I disagree, Jim. If trap losses were really significant, 1.5 kW would
burn them up very quickly. Sure, a trapped beam is less effective than
full sized monobanders, but can be made to work quite well. Witness the
venerable TH7, which I used for 29 years very successfully. Not everyone
has room even for a full-sized trapless tribander.
I recently replace the TH7 with trapless tribander, not because the TH7
performed poorly, but because I was concerned about bugs getting into
the traps. It was almost 30 years old, and, as far as I could tell,
performed exactly like it did when it was new.
73,
Scott K9MA
On 9/12/2019 14:42, Jim Brown wrote:
On 9/12/2019 11:22 AM, K9MA wrote:
The moral of the story is don't even think about going to the trouble
of putting up an MFJ/Cushcraft beam without taking apart all the
traps and fixing the above problems.
I have two very different takes on this. First, traps are an
inefficient way to build a multi-band antenna. That means they suck up
gain. Also, because the elements are shorter, their radiation
efficiency is reduced. The best multiband antennas don't use traps.
Second, buying ANYTHING from MFJ is probably a bad idea. I was VERY
disappointed when G0KSC farmed out the NA production of his smaller
antennas to MFJ a few years ago. I've been very impressed with his
designs.
73, Jim K9YC
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
--
Scott K9MA
k9ma@sdellington.us
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|