[TenTec] Coax For Low Power HF

[Jim Brown]

On Thu, 16 Sep 2004 08:13:06 -0400, n4lq wrote:

>What does 44 and 88 feet have to do with anything other than radiation 
>pattern? 

W8JI has done analysis (reported on another list, and possibly on his 
website) showing that these lengths are terrible for 40 and 80 meters, even 
when fed by "magic" open wire line. 

Loss in small coax (RG-58, RG-8X, RG-59) is quite reasonable below 30 
MHz as long as the antenna is even close to a match (3:1 or better) and the 
transmission line isn't terribly long (a lot more than 100 ft). See the ARRL 
Handbook and ARRL Antenna Book for a discussion of how little a moderate 
mismatch really affects loss in transmission line. You WILL need a tuner to 
get the transmitter not to "throttle back" due to the mismatch, but you will get 
power to the antenna and it will radiate. 

I am a great believer in resonant antennas. 


Jim Brown  K9YC