS radios for "R5800 RX only" radios and find that the reception at longer ranges is now equal to the R8-3.?ÿ The older R5800 RX radios use solid brass contacts to ground the radio door to the receiver housing while the newer units use foam pads.?ÿ Seems the brass contacts?ÿprovide significantly better reception at longer ranges.?ÿ ?ÿworks for me..
The base/rover set-up works best with an external radio, the R8's are great but have a limited distance using the radio in the base (R10's are better but also limited). Line of sight will work for a long way (2-3 miles) but any obstruction will shut down the range quickly. Adding a repeater radio is SOP with those units. It will make a huge difference. They are usually placed on a good radio spot, they can be miles from the base and still work well. The interesting thing about them is that they will pick up the base signal where the rover has no chance of hearing it. So you can carry it with you and put it out even over a hill and still hear the base using the repeater to continue to work RTK. Honestly, I would not buy an R8 base/rover unit without a repeater radio.?ÿ
And as Bill said, if you are getting walked on the radios will not work well.
The R8s only has a 0.5w radio so you will have limited distance.?ÿ The brochure says 3-5 km (1.8 - 3.1 mi).?ÿ ?ÿI really don't believe that because you would need the ideal environment.?ÿ If you have a external radio, you can pump that up to 35W (with a license) and depending on the situation, go 6 miles and sometimes more depending on setup, etc, etc.
The R8s only has a 0.5w radio so you will have limited distance.?ÿ The brochure says 3-5 km (1.8 - 3.1 mi).?ÿ ?ÿI really don't believe that because you would need the ideal environment.?ÿ If you have a external radio, you can pump that up to 35W (with a license) and depending on the situation, go 6 miles and sometimes more depending on setup, etc, etc.
I never realised that distance was that short. I operate exclusively on an island in Greece with an area of 4.5 sq.km apporx.
My latest projects
-3.66km baseline succesfully established
-attempt at 4,4km and a 6km failed respectively.
A neighbour of mine with topcon equipment and external antenna says he can reach the entire island (except a location where we beleive signal is jammed)
The base/rover set-up works best with an external radio, the R8's are great but have a limited distance using the radio in the base (R10's are better but also limited). Line of sight will work for a long way (2-3 miles) but any obstruction will shut down the range quickly. Adding a repeater radio is SOP with those units. It will make a huge difference. They are usually placed on a good radio spot, they can be miles from the base and still work well. The interesting thing about them is that they will pick up the base signal where the rover has no chance of hearing it. So you can carry it with you and put it out even over a hill and still hear the base using the repeater to continue to work RTK. Honestly, I would not buy an R8 base/rover unit without a repeater radio.?ÿ
And as Bill said, if you are getting walked on the radios will not work well.
?ÿ
Did not think of that. Could you recommend a specific product (model/make)
Sometimes when we go to a remote location where we want to minimise the amount of gear we take but get as much range as possible, we run the base off its internal 0.5W radio, but have a 3m extension cable to the aerial port. We find a long stick or cut a tree branch and set that in the ground next to the base and get the aerial - which would otherwise be on the underside of the base unit - as high up as possible, like this:
Other times, particularly when ranging far observing control stations, when we are running an external radio at the base but can't get reception at the rover, we use that same cable at the rover and just hold it up at arms length and that usually does the trick.
I heard somewhere that Trimble and the like went to 0.5W internals to keep the power below the "FED's radar". Having said that, I also have it in my mind that Topcons have 2W internals.
We use the TDL 450H. It will work for what you need, however it may be more than what you need. It will broadcast at different wattages, I can't imagine you would ever need it at 25 Watts.?ÿ
There are other cheaper less powerful options. I'm not sure what would be best for you for such a small area but the TDL 450H should cover the entire island. If you have some deep canyons, you would still need to move it around. It operates independent of the Base location, you can move it anywhere as long as it can hear the base.?ÿ
What you really need is the little repeater Pac Crest used to make. It was 2 watts and about the size of a couple of cell phones. It would power up from two camcorder batteries. I can't say if they are still available but ours no longer works with Trimble's newer equipment. I don't know if there are some small repeaters anymore, that would be perfect for you.?ÿ
Be very careful that what you are buying will do what you need.
There are so many things that can affect the radio signal.?ÿ Jamming, trees, cables, power....?ÿ
Being that low of power limits you.?ÿ ?ÿYou could add an external antenna and get it as high as possible.?ÿ ?ÿThe higher the better.?ÿ ?ÿAnother thing is the radio works best with line of sight.?ÿ ?ÿIf you have a mountain or hill between you and it, the signal can be lost or very weak.?ÿ ?ÿYou can locate a another 2w radio (Trimble 45ol) or even the Trimble 450h (35w) radio to help boost the signal either as a repeater (as others suggested) or hook it up to the R8s and use it to broadcast.?ÿ ?ÿEven move your base to the hill would be a better solution.?ÿ Again, the higher the antenna the better.?ÿ ?ÿI have a base at my office with the radio antenna on top of a 30 foot power pole.?ÿ
Signal jamming is possible.?ÿ ?ÿYou need to make sure the frequency you are using is clear.?ÿ You can get a radio to listen to the frequency.?ÿ I believe all the radios now are set to only broadcast when the frequency is clear.?ÿ Good luck.
We use the TDL 450H. It will work for what you need, however it may be more than what you need. It will broadcast at different wattages, I can't imagine you would ever need it at 25 Watts.?ÿ
There are other cheaper less powerful options. I'm not sure what would be best for you for such a small area but the TDL 450H should cover the entire island. If you have some deep canyons, you would still need to move it around. It operates independent of the Base location, you can move it anywhere as long as it can hear the base.?ÿ
What you really need is the little repeater Pac Crest used to make. It was 2 watts and about the size of a couple of cell phones. It would power up from two camcorder batteries. I can't say if they are still available but ours no longer works with Trimble's newer equipment. I don't know if there are some small repeaters anymore, that would be perfect for you.?ÿ
Be very careful that what you are buying will do what you need.
So the TDL450H is a repeater meaning i can set it right next to the base, or even anywhere in listening distance? I made a quick ebay search. Seems cannot get it for less than 2500Euro, this is a major setback unfortunately.
For radio, i suppose only the transmitter must have the range, not both devices right? For example with bluetooth, in order to achieve class 1 (100m) both ends must be equiped with class?ÿ unit. In this case only the radio transmitter must be strong, and the receiving end can lock the signal with the internal 0.5W antenna?
Sometimes when we go to a remote location where we want to minimise the amount of gear we take but get as much range as possible, we run the base off its internal 0.5W radio, but have a 3m extension cable to the aerial port. We find a long stick or cut a tree branch and set that in the ground next to the base and get the aerial - which would otherwise be on the underside of the base unit - as high up as possible, like this:
Other times, particularly when ranging far observing control stations, when we are running an external radio at the base but can't get reception at the rover, we use that same cable at the rover and just hold it up at arms length and that usually does the trick.
I heard somewhere that Trimble and the like went to 0.5W internals to keep the power below the "FED's radar". Having said that, I also have it in my mind that Topcons have 2W internals.
Are you sure that extending "a little higher and to the left" can actually improve the transmission. How can this be explained besides having noticing that it sometimes works in the field
Two comments from practical experience.
Over the years we have had similar range problems from time to time. A small bracket which took the receiver external aerial from underneath the unit to up alongside it was fabricated and tested. Sometimes it improves matters, sometimes it doesn't, but it NEVER makes it worse, so we use these brackets on base and rover all of the time.
When we expect there to be poor range (obstructions, etc) we put additional extension poles under the base receiver to increase the height by one or two metres (three on the very rare occasion). You do need to ensure that the set-up is stable and it isn't suitable in strong winds, but it does increase the range significantly.
Add to the last post - if you carry spare extension rods with you at the rover you can add those to increase the rover height by a similar amount. Especially in trees the improvement is very noticeable and you can see the satellite count go up as well.
So if i get such a repeater with a yagi antenna how better will things get
I kept the 6 original aluminum 4ft section rover poles that came with my PM3s and can put them together for an HI of little over 24ft to obtain a good reception when needed.
Most of the time 12ft is enough and can be done with a three legged bipod.
For 24ft had to setup my TS to assure it is plumb and it still beats having to run half mile or more thru thickets to obtain the location of a monument.
They are good to put one 4ft section on a tribrach setup for extra height also.
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