Description
NEW Qty and EXPRESS shipping options!
Due to the hig demand for this item and urgent needs for replacements we have added new Qty bundles and option for US Mail EXPRESS (1-2 day) delivery.
See options in the drop down menu above:
BRx7 OEM antenna 1pc @ $49.95
BRx7 OEM antenna 4pc @ $180.00
BRx7 OEM antenna 2pc with USPS EXPRESS @ $137.90
BRx7 OEM antenna 4pc with USPS EXPRESS @ $218.00
! NOTE: US Mail EXPRESS shipping is ONLY available to valid U.S. Mailing addresses in the 48 contiguous States (not Alaska & Hawaii).
You must enter a valid U.S. Mail address in our shopping cart in order to receive the shipment.
Orders returned to us by the Post Office will be billed an additional $45.00 to re-ship.
Express orders MUST be placed BEFORE 2:30PM EST for 1-2 day delivery.
1-2 day delivery depends on USPS delivery schedule for your area. We cannot garranty delivery in any time frame.
Carlson BRx7 OEM UHF Antenna information
Specifications:
- Labeled for 440-470MHz (high UHF band)
- Tuned for center frequency of 438.00MHz (not in the U.S. UHF band)
- 12″ overall length
- Thread on connector (RFT male)
- Flexible whip
Tired of breaking your radio antenna?
If you purchased your BRx7 from us you would have our exclusive Flexible Coupler:
Click here to learn about our Flexible Coupler!
Our test of the OEM UHF Antenna (QT400-T provided with the BRx6 and BRx7) shows a center frequency of 438.00MHz with losses rising rapidly with higher frequency. see graph below.
Peak efficiency is the bottom of the Curve of the Yellow line. See image below.
At 438MHz loss is measured @ 1.36 SWR
At 450MHz loss is measured @ 2.27 SWR
At 470MHz loss is measured @ 5.36 SWR
The effects of this are two fold:
- Loss of transmitter power when using a frequency off of antenna center frequency.
- Loss of signal strength when trying to receive a frequency off center
You will experience this as less than ideal range between Base and Rover, and find
that you encounter MORE interference from nearby sources.
By comparison our Exclusive Aftermarket UHF antennas are tuned for a center frequency of 462MHz.
At 462MHz loss is measured @ 1.41 SWR
At 450MHz loss is measured @ 1.74 SWR
At 470MHz loss is measured @ 1.80 SWR
This puts the “sweet spot” of efficiency of our Aftermarket Antenna right in the middle of the U.S. Commercial UHF band (450-470MHz).
Why is this important?
EFFICIENCY of radio transmision and Reception which directly affect RTK Range and performance.
Why are the receivers shipped with antennas tuned for 438MHz?
- Only the U.S. market operates in the high UHF band (450-470MHz). Most other countries use the lower UHF band (400-440MHz). Since the rest of the world is a larger market we suspect they ship antennas that meet the needs of their largest user base.
ONLY Carlson Survey Supply knows about this and is supplying our Aftermarket antennas with our BRx7 Base-Rover Packages so our customers get the BEST PERFORMANCE POSSIBLE!
