hamstick dipole ?
am considering putting up a hamstick dipole for 80 meters, mostly for cw and psk work so power isnt an issue. if i run this thing as a vertical dipole off of the back of the house is the mast material of any great importance? ive got some metal push up poles but thinking i may need to go with some pvc pipe as the shield leg of the dipole will be next to it. if pvc could i slide the sheild leg down into the pipe for added support? ideas? opinions?
Power may be more of an issue than you realize.
Originally Posted by KM5QF
Someone measured the power output of a hamstick dipole for 80m as 20 dB down from a 1/2WL dipole. That means an 80m hamstick dipole is 99% efficient when used as a dummy load, 1% efficient when used as an antenna. You can easily increase your radiated power by a magnitude by adding a little length and using high-Q loading coils.
Top rated legal 80m mobile antennas are about 10% efficient. An 80m mobile hamstick has been measured 12 dB down from that, i.e. less than 1% efficient.
Hamstick dipoles make fair antennas on 20m-10m but they are essentially a leaky dummy load on 80m. You would be running ~1 watt QRP. I don't want to discourage your experiments, but they have been done before. Everyone I know who has tried an 80m hamstick dipole has given up on it.
73, Cecil, www.w5dxp.com
The maximum power transfer theorem works just as well for a non-resonant antenna as it does for a resonant antenna.
and i just did also.
will have to forget much on 80 till i move.
Years ago I was in a military housing unit in west TX, I had a stealth antenna for 80 M, made of thin wire 66 ft long and run over the roof of the little house and into a tree, was barely visible. I used all the house wiring grounding connections for a counterpoise.
with 30 W of AM, I could be heard 50 miles away in daylight. Also much better DX at night.
There must be a way unless your landlord uses a magnifying glass to check up on you !
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Can you hang a clothes line? if so just make it out of wire and load it up. With a little tweaking you can use it as a multi band folded dipole.
no landlord to contend with but my HOA was trained personally by the nazi death squads. once a month these nitwits roam the neighborhood, stand in front of your house, and go thru a checklist looking for anything they can write you up for. thank God we are moving in 1 to 2 yrs and will never again deal with an HOA.
ive got a G5RV cut for 40 and up. using a tuner to load up on 80 meters i think the math was 3 watts erp. (100 watt rig) ive run hamstick dipoles before but not on 80 and was satisfied with the results. i remembered hearing the 80m hamstick was just a tuned dummy load before and this just cements it. im not going to the trouble. there is enough spectrum to keep me busy elsewhere.
my wire ant now takes up all the avail room i can spare. any other configuration whatsoever would leave bits of it visible from the street and i get enough postcards from hitler as it is. pull this weed, trim this bush, clean beer cans out of the back of your truck, etc etc etc....
to ans your question no, clotheslines are expressly prohibited. while not visible from the street all it takes is a neighbor to complain about it. mine would.
I agree with the others. A 40m hamstick dipole may be worth the time and trouble, but still not near as efficient as a resonant dipole. As was said before, 20m and down, its worth talking about, since it is getting closer to physical size to be near resonant.
Otherwise, its a lot of wasted time and money. The only way to efficiently get on 80m (or 160 for that fact, or heck... any other band) is to insure the physical size of the wire is at least resonant on the frequency.
Im still a new ham, but my short life of experimenting, I learned that the hard way! (even though, its in print and is common knowledge among the experienced ops! HA HA!)
While I will agree that a HORIZONTAL dipole is a waste of time with 75m Hamsticks when compared against a 75m folded dipole at the same height off the deck, for DX my simulations (and results thus far) show the Hamstick VERTICAL dipole to be at least 3 db UP over a 75m dipole at a max height of 21' AGL when looking at the low end of the lobe(s), where you need signal to be strongest for DX. Of course when it comes to NVIS, the cloudwarmer dipole will stomp the little whip flat... But I'm doing just fine with my 75m Hamstick dipole right now, making good QSOs without horrible effort on 100W, and with better signal reports and stronger received signals than with my old wire folded dipole. Of course, if I could have that dipole a half wavelength AGL, I'd surely go with it, as it would be tons better; however, this can't always be done (as in this scenario).
And of course, there's that very interesting combination of a Hustler 4 or 5BT-V with Hamsticks as radials (4, you choose which bands and then tune the Hustler to your spec using wires for ground, then tune the Hamsticks aftewr replacing the wires with them. That one looks very nice, and once I get my 5BT-V, I will probably get the remaning Hamsticks for the bands I want to work plus a bunch of QDs and go to town with something even better than the Hamstick dipoole.
Last edited by KI6QYJ; 08-01-2008 at 02:16 AM.
Wow! That's crazy talk. I can't imagine living in a place where my neighbors can tell me to clean out my car.
Originally Posted by KM5QF