Bandhopper HF Antenna

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Mark Brueggemann:
Anyone have any documentation on the "Bandhopper" HF mobile antenna?

From what I can tell the creator of this antenna is SK, his domain is for sale and there is also a reference to another firm (Avtech of Montana) who's domain is also expired.  I picked one of these antennas up at a hamfest and while it works OK, I like to collect documentation for items I have.

Any anecdotal information would also be useful, can't say as I've seen too many of these things in use.

Mark K5LXP
Albuquerque, NM

Gerald Clough:
Here is an archived text information file from the Bandhopper site, via the WayBack Machine mirror at I.S.I.S. Egypt.

Unfortunately, the WayBack didn't preserve the old .PDF files from the site, but at least it's something.

This next one is via the main WayBack site and has two of the diagrams preserved, at least:

This next is the 2007 archive of the BandHopper home page. Photos are not archived. The Rogues Gallery link doesn't have photos, but the photo refs are the call signs of users, so you have some possible contacts for information and user experiences.

Most of the links at the bottom are just to the HTML version of the text file above. The Parts List and Price List links work.

If you get the WayBack Machine "Failed Connection" message on any of the above links, keep trying. Their servers always seem to be under a good bit of strain, but I accessed all those I listed today.

You can poke around all their archives of that domain at:*/

and through the Egyptian mirror at:*/

I doubt you'll find more archived links, but it's possible.

Alan Applegate:
Mark, it uses a B&D screwdriver motor assembly replete with its plastic gear assembly. There is typically a 10 to 15 resistor in series with the motor to reduce the voltage under load to about 50%. The motor draws about 2 amps normally.

The bottom part of the antenna is pressed on, and a real bear to get apart. You can always tell units which have been worked on, as they are pop riveted back together.

The coil is about 1.5 inches in diameter, so the efficiency is about average as HF mobile antennas go.

After the owner died, a truck driver who had been using the antenna took over the service calls, and even stated he had some parts. I got talked into working on one, and needed an outer cover, and even after about 10 phone calls (only two were returned), I never did get the parts I needed. I finally tossed the whole mess!


Mark Brueggemann:
Thanks for the links, Gerald.  Took a few tries to get through as you said but eventually I was able to get whatever was left of the text and images in the archive.  Way more information than I had before, so it was well worth the time.

And Alan, I was thinking the same thing when I first got the antenna, that's a pretty skinny coil.  But it's in decent shape, it works, and the dB/$ ratio was right (basically free).  Just need to come up with a control box and a whip for it and I'll play around with it on the air.

Thanks guys.

Mark K5LXP
Albuquerque, NM

Alan Applegate:
Just by happenstance, I've been working with a amateur in Texas, who is trying to get his Bandhopper to play with an automatic controller. Part of the issue is the requisite resistor in series with the motor.

The B&D screwdriver unit runs a 3.6 volts, but most of the antennas that use them, run them on about 9 volts. Sooner or later, they go bad. The gears are plastic which adds insult, but if you're careful I suspect it'll work okay.

I won't give the secret away, but if you ever removed the heatshrink cover, you'll notice something very peculiar with respect to how the coil is wound.

Alan, KØBG


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