[TowerTalk] 10 throu 20 beam traps or no traps

[Bill Turner]

ORIGINAL MESSAGE:          (may be snipped)

On 6/20/2014 5:17 AM, Herbert Schoenbohm wrote:
> Why not many serious DX-ers and contesters consider Tri-band or even 
> Five-band quads is a mystery to me. 

REPLY:

I can perhaps explain it from my own experience. A quad large enough for 
20 meters is a mechanical nightmare. Unlike a yagi, a quad is a three 
dimensional object and that makes all the difference. I put up a four 
element Cubex three band quad years ago and will NEVER do it again. The 
quad works very well once you get it up in the air, but getting it up 
there is a real hassle.

It's true that a two element quad is about equal to a yagi of three 
elements, but adding a third element to a yagi is child's play compared 
to the hassles of a quad.

I am presently running a CushCraft X7 which is a very clever design, 
IMO. Been up for years with no troubles. It has traps, but NOT in the 
driven element(s), which avoids most trap problems. The driven element 
is actually a four element log-periodic which gives great SWR bandwidth, 
and the rest of the antenna is a conventional yagi. As a bonus, it works 
(with lower gain) on 17 and 12 meters, with a somewhat higher SWR. I do 
restrict the power on 17 and 12 to 100 watts just to be safe, but it 
works much better than a dipole for those bands, at no extra cost.

By the way, the balun on the X7 is extremely low loss. As a test, while 
it was on sawhorses, I ran 1500 watts steady carrier for ten minutes 
through it on the three bands. The heating in the balun was barely 
noticeable, no more than 1 or 2 watts by my estimate. Pretty impressive.

73, Bill W6WRT
dezrat at outlook.com