I barely managed to get my new Unified Microsystems (W9XT) BevFlex-4X Beverage installed and operating for the CQ CW contest last weekend. I installed it Friday but encountered problems with one of the feedlines; that problem wasn't corrected until Saturday morning. It appeared to be a bad arc capsule in the lightning protector for that antenna. I replaced the capsule and all was well. It took a lot longer to find than it did to fix, of course. The antenna isn't really fully installed yet, just "roughed in". I still need to go back in the woods and secure the terminator and feed boxes to their supporting trees and waterproof all the connectors.

I chose the BevFlex antenna because it allows for bidirectional patterns, and the feedpoint can be located anywhere along the antenna. It's constructed using RG-6 coax, and all connections to termination boxes and the feedpoint box are F connectors. The design requires separate feedlines for the Forward and Reverse feeds. I used a 100' length of "siamese" dual RG-6 Quad shielded coax to run the feeds to the station. It's necessary to terminate the unused direction's feedline with a 75Ω load to make the reflection transformers work properly. A small switch box that does this is included as part of the kit. Since all my switching is remotely controlled, I built a new relay box to handle the reversal function under software control. My property can support a length of about 350 feet in the NE-SW direction I ran the antenna, so that's the length I used. I just mounted the coax by running it through  a series of screw-in insulators installed about head high in the trees. The feedpoint is located about 240' from the NE end.

Initial checks with AM broadcast band stations looked encouraging. Even with daytime propagation, there was obviously a real signal strength change when the two directions were selected. The rather short 350' length made the antenna pretty much omnidirectional below 1200 kHz, but at 1400 kHz and higher  there was a noticeable change in signal strength on many BC stations when the direction was changed. In a couple of cases, one station was actually replaced with another.

Returning to the contest, I first tried the Beverage on 20 meters. By the time I got back on the air, around 2000Z, 20 meter propagation to Europe was essentially gone for me. I wasn't hearing many signals other than strong US and VE stations. It wasn't clear whether or not the Beverage would be useful on 20. When I changed to 40 meters it became obvious that the Beverage was going to be very useful. I was immediately hearing  lots of weak EU signals on the Beverage that were difficult or impossible to hear on the inverted vee transmit antenna. Using a combination of the transmit antenna and the Beverage in Diversity mode made copy of weak DX stations dramatically better. I was literally hearing a whole new layer of DX signals that were extremely marginal copy on just the transmit antenna alone. Sometimes when QSB would take the signal out on one antenna and it would be Q5 copy on the other. Most of the time I used the Beverage in the NE direction since most of the DX was from Europe. Switching the Beverage to the SW direction would usually make the EU signals completely disappear. Unfortunately, this vastly improved receive capability proved to be  a double-edged sword. I found I was clearly hearing a bunch of DX that couldn't hear my 500W to an inverted vee at all. Repeated calls to many Q5 EU stations went unheard on their end.

Around sunset, I went to 80 meters and had similar results. The superiority of the Beverage to the inverted vee transmit antenna was even more dramatic. In Diversity mode, many times  I could easily copy EU stations on the Beverage that I couldn't hear at all on the transmit antenna. In some cases, I could hear them working other EU stations and both sides of the QSO were inaudible on the transmit antenna. Of course, the disparity between receive and transmit capability was even more apparent on 80 than on 40. It quickly became evident that if I want to work DX on 80 I'll need to come up with a significantly better transmit antenna.
I have no 160 meter antenna so far, so I just spent a few minutes listening on 160 meters. I was able to hear some EU stations on the Beverage quite well. Unfortunately, I also found that there was some kind of ugly local electrical noise on 160 that I'll need to track down and get fixed before I can expect to do anything on that band.

After the contest, I've been listening around on the bands to get a better idea of what the Beverage can do. I've found that it does work pretty well on 20 meters and definitely improves copy on marginal signals in Diversity receive mode. It's also extremely effective on 40 meters, especially at night. In the Wednesday morning CWT session it didn't really seem to do much on 40, but signals for the most part were short skip and quite strong. On 80 meters I found that it is definitely useful on stateside signals. In the Wednesday CWT it helped a lot in improving copy on many domestic signals, even in the morning. I also hooked just the Beverage up to my Airspy HF+ Discovery SDR and tuned up and down the AM broadcast band. Above about 1300 kHz the Beverage starts to develop very good directivity and on many frequencies switching directions would replace one station with another. This effect was especially noticeable at night.

In summary, This Thing Works! I'm very happy with the station receive capability improvement it gives. As a matter of facti, I'm now looking at installing a second BevFlex-4X in a SE/NW orientation. It's somewhat uncommon for an antenna project that involves a modest amount of effort and expense to make a dramatic difference in station performance. This one did.

73...
Randy, W8FN