Vertical antenna at ground with 12 radials compared with elevated position with 1 radial. Part 1.
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- Опубліковано 5 вер 2024
- Comparing a 1/4 wave vertical antenna deployed on the ground with 12 radials with an elevated position and only 1 radial. Measuring the average SNR by switching 34 times back and forth between those two setups.
After watching your video I constructed a 20 meter version of the antenna & counterpoise using wire, and fed with coax. The wire was hung from a tree and counterpoise elevated about 3 feet off the ground in a westerly direction. I have operated from this park quite a few times (US10650) and have had very limited success contacting stations west of the Mississippi River using a variety of antennas. With very challenging conditions this weekend I worked about 20 stations, and half were west of the Mississippi, and even into CA which in recent weeks has not happened for me. So in this test the antenna definitely favored the direction of the counterpoise, and the other contacts were about evenly spaced around the continental US. Even getting 20 contacts was pretty good for conditions lately (I run QRP CW) ... I would definitely suggest others try a raised counterpoise/radials, as even a simple wire construction of the antenna proved to be quite effective. Thanks for the video! Paul NA9M
thank you too for also testing it!
Excellent test, this is how it should be done. Nice base plate for the antenna!
I have the exact same base !
Thank you very much!
Experimentation is a great feature of ham radio. In this case I think you might find that the one elevated radial signal was helped by the ground radials even though they were not connected to the system. There has been some experimentation that shows that a ground screen formed by radials that are not connected to the antenna system still improve the signal for a vertical with am elevated system. Nice video!
that could be. do you have a link for that experimentation? thank you.
@@CrazyChekov
Check Out ON4UN's Low Band DXing Section 2.2.13 Elevated Radials combined with Radial Screen On the Ground. The book is out of print but it shouldn't be too hard to find a copy perhaps online.
Larry
Thank you for sharing your test results. Enough samples were taken to make your data and conclusions reliable and conclusive. In addition... the elevated counterpoise will provide a small amount of gain in the direction of the wire. A vertical with a raised counterpoise is essentially a bent vertical dipole. The best results for this type of antenna is with the vertical high enough to drop the radials at a 45 degree to the vertical. It should be kept in mind, that this type of antenna is susceptible to common mode currents on the coax, which in deed will and can affect performance and SWR. So it is recommended that some kind of coax choke be installed at the feed point of the antenna to keep the coax from radiating. In essense, the coax without a choke or 1:1 balun is just another counterpoise whose length can affect tuning. A choke (hopefully) takes the coax out of the equation. Best 73s Dan K1YPB - On the air since 1962
thank you. I will add a choke on the antenna feedpoint for a future test. there was one at the transceiver but none at the antenna feedpoint. 73!
Really like your real life tests. Well done👍👍
Thank you!
As you pointed out, the isn't a lot of difference between the two... The elevated is a little stronger on transmission, ground radials a little better on receive. While the elevated has less to carry, there is one BIG advantage to the ground radial system.... Chaning bands.
The elevated requires an entirely new tuned radial to change bands... Meaning a different length, with a separate attachment point. That is, unless you make a linked radial, staked out at it's farthest position, at which time you always have 16ft worth of line constantly elevated, just waiting for someone to trip into 😂... And that is only if you are limiting yourself to the high bands. 40M and 80M, if you have a loading coil, would require considerably longer, meaning higher elevation to account for sag.
Ground radials, on the other hand, you just adjust the whip/coil. As the radials couple to the ground, their exact length isn't much of a factor. Changing bands can be done in a matter of seconds. My portable setup runs 18 3M long radials and I've been able to tune it from 80-6M using my 5.6M telescopic and my Wolf River Coil Mini. I'm sure I lost some gain on the lower bands, but I also didn't have to have a ~20M wire elevated at least 3ft off the ground either. Also, because the radials are short, light, and don't easily tangle (26g silicone insulated wire), they pack fairly small (using a 6" kite string winder) and can be deployed just as quickly, if not faster, than an elevated system, being that nothing is needed to suspend them in the air. That also means placement is easier, as my footprint is less than 6M in diameter *and* can be walked over, this less likely to be walked into by sometime stray pedestrian....
73
thx for the comment. kite string winder....need to check that out. most time consuming for me is always cable stuff. maybe thats a solution. thx.
@@CrazyChekov Yeppers. When I go to pack them, I just unhook them from the tripod mount, then pull them all up simultaneously, and wind them on the winder.... Takes all of 30 seconds, if that. I then secure them via a Velcro strap. Deploy them almost as easily.... Unwind, separate the bundles, toss them in each direction, attach them to the mount, and finally spread them out over their respective section by running them between my fingers (6/bundle, 3 radials in each hand) to individually separate them.... Takes maybe a couple of minutes and they're ready to go. No need to touch them again till I'm ready to pack.
👍Thanks for doing the test and sharing. Though, I did wonder what the results would be with the same number of ground and elevated radials.
good idea...maybe I will try that.
Great experiment. The music is distracting however.
sorry!
Why one radial? if you add a second one you will cancel/reduce radial radiation and probably get different results. And, it would help if you had a common mode choke on both antennas to eliminate the coaxial cable impact on final results. 73 Danny E73M
thx for your thoughts, I will keep that in mind for future tests. 73!
Hey Cc. Sorry if I missed it but curious as to which way your radial was pointing relative to the stations you were receiving at? There’s asymmetry from 1 radial, but not huge. Greg from CA (a big POTA guy-forgetting his call rn unfortunately) has a lot of success running 2 elevated radials at 90° from each other to get additional gain between the span of those 2 radials. If they’re 180° from each other it is supposed to tame the asymmetry quite a bit. … overall I think your conclusion is a good one, that the single radial is a nice contender. There are potentially additional benefits from raising the radiator, since you’re able to clear obstacles in the near field better like cars and things. I got a clamp for camera equipment which I attach to the roof rails on my SUV vehicle and screw the whip that way and attach a tuned radial since my sunroof is massive and there isn’t much metal up there. That is of course when I have the car, which is not always. But it can forego the extra support structure, and becomes just as easy as the ground stake. … btw your machining skills look cool. Nice homemade base unit
thank you for the comment!
the radial is pointing to the receiving station. i think that should generate the maximum gain for the targeted station from what I know.
The radials don't radiate far field owing to symmetry. So they're a pure loss into the ground, not storing unradiated energy and offering it again the next cycle. The point of multiple radials is to reduce the current in each, which after I squared losses results in 1/N less radiation into the ground with N radials. Elevated radials avoid loss into the ground instead just by not being near the ground. Hence you need lots of radials on the ground vs much fewer if they're elevated.
yes the more the better. but for a portable operation I wouldn't carry a lot...so thats why I dont want to make the comparison with more than 12 (alread a lot). for a stationary antenna I would for sure go with more.
not a radial, you made a dipole.
An elevated wire is a counterpoise not a radial.
This is 100 year old tech, you cant make up your own
you right its called counterpoise.