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Author Topic: Antenna-hamsticks  (Read 489 times)
AK4RL
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Posts: 11




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« on: November 22, 2004, 09:55:52 PM »

I would like to use two hamsticks as a dipole for multi-band use. Which hamstick should I use, the 10 meter or the 75 meter?  I know I will have to use a tuner for multi-band. Thanks, Ray
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N6AJR
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« Reply #1 on: November 22, 2004, 10:23:03 PM »

please do a search here on elmers search.. this has been coverd about 20 times just this year.. please..
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W8JI
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« Reply #2 on: November 23, 2004, 02:21:03 AM »

Hamsticks are bad enough when used on lower bands the way they were intended to use, as a single band mobile antenna.

They will be horrible when used on multiple bands, they are very bad when used on 75 and 40 as dipoles even when you use the antenna designed for that band.

You should look at other options. Almost any wire antenna you put up and used with twinlead and a tuner would be much better on lower bands.

73 Tom
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AA4PB
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« Reply #3 on: November 23, 2004, 03:29:03 AM »

Hamstick dipoles make a good portable antenna. There are usually better (lower loss) options for a fixed antenna. Hamsticks should only be used on the band for which they were designed. The loss will be extremly high if you try to force feed it on some other band with a tuner. In addition, you risk the close turns of the Hamstick coil arcing over if you use it on the wrong band.
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K5LXP
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« Reply #4 on: November 23, 2004, 06:45:39 AM »

If you're going to use a tuner anyway, there's no point in terminating it with a dummy load like a hamstick, which become more so off-resonance.  Hook up a random wire and counterpoise, or a ladderline fed doublet and you will spend way less money and have a much better performing system.  Resonant dipoles or a multiband dipole would save you the cost of the tuner too.

Mark K5LXP
Albuquerque, NM

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KF3EH
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Posts: 35




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« Reply #5 on: November 23, 2004, 08:19:59 AM »

Not everyone has room to put up a full size dipole in their yard - I know I sure don't.  And using a random wire is just ASKING for RFI issues.  In many situations, such as the one I find myself in currently, about my only option is going to be something like a hamstick dipole or buddipole, and QRP power.

Jeremy, NW7JU
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KT8K
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Posts: 1490




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« Reply #6 on: November 23, 2004, 09:03:21 AM »

A thin wire (18 gauge or smaller) vertical and radials would be practically invisible, and performance will be a LOT better than anything made of hamsticks.  Bandwidth will be broader, and it will be possible to tune to other bands (try that with a hamstick and you will be sorely disappointed).  

A thin wire dipole can be laid down on roof shingles as an inverted vee, or the ends pulled through nearby trees and even hung down if they're too long, and you will be very pleased with the results, especially compared with hamsticks.  And if you really want to save space, you can wind your own loading coils (or traps) and shorten it up even more.  

On any band where it totals a half-wave in length it will do very well, and it will work fairly well with a tuner if it is longer than a quarter wavelength.  Hamsticks are nice for portability, and designed for mobile operation where length is a near impossibility, but you can do much better even if your back yard is a postage stamp (think "vertical with hidden radials - buried or elevated").

Have fun constructing your antenna farm, and feel free to email me if you have questions.
Good reception & 73 de kt8k - Tim
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WB2WIK
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« Reply #7 on: November 23, 2004, 10:11:22 AM »

I don't understand why "a random wire is just ASKING for RFI problems."

That hasn't happened to me, anywhere I've ever lived.  I've even operated from motel rooms with end-fed wires and not bothered a soul with 100W PEP or CW.

The trick is using an appropriate wire length, a reasonable counterpoise and a tuner located in the right place.  In my case, even in a motel room, I put the tuner in the windowsill so the tuner, and the entire radiator, are all "outside," not inside, and hang a counterpoise wire of appropriate length from the tuner's ground terminal.

To say that this system beats the daylights out of a "Hamstick dipole" would be putting it mildly.

WB2WIK/6


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KF3EH
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Posts: 35




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« Reply #8 on: November 23, 2004, 08:03:04 PM »

Well, my current situation is ... a yard with no more than about 50 ft in any given direction, no trees to speak of, a duplex apartment, no real roof access.

As far as a random wire goes, EVERY time I've used one, there was terrible TVI on the higher bands when operating at full power.  Plus, you end up getting RFI hash on your received signal as well, from every little piece of electronic equipment in your shack.  Right now, I use a random wire antenna for receive purposes, and I can't listen on anything below 14MHz, because I have a S-9+10 noise floor thanks to my computer.

But, all I was trying to say is, instead of insulting us because of the choice of antennas we make, how about HELPING, as that is what his forum is all about!
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KT8K
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« Reply #9 on: November 24, 2004, 06:40:33 AM »

Sounds like you might be able to make some headway by addressing the RFI from your computer.  I used to ground the chassis of my old desktop machine to my station ground, and made sure all my cables were as short as possible and had chokes in them to prevent radiation and RF pickup.  I never had to go to fully shielded cables, but thought about it at one point.

This past year I got a used laptop, and now I can only hear noise from the PC when the atmospheric noises are *extremely* low (like S3 or below on 80m) and my neighbor is NOT on his treadmill, which makes horrible hash (and I just haven't gotten around to working on it because he uses it, at most, 20 minutes per day).  Laptops generally have much lower noise levels than desktop machines, and even desktops seem to have become less noisy in recent years.

As for RFI from a random wire ... I cut my "random" wire antennas to a length such as around 65', which is a quarter wave on 80m, a half wave on 40m, etc.  With the addition of a proper counterpoise wire (as described by WB2WIK/6 above) you should have practically no RF in the shack or house to bother things.  Of course, if you're running a kilowatt (which I would NOT advise in your situation) the RF levels may still be high enough to be a problem, but I think that's overkill.  I run 5 watts HF to low verticals and a wire loop at the level of the second floor eaves (with a small autotuner), have houses 10 feet away on both sides, and still worked I7RIZ on the low end of 40m last night - no problem, and no RFI.

I think you can get your station into much better shape with relatively little trouble and expense.  I also thought the insults were mostly to the hamstick antenna, and not at you.  Your questions are good ones, and I'm sure the discussion is helpful to others.  Thanks for asking, and good luck with your station.
73 & best rx de kt8k - Tim
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WB2WIK
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Posts: 20547




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« Reply #10 on: November 24, 2004, 08:21:12 AM »

KF3EH, nobody insulted you.  I just commented that an end-fed wire antenna isn't any more of an RFI pig than almost any other kind of antenna: The problems you've encountered -- and you're certainly not alone -- are due to deployment and possible lack of experience, not the wire antenna itself.

I solve the "computer RFI" problems in a variety of ways, but the simplest one, and the one I use most, is to turn the computer off.  I don't need a PC to operate my station.  I've quieted down the XYL's and my kids' computers to the point where I can't hear anything out of them (on my ham gear).

Anyway...an end-fed wire can surely be used with zero RFI problems if you engineer the installation well.  It might take a bit of experimentation, too, and I realize this can be tough in an apartment where you might have several sets of eyeballs on you every time you want to play with antennas.

But to start:

-Obviously, you need a tuner.  The tuner should be metal shielded and well grounded if at all possible.  If not, then 1/4-wave (cut to length) radials should be directly attached to the tuner chassis for those frequencies you want to operate.  The radial wires can (and should) be insulated, and can just tuck under the carpet, run around room edges or whatever to keep them out of the way.

-Put the tuner as close to the outside as possible.  One good place is a window opening.  If it's inconvenient to leave it there all the time, pull the tuner inside when you're not using it, and put it back in the window when you are.

-An automatic tuner is great for this, since you don't have to look at it; but a manual tuner will often have more tuning range, and also cost less, and will still work fine as long as you can get at its controls for occasional adjustment.  Make a "tuning chart" for various frequencies, so once it's been adjusted, you can find the correct settings fast every time you change bands, or change frequency much within a band.

When you said "TVI," that surprised me a lot, since TVI *should be* a thing of the hazy, distant past by now -- almost everybody is using either cable or satellite TV, and if installed properly, those are very difficult to interfere with.  I run a kilowatt output on 160 meters through 2 meters and I think the last time I actually had any TVI was in 1978, before we switched to cable permanently.  I'm very active, and that was 26 years ago, and having moved seven times since then I have always run kilowatts and have never had TVI anywhere.  So, something is amiss there.

"TVI" is pretty easy to troubleshoot and debug, but of course you have to experiment.  It's always the TV's fault, or the fault of something connected to it (more likely) like a VCR, DVD, Nintendo game, stuff like that.  Those all stink when it comes to RF, but each can be debugged on its own to completely eliminate TVI.  One thing that drove me nuts at my current QTH was "game interference" from Nintendo or Sony game boxes.  Those darned things use power supplies that will shut off if any RF even comes close to them, and to re-boot you have to unplug them and plug them back into the wall outlet -- very inconvenient.  I finally solved all the problems with a lot of ferrite cores and wires wrapped multiple turns through them.

Anyway, don't give up.  And surely don't give up on end-fed wire antennas.  I think I finally learned how to use them properly after about thirty years in the hobby or so...

WB2WIK/6




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KE6VG
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Posts: 298




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« Reply #11 on: November 24, 2004, 04:55:52 PM »

If you want to play around with hamsticks here is a website with some hamstick projects.

http://www.hamuniverse.com/antennas.html

I believe they have a beam, a vee beam and another one that might work for you that is multi-band. They used an LDG RT11 autotuner at the feedpoint to tune it.

Hope this helps.
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