Using a 102" as a base

[CDX-007]

No 007, I thought you were referring to Skirtchaser's 1/4 wave without a ground plane.

I agree that a direct fed 1/4 wave with an effective ground plane is a very effective antenna if you get it up 30'+. However, I doubt that the matching devices used in most of the antennas we talk about in CB are loosing as much as 4db due to the matcher. There is some loss involved with transforming any impedance to another value in order to make a transmitter happy, but I don't know of anyone here capable of actually measuring what this value is.

I have had several A99's over time and I agree some act bad, but I have never seen one that did not talk good and the one I use today is one of the original A99's and it does not cause TVI. But with the thousands of A99 out there it would not surprise me that some are bad and maybe don't perform as well.

In my area here in Houston probably 99% of the stations that talk locally here hit my stations with signals from S3 - S9+. Now if one is 4db better than another, what difference does that make?

I guess I get a little irritated when it comes to the subject of A99s. I've owned 9 over time, (all of them except the first two were given to me when their X-owners switched from the A99 to an antenna) since their debut in the late 70's / early 80/s, I don't remember precisely when, - but to advertize an antenna as having 9.9dB gain when it was 2.5 - 3 S-units inferior to my honest 5.15dBi Penetrator really chaps my ass.

I have played with most of the antennas on the market and many that are no longer, I own 3 Penetrators and 1 Sigma 5/8 and have had two IMAX-2000s which I tested against several A99s and I have always been amazed that such a wonderful dummy load could find it's way into so many mediocre stations instead of a very similar but oh-so-much-better antenna the IMAX is, and for a measely $50 more which is zip in comparison to the years of enjoyment (instead of frustration) one will have with their station if it works well.

I appreciate quality and honesty in advertizing and when I know what so many people have fallen prey to I just get pissed.

I guess I shouldn't concern myself so much over it, but as Master Chief reiterated, the antenna is the most important part of the station.

I just hate to see people get taken and end up with mediocre performance at best when a few more bucks could make such a positive difference in their radioing experience.

It's rarely the wise and knowledgable who get taken, so I feel somewhat of a duty to make sure the true performance expectations are clearly stated or else people seem to flock to the bottom price / bottom performer.

OK, I'll shut up now...

 

[Marconi]

Well I appreciate your comments, but that has not been my experience. Surely having 9 - A99's that were all bad had to be real bad luck. My dummy load will talk maybe a block or three. Are you telling me that none of the A99's you had would talk more than a block or three? I don't disagree that there are bad A99's out there, but the A99 is far from producing no better than a dummy load.

As far as advertising claims go, I have never let the BS others state bother me that much, because I felt I knew better. If we just look at the rath of lies and desception in advertising today, it must drive you to drink.

 

[CDX-007]

Obstinance

Well I appreciate your comments, but that has not been my experience. Surely having 9 - A99's that were all bad had to be real bad luck. My dummy load will talk maybe a block or three. Are you telling me that none of the A99's you had would talk more than a block or three? I don't disagree that there are bad A99's out there, but the A99 is far from producing no better than a dummy load.

As far as advertising claims go, I have never let the BS others state bother me that much, because I felt I knew better. If we just look at the rath of lies and desception in advertising today, it must drive you to drink.

Well, my good man, how estute of you as I am enjoying a Spaten Optimator even now as I type!

No I didn't have 9 "Bad" A99s, THEY'RE ALL BAD!!!

It's not only the design of the lossy inductive matching network, it's the execution of the assembly that also offers sub-level performance.

I've used them high atop a 5 section mast, on top of a 2-story home, low on a rear metal pipe guard rail for stairs, in a tree, on top of a tree, directly on a roof top, on a tent, tilted up beside a bicycle and mounted horizontally out from a 3 section mast, up through a 5 element Hy-Gain Yagi, up through a MACO 3 element Yagi, and even on top of a forestry lookout.
They function, period.

If you put a MACO V5/8 in place of an A99 you will see about 1-1.5 S-units gain at 1 block, 1 mile, 100 miles, and everywhere between.
Do the same with an IMAX-2OOO and you wil see an increase of closer to 2 S-units gain. See: http://www.video-observer.com/imax/imax2000.htm
Do the same with a Penetrator-500, Sigma-5/8, I-10K, etc... and you'll see about 2.5-3 S-units gain over the A99.

Anyone who doesn't care about performance so long as they can be heard on their A99 by those few with whom they wish to communicate are blessed in two ways, they won't be a problem to talk over, and are easily contented.

As for me, I prefer getting the best performance possible for my effort, space and costs involved. That's why I have collected several REAL antennas from the good old 70's, and when $300+ isn't a significant amount I'll do as my neighbor 'President Ely' has done and try out an I-10K, reporting, of course, on how well it performs in comparison to a Hy-Gain Penetrator 500...which is mine, and NOT my "Daddy's Penetrator", thank you very much.

The Doc has it right on, by the way. All one has to do to get very good performance is drop an 8' 9" wire down from the feed point's shield, (a 1:1 balun would be nice and help cut feedline radiation, but not necessary) and another 8' 9" wire / whip / aluminum shaft attached directly to the center of the coax and placed vertically up from the feed point and you'll see 2dB / 4.15dBi gain over a 1/4 wave ground plane, and it can be done for only a few dollars of wire.

...and would surely beat the performance of an A99 at similar height.

I just don't see why people allow themselves to be taken in by the A99 when any other decent antenna out there will outperform it, ESPECIALLY on receive.

OK, I've beaten this dead horse to life enough times. If you have an A99, enjoy it. If you replace it, try to replace it with an I-10K. I know they're expensive but you'll be able to depend on it for decades to come, and the performance will astound you if you're used to your A99. You'll think you have a beam up there the difference will be so incredible.

73zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz

...and now for a 2nd Optimator!

hmmm, "Optimator", see, even my BEER is high performance.

 

[Mr Clean]

Why not make a wire dipole. Run it up and down or in a inverted V

 

[CDX-007]

Why not make a wire dipole. Run it up and down or in a inverted V

A wire dipole is what was discussed earlier, but a vertical version as for what he's wanting vertical would be what he needs.
...and an inverted vee is a fair compromise antenna, especially for 80m / 160m on a city lot where there isn't room for a flat top, but offers an inherent 2.7dB loss in comparison to a 1/2 wave flat top dipole.

Nowhere near the performance of a good vertical 5/8 - .64 wave GP for 10m/11m.

 

[W5LZ]

An inverted 'V' has an "inherent 2.7dB loss" compared to a 'flat-top'? I don't think so. Or did I read that wrong?
- 'Doc

 

[CDX-007]

An inverted 'V' has an "inherent 2.7dB loss" compared to a 'flat-top'? I don't think so. Or did I read that wrong?
- 'Doc

Greg has a pretty good website here:

http://www.seed-solutions.com/gregordy/Amateur Radio/Experimentation/IVee80.htm

Scroll down about 15% to the first grey box:

"At the same time, the radiation pattern of the vee will no longer be the pattern found in the initial dipole. I modeled both a dipole and inverted vee at 3.8 MHz using EZNEC. The antennas were 124 feet long. Each center was 50 feet high. The dipole was uniformly 50 feet high, but the inverted vee sides slope down at 45 degrees, ending at approximately 6 feet off of the ground. The ground model was real, with average quality. Here are some of the characteristics of the two antennas.

Resonant Dipole and Inverted Vee Comparison (3.8 MHz, 50' Apex)
Antenna:
Dipole ................................ Inverted Vee (90 deg.)
Maximum Gain 6.44 ................dBi 3.35 dBi
Take-Off Angle (max. gain)
90 degrees......................... 90 degrees
Feed Point Resistance
71.52 Ohms........................ 47.3 Ohms
SWR Bandwidth (2:1)
230 KHz (75 Ohms).............. 150 KHz (50 Ohms)

The inverted vee does give up 3 dB at high take-off angles. Other than the gain difference, at high angles, both antennas have basically round patterns. Due to the relatively low height above ground, both antennas shoot straight up. At lower take-off angles, however, the inverted vee maintains a uniform azimuth pattern, whereas the dipole becomes increasingly bi-directional. The next picture is a graphic overlay of the antenna patterns for the azimuth response at a 36 degree take-off angle."

In this case he sees a lttle more than 3dB difference, but the average I've seen is about 2.7dBd.

 

[W5LZ]

A dipole has 6.44 dbi gain? I suggest you try modeling that again.
- 'Doc

 

[CDX-007]

Actualy I see what you're point is, if it's dBi, it's in reference to an isotropic radiator, so he should've left off the i.

But the point is the ~3dB loss of an inverted Vee in comparison to a flat top.

Makes sense considering the inv. vee has basically an omni pattern whereas the dipole is bi-directional.
Double the area covered, lose 3dB in the direction covered by the dipole.

 

[Unit 194]

Re: Obstinance

I just don't see why people allow themselves to be taken in by the A99 when any other decent antenna out there will outperform it, ESPECIALLY on receive.

Not at my station (application)......

 

[W5LZ]

CDX-007,
First, I think I'd better explain something. I didn't read the example close enough so made the 'typical' assumption that the 'inverted 'V' was actually more of a 'drooping' dipole rather than having an included 'leg' angle of 90 degrees. That changes a lot of things, making my 'suggestion' sort of dumb (I'm trying to think of a good excuse for making that mistake, can't even claim not having enough coffee yet, oh well.). The dBd and dBi thingy wasn't what I was commenting about, the amount, 6+ dBi, of the gain for a dipole was. That's just too much even translating between dBd and dBi. A direct comparison between a 'real' antenna and an isotropic one is impossible to start with, but, just a tad over 2 dB is the typical difference.
'NEC' antenna modeling programs come in several versions, none are completely accurate or comparable without a huge amount of available data to plug into them. They are certainly a nice indication of what to expect though, and I've enjoyed playing with a couple of versions for years. As long as you have an idea of where/when to not believe them, they work just fine. Unfortunately, that 'grey' area between 'right' and 'wrong' isn't very well apparent. That's where experience comes in real nice to tell you that something just isn't 'right' about the results. (My favorite version is an older one, NOT always 'close' sometimes, but very easy to use. Sort of a "NEC for Dumbys" kind'a, "Nec4Win95". When I can afford/justify the latest version of NEC, I plan on getting it... might be a while.)
One other comment. A real-live inverted 'V' antenna isn't actually used much. A 'drooping' dipole is what's usually called an inverted 'V' by most people. Big difference in characteristics between the two. With the included 'leg' angle something around 120 to 160 degrees, there's almost no practical difference between that 'droopy' dipole and a 'flat-top' (including conductor stretch! ).
- 'Doc

[If I could actually put up the antennas required for testing all this, half of this state would be covered with my antennas! Just wish I could afford to own half of this state... On second thought, I ain't gonna do it, the taxes would be prohibitive.]

And since this is sort of 'off topic' for the thread, I apologize. sorry 'bout that...

 

[Marconi]

CDX007 Posts:

"At the same time, the radiation pattern of the vee will no longer be the pattern found in the initial dipole. I modeled both a dipole and inverted vee at 3.8 MHz using EZNEC. The antennas were 124 feet long. Each center was 50 feet high. The dipole was uniformly 50 feet high, but the inverted vee sides slope down at 45 degrees, ending at approximately 6 feet off of the ground. The ground model was real, with average quality. Here are some of the characteristics of the two antennas.

Resonant Dipole and Inverted Vee Comparison (3.8 MHz, 50' Apex)
Antenna:
Dipole ................................ Inverted Vee (90 deg.)
Maximum Gain 6.44 ................dBi 3.35 dBi
Take-Off Angle (max. gain)
90 degrees......................... 90 degrees
Feed Point Resistance
71.52 Ohms........................ 47.3 Ohms
SWR Bandwidth (2:1)
230 KHz (75 Ohms).............. 150 KHz (50 Ohms)

The inverted vee does give up 3 dB at high take-off angles. Other than the gain difference, at high angles, both antennas have basically round patterns. Due to the relatively low height above ground, both antennas shoot straight up. At lower take-off angles, however, the inverted vee maintains a uniform azimuth pattern, whereas the dipole becomes increasingly bi-directional. The next picture is a graphic overlay of the antenna patterns for the azimuth response at a 36 degree take-off angle."

In this case he sees a lttle more than 3dB difference, but the average I've seen is about 2.7dBd.

You also seem to ignore the author's note that the 80m model shows the loss at High Take Off Angle. The 11m verson would not be exhibiting such a pattern if installed at 1.4 wavelenght.

I don't think it is reasonable to compare these 80m antennas to similar installed 11m----as having similar results with gain or TOA. The 80m antennas are much closer to the earth relative to the wavelength and therefore act differently and in particular regarding the take off angle and resulting gain. If you mounted the 11m antennas in a similar fashion then the results would be more in line with the aurthors results for the 80m models, maybe.

Furthermore, the high TOA may be of advantage to local type communications at 80m and that is not typically so for 11m.

 

[CDX-007]

CDX-007,
First, I think I'd better explain something. I didn't read the example close enough so made the 'typical' assumption that the 'inverted 'V' was actually more of a 'drooping' dipole rather than having an included 'leg' angle of 90 degrees. That changes a lot of things, making my 'suggestion' sort of dumb (I'm trying to think of a good excuse for making that mistake, can't even claim not having enough coffee yet, oh well.). The dBd and dBi thingy wasn't what I was commenting about, the amount, 6+ dBi, of the gain for a dipole was. That's just too much even translating between dBd and dBi. A direct comparison between a 'real' antenna and an isotropic one is impossible to start with, but, just a tad over 2 dB is the typical difference.
'NEC' antenna modeling programs come in several versions, none are completely accurate or comparable without a huge amount of available data to plug into them. They are certainly a nice indication of what to expect though, and I've enjoyed playing with a couple of versions for years. As long as you have an idea of where/when to not believe them, they work just fine. Unfortunately, that 'grey' area between 'right' and 'wrong' isn't very well apparent. That's where experience comes in real nice to tell you that something just isn't 'right' about the results. (My favorite version is an older one, NOT always 'close' sometimes, but very easy to use. Sort of a "NEC for Dumbys" kind'a, "Nec4Win95". When I can afford/justify the latest version of NEC, I plan on getting it... might be a while.)
One other comment. A real-live inverted 'V' antenna isn't actually used much. A 'drooping' dipole is what's usually called an inverted 'V' by most people. Big difference in characteristics between the two. With the included 'leg' angle something around 120 to 160 degrees, there's almost no practical difference between that 'droopy' dipole and a 'flat-top' (including conductor stretch! ).
- 'Doc

[If I could actually put up the antennas required for testing all this, half of this state would be covered with my antennas! Just wish I could afford to own half of this state... On second thought, I ain't gonna do it, the taxes would be prohibitive.]

And since this is sort of 'off topic' for the thread, I apologize. sorry 'bout that...

Hey Doc,

Nothin' to apologize about, you're absolutely right on both counts. I have & use an Inv Vee for 75-80m / 40m / 20m and the higher in freq I go with the:
90* x 180* @ 123',
the weirder the performance gets.

I once talked into Ohio from Ca and hit Jack with S-8 running a Drake L4B at ~900w (240v sag) whilst my friend in the bay area with his KT-34 / tower / Alpha amp (can I safely say "MORE than 900w?"!) hit Joe with only S-5 - but that kind of lucky performance doesn't happen very often, usually I wonder "WHO IS hearing me?", as the station I'm trying for on 20m evidently isn't.

On 75-80m it does great, 53' apex, ~15' ends, fed directly by 450ohm thru a balanced tuner, and I get all kinds of questions about what I'm running from operators who seem impressed by the signal.
BUT
My friend Mike just a few miles uphill from me trounces my signal with his flat top dipole - he's running twice the power but typically has me by 8-10dB! Now, he has 3dB more power but that doesn't account for the additional gain. I believe at least part of that is his flat top dipole at 30', and with a little more NVIS.

Oh, and I'm embarrassed I didn't catch that dBi gain factor, good eye! I'm going to email Greg and ask him about that. I'll post his reply if I get one.

73

 

[CDX-007]

CDX007 Posts:

"At the same time, the radiation pattern of the vee will no longer be the pattern found in the initial dipole. I modeled both a dipole and inverted vee at 3.8 MHz using EZNEC. The antennas were 124 feet long. Each center was 50 feet high. The dipole was uniformly 50 feet high, but the inverted vee sides slope down at 45 degrees, ending at approximately 6 feet off of the ground. The ground model was real, with average quality. Here are some of the characteristics of the two antennas.

Resonant Dipole and Inverted Vee Comparison (3.8 MHz, 50' Apex)
Antenna:
Dipole ................................ Inverted Vee (90 deg.)
Maximum Gain 6.44 ................dBi 3.35 dBi
Take-Off Angle (max. gain)
90 degrees......................... 90 degrees
Feed Point Resistance
71.52 Ohms........................ 47.3 Ohms
SWR Bandwidth (2:1)
230 KHz (75 Ohms).............. 150 KHz (50 Ohms)

The inverted vee does give up 3 dB at high take-off angles. Other than the gain difference, at high angles, both antennas have basically round patterns. Due to the relatively low height above ground, both antennas shoot straight up. At lower take-off angles, however, the inverted vee maintains a uniform azimuth pattern, whereas the dipole becomes increasingly bi-directional. The next picture is a graphic overlay of the antenna patterns for the azimuth response at a 36 degree take-off angle."

In this case he sees a lttle more than 3dB difference, but the average I've seen is about 2.7dBd.

You also seem to ignore the author's note that the 80m model shows the loss at High Take Off Angle. The 11m verson would not be exhibiting such a pattern if installed at 1.4 wavelenght.

I don't think it is reasonable to compare these 80m antennas to similar installed 11m----as having similar results with gain or TOA. The 80m antennas are much closer to the earth relative to the wavelength and therefore act differently and in particular regarding the take off angle and resulting gain. If you mounted the 11m antennas in a similar fashion then the results would be more in line with the aurthors results for the 80m models, maybe.

Furthermore, the high TOA may be of advantage to local type communications at 80m and that is not typically so for 11m.

I'm not sure your point about "Ignoring the loss at a high TOA." as a flat top has reasonable NVIS GAIN when mounted closer to the ground.

Good point on the much greater relative-elevation based on frequency / wavelength.
From what I've seen an inverted vee tends to have a fairly spherical pattern when well above a 1/2 wave at the apex.
Still, I believe it would work well for all-TOA omni but without any gain in comparison to a dipole(2.15dBi), and a good 5/8 shows ~5.15dBi, omni, but mostly at a low TOA.
In decaades of playing radio I've seen a much greater gain in S-units from a 5/8 in comparison to a Starduster / Ringo level omni than only a couple of dB, usually increasing as the distance factor comes into play.

At, say, 20 miles, running 100w, I would 'expect' about an S-9 from the receiving station on the 5/8, about S-7 from the 1/2 wave, and around S-4 to S-5 on an inverted Vee for 11m at 50' apex / mounting height.
And there's one drawback I immediately notice, the inv vee begins at the top of the mast and drops down each direction while a vertical starts at the top of the mast and extends up it's overall length from there, adding additional height performance.

I've never tried a 10m - 11m inv vee at that height but it might be interesting to do, logging the performance difference in comparison to the the Hy-Gain Penetrator.

Over the weekend I decided to do a half-assed performance test. I have a Ringo I keep in the rear of the house which I use mostly for local listening as it's only at 30'. I swapped an A99 in and checked with only two stations available yesterday. One is 3 miles and the other is 14 miles from here.

~40w from my ICOM IC-751A:

At 3 miles the Ringo was S-9 + 15dB, the A99 was S-9 + 7dB, TS-940S meter

At 14 miles the Ringo was S-7 the A99 was S-5.3ish - he said, "A little over 5", ICOM IC-756proII meter.

And that's AGAINST A FRIGGIN' RINGO! ...sad

- The receive was commensurate, but I noticed the weaker background signals were reasonably audible with slight meter movement on the Ringo but basically in-the-noise on the A99, and at 14 miles he was a little UNDER S-5.
This A99 was given to me, is the only one (I forgot) I still have, and was used by a father-son mobile to base set up for 2 years, stock radios from the 'Shack', and from what I can tell is basically like-new with a slightly lower SWR than the Ringo.

73

 

[ajw2685]

Back from the depths of the dead...

I will be working on a design to use a 102" as my base antenna in a week or so. I plan on running it at 20-25 feet and I will attempt to take pictures and document the whole process. I plan on doing it because many have told me it can't be done or is not worth my time/money. So, naturally, I have to prove them all wrong. I don't expect miracles out of this setup. I get as much fun out of listening to the skip as I do shooting it. The main purpose of this setup is short distance (<20 miles communication).

Also, I could possibly be setting up a dipole as another experiment to help teach myself some more.