[TowerTalk] 5Band antennas

[Joe Reisert]

Mauri,

Don't forget to mention the Hygain TH-11 which covers 5 bands (20, 17, 15, 
12 and 10 Meters). It has LPDA driven elements and reflectors without 
traps. In fact, it only has 6 single frequency well made low loss traps 
only in the directors.

Best of all, the TH-11 (yes, that is what I use) performs very well on all 
5 bands (although on 12 meters the gain is down a little since that band is 
only an LPDA).

Traps don't have to have high loss. They need the proper construction. 
Furthermore, only use ONE resonant circuit in each trap (not the multiband 
Mosley type). HyGain had the answer since they used a large diameter coil 
form, large diameter copper wire well bonded on the terminations, a space 
between the coil winding and the termination, and (a big AND), large 
diameter tube over the trap. If you do all this right like HyGain did, the 
Q of the trap can be 200 or more and be very low loss.

73,

Joe, W1JR

At 09:46 AM 7/19/00 +0200, i4jmy@iol.it wrote:

>One of the few 5/6 bands directional antenna that really work is the
>LPDA.
>Trapped or shortened yagis have instead the typical problems of losses
>(again, losses are not only in heating and confined the in the traps or
>coils)and more bands lead to have more losses nearly everywhere.
>Yagis with half wave resonant elements do not work when the elements
>frequency is close to each other (i.e. a 24.9 Mhz director and 28 Mhz
>reflector) and when too much aluminium is in close proximity.
>Concentrical loops, if resonant, suffer like the yagi plus some extra
>harmonically related troubles (not only on odd multiples) and because
>of coupling (link effect)
>Like in many other life fields one person can decide what to buy or
>built, it can be an object or a dream. Choosing for the object we pay
>and bring home something real, choosing the dream we pay to believe it.
>
>73,
>Mauri I4JMY
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