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Re: Topband: Some experiments with a short beverage, not succeeding very

Subject: Re: Topband: Some experiments with a short beverage, not succeeding very well
From: Artek Manuals <>
Date: Tue, 30 Jun 2020 16:59:44 -0400
List-post: <>

Tell us more about the transformer? My own experience is that core material and impedance matching at the frequency of interest often pays off.

I have a 200' BOG (N-S) and a 460ft� x 6ft Beverage (E-W) . Both antennas work very well for what they are comparing them to what I hear on the Xmit antenna. In the "development " phase I found that measuring the actual feedpoint impedance and then making sure that the impedance matching� ratios are "close" resulted� in very predictable and repeatable results. I dont have my notes handy , and both my antennas are essentially "Reversible" coax antennas. One transformer turned out to be 3:1 and the other 5:1. I get performance on 160-40, noticeable poorer performance 30M� and� very poor signal signal 20M and above. I attribute this to the matching transformer design which favors the lower frequencies.

Everything for the moment was done using� cheap RG-6. But I will be replacing all of that with a RG-58 construction in the fall.


On 6/30/2020 2:56 PM, Mark Lunday wrote:
"Beverages just want to work" is what I have heard.

Not having much luck with that here. I suspect operator/installation error.

I did a lot of reading and I must be doing something wrong.

* 250 feet of insulated wire strung out in 030 degrees direction toward EU, pretty straight, varying in height from 4 to 6 feet, running through thick brush with no metal objects or artificial elements along the run.
* 9:1 transformer at feed point with ground rod
* 300 feet of coax, mix of RG-8, MMR-400 to get to the edge of the woods from the house
* No terminating resistor

On bands 160-40, the signals are very weak. I am monitoring WSPR, FT8. I can hear signals on 160-40 but they are way down compared to dipoles and inverted L on the same bands. Like 20-30 db down. From what I read, I should NOT need an HF pre-amplifier, right?

Signals on 30 and 20 seem to be better and I can copy some DX from EU on FT8.

I will try installing a new ground rod, the old one is 10 years old and perhaps not making a good ground connection at the feedpoint. The transformer is brand new, so that's not an issue. The coax has tested out fine. Soil is central North Carolina clay, a bit dry at this time.

I am guessing performance is poor on 160-40 because of the short length and that it's bi-directional (no terminating resistor), which I am seeing on 30 meters. But I did not think it would be THIS bad on 160-40....

Mark Lunday, WD4ELG
Greensboro, NC FM06be<>
SKCC #16439 FISTS #17972 QRP ARCI #16497

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