Add 17 Meters To a Hustler (Newtronics)
The Hustler 4BTV is a multi band
vertical covering 40, 20, 15, and 10 meters as it comes from the factory
as you probably know.
There is very little weight to 13 feet or so of wire so I don't think you need be concerned with the weight bending one of the Top Hat elements. (See additional mods below)
The wire can be simply attached near the feed point on the tubing above the bottom feed point with a hose clamp. This is the area just above where the coax is normally attached; and then just extend it to the top of the antenna, however, this may give you swr problems with wind blowing it close to or touching the main element. I first tried it this way but noticed the swr changing with the wind........... although not much.
This is why I used the bottom extender or spacer to get the wire away from the main element.
This also changed the tuning of the wire to get it to an acceptable swr and match for 17 meters.
I made the spacer from a short flat (about 6 inch) piece of aluminum and about 3/4 inches wide.
I formed it into an L shape and drilled one small hole at the longest end so the wire could get thru it. You could also just attach the end of the wire on the end of the CONDUCTIVE spacer using nuts, bolts etc, as long as it (the wire), is making electrical contact with the main element of the 4BTV base. In other words, the spacer would become part of the 17 meter antenna. Again....see pictures.
Attaching and tuning the wire was the hardest part of this project.
I removed the main portion of the antenna from the base mount and layed it on the ground.
I then attached the "top" end of the wire to a nylon cord (acting as an insulator) and tied the other end of the cord to one of the Top Hat elements making certain the the wire would hang straight down and parallel with the rest of the antenna and not twisted around the vertical element.
Then I re-mounted the 4btv back on it's base mount, attached the remaining end of the wire to the connection point near the feed point.
After several attempts at "tuning" the 1/4 wave section of the wire, I finally arrived at an acceptable swr and match.
2 to 1 SWR bandwidth
18.068mhz 1.1 to 1
18.168mhz 1.2 to 1
Match efficiancy 99% (all readings above using MFJ 259b)
After final installation of the modification, swr was checked on the "normal" bands, 40, 20, 15 and 10 meters with no noticeable change from previous readings. Some builders of this project mod have experienced a slight swr problem on 15 meters, but adjusted that portion of the original antenna with no problems afterward.
It should be noted that the 4BTV is not a very tall antenna. It is only approximately 21 feet tall from the ground and can be easily handled ON THE GROUND BY ONE PERSON.
Attempting this project up on a roof or ladder by yourself could cause some very serious harm to more than the antenna! Get some help and remember to keep it away from those power lines!
Also as an afterthought remember that your installation IS and WILL BE different from mine. I used NO ground radials and the antenna is ground mounted in poor dry Texas soil...clay and sand!
Your length of wire will probably be different than mine so some fun will be had in tuning this antenna. The starting point for the wire length is 1/4 wave long or a bit longer.
234/freqmhz = length IN FEET. This should be the length from the main radiator at the bottom of the main antenna to the tip of the modification, but allow a few inches for tuning if needed.
If you try this modification and have any input as to different ways to do this with the 4BTV that will help others....email me.....I would love to hear from you! 5BTV and 6BTV owners.....EXPERIMENT! See results in links below.
The proof is in the pudding!
On the air tests made my Yaesu FT-107 come ALIVE on 17 meters with this modification and I am still making contacts while I write this article!
I had NONE on 17 meters before!
Italy was 5 9 + 10 over today! California was a bit weaker!
IS 12 METERS NEXT??? !!! 73 Don.....N4UJW
PICTURES BELOW (Original artwork Copyright Newtronics. Mods N4UJW)
NOTES: In drawing above left, the 2 ovals near the bottom do not represent coax shield. They represent nylon wire ties to secure the wire to the aluminum bracket.
These are the ruff measurements that I
used above. Your wire lengths may be different! Connection at the base
feed point area (left picture above): aprox 3 inches from bottom L
Comments from builders:
"Thanks for the simple 4BTV mod--works
great on 17 now. Good flat SWR.
"The very first time I fired it up, the SWR was less than 1.1.,
So I left it alone.
And as in the original mod, the other bands were not affected.
This was an easy and fun project. I wish I'd thought of it myself! hi hi"
AND ON AND ON BY OTHERS!
More Input Below!
"I recently did this same 17 meter modification with a Cushcraft AV-5 (one they don't make anymore).
I ran a 13 foot piece of wire parallel to the center element using 3 inch stand-offs and shorted it at the botton area of the feed point.
17 meters resonated very nicely with less than 1.5.1 without a tuner.
I then employed a tuner in line and was able to operate on 160 meters. Running digital PSK31, my first contact from Topeka, Ks to DesMoine, Iowa was logged and the other contacts as far away as Seattle, WA.
My AV-5 is mounted on a chain link fence post, 4 foot off the ground with no radials. A 1/2 inch copper pipe seven feet in length is the ground rod for this setup. And the neighbors to the south and to the north of me have the same fencing and we are all interconnected. One great counterpoise 4 foot off the ground."