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Full wave antennas for CB
- Thread starter linearone
- Start date
Can anyone help me? I'm using a 66' 18 gauge wire end fed antenna up 40' in a sloper/slanted L configuration pointed northwest/southeast direction using 50' of rg8x coaxial cable. I read that end fed wire need a counterpoise wire to work efficiently. Can someone please tell me what would the correct length to use. I listen on 80-10 meters but transmit on 11 meters so that's the length I need the counterpoise wire for. Any help would be greatly appreciated.
Are you using a balun?
if so , 6:1, 9:1, 4:1?
then is there space for this?
http://www.w8ji.com/windom_off_center_fed.htm
if not is there space for half of this?
Separate inverted "L" for 80m ?
just some thoughts.
if so , 6:1, 9:1, 4:1?
then is there space for this?
http://www.w8ji.com/windom_off_center_fed.htm
if not is there space for half of this?
Separate inverted "L" for 80m ?
just some thoughts.
Okay then ,
then is there space for this?
http://www.w8ji.com/windom_off_center_fed.htm
if not is there space for half of this?
Separate inverted "L" for 80m ?
or , http://www.sral.fi/turva/G7FEKantenna.pdf ?
Chester, I'm sure many people find end fed antennas at least adequate if not the greatest thing since boobies. I'm not one of them. I recommend an end fed antenna somewhat less than a colostomy or rectal exam .
For one there really isn't such a thing as a true end fed as your equipment makes up the ground side of the antenna. You might think a walkie talkie uses an end fed but is actually emulating a 1/4 wave ground plane. Counterpoise is just another name for the other half of the antenna. So how does it get called an end fed anything? About the time you resort to a 49:1 transformer (voltage balun in nearly all available retail offerings) common mode current on the feedline is inevitable.
Motorboats, growling, feedback, narrow tuning, false resonance and peaks, and anything to the left of Attila the Hun are common symptoms of end fed antennas.
I'm really just attempting to offer alternatives that match what you have on hand with what I assume is limited space and other limitations.
then is there space for this?
http://www.w8ji.com/windom_off_center_fed.htm
if not is there space for half of this?
Separate inverted "L" for 80m ?
or , http://www.sral.fi/turva/G7FEKantenna.pdf ?
Chester, I'm sure many people find end fed antennas at least adequate if not the greatest thing since boobies. I'm not one of them. I recommend an end fed antenna somewhat less than a colostomy or rectal exam .
For one there really isn't such a thing as a true end fed as your equipment makes up the ground side of the antenna. You might think a walkie talkie uses an end fed but is actually emulating a 1/4 wave ground plane. Counterpoise is just another name for the other half of the antenna. So how does it get called an end fed anything? About the time you resort to a 49:1 transformer (voltage balun in nearly all available retail offerings) common mode current on the feedline is inevitable.
Motorboats, growling, feedback, narrow tuning, false resonance and peaks, and anything to the left of Attila the Hun are common symptoms of end fed antennas.
I'm really just attempting to offer alternatives that match what you have on hand with what I assume is limited space and other limitations.
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Respectfully, I am.
My 10/20/40 MKII from LNR Precision just plain works. Without counterpoise. Doesn't matter if in my attic or in the back yard strung between a tree and the fence. Just hang it up, hook the radio to it and make contacts.
Let's see . . . Theory versus actual results. Hmmm.
I'll take actual results.
You're not alone there. I had the opportunity to devise and implement low viability antennas for remote use attached to AN/PRC-25/77. The PRC-25 had a robust tube final, the 77 was fully sand state. Imagine having to make do with less than 2 watts in most cases between 30 and 75MHz(FM btw). By the time signal arrived at an antenna more than a half mile away efficiency was crucial but low visibility was still a requirement. Getting RDF'd was bad enough without being visibly detected. The compromise was dummy dipoles (as a diversion) and verticals (the real antenna) that were for all intents end fed for actual radiators. Baluns wound on a cheap transistor radio loop-stick from the c-store were another story left as an exercise for the intuitive.
In any and all cases an end fed is a compromise antenna that is the result of choices made for you. If you have any other choice use something, anything else.
Heck, Kop, my life is a compromise so the end fed is a perfect fit for me.
On that note, I do have a cobweb in a box. It will give me a few additional frequencies as well as full power capability. (My end fed is rated 25 watts max.) Still waiting on the weather to cooperate.
Let's see . . . Theory versus actual results. Hmmm.
I'll take actual results.
Lol, "theory vs actual results" and the more common "theory vs reality"... Those lines always amuse me. The fact of the matter is antenna theory is what is misunderstood, which often leads to such perceptions. There is nothing in actual antenna theory that disagrees with the result you got.
I actually have a similar antenna to that laying around here somewhere myself. I use it when traveling as an easy antenna to set up. It works well, no complaints.
The DB
I wasn't yanking Kop's (or anyone else's chain) with that remark.
But am surprised it didn't get a better response out of him.
I know enough antenna theory not to lay my end fed directly on the ground or stick my tongue to it while my wife keys the mic.
And enough basics not to screw up my radio while experimenting with what works. Hence, theory versus actual results.
That said, Antenna Theory always been interesting to me. Antennas perform in a certain manner according to a proven set of rules until variables are introduced, don't they? Speculation (theorizing), it seems, should only come about when trying to determine how they will perform in conjunction with outside influences, whether nature's or man-made.
Anyway, you hit the nail on the head when you said, "It works well, no complaints." That's my new go-to response concerning end feds.
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Hi.. Reading this about a full wave dipole.. We.. As I my dad and I did many experiments with antennas while out on camping trips .. Bone of them was a full wave dipole we had hung about 20 feet above the ground . Yes we did some climbing with pole spikes.. Anyway we used 18 gage stranded wire.. Had a Teflon insulator.. 1/4 wave ground . Full wave radiator .. But we fed it from the antenna with 6 feet of 75 ohm cable coupled to 50 feet of 50 ohm rg8x.. With a little bit tuning (folding over the end ) we got a 1:1 to 1.. SwrHas anyone other than myself tried this?
YEARS ans YEARS ago I made a full wave wave dipole for 11m. I had it horizontal about 12 ft. off the ground and just about stretched across the yard suspended from pcv insulators from tree branches made of solid #10awg. it had a high swr with no matching device. well... high by cb standards for hamsters it was perfectly acceptable, over 2:1 maybe, I really cant remember... anyway I didnt care becasue I didnt have a tuner and apparently if you read the manual Galaxy says its saturn base can run into a 2:1 swr indefinetely with no ill effects (read the manual, Im not lying).
I had mixed results, it was way more narrow than I expected, perhaps because it was so low to the ground. it made my signal lose all its carrier and on the recieving end it was all swingy. but loud. perhaps since it had the appearance of no carrier it sounded all crappy and wooshy and swingy to the reciever. I dunno. I never played with it much after this. I still have it somewhere in the closet. I would like to build a small tuner for it just to see how it would compare to a half wave dipole in the yard...
anyone else done this?
Does it have any benefit?
.. We talked from under the trees back to out home town 75 miles or so with out any amps.. Our next trip to the same site we made what was called a Texas tornado antenna .. Usesed the same setup but with 10 full wave lengths of wire.. It brought our signal up from s2 to s3 so we were told by our ham buddy..
The 75 ohm cable was our matching system they both had geat recieve that little bit extra kick on the transmit might have worked better if we were able to get into an open field and higher . It was fun
We started building quad beams after that.. Actually worked better using some of the same principles .. Build a couple out of bamboo . When perfected. We used fiberglass and aluminum ..
Hope some of this was us full..
Have a great one 73s
When you say fold it over, do you mean folding over the end and shorting it to itself to shorten it or do you mean just folding it over like a u and keeping it separated
Hi folding to shorting itself over itself.. As if 1 Piece .. Did try keeping it separate or windind it like a load .. didn't work got various reading with out touching any adjustments just make sure it's a solid wrap
One more thing I forgot to mention
.at the point where the 50 ohm cable meets the 75 ohm. Make a choke on the 50 ohm cable of the side of the barrel
. 3 turns of cable through a clamp on type choke works well
check out the extended double zepp. near-lossless balanced feed matching, 1.25 length total, big broadside gain. if you want to match a full wave, you need a quarter wave piece of ladderline, which makes a 50ohm load, and then a 1:1/dirty coax choke