Topband: Beverage Antenna Tuning

[k8gg at voyager.net]

Hi Ash, Hello All,

As a long time Beverage user, I can definitely say that the performance
can be enhanced by having good ground at the termination resistor end of a
beverage.

Operating from Aruba in a CQ160CW contest, W8UVZ, KD9SV and I put out a
proper 470 ohm non inductive resistor on the end of a 560 foot long
beverage, and in addition to the ground rod, fanned out about 8 radials
each about 17 feet (5 meters) long beyond the end of the beverage antenna
wire.

I will also state that putting a Hi-Pass filter in series with the coaxial
cable at the receiving end in the radio room was a big help.  I lived 1/2
mile from an AM 930 station that made it impossible to make measurements
with an SWR bridge in a receiving mode.

The only way I could evaluate my RX antennas was to transmit 2 - 3 watts
into the beverage and use a low power SWR bridge to look at the forward &
reflected power, which worked very well for me.  My typical SWR on 160
meters was 1.5:1 from 1800 to 1915, and I considered that good enough.  I
did not worry about the SWR on 80 or 75 meters, but found good receiving
advantages compared to my transmitting antenna most of the time.

73,   Good luck,

George,  K8GG




> At 14:33 2018-07-06, Ashraf Chaabane wrote:
>>Hi Mark, Peter,
>>
>>The BC station to be used to minimize the back lobe would be in
>>Egypt or Saoudi Arabia right on the back of my beverage antenna.
>>That should offer signals coming well above 10deg (I presume!).
>>Comment noted regarding how efficient that will be on 1820 kHz. I
>>know Egypt has BC station on Medium Wave which isn't that far from 160m.
>>
>>Frank,
>>
>>I have two 3-feets rods at each end so far with two buried radials
>>at the feed end. I will add radials at the termination side as well
>>as you recommend.
>>
>>For the sake of experimentation, I  will play a bit with the
>>termination resistor trying to flatten the SWR curve as much as
>>possible, although, as many said, I shouldn't expect a noticeable
>>improvement in reception.
>>
>>Thank you all and those who wrote me in private. This generous
>>technical support is needed for developing experience on 160 among
>>3V hams (mostly youngsters). I hope we will be ready with strong
>>100W signals this winter!
>>
>>73 from Tunisia
>>
>>Ash 3V8SS/KF5EYY
>>www.kf5eyy.info
>>
>>
>>
>>------ Original Message ------
>>From: donovanf at starpower.net
>>To: topband at contesting.com
>>Cc: "Ashraf Chaabane" <ash.kf5eyy at gmail.com>
>>Sent: 04/07/2018 19:00:33
>>Subject: Re: Topband: Beverage Antenna Tuning
>>
>>>Hello Ash,
>>>
>>>Your results are normal for a typical Beverage. Receiving performance
>>>is not significantly degraded by imperfect matching of the coaxial
>>> feedline
>>>to the Beverage feed point or by non-optimum termination resistance.
>>>You could optimize your matching transformer and termination resistor
>>>but the improvement in receiving performance will be very minor.
>>>
>>>On the other hand, Beverage antenna receiving performance can be
>>>significantly degraded by:
>>>     - nearby antennas, power lines and other long conductors, and
>>>     - common mode signals coupled into the feedline
>>>
>>>You could optimize your matching transformer to reduce the VSWR to
>>>closer to 1:1 on the frequencies you care about most, but you won't
>>>notice any improvement in receiving performance.
>>>
>>>You could optimize your Beverage termination by:
>>>    - adding extra ground rods and/or short radials to improve
>>> ground resistance
>>>       stability at the connection to termination resistor.
>>>    - adjusting the termination resistance to minimize the VSWR
>>> excursion
>>>       as you sweep from 1.5 to about 10 MHz
>>>
>>>73
>>>Frank
>>>W3LPL
>>>
>>>--------------------------------------------------------------------------------
>>>From: "Ashraf Chaabane" <ash.kf5eyy at gmail.com>
>>>To: topband at contesting.com
>>>Sent: Wednesday, July 4, 2018 2:13:27 PM
>>>Subject: Topband: Beverage Antenna Tuning
>>>
>>>Hi All
>>>
>>>I measured the SWR in my beverage antenna; the SWR fluctuates between
>>> 1.5
>>>and 3 in a range of 1.8 to 7 MHz. (See:
>>>https://drive.google.com/drive/folders/0B9AtNpPfAOUMRDNsaXROMG1VUTg?usp=sharing
>>>)
>>>I know SWR should not vary too much. However, some people are suggesting
>>>adjusting the termination resistor. Others suggest checking the
>>> transformer
>>>number of windings for a good match. What shall I do?
>>>
>>>73 Ash 3V8SS/KF5EYY
>>>_________________
>>>Topband Reflector Archives - http://www.contesting.com/_topband
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>
> Nick Hall-Patch
> Victoria, BC
> Canada
>
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