I live in Georgia and recently I was in a QSO (for you new Extra Class hams, a QSO is a contact between two stations) with a fellow in CA on 20 meter PSK-31. I was using my 80 meter full-wave loop which works great on all bands except 160. I was copying him solid with no dropouts. He said he was getting 70 to 80% of my copy. Then he said he was using a 4btv vertical. I told him I had one and it didn't work very well so I never used it. He became irate, "The 4btv is the best antenna in the world!" So I asked him, "Then why aren't you reading me, when I'm getting you 100% with a loop of wire?" He didn't answer. Of course, if you have no other antenna to compare the 4btv to, and it picks up SOMETHING you might think it is a terrific antenna. It isn't.
I've been a ham for over 60 years and off and on I have tried all kinds of verticals. My experience with both commercial and homemadeversions is that they ALL radiate equally poorly in all directions. My latest attempt was with the 4btv. I bought it from DX Engineering and bought the base plate to go along with it. Here are my observations
Radials for the 4 bands this vertical is supposed to cover were installed. I used "lawn staples" to hold the radials firmly to the ground until they relaxed enough to lie level on the surface. I also used a lot of coax-seal because this antenna is naturally exposed to all kinds of weather. One ofhe radials was connected to a long fence that backs up to my property. In fact, attaching the ground plane for an antenna such as this is aided considerably if you can connected to any available fences.
Using the analyzer it was obvious that the 4btv resonates low on all the bands it should cover . For instance on 10 meters it is resonant at 27.6 Mhz (pretty good if you are a CBer!). On 15 meters it is resonant at 20.8, nearly a half Mhz low in frequency. , It was also low on 20 meters, but how about 40? On 40 the length (disregarding the traps) is close to 1/4 wave so it would be close. Let"s check it out." Resonates at 7.1+. But I think we could work with that through an antenna tuner.
Yes, the 4bv is off resonance on all the bands it should cover. To their credit DX Engineering gives instructions on how to open the traps and manipulate them to get the vertical near resonance, but at the price we have to pay for this thing it really should not be necessary for hams to have to "field engineer" an antenna. This antenna has been in production for a LONG time. They should have fixed the off-resonance problem long ago. I don't use the 4btv since my loop and beam do a far superior job. It does, however, look nice nestled up against the pines in my backyard. Maybe I'll paint it green. Any comments? Send them to firstname.lastname@example.org