Search This Blog

Tuesday, July 28, 2009

Hustler 5BTV Antenna Completed

I finished my Hustler 5BTV (5 Band Trapped Vertical) antenna and here are some pictures to show it while testing and prior to burying the coaxial cable.

First off, here is the radial base which does not employ a radial base plate. I simply attached the radials to the base mount. The base of the antenna is 4" off the ground per the instructions from Newtronics/DX Engineering.


The radials fan out and fake the antenna into thinking the ground is more conductive than it really is. The more radials the better. I plan to eventually keep adding radials over time, some longer ones, maybe 1/4 wavelength at 80M over 180 degrees could happen, the other 180 is about 10 feet from my property line, so I'm not going to bother! Many small radials along the property line will do a lot better than the current zig-zag I have right now.

I wound a coaxial cable 1:1 choke balun with the RG-8 and a 6.5" paint can as a form (in the background). The manual asks for 6" but this is fine and its not critical to get exactly 6 inches. The balun simple stops any induced (from the energy being radiated by the antenna) RF traveling down the outside of the coaxial shield as there should be NONE, due to the skin effect it stays on the inside shield of the coaxial cable closest to the center. The balun DOES NOT inhibit the RF in the cable, only on the outside. I made sure it would keep its form, hence the duct tape, while the RG-8 provides enought stiffness with plenty of margine! I used wire ties going through a slit in the duct tape on the second, and second to last windings to provide strain relief for any tension on the coax.

Ok, the next picture is not really good I will appologize for the blurryness (I would love to own a Nikon D80 SLR after taking a non-photo major photo course at RIT... but my point and shoot has to do!). Using a borrowed MFJ-296 Antenna Analyzer I tested and tuned the antenna. The Hustler 5BTV requires that a choke balun be placed no more than 8 feet from the antenna AS WELL AS 8 feet from the transciever. If you do have one you MUST have both, they trap the RF on the outside shield to bounce between each balun, eventually attenuating (turning into heat). If the second is not used at the transmitter there will be a large SWR mismatch (>31:1 according to the MFJ-269). I wound a quick test balun with some spare coaxial cable. During this testing I identified the corroded adapter near the antenna feedpoint which was eventually replaced so that no adapter was needed. I also located myself as far as possible from the antenna while measuring to reduce any influence I may have on the antenna.

Lastly here is the final balun that is now used with the Yaesu FT-897 transciever on 80-10M in the radio room (shack!). I bought some high quality Belden RG-58 from my local independent electronics supplier, and its definitly nice stuff! It uses both a braid and foil for the outer shield and has a stranded center conductor (better flexing). Again, the paint can was used for a form and tape holds the windings together with wire ties at both ends for strain relief.


Results

No tuner is used ( I use mine in bypass mode) and the antenna is close to a 2:1 match on all bands! The bandwidth on 80M is only good for the phone band but its not the greatest resonater down that low either! I was up testing the transciever balun around 1 AM Sunday July 26, 2009 and heard several VK stations! That's Austrailia which I have rarely ever heard. What struck me as amazing was that I was on 20M (14 MHz) at 1:30AM listening to Austrailia. First off, most of the time 20 meters dies at night and while there was probably some great propagation that night as compared to normal, being able to clearly hear several station in VK land with such little background noise was amazing. The Hustler 5BTV definitly turned from a fancy aluminum rod shoved into the ground into a vertical antenna with a low takoff angle. The radial system is the difference between night and day!

I have linked to the audio recording of VK4MA that was heard on the Hustler 5BTV. Notice how little background noise there is considering my area of Massachusetts is relatively noisy. I switched to no antenna near the end but didn't edit it out of the recording.

Audio Recording at 1:30AM on the Hustler 5BTV hearing VK4MA on 14.260 MHZ

I hope this article provides enjoyment and some pointers. Feel free to contact me for any questions regarding this antenna or anything else on your mind! I have notice people tweeting some of my posts and really appreciate that others enjoy some of my projects and experiences! Thanks!

Bryce

4 comments:

  1. Looks very nice, I ran a 4BTV for a couple of years and made over 4000 contacts, very pleased with the antenna. I am sure the 5BTV is a bit better and it looks like you have some good engineering there. I hope to work you guys on the air at some point.

    73 de KJ5T

    ReplyDelete
  2. Thanks Steve! It's been a great antenna so far and maybe I will get the performance data on the blog soon if I get a chance to finish it. It includes SWR and impedance/reactance for the bands. The 5BTV is exactly the same as the 4BTV except that there is an extra trap/whip on the top to provide 80M (3.5-4.0 MHz). It doesn't really get out well on 80, which is to be expected on that low of a frequency. Get as many radials as possible to improve this antenna. If the antenna is ground mounted it doesnt really matter on the length or if they are insulated/non-insulated. This does tend to differ for roof mounted however.

    ReplyDelete
  3. Can you put the 6" balun around the base of the 5BTV antenna rather than off to the side to save space?

    ReplyDelete
    Replies
    1. I did that, and it works fine. I encircled it with bricks.

      Delete