[TowerTalk] 80 Meter beam

[Grant Saviers]

I (try to) work 80m LP SSB to EU many winter mornings from Redmond, WA.  
There are about a half dozen west coast stations that can often work 
them if they are there and 2 or 3 that can generate a pile up in EU.  
The "biggest gun" is N7UA nearby in Poulsbo, WA who has some monster 
wire antenna I think at 240'.  Height for horizontal polarization is 
everything on 80m to get the radiation angle lower. Next are a couple of 
80m 3L beams in WA and OR.  Then a couple of 4 squares, particularly one 
in the CA alkali desert which is about as conductive as salt water.  
Even lower angles than horizontal antennas.  As Jim noted, ground 
conductivity is everything with verticals/4 sqs.  Then maybe several 
others and me with a 2L at 157'.  The N7UA reported signal vs mine is 
often 10db or more and my location is pretty good.

Yes, you have to really want a beam for 80m as they are a major 
investment and can be a maintenance headache.  My tower guy quipped, 
"put up a big one, and I'll see you twice a year."

Peak gains referenced to a dipole at 70' for a 5 deg take off angle 
(common EU to west coast) - EZNEC Pro/4 analysis I did for a club 
presentation:

dipole at 100' +2.8db
dipole at 125'  +5.6db  (this is where 80m dipoles begin to play well 
for my path to EU)
single vertical average gnd  +3.9db
4 sq average gnd  +5.28db
vertical on the beach, 2 elv radials  +13.4db - directive seaward (see 
my QST "Verticals on the Beach" article)
2L beam @ 157'  +12.8db
4 sq over salt water +19db  wow, that will hurt their ears!

Happy so far with my JKantennas 80m 2L beam and it covers 3.5 to 3.84 
with switched inductors.  Tower guy not called back.  I do think I 
gained about 10db @ 5deg over my prior rotatable 80m dipole at 102', 
which was the plan.  Of course gain is one indicator of often very 
important noise reduction.  My DXEng 4 sq receive almost always beat the 
dipole at 102' and hardly ever beats the beam at 157'.  The beam F/S is 
usually adequate to null the Chinese OTH radar coming from NW for EU LP 
to the SW.  RDF is good enough on the 4 sq that it is close to beam 
performance which is what the calculated RDF numbers indicate.

My way back QTH in EMA dipole at 50' was a slam dunk to work EU, too bad 
I didn't save the QSL cards.  HFTA puts the average arrival angles there 
at around 40 deg vs very little above 10 deg in WWA. As always it is 
location, location, location and then who you want to talk to.

I would add that there are some interesting wire antennas (what started 
this thread) with low angle gain such as phased dipoles, V's and delta 
loops that well done aren't mega investments.

Grant KZ1W



On 3/31/2017 17:37 PM, john at kk9a.com wrote:
> You really have to want a rotatable 80m yagi as there are numerous
> challenges and expenses.  I think a 4sq is about as good and it has greater
> bandwidth.
>
> John KK9A
>
>
>
>
snip