[SCCC] 160M residential lot antenna

[Michael Tope]

On 2/1/2011 7:27 PM, Bob Selbrede, K6ZZ wrote:
> Tim,
>
> Try shorting the center conductor to the shield on your 80M
> Inv Vee feedline and tune it with your tuner.  Acts somewhat
> like a vertical with top loading.  I've heard it works
> fairly well although I haven't tried it yet myself.  I'm
> sure it's better than loading up the XM-240.
This does indeed work. I worked quite a bit of DX on 160 running an 80 
meter inverted-vee hanging from a 40ft Rohn push-up mast by shorting the 
inner conductor and coax of the feedline of the inverted-vee together 
and then driving this with a tuner against a ground rod and a couple of 
radials. That's how I worked JT1CO. This despite the fact that the coax 
was taped to the steel push up mast and the push-up mast was sitting in 
the mud without insulation :-) Admittedly, however, conditions were 
really good that morning and K4ZW had setup good receive antennas at 
Chak's QTH.
> Another option.  You have plenty of top loading, so a
> shortened 1/4 sloper is also an idea.  Build one or try the
> Alpha Delta DX-A.  It works pretty good if you have plenty
> of top loading and a good ground path down the tower.
> Attach a braided stainless steel strap or similar to your
> mast and to a tower leg above the rotator.  That ensure a
> good connection to the top loading.  Since you are using a
> crankup, you may want to drop a ground line down the side
> (or inside) the tower from the top to the ground system at
> the bottom as well to ensure you have a good path to ground.
>   You could shunt load the tower as well, but to really do it
> right, you would need to run all your feedlines and other
> cables through the inside of the tower which is a pain.
>
> 73, Bob K6ZZ

WB6RSE shunt feeds and crank-up (70footer I think) and does very well 
(he has 180+ countries on 160 from his city lot in LA). Not sure if he 
drops his feedlines down through the center of the tower or not, 
however. For coax you can bond the shields at top and bottom of the 
tower and leave the cables on the standoffs. If the rotator cable is 
unshielded, then its possible you would need to bypass it at the top and 
bottom of the tower, but this is probably no more likely to be needed 
than it would be on a fixed tower since the coax cable bundle should be 
electrical similar to a tower leg if the coax shields are bonded at the 
top and bottom of the tower.

Good luck!

Mike, W4EF............

> ----- Original Message Follows -----
> From: "Coker, Timothy J"<TJCoker at lasd.org>
> To:<sccc at contesting.com>
> Subject: [SCCC] 160M residential lot antenna
> Date: Tue, 1 Feb 2011 07:57:34 -0800
>
>> Are there any antenna gurus on the list that wouldn't mind
>> helping me develop a 160m antenna for my place? The last
>> time I asked about 80m I got lots of great ideas and
>> encouragement which led me to build a full size inverted-v
>> , with folded ends. Sometimes it takes me asking a
>> question and getting ideas to do what should have been
>> obvious to me in the first place.
>>
>> I can provide a .pdf copy of my yard and antenna
>> installation, measurements, photos, BBQ dinner, beer,
>> etc...
>>
>> I want to do better than my XM240 2 element yagi for 160m.
>>
>> I have a 55' crank up with C31XR, A3WS, XM240, and 80m
>> inverted-v now. My wife isn't yelling yet about all the
>> aluminum and wire... so I better get something up before
>> she starts to challenge the visual impact...
>>
>> The tower is 4 feet from my house and surrounded by
>> concrete. I do have the ability to run some radials
>> through a 1/4" cut in my concrete to my grass (a 60'
>> north-south x 15' east-west rectangle) 10' to the west of
>> my tower. My backyard / house portion of the property is
>> 75' wide by 75' long (I don't want to push the wife too
>> much by running aerial wires over the front yard).
>>
>> Pictures of the qth are on a link from my QRZ bio.
>>
>> I'm not in a huge hurry, but I have lots of wire, coax,
>> and 50' of fiberglass push up mast that can be used.
>>
>> 73,
>>
>> Tim / N6WIN.
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