[TowerTalk] verticals in woods vs. in a field

[dennis o'connor <k8do@mailblocks.com>]

Interesting that this topic comes up at this moment... Yesterday I 
finished putting up a 3el vertical beam for 80 meters... It sits in a 
meadow in the middle of a pine forest  sorrounded by 60 foot trees, 
which are especially dense in the major beam direction (NE)..
The beam is 52 feet high X 70 foot boom length (which is the width of 
the meadow, else there would be 5 elements :) -  with Moxon folded 
elements making up the REF/DE cell and a folded director out front...  
Element spacing is 0.125 lambda... ELNEC shows the 3dB horizontal beam 
width to be 120 degrees, with a low take off angle...
Each element was resonated using an MFJ-259B and measured Z = 36 ohms, 
X = 0,  at the calculated resonance frequency, respectively, after 
trimming...
Average number of 0.25 lambda radials is 9 (at the moment) under each 
element...
Feedline is 200' of RG-213 with a measured loss of 1.1dB at 3.5 mc...

The comparison antenna is an Inverted Vee at 95' apex, ~150 feet behind 
the vertical beam and at a right angle to it (not that rotation means 
much for a vee)...

Unfortunately, the band was punky into EU last night, and being a week 
(weak?) night, there were no copyable EU stations on between 2300Z and  
0030Z, so I had to content myself with VE and W1 - W2 stations...  The 
consistent difference reported in A-B comparison was 2 S-units stronger 
on the beam...   The EU stations I could hear on the beam (but not make 
enough copy to call), were below the noise level on the vee...

More testing to come...  The inverted vee will become an almost 
horizontal dipole at ~140' and running N-S, this weekend...  This is 
mostly behind, and to one side, of the beam at a 45 degree angle to it, 
and ELNEC shows minimal interaction and field distortion between the 
two, with a markedly improved E-W dipole pattern compared the inverted 
vee...


K8DO  -    Denny (SSB) / Doc (CW)

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