So, I am still trying to understand why my RX range nearly tripled in range when going from a high end Diamond 7.8 dBd gain, a 5/8 over 5/8 over 5/8 (yes, a triple collinear) vertical to a single 5/8 vertical (which has virtually no gain over a 1/4 wave)
The rest of the system was identical in both cases, 15 feet 1/2 Heliax with N-connector (all trimetal), a preamp (which was OFF in both tests), two TX/RX Bird tuned cavities set with a 0.59 dB insertion loss each and 70+ dB attenuation at anything beyond 0.5 Mhz (to deal with the flamethrower uber-1400-foot-tower) and a Vertex Standar EVX-5300 radio.
So, initially I went the route of adding more dB gain to the system, first added a high gain antenna, then cavities, then the preamp, all that under the clear assumption that more dB will get me more RX/TX range, but so far it seems that the more gain I throw, the faster the RX range goes south. While the TX range is noticeably better with the 7.8dBd antenna, what I can't understand is why the RX decreases? shouldn't the RX range increase as well with a higher gain antenna?
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gman1971
So, I am still trying to understand why my RX range nearly tripled in range when going from a high end Diamond 7.8 dBd gain, a 5/8 over 5/8 over 5/8 (yes, a triple collinear) vertical to a single 5/8 vertical (which has virtually no gain over a 1/4 wave)
The rest of the system was identical in both cases, 15 feet 1/2 Heliax with N-connector (all trimetal), a preamp (which was OFF in both tests), two TX/RX Bird tuned cavities set with a 0.59 dB insertion loss each and 70+ dB attenuation at anything beyond 0.5 Mhz (to deal with the flamethrower uber-1400-foot-tower) and a Vertex Standar EVX-5300 radio.
So, initially I went the route of adding more dB gain to the system, first added a high gain antenna, then cavities, then the preamp, all that under the clear assumption that more dB will get me more RX/TX range, but so far it seems that the more gain I throw, the faster the RX range goes south. While the TX range is noticeably better with the 7.8dBd antenna, what I can't understand is why the RX decreases? shouldn't the RX range increase as well with a higher gain antenna?
Any help would be appreciated.
Thanks!
G.
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