So far I have seen little real comparisions of the Sommer XP708 to any
competitive antenna. I agree with Steve that one proof of an antenna
really working is the number of competitive stations using the antenna and
for the length of time the large sommer model has been around there are
few users compared to the KT34 and Th6/7 series.
But on the side of do they work...I suggest the series of articles by KM1E
in DX Magazine several years ago. He compared several antennas and like
many of us trying to get as much on one tower he went with the XP70X with
X=the number of bands. I find many who buy the Sommer are really active on
the 30, 17, and 12 meter bands. I seem to remember that his sommer did
quite well against KA1PE's big 17 meter beam.
Bob, N4VZ has the same antenna and does very well. As far as I know he has
more countries on 12 and 17 than anyone. He is usually about 1S point
stronger than I am on 17 (I use my 40 meter beam and estimate about 5Dbd
gain for me). I stay even with the A3WS (334 on 17) if they are high and
beat then when they are 60' or lower. There are several others using the
XP70X (a W2 2 letter in Western TN and a W2 two letter in NJ) and they all
do well on 17 as well as 20 and 15.
The reason many have not bought the antenna is threefold:
1. The price.
2. the assembly
3. Its hard to get max performance.
Properly tuned they work well. They have no traps or coils except on 30 and
40 meters. However, the are not really yagi/Uda arrays because on most
bands they are not 1/2 wave antennas.....I think the unique part is Sommer
has found a way to cover the amateur bands with an efficient antenna, that
is well built, and he uses the entire element on each band. Now go back and
review the 3 three reasons!
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