[TowerTalk] [Antennaware] Height for horizontal loops

[Michael Saulsbury]

John:
To determine operating height you need to know: what the intended 
operating frequency range, the size of the loop and the operational area 
you wish to communicate with.  Also if you will be operating on multiple 
bands, square loops have phasing problems on even harmonics.  For NVIS 
to 400 to 600 mile radius on multiple bands the Double Delta at 30' is 
optimum for 1.8 Mhz to 15 Mhz continuous and has gain over a  one wave 
length loop.  During field day operations I use my portable  DD Loop at 
16" and was using a SG2020 with 20 watts. There were less than a dozen 
stations which I heard which I could not work.  And I was working 
stations the rest of the group on the mountain could not hear on their 
rig/antenna setups.  Rough dimensions for the DD Loop are 150' x 80' 
with 500' of radiating wire fed with ladder line to a transmatch.  I 
however use a 1:1 w2du balun and rg8-x in the portable setup to a 
Dentron Monitor Jr. transmatch.  The layout of the DD Loop can be 
altered BUT you MUST use a design program as little as a foot or two of 
spacing change can alter the phasing dramatically.  The feed point 
impedances vary all over the map when used over a wide frequency range.  
I use mine on both ham and non ham frequencies.  SO... open ladder line 
is best for long runs.  Keep Coax short if you are using power!  And, a 
transmatch is a must.

Overall the DD Loop on 1.8 to 15 Mhz should not be lower than 16' as the 
gain drops dramatically.  However as we all know use what you can get 
away with and what will do the job.

PS: I do a lot of HF Emcomm field work/design here in the state of Oregon

Also if you are trying to do DX with a horizontal loop ... different story.
I hope this helps.

Michael

John Geiger wrote:
> How high does a horizontal loop (the look skywire) need to be for decent performance?  A quick google search revealed that people were running them at 25 or 30 feet with good results (in their opinion).  I know that high is better, but how high does it need to be to show real improvement over a dipole?
>
> 73s John AA5JG
>
>
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