half wave antennas not needing ground elements?

[Robb]

In a perfect location with no objects to detune it; the .64 still has a better radiation pattern. With a slightly better capture area. And a small increase in gain on transmit compared to others. It doesn't matter if the TX gain is only slightly better - it is still BETTER.

OK; so there are 3 things in its FAVOR.
So; what is not to like? If I were to build an antenna from scratch and using what he has - as Booty is TRYING to do with this thread - I would want to go for a design that has the best characteristics available. Wouldn't you? SO Booty has asked the question to his dilemma of the members here and needs enough banter to find out what to do with his antenna to make it work for him, keep his landlord happy, and not lose any efficiency. Maybe even find some gains if it can be reasonably done - too!

So; ask yourselves where this thread has started from, and where it is now.

Booty; I would take advantage of the fact that you can make it a .64. That you can make a loading coil for it. You still need to make a coil regardless of what length it will be. But I also see that you need some more definitive answers before you can get the job done. WE know that the velocity factor for Al. We don't know what formula would determine any change in width of the radiator twards the need of accounting of its resonant freq. We know a 10 turn coil @ 1 1/2 inch wide form would be best. What else do you need to know to make this project to work for you?

Let's get this thread back on track and see if these egos can focus on the subject at hand rather than get too far away from the REAL point of this thread. That is - to get BootyMon's antenna right!
FOCUS!

 

[CDX-007]

- Just to wrap it up on my end, Sorry Shock but I choose not to be a subscriber to your theory camp, and recall certain commercial numbers which contradict certain other claims.
- My intuition, though unpopular, was evidently correct at the time.

Now, what exactly are the current nodes and theory behind the Skelton non-J pole none apparent colinear phased cone .82 wave monopole?

Harp all you want on the worst-case scenarios and straw-man arguments to prove we are all doing it wrong, but I have the luxury of both decades of successful experience and proven theory to know the difference.

I feel I've already wasted far too much time on this fruitless off-topic debate about which length of 5/8 wave tubing can, but can't, match which so-called ultra-efficient matching network which just happens to have an identical radiator to a completely different 40-year old network, coincidences favoring your claims but so-called absolute ignorance of antenna theory necessarily refuting mine.
I've better things to do with my time.

Oh, and keep up the theoretically perfect 6dB-per-S-unit camp while ignoring the several links I offered to well written tests showing otherwise.
I understand why you need it to be that full 6dB.

Now back to raising my mis-measured, non-performing POS .64, if only I would have been smarter and bought a nice, compact Maco-V5/8 with all it's increased performance enhancing match inductance.

Maybe soon they'll produce an ultra-efficient mega-inductive-matched 10 foot .82 saving so much aluminum! :w00t: Remember, "It's only the electrical length that matters". They would never call it a .64 because it's .64 long.

Booty, figure out what is the most inconspicuous form of a ¼ wave counterpoise, then enjoy your .64!

73

 

[BOOTY MONSTER]

hey Robb , i do appreciate your effort to keep the thread focused on my particular needs , but i feel the thread is going just fine . as ive said in other threads .... i have absolutely no issue with any thread i start getting off topic as long as good information or a good debate/discussion is still happening , and that IMO is definitely happening here . as some may have noticed it seems that every time i get an answer i get more questions . i always enjoy the knowledge shared when a thread evolves beyond the original post and rarely or less discussed information is bought to light .
thanks again though for wanting to be sure i got the answers i needed for my OP though .

as far as my original question about a 1/2 wave needing ground elements . it seems it can work without them but will work better with them . but going from a 5/8 to a 1/2 wave is a significant step backwards , which i already knew . but i thought the potential of good performance without ground elements might be worth it . now i don't .

right now best first option seems to be to keep using my 5/8 or .64 vertical and put a very steep slope/droop on my current ground elements so they don't stick out so far to the sides . second best seems to be to cut them in half and leave and leave them horizontal . and 3rd seems to be combining the two using steeply sloped 1/8 WL ground elements . lastly is using the mast as a ground element . id rather not use the mast as a ground element since i like to keep the antenna insulated from the mast and earth ground so the only thing radiating is up in the air .

ill be able to discuss my options with my landlord this weekend and see which ones he can live with and go from there . ive got it in my head that i want to make a typical coil on a former as was described earlier in this thread . i went to home depot and lowes last night and looked at stuff to make one and ive got an idea in mind . ill start another thread about making the coil though . ill do it in the home brew section .


when i went from my home brewed wire star duster aka 1/4wgp to my 5/8 (in the exact same location , the 5/8 having a 1 or 2 foot lower feed point) i got local reports of up to 4 s-units more registering on their meters . before i made the swap i made a list of some locals names and asked what their meters were showing so i wouldn't have to rely on my or their memories to document the difference for my self . i by no means believe there was a 24 db difference between the antennas , but it really drove home how inaccurate meters on CB radios are . i was told the lobes in the 5/8 had a significant impact on those numbers too . i do know i could hear folks on the 5/8 couldn't hear at all before on the 1/4 and that i could talk to folks barefoot on the 5/8 that i had to use power to talk to befor on the 1/4 . these were contacts in surrounding counties and the other side of Richmond .

 

[CDX-007]

...right now best first option seems to be to keep using my 5/8 or .64 vertical and put a very steep slope/droop on my current ground elements so they don't stick out so far to the sides . second best seems to be to cut them in half and leave and leave them horizontal . and 3rd seems to be combining the two using steeply sloped 1/8 WL ground elements . lastly is using the mast as a ground element . id rather not use the mast as a ground element since i like to keep the antenna insulated from the mast and earth ground so the only thing radiating is up in the air .

ill be able to discuss my options with my landlord this weekend and see which ones he can live with and go from there . ive got it in my head that i want to make a typical coil on a former as was described earlier in this thread...

What about coil loading shortened, sloping counterpoise radials?

Set the .64 for ~zero reactance with the full size radials, remove them, then using a small 1/2" - 5/8" fiberglass rod or dowel and some wire, wrap it until it tunes the 1/8 wave radial & antenna for zero reactance.

I would seriously consider a coil-loaded radial that places the coil near the outer ends.

Make one shortened radial at a time, simply copy the first correctly tuned & completed.

Once all 3 - 4 are installed recheck for ~zero reactance and if it's elevated, discern which way and retune the coil slightly to bring it back.

?

 

[CDX-007]

i used an average vf for aluminium to highlight lack of it,in reality depending on other variables it may be a percent or two either side.
the point i was making was the vf was missing altogether in other experts calculations,but like most things in antennas there is variables dependent on materials used,location etc,like radiator lengths being adjustable to take into account impedance changes due to surrounding objects,thats why all decent antennas are tuneable and not preset.

You confuse K factor of a radiator with velocity factor of a feed line.

in answer to your first point on the 102 inch whip,i can only assume this extra 5.5 inches brought a further 6db gain going by previous statements,

Though perhaps fomented somewhat obtusely, you're correct.

An Imax is a .625, (contrary to popular misconception) and therefore adding ~6", then retuning the rings for ~zero reactance, approximates a .64 thus adding to the DX ground-wave performance.

 

[Shockwave]

- Just to wrap it up on my end, Sorry Shock but I choose not to be a subscriber to your theory camp, and recall certain commercial numbers which contradict certain other claims.
- My intuition, though unpopular, was evidently correct at the time.

Now, what exactly are the current nodes and theory behind the Skelton non-J pole none apparent colinear phased cone .82 wave?

Harp all you want on the worst-case scenarios and straw-man arguments to prove we are all doing it wrong, but I have the luxury of both decades of successful experience and proven theory to know the difference.

I feel I've already wasted far too much time on this fruitless off-topic debate about which length of 5/8 wave tubing can, but can't, match which so-called ultra-efficient matching network which just happens to have an identical radiator to a completely different 40-year old network, coincidences favoring your claims of antenna theory necessarily refuting mine.
I've better things to do with my time.

Oh, and keep up the theoretically perfect 6dB-per-S-unit camp while ignoring the several links I offered to well written tests showing otherwise.
I understand why you need it to be that full 6dB.

Now back to raising my mis-measured, non-performing .64, if only I would have been smarter and bought a nice, compact Maco-V5/8 with all it's increased performance enhancing match inductance.

Maybe soon they'll produce an ultra-efficient mega-inductive-matched 10 foot .82 saving so much aluminum! :w00t: Remember, "It's only the electrical length that matters". They would never call it a .64 because it's .64 long.

Booty, figure out what is the most inconspicuous form of a ¼ wave counterpoise, then enjoy your .64!

73

You don't have to apologize for not believing me CDX it hapens all the time, or challenge me to fully explain the theory behind the Sigma IV. Keep in mind even Blaise the inventor nor Cebik the expert never explained the radiation currents in this design. If you ever meet someone who can do this, please introduce me to them. Keep in mind I've seen the models and they present more questions in this regard then answers.

Having decades of successful experience when the tests are clearly not conducted in a controlled scientific manner might cause you to reconsider your method of testing. I am not the only knowledgeable person who has pointed out the problems in your pictured test condition but you're sure you know more then those who offered advice. Finding the Sigma design behind the .64 wave makes me curious what that test setup looked like.

Yes, the .64 wave is an excellent omni antenna. I never said yours will not perform well. The .64 wave is the second best omni beating the 5/8 wave by mere tenths of a db and falling short of the Sigma IV by nearly a full db. If you're happy with the 5/8 or .64 wave, it's nothing to be surprised at since it's a great antenna. However, there are others interested in knowing about the best performing omni. In Booty's case the Imax would serve him well. One 1/4 wave radial on the current 5/8 wave will cause directional effects and could fall short of matching the impedance correctly.

PS, how do you get ground wave beyond about 3 MHz? Ground wave propagation is not possible on 11 meters. It's simple line of sight propagation.

 

[BOOTY MONSTER]

"What about coil loading shortened, sloping counterpoise radials?"

i could put a top hat on the end of each one too and then id have four merlin antennas for a ground plane hahahahaha

sorry , couldnt help myself . it is a option i hadn't considered though . thanks 007 .
i hope option 1 is acceptable though

 

[Shockwave]

"What about coil loading shortened, sloping counterpoise radials?"

i could put a top hat on the end of each one too and then id have four merlin antennas for a ground plane hahahahaha

sorry , couldnt help myself . it is a option i hadn't considered though . thanks 007 .
i hope option 1 is acceptable though

Option 1 will work and it's a good idea too. The sloped radials may shift the impedance slightly but you should be able to retune the match easily.

 

[CDX-007]

You don't have to apologize for not believing me CDX it hapens all the time,

Why am I not surprised.

or [You don't have to] challenge me to fully explain the theory behind the Sigma IV.

But I DID ask you to explain the theory?

Keep in mind even Blaise the inventor nor Cebik the expert never explained the radiation currents in this design. If you ever meet someone who can do this please introduce me to them.

Hmmm, just one of nature's wonders I guess. No explanation forthcoming, simply ACCEPT! .

Having decades of successful experience when the tests are clearly not conducted in a controlled scientific manner might cause you to reconsider your method of testing.

Why, they work perfectly.

I am not the only knowledgeable person who has pointed out the problems in your pictured test condition but you're sure you know more then those who offered advice.

There's always another dissenting opinion.

Finding the Sigma design behind the .64 wave makes me curious what that test setup looked like.

Mast, coax, radio, you know, the normal mistakes.

Yes, the .64 wave is an excellent omni antenna. I never said yours will not perform well. You said that because you may be more interested in arguing then learning.

Au contraire, I enjoy learning within the context of reality.

The .64 wave is the second best omni beating the 5/8 wave by mere tenths of a db and falling short of the Sigma IV by nearly a full db.

More near-field hoopla.

If you're happy with the 5/8 or .64 wave, it's nothing to be surprised at since it's a great antenna. However, there are others interested in knowing about the best performing omni. In Booty's case the Imax would serve him well. One 1/4 wave radial on the current 5/8 wave will cause directional effects and could fall short of matching the impedance correctly.

You forgot a word, minimal. Could cause minimal directional effects, and would match the impedance perfectly, BTW.
Only a single counterpoise is necessary, however more tend to maintain a consistently lower TOA in all directions, plus help prevent RFI.

However, Booty is in a restricted situation, talking about a perfect world scenario is irrelevant to this strand and mostly why you and Jazzsinger have wasted so much of my time.

 

[CDX-007]

...i could put a top hat on the end of each one too and then id have four merlin antennas for a ground plane hahahahaha...

YES YOU CAN! And that's why capacitance hats work when you are forced to use something shorter than a ¼ wave.
- There's another possibility for shortening the radials, however, that might look even worse!

 

[jazzsinger]

You confuse K factor of a radiator with velocity factor of a feed line.

Call it whatever you want but its still velocity factor due to the conductor being surrounded by air and not free space,the only difference between the antenna radiator and the transmission line is the dielectric,the end result is the same,the slowing of rf propagation,and you still didn't account for it.

Though perhaps fomented somewhat obtusely, you're correct.

An Imax is a .625, (contrary to popular misconception) and therefore adding ~6", then retuning the rings for ~zero reactance, approximates a .64 thus adding to the DX ground-wave performance.

Ground wave on 11m,thats a new concept,as shockwave already pointed out groundwave is non existant above 3 mhz where line of sight predominates.

 

[CDX-007]

Call it whatever you want but its still velocity factor due to the conductor being surrounded by air and not free space,the only difference between the antenna radiator and the transmission line is the dielectric,the end result is the same,the slowing of rf propagation,and you still didn't account for it.

That's what K factor is and why I use it, contrary to your accusations.

And it's exactly the difference in dielectric which is in question. I notice you didn't state what the difference in dielectric constant is from air to poly foam, or any other solid dielectric .

Dielectric Constants

Vacuum .......... 1
Air ................. 1.00059
Neoprene ........ 6.7
PVC ............... 3.18

Well, it appears air is no where near the RF inhibitor you imply. .95 VF doesn't carry any weight in fact nor antenna design either.

 

[jazzsinger]

Now you're attempting to muddy the water with a feeble implication that all >3mHz RF is skywave, and therefore using the E or F layer. Well I guess I shall throw away all my handbooks, the jazzsinger has spoken.

i was backreading your posts, and still learned nothing.

now your trying to convince us that line of sight is skywave.



So on that note i'll bow out of this thread.

 

[Shockwave]

The statement was that groundwave does not exist on 11 meters ever. Groundwave occurs only when a very low frequency like standard broadcast AM propagates beyond the horizon because the wavefront has been pulled down towards the ground.

 

[CDX-007]

Great, and I really wasn't expecting any response from you to the whole velocity factor maths and VF of 95% turned 99.9% or anything.

.99941 VF is really oh so close to 1. It truly is.

Yes, OK, very fine choice.

Toodaloo