I have found that external antennas on our rovers work orders of magnitude better than the rubber duck antennas. I was having difficulty maintaining radio link today so I decided to hook up my spare base antenna to my rover and wow what a difference. My rovers are mounted on atvs / UTVs so I would like some antennas I can mount on them.
Wondering what the best options are. Do I want an antenna with gain or 0 db? The one I was using today was zero db but would one with gain be better?
The cheaper the better as antennas on atvs get broke often. Do I need to stick to something with tnc connectors or could I get a regular nmo style antenna and adapt it to tnc to fit the receiver?
The antennas with "gain" are all directional, even if that just means that they flatten the pattern more towards the horizon, i.e., flatten from a sphere into a plate. That's fine if the receiver and transmitter are within or near the same plane, not so fine of one is on a mountain top and the other is in a valley. So a gain antenna could be a good thing or a bad thing. It depends!
> The antennas with "gain" are all directional, even if that just means that they flatten the pattern more towards the horizon, i.e., flatten from a sphere into a plate. That's fine if the receiver and transmitter are within or near the same plane, not so fine of one is on a mountain top and the other is in a valley. So a gain antenna could be a good thing or a bad thing. It depends!
Thanks. I am rarely in areas with more than a couple hundred feet in elevation change. My base antenna is 30' tall.
I have been using antennas like this http://www.ebay.com/itm/Whip-Antenna-for-trimble-Freqency-range-450-470-MHz-24253-46-TYPE-/121167330225 which are $100 and then you need the mounting base like this http://www.gpac.biz/RTK_NMO.html which is $80 and then
$50 for a tnc-tnc cable.
Seems like I could find something that works for a lot less than $230 per antenna setup.
Have you looked in to using a repeater. Not sure what the cost would be. I have used one in the past and it worked well.
D,
JFC on a cracker! Tell me again how much you paid for your GPS setup? Pay the ticket and get on with your work. By the way, the only way you could improve on the antenna you linked to is to cut both the transmitting and receiving antennas to exactly 1/4 wavelength of the particular frequency you're using.
Dave
Don't want a repeater. That is more time to set up and tear down daily. I think external antennas will work and are cheaper.
I don't mind paying what I need to in order to make it work I just don't want to waste money unnecessarily. I have some 2 way radios and you can get good antennas for them for fifty bucks. Just wondering what was so special about these rtk antennas that makes them so expensive.
Try your local land mobile radio dealer. The prices you mention seem a bit high.
D,
Any antenna with the right connections and cut to the right length will work. An antenna is an antenna.
Dave
several years ago I bought one at radio shack and like someone else said, you could cut it to length.
Rubber duck antennas are just about the worst antennas there are. The advantage is that they are small and sturdy. A long whip antenna on top of a GPS would put a lot of strain on the case, particularly if you are constantly moving it around.
Yes, any antenna covering the correct frequency range (450-470Mhz?) and the correct feedline impedance (usually 50ohms) should work. NMO mounts work fine and are pretty strong. If your vehicle doesn't have a ground plane such as an automobile body, consider a non-ground plane antenna. Antenna cables are usually RG58u and typically have a male BNC connector or a male VHF connector (PL259). Adapters are available to convert to a TNC connector or you can have one installed, or you may be able to order the mound/cable with a TNC connector already installed. RG58 cables are usually good for short runs - RG400 is better for longer runs, but is a lot more expensive.
If the antenna is tunable, there is often a chart indicating how long the antenna should be for a given frequency.
Good info from Tyler. Mount the antenna to the pole and cable to the GPS.
Get a 5 dBi gain antenna (old style Trimble 4700, 5700), get a bracket sold by Seco. Use the rubber duckie 0.5 dBi antenna. When you loose radio, swap antenna, you should regain link then. (The 10 metre mast with anchors that Seco sells to base radio antenna could be an option too, I did not try)
I experienced this when the 5800 came out, could not get radio signal where I previously did with the 4700/5700 systems.
Try the antenna swap trick before sinking a bunch of money on a repeater.
