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: donov...@starpower.net
To: topband@contesting.com
Cc: "Ashraf Chaabane" <ash.kf5...@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.kf5...@gmail.com>
To: topband@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
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