[Antennas] Dipole Height

Thu Sep 17 11:26:28 EDT 2015

In my opinion, using the 1 5/8" coax in place of LMR-400 or RG-213 does 
not make any practical sense. It would be excessive overkill which 
would make the installation far more complex than it needs to be and not 
cause any noticeable improvement in 40 meter performance.
The cost of the connectors and trouble installing them, plus the 
tremendous weight difference are real negatives to the larger cable. If 
your dipole is center fed, you would have to use a much heavier antenna 
wire to sustain the weight. Your end support hardware would have to be 
much heavier and costlier.
Again, the difference in losses experienced in daily operation between 
the two would be hardly noticeable at 40 meters. You would not realize 
it on receive and the DX station would not realize it either.
Save your 1 5/8" coax for a VHF-UHF application where it would make a 
significant difference. It's a nice gift. Use it where it offers a 
real advantage, or trade it for something else you need.
Enjoy,
Ray, W4BYG
On 9/17/2015 11:05 AM, JK wrote:
> Someone gave me 150 feet of Heliax AVA7-50 1-5/8" coax. I think that 
> will be lower loss than LMR-400 or RG-213.
>>> Jay NE2Q
>>> On Thu, Sep 17, 2015 at 10:42 AM, Ray, W4BYG wrote:
>>> I don't think I agree with this suggestion.
>>>> At 40 meters typical RG-8 cables losses are much less for 90' to 100' 
>> of cable, than the significant gain in low angel of radiation that 
>> would occur with the higher installation. RG-8 cable loss at 7.2 MHz 
>> for 100' at a VSWR of 1:5 to 1 are about 1/2 db. See:
>>>> http://www.kc7hxc.us/links/radio/Coax%20Calc/Coax%20Calculator.html
>>>> With antenna height of 7' AGL most of your energy is NVIS and going 
>> straight up and down warming the clouds and worms. At 90', most of 
>> your energy is going out on the horizon at good angles where it 
>> should be, for DX contacts.
>>>> Big difference!
>>>> 73,
>> Ray, W4BYG
>>>>>> On 9/17/2015 10:05 AM, David Robbins wrote:
>>> once you factor in the extra loss for the feedline needed to get it 
>>> up that high the improvement will be negligible.
>>>>>>>>> Sep 17, 2015 09:34:15 AM, jkolin at optonline.net wrote:
>>>>>>>>> Hey Ray,
>>>>>>>>> Will my 40 meter dipole work better for DX at 90 feet above ground
>>> instead of 7 feet above?
>>>>>>>>> Jay...NE2Q
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