Bb7v
- Thread starter k1agh
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k6cpo
Member
Is that BB-8's younger brother? (Sorry, I just had to... 
)
)
majoco
Stirrer
If only I understood the question.....
prcguy
Member
I'm very sorry to hear this. Hope you can return it. To answer you question a little more to the point with another question, if you add radials to a 50 ohm dummy load will it work any better?
prcguy
prcguy
Is that BB-8's younger brother? (Sorry, I just had to...
It's a Star Wars reference and I thought it was pretty funny. YMMV
https://en.m.wikipedia.org/wiki/BB-8
I'm sorry I asked- i know some here do like vertical hf antennas. I brought it to try it out as the reviews online and the you tube videos show that the newer design works better then the old one. I just wanted to know if it would hurt anything to add radials to an antenna that doesn't require them. I've read online that some say yes and some say no with the notion that it may help it some more. Again sorry i asked for opinions or thoughts.
prcguy
Member
Adding radials will make it work better. If its mounted above ground like on a roof then at least four tuned radials per band will be beneficial. If its on the ground then tuned radials get detuned and ground losses creep in, so its much better to saturate the area around the antenna with lots of short radials like 20 or 30 radials 20 or 30ft long each.
Or you can make a more effective ground using 4ft wide chicken wire laying two overlapping strips in an X pattern and planting the antenna in the middle of the X. Two strips maybe 50ft long each making four 25ft "radials" heading out from the antenna would be great.
With all that you still have a very poor antenna, not because its a vertical but because its a terribly designed vertical. If you had the same length of metal tubing in the air and an auto tuner at the base people would think you turned on a huge amplifier compared to the stock Diamond.
Sorry about including a trashing session with my response but I wish there was more information about the Diamond and Comet no ground plane verticals out there with real world comparisons to other antennas so people would not spend good money on a very poor performing antenna that is not cheap. For about the same price I believe you can put together a similar height vertical with an auto tuner at the base and actually have a great performing antenna.
prcguy
Or you can make a more effective ground using 4ft wide chicken wire laying two overlapping strips in an X pattern and planting the antenna in the middle of the X. Two strips maybe 50ft long each making four 25ft "radials" heading out from the antenna would be great.
With all that you still have a very poor antenna, not because its a vertical but because its a terribly designed vertical. If you had the same length of metal tubing in the air and an auto tuner at the base people would think you turned on a huge amplifier compared to the stock Diamond.
Sorry about including a trashing session with my response but I wish there was more information about the Diamond and Comet no ground plane verticals out there with real world comparisons to other antennas so people would not spend good money on a very poor performing antenna that is not cheap. For about the same price I believe you can put together a similar height vertical with an auto tuner at the base and actually have a great performing antenna.
prcguy
Vertical antennas on HF have their place and some folks do find them acceptable for their purposes. But, they are generally a poor substitute for properly designed and installed dipole or Yagi antennas.
The antenna in question, the Diamond BB7V, is a compromise on many levels. First, it is a vertical antenna and verticals are typically more susceptible to noise than horizontal antennas. Second, at only 22 feet long, it just isn't going to be an efficient radiator at lower frequencies in spite of Diamond's advertising copy. Third, while Diamond may tell you that the antenna will work without radials, that just flies in the face of common antenna design knowledge. The only vertical antenna that does not require radials is a half wave and a 22 foot antenna is no where near long enough to be a half wave on the lower frequencies. This antenna is only rated 3.5 out of 5 on eHam.net and one "review" sums it up pretty well "What do you expect from this vertical antenna?" The bottom line from my perspective is that the BB7V is going to be a poor radiator and a lot of your transmitter's energy is going to be used up generating heat in the loading coil at the base of the antenna, your feedline, or your antenna tuner.
If a vertical antenna is the only thing that you can fit into your situation, there are other choices. For the $400 that a BB7V costs new, you could put up a 43-foot non-resonant vertical along with a good field of radials and have money left over.
The antenna in question, the Diamond BB7V, is a compromise on many levels. First, it is a vertical antenna and verticals are typically more susceptible to noise than horizontal antennas. Second, at only 22 feet long, it just isn't going to be an efficient radiator at lower frequencies in spite of Diamond's advertising copy. Third, while Diamond may tell you that the antenna will work without radials, that just flies in the face of common antenna design knowledge. The only vertical antenna that does not require radials is a half wave and a 22 foot antenna is no where near long enough to be a half wave on the lower frequencies. This antenna is only rated 3.5 out of 5 on eHam.net and one "review" sums it up pretty well "What do you expect from this vertical antenna?" The bottom line from my perspective is that the BB7V is going to be a poor radiator and a lot of your transmitter's energy is going to be used up generating heat in the loading coil at the base of the antenna, your feedline, or your antenna tuner.
If a vertical antenna is the only thing that you can fit into your situation, there are other choices. For the $400 that a BB7V costs new, you could put up a 43-foot non-resonant vertical along with a good field of radials and have money left over.
prcguy
Member
I've played with lots of verticals and I have a 43ft with auto tuner at the base over about 30 short radials that really works well. There is a ZS6BKW dipole at about 25ft high on the same property and the 43ft vertical works a little better on 40 and 20m DX. It also works surprisingly well on 80 and 160m.
My 43ft started out with its supplied 4:1 balun and it was a dummy load from day one. I monitored its performance as I added radials and from none to the first four made a noticeable difference, 12 was better and it got a little better still with about 30.
With the 4:1 balun and radials it was way down from the ZS6BKW dipole on 40 and 20m DX but did receive 160m better than the dipole, although it could not make any contacts there. I swapped out the 4:1 balun with an SGC-230 autotuner at the base of the antenna and it was like I put in a new antenna, everything perked up and I was making easy contacts on 160m out to 200mi. The autotuner upgrade was almost too good to believe.
A 43 ft vertical over ground radials with a 4:1 balun is a dog of an antenna but its a huge improvement over a Diamond BB7V or a Comet CHA250B. I suspect going from a BB7V to a 43ft vertical with 4:1 over ground radials would be as big of an improvement as going from a 4:1 balun to an autotuner on the 43ft. Going from a BB7V to any vertical over lots of radials and an autotuner would probably send the owner in to change his shorts as his bladder would let go from too much excitement.
prcguy
My 43ft started out with its supplied 4:1 balun and it was a dummy load from day one. I monitored its performance as I added radials and from none to the first four made a noticeable difference, 12 was better and it got a little better still with about 30.
With the 4:1 balun and radials it was way down from the ZS6BKW dipole on 40 and 20m DX but did receive 160m better than the dipole, although it could not make any contacts there. I swapped out the 4:1 balun with an SGC-230 autotuner at the base of the antenna and it was like I put in a new antenna, everything perked up and I was making easy contacts on 160m out to 200mi. The autotuner upgrade was almost too good to believe.
A 43 ft vertical over ground radials with a 4:1 balun is a dog of an antenna but its a huge improvement over a Diamond BB7V or a Comet CHA250B. I suspect going from a BB7V to a 43ft vertical with 4:1 over ground radials would be as big of an improvement as going from a 4:1 balun to an autotuner on the 43ft. Going from a BB7V to any vertical over lots of radials and an autotuner would probably send the owner in to change his shorts as his bladder would let go from too much excitement.
prcguy
Martin, G8JNJ has done a marvelous job of getting inside the nitty gritty of these radial-less verticals:
MARTIN - G8JNJ - Comet CHA-250B
And yep, for the diy vertical with a balun, change that to an UN-UN for an immediate improvement. The next step of course is the base-mounted autotuner instead. But be sure to use an UN-UN, and not a balun if that is the way one is going....
MARTIN - G8JNJ - Comet CHA-250B
And yep, for the diy vertical with a balun, change that to an UN-UN for an immediate improvement. The next step of course is the base-mounted autotuner instead. But be sure to use an UN-UN, and not a balun if that is the way one is going....
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