[TowerTalk] 80 m. DX Ant's Re: TowerTalk Digest, Vol 228, Issue 2

Sun Dec 5 18:34:27 EST 2021

80m DXCC was tough for me too when I had limited space, and my Hustler ground mounted vertical just didn't cut it.  I managed to get DXCC on 80m in one year using the JK-801 tunable dipole mounted at the very top of my 100ft tower on a 10ft mast above the top of the tower.  Height is not ideal, and would be better at about 130ft, since my height affects the pattern.  At least it's quiet, and I can usually work whatever I hear.  Having a tunable dipole makes it easy to work anywhere from CW to phone with good SWR.  Something to consider.
Steve W9DX

-----Original Message-----
From: Steve Davis | Davis RF 
Sent: Dec 5, 2021 1:28 PM
To: towertalk at contesting.com 
Cc: dsolberg8132 at gmail.com , jim at audiosystemsgroup.com 
Subject: [TowerTalk] 80 m. DX Ant's Re: TowerTalk Digest, Vol 228, Issue 2

Hi Don, I completely agree with Jim's observations and suggestions.

Also,. back in the day, a "lazy H" antenna was excellent on 80 m. Quite possibly this is a name for what Jim is suggesting, maybe not. Without further research I can't opine on the name as being same or relative to what Jim is describing, but it seems similar.

Any other suggestions would be interesting to hear. Ref. receive ant's: Jims ref. to Beverage is all out the best ant. in my book.

Cheers, Steve Davis, K1PEK DAVIS RF Co. also: Davis Rope, LLC

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Message: 1
Date: Sat, 4 Dec 2021 11:43:29 -0600
From: Don Solberg
To: towertalk at contesting.com
Subject: [TowerTalk] Looking for recommendations for an 80 M DX
antenna
Message-ID:

Content-Type: text/plain; charset="UTF-8"

My QTH is in northern Wisconsin, in the middle of a pine forest, with all
sand soil. My current 80M antenna is an inverted V up about 50 ft in a
pine tree. This works very well for local nets but obviously is not the
right antenna for DX.

I also have a 72ft crank up US Tower, which is supporting a homebrew 40M
rotatable dipole and an M2 LEO pack for satellite operation.

My goal is to be able to get DXCC on 80 meters, using CW and FT8. I can
run up to 1KW.

I understand that a vertical is probably my best choice but when I model a
vertical with my soil conditions, putting an inverted vee up 72 ft on the
tower appears to be almost as good for DX and much better overall.

If I do a vertical, can I run a parallel vertical wire alongside the
tower? How will this interact with the tower? I don't know if it would
work to shunt feed this type of crank up tower?

I have plenty of room for radials in the forest but I can't do anything to
improve the soil conditions in the far field.

I would welcome any recommendations and experiences.

73,

Don K9AQ

------------------------------

I have a similar situation, in a redwood forest. Dense forests like ours
soak up vertically polarized RF, so verticals are a bad idea for us. My
only verticals are for 160M, where any horizontal antenna would be VERY
low electrically, and thus a cloud warmer.

I've studied this situation extensively, and I strongly recommend the
highest flat dipole(s) you can rig at right angles to each other and fed
with RG11.

Equally important, concentrate on HEARING the DX. First, work on
cleaning up your RF noise -- that in your own home and, if possible,
from your neighbors. Study http://k9yc.com/KillingReceiveNoise.pdf and
utilize what you learn. The average home includes dozens of nasty noise
sources, which must be searched out and killed. I run legal limit on FT8
on 6M and 160, and I regularly get signal reports that are 10 dB worse
than I give. Since FT8 reports are all about signal to noise, this makes
clear that the average ham is DEAF. If we can't hear 'em, we can't work 'em!

Second, work on RX antennas. Beverages are great if you have room.
Single wires of about 275 ft are ideal for 80M, but shorter ones will
still work, and are easy and cheap to build. I support mine both with
laying them on brush and with sections of 1/2-in PVC conduit slipped
over sections of 1/4-in rebar stuck into the ground. I have two
reversible Beverages using DX Eng electronics, one to EU/VK and the
other to JA/SA (I'm near San Francisco).

And last, work contests. It's a great way to get a head start on DXCC. I
have 224 confirmed on 80 in 15 years from this QTH.

73, Jim K9YC

Message: 4
Date: Sun, 5 Dec 2021 02:56:57 -0800
From: Jim Brown
To: towertalk at contesting.com
Subject: Re: [TowerTalk] Questions on Low band receiving antennas in
forests and wetlands along ridgelines and ravines.
Message-ID:

Content-Type: text/plain; charset=UTF-8; format=flowed

On 12/4/2021 3:09 PM, kq2m at kq2m.com wrote:

My EU/VK Beverage works all the way up to 20M -- I used it a lot to copy
EU when all I had for TX was a high dipole. They get narrower as they go
up in frequency.
>
> 12) How many wavelengths on 40 is too long and how many is too short?
> Same question for 80?? Same question for 160.? I know that these answers
> vary by band which is why I am asking.

I have a pair of VE3DO loops spaced 5/8 wavelength for 160, steered with
an NCC-1 box. They work well when something hasn't fallen on them.:)
They are written up on my website, k9yc.com/publish.htm
>
> They are challenging questions that are not really covered in anything
> that I have read.? I would appreciate all of your thoughts and insights!

It's worth doing more reading. The ON4UN book has a lot on Beverages and
other RX antennas. W3LPL and N0AX recently authored a QST piece on
Beverages.

73, Jim K9YC

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