ka7niq wrote:
JIMMIE;735930 Wrote:
On Mar 6, 12:24*pm, ka7niq wrote:-
Cecil Moore;735465 Wrote: On Mar 5, 9:25*am, ka7niq
wrote:--
I got to thinking WHY not take a hustler vertical
with only ONE *Tuned "radial" for each band ...--
-
You are trusting that each radial will be resonant on only one band
akin to a fan vertical antenna. What may happen, for instance, is
that
the 40m radial may accept an appreciable amount of energy on 15m and
direct the 15m signal up at a high take-off-angle - less than optimal
for 15m operation. Other interactions are possible, e.g.
28MHz/4MHz=7,
18.14MHz/3.6MHz=5, etc. Any vertical radial resonant at 3/4WL, 5/4WL,
7/4WL, etc. will have a suboptimal effect on the take-off-angle.
--
73, Cecil, w5dxp.com-

I never considered this Cecil. Would you think it better to use a wire
trap dipole instead of the Hustler 4BTV
and hang it vertical in the tree ?

--
ka7niq-

My experience with the Hustler 4BTV hasn't been good. Over two hamfest
I bought 4 of them, lucky for me I was only buying then for the tubing
and mount and paid around $10 each for them. I dont think any of them
had a trap that wasnt bad.

Jimmie I have decided against the use of the Hustler 4BTV. I am going to buy a
CB antenna for use on 17 through 10 meters, keep the feed line short,
and use it with a tuner. I have been reading that several Hams are doing
exactly this with the Antron 99 and Sirio Gain Master CB antennas, with
decent results. I do plan on a self supporting tower one day, but this
will get me on the air, until then.


If you put an autotuner at the base of a 1/4 wave 10m vertical (i.e.
2.5m long), and some random length radials, for 10,12,15,17, and 20, it
will work fairly well.

The feedpoint impedance of a half length antenna (i.e. 1/8 wavelength
vertical) isn't so horribly different that losses will bite you.
(for comparison.. I ran some models a while ago for a 20-odd foot
vertical. resonant (Z=39 ohms) at 9.4 MHz, and at 4.7 MHz, the z was
14-271j. I just happened to have that data handy.. you're looking at a
shorter antenna and higher frequencies, but the ratios are likely to be
similar.

W9CF's tuner calculator says a T network for the first case (Z=39 at
9.4MHz) would have 0.1 dB loss (3%), and for the second case, you'd have
1.7dB loss (33%)

While it's not great to burn a third of your power in tuner/feedline
losses, on the other hand, it's also not horrible.

If you can put up something that's around 3-4 meters (10-13 feet) long,
that will work even better. A piece of plastic pipe with some 12gauge
wire inside it, for instance. or a 10 foot length of thinwall 1/2"
conduit (sure, it's steel, but it's also got pretty good surface area..
without actually doing the calculation, it's probably comparable to a
12AWG wire in resistance)