Radio Modems: Difference between revisions
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== Overview == | |||
[http://www.pacificcrest.com Pacific Crest] makes radio modems, principally for connecting a GPS rover with a fixed reference station to allow submeter accuracy. | |||
I have 3 RDDR-96 "Blue Bricks". I got them at a garage sale along with a [[Magnavox GPS reference station]] Also included were some rubber ducky omni directional antennas, a Larsen base station antenna, a Larsen YAGI directional and a [[TPL Communications PA6-1AC amplifier]]. | |||
The | The Blue Bricks can operate in two modes, transparent and packet. In transparent mode a pair of the radios acts as a replacement for a serial cable operating at 9600 bps. In packet mode, one radio can be the source of a data stream and several can be receivers, allowing for example in my case one base station and two rovers. | ||
So far I have | So far I have powered them up individually with their rubber ducky antennas attached and confirmed they transmit by tuning my Kenwood TH-6A handheld to their frequency and listening the bleeps when I type. | ||
My radios came from the factory tuned to 420 Mhz. This means that I can operate them using my amateur radio operator's technician license. It's in the 70cm band. | My radios came from the factory tuned to 420 Mhz. This means that I can operate them using my amateur radio operator's technician license. It's in the 70cm band. (See http://www.arrl.org/FandES/field/regulations/bandplan.html#70cm) | ||
(See http://www.arrl.org/FandES/field/regulations/bandplan.html#70cm) | |||
== My applications == | |||
I have a couple ideas for things I want to try with this set up. | |||
=== DGPS === | |||
Send out DGPS corrections from the GPS reference station. | |||
The rover will be a Leica 9400 or a Garmin or possibly a Trimble. Probably all three but not at the same time. | The rover will be a Leica 9400 or a Garmin or possibly a Trimble. Probably all three but not at the same time. | ||
=== Garmin Fleet Management === | |||
Connect to a server running software compatible with Garmin's Fleet Management protocol. Put a radio modem in a car that has a Garmin PND in it and see what we can do. | |||
== Antenna set up == | |||
I am not sure what part of town I will be in, so I am trying the omni antenna first. | |||
Larsen BSA Kit = "Base station antenna" | |||
Cut radials - for frequencies above 400 MHz they should be 7 inches. | |||
My main element is a PO series. For 420 Mhz, the lower portion should be 10 inches. | |||
Latest revision as of 01:52, 28 February 2010
Overview
Pacific Crest makes radio modems, principally for connecting a GPS rover with a fixed reference station to allow submeter accuracy.
I have 3 RDDR-96 "Blue Bricks". I got them at a garage sale along with a Magnavox GPS reference station Also included were some rubber ducky omni directional antennas, a Larsen base station antenna, a Larsen YAGI directional and a TPL Communications PA6-1AC amplifier.
The Blue Bricks can operate in two modes, transparent and packet. In transparent mode a pair of the radios acts as a replacement for a serial cable operating at 9600 bps. In packet mode, one radio can be the source of a data stream and several can be receivers, allowing for example in my case one base station and two rovers.
So far I have powered them up individually with their rubber ducky antennas attached and confirmed they transmit by tuning my Kenwood TH-6A handheld to their frequency and listening the bleeps when I type.
My radios came from the factory tuned to 420 Mhz. This means that I can operate them using my amateur radio operator's technician license. It's in the 70cm band. (See http://www.arrl.org/FandES/field/regulations/bandplan.html#70cm)
My applications
I have a couple ideas for things I want to try with this set up.
DGPS
Send out DGPS corrections from the GPS reference station.
The rover will be a Leica 9400 or a Garmin or possibly a Trimble. Probably all three but not at the same time.
Garmin Fleet Management
Connect to a server running software compatible with Garmin's Fleet Management protocol. Put a radio modem in a car that has a Garmin PND in it and see what we can do.
Antenna set up
I am not sure what part of town I will be in, so I am trying the omni antenna first.
Larsen BSA Kit = "Base station antenna"
Cut radials - for frequencies above 400 MHz they should be 7 inches.
My main element is a PO series. For 420 Mhz, the lower portion should be 10 inches.
