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?
You can post now and register later.
If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.
Question
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.
13 answers to this question
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.