As a followup to the tests I wrote about in an earlier post, today I hooked up my Surecomm SW-102 to the Midland MXT275 and ran tests with both of the antennas. I didn’t expect the SWR variation I got using different frequencies. Maybe someone more knowledgeable than I can forward a possible explanation….
All the test were performed in an open area, using the Midland MXTA12 Antenna Mag Mount with the original cable length. The antenna is mounted behind the moon roof in the center of the rear portion of the roof with steel dimensions of 14 x 40 inches. The rear tailgate/spoiler roof is behind that steel roof, and is about the same dimensions. That portion of the roof is non magnetic (some sort of plastic), and houses all the vehicle antennas (GPS, Wireless, AM/FM, Cellular) with a flat aerodynamic, raised hump in the center. The distance from the hump to the antenna mount is about 10 inches. All those system radios were operating at the time of this test, except for Cellular.
I still have not received the 1/4 wave Laird whip I ordered. I will test that antenna as soon as I receive it. Should have it in about ten days as it seems to be back ordered.
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jas
Hi All,
As a followup to the tests I wrote about in an earlier post, today I hooked up my Surecomm SW-102 to the Midland MXT275 and ran tests with both of the antennas. I didn’t expect the SWR variation I got using different frequencies. Maybe someone more knowledgeable than I can forward a possible explanation….
All the test were performed in an open area, using the Midland MXTA12 Antenna Mag Mount with the original cable length. The antenna is mounted behind the moon roof in the center of the rear portion of the roof with steel dimensions of 14 x 40 inches. The rear tailgate/spoiler roof is behind that steel roof, and is about the same dimensions. That portion of the roof is non magnetic (some sort of plastic), and houses all the vehicle antennas (GPS, Wireless, AM/FM, Cellular) with a flat aerodynamic, raised hump in the center. The distance from the hump to the antenna mount is about 10 inches. All those system radios were operating at the time of this test, except for Cellular.
I still have not received the 1/4 wave Laird whip I ordered. I will test that antenna as soon as I receive it. Should have it in about ten days as it seems to be back ordered.
The results:
Midland MXTA25 – “3 DB” Ghost:
Channel 1 - 462.5625 – SWR 1.08
Channel 16 - 462.575 – SWR 1.14
Channel 22 - 462.725 – SWR 1.15
Channel 15RP – 467.5500 – SWR 1.72
Channel 18RP – 467.6250 – SWR 1.74
Channel 22RP – 467.7250 – SWR 1.74
Midland MXTA26 – “6 DB” 32” Whip
Channel 1 - 462.5625 – SWR 1.11
Channel 16 - 462.575 – SWR 1.24
Channel 22 - 462.725 – SWR 1.21
Channel 15RP – 467.5500 – SWR 1.01
Channel 18RP – 467.6250 – SWR 1.01
Channel 22RP – 467.7250 – SWR 1.01
All the best,
JAS
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