Jeff’s Beverage Experience
Gary, VE1RGB and I had been discussing Beverage antennas for a while. Gary had purchased a set of DX Engineering boxes to be used with a 2 wire reversible Beverage and I had decided to build ( read:re-invent the wheel)
Both of us came up against one big stumbling block: no real estate for beverage antennas. There are lots of glowing articles out there about how well multiple wavelength Beverage wires work for reception on the low bands. Well, neither of us have room for that, especially for 160 and 80 M use. I like to participate in the QRP Fox hunts on 40 and 80M in the winter and last year had dismal results with dismal antennas. On top of that, being in the NE of the continent is another major hurdle for these hunts. Most of the participants are in the mid West.
2006 was a major antenna improvement year for me. I now have two Windom wires with their centers supported at almost 50 feet, a 30 foot aluminum mast that is loaded for 80, 40 and 30M with radials, a ¼ wave inverted L for 160M and a 2 element Steppir yagi for 20M and up ( really great antenna, BTW). All of these new antennas have been confirmed as big improvements for DX use.
My last project was to fit as good a Beverage as possible onto my city lot.
With a bit of stretching, 200 feet was possible. Plus I could run it in an E-W direction which is desirable for me. I fired up my EZNEC modeler and created a series of models for 160, 80 and 40. 80 and 40 looked pretty good right off the bat. A good F/B ratio and reasonable approach angles. 160 wasn’t much better than an omni directional receive antenna. Still worth doing I reckoned, since Beverages are reported as having low noise and improved SNR, which is really the main goal of receive antennas. I figured that some center loading might improve the 160 performance and added a 100 uH choke reactance to the model. Low and behold, that immediately produced a 8 dB F/B ratio !
I checked out my old addition of the ON4UN Low Band book, but John Develdore had little good to say about short Beverage wires. I did find a good article by well known RF guy, Gary Breed, K9AY at www.aytechnologies.com/TechData/ShortBev.htm It is worth reading, and his models confirmed mine with respect to loading reactance. I also found some sketchy information on how to use twin lead feeders as the antenna element and some information on the transformers that were going to be required. I elected to use type J/75 mix ferrite toroids and ordered up a batch from DigiKey.
My project then was to create a feed point with transformers and a relay to switch directions, a center loading element with a shorting switch for experimenting without the loads and a termination end with a reflecting transformer. I had some 300 ohm twinlead, so that became my element.
My first round of construction worked, but not quite as I had expected. There were some puzzling results. I also managed to get a soft and hard addition of ON4UN’s Low Band DXing 4th addition in the middle of the project. ( Thanks Gary, Bruce and Al Penney !) This new addition is chock a bloc full of new how to info on these antennas, including a complete reversal of the “Long is the only thing that works” philosophy. There is detailed design and building information on the transformers as well. This new information allowed me to customize my rigs to fit my antenna.
Some views of the antenna. It is 2M above ground ( approximately)
I managed to get 4 ground rods in a few feet at each end. This is very poor ground, mostly rock. However, the Beverage will not work very well over good ground, so it is a natural for us Nova Scotia “Rock” farmers !
How does it work ?
Pretty darned good ! I have a slight imbalance between the two directions, but I can live with that. It was necessary to create a reed relay “Short” across the Beverage port on the Pro 3 to kill some of the feedback path into the receiver. This was a big problem on 80M. I had to run the Beverage right underneath my 80M Windom, which is a no-no. I had no choice. The port saver solved the problem however, and I have the added benefit of actually improving my Windom match in the process.
There is clear F/B ratio on 160, 80 , 40 and even 30M. The antenna is much quieter than the L on 160 and has already garnered some DX contacts on 160 that I could not have worked any other way. It seems to work best in the West direction which is perfect for the QRP fox hunting activities.All signals have less strength on the Beverage, but much better SNR’s, especially the weak signals. In listening with the reactance/loading device in and out, I prefer to leave it in, even on the higher bands. With it out, the antenna is still quieter than my inverted L on 160.
One small issue that I discovered : It isn’t clear from the literature about how to ground the far end of the wires with the reflecting transformer. One article clearly only grounds through the secondary winding, and another grounds one of the wire elements directly. I have tried both, and believe the antenna is a little better balanced with the wire grounded in addition to the secondary winding. After a few weeks of use, I will switch it back to see if it makes any difference.
I am convinced that a short Beverage ( if you are limited in space) is well worth the work and investment.