Re: Topband: Orientation of a 160 meter receive loop?
The main use of the coax loop or any loop for that matter is not gain but low noise directivity. Placing it on a small TV rotator allows for the nully of local noise to help improve the SNR for the desired signal. A preamp may not be necessary especially of it increases the desired signal and the noise the same amount. As with any loop, it will interact with nearby resonant antennas and that can be positive or negative depending upon the orientation and distance between antennas. The coax loop was my first RX only antenna at it really helped. I highly recommend making it rotatable because local noise sources are guaranteed to change. GL - Steve WB6RSE >> >> Thanks, in advance for any 'advice' or reaffirmation I am on solid` ground >> here. >> >> 72 de Jim Rodenkirch K9JWV _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Orientation of a 160 meter receive loop?
I goofed with those gain numbers. Forgot to do the average gain test in EZNEC. The program was making big errors due to too many segments. The real answer is that there is only 2.4 dB less gain for the horizontal loop. Jerry, K4SAV On 9/30/2016 9:50 AM, K4SAV wrote: A small loop mounted horizontally will be omnidirectional, mostly horizontally polarized and with a null overhead. An omnidirectional antenna isn't usually a very low noise receiving antenna. The gain will drop by a lot if the antenna is at low heights. A square loop 5 ft on a side placed horizontally at 10 ft above average ground should have a peak gain of about -44 dBi at 44 degrees elevation on 160 meters. The same loop mounted vertically with the top of the antenna at 10 ft (either apex up or top flat) should have a gain of about -25 dBi. Jerry, K4SAV On 9/30/2016 8:03 AM, James Rodenkirch wrote: I have a 160 meter rcv loop - kc2tx product - I want to employ this season. I don't have a lot of band noise here in s/w Utah and don't want to bother with a rotor socan I mount the loop in a horizontal configuration and expect some improvement in rcv signal strength? I seem to recall Tom, W8JI, cautioning me to ensure I have the loop perfectly level. I do have a kd9sv preamp to employ and the Zo at the antenna is 50 ohms (verified on my Autek ant analyzer) so I can use 50 coax for the feedline. Thanks, in advance for any 'advice' or reaffirmation I am on solid` ground here. 72 de Jim Rodenkirch K9JWV _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Orientation of a 160 meter receive loop?
A small loop mounted horizontally will be omnidirectional, mostly horizontally polarized and with a null overhead. An omnidirectional antenna isn't usually a very low noise receiving antenna. The gain will drop by a lot if the antenna is at low heights. A square loop 5 ft on a side placed horizontally at 10 ft above average ground should have a peak gain of about -44 dBi at 44 degrees elevation on 160 meters. The same loop mounted vertically with the top of the antenna at 10 ft (either apex up or top flat) should have a gain of about -25 dBi. Jerry, K4SAV On 9/30/2016 8:03 AM, James Rodenkirch wrote: I have a 160 meter rcv loop - kc2tx product - I want to employ this season. I don't have a lot of band noise here in s/w Utah and don't want to bother with a rotor socan I mount the loop in a horizontal configuration and expect some improvement in rcv signal strength? I seem to recall Tom, W8JI, cautioning me to ensure I have the loop perfectly level. I do have a kd9sv preamp to employ and the Zo at the antenna is 50 ohms (verified on my Autek ant analyzer) so I can use 50 coax for the feedline. Thanks, in advance for any 'advice' or reaffirmation I am on solid` ground here. 72 de Jim Rodenkirch K9JWV _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Orientation of a 160 meter receive loop?
I have a 160 meter rcv loop - kc2tx product - I want to employ this season. I don't have a lot of band noise here in s/w Utah and don't want to bother with a rotor socan I mount the loop in a horizontal configuration and expect some improvement in rcv signal strength? I seem to recall Tom, W8JI, cautioning me to ensure I have the loop perfectly level. I do have a kd9sv preamp to employ and the Zo at the antenna is 50 ohms (verified on my Autek ant analyzer) so I can use 50 coax for the feedline. Thanks, in advance for any 'advice' or reaffirmation I am on solid` ground here. 72 de Jim Rodenkirch K9JWV _ Topband Reflector Archives - http://www.contesting.com/_topband
