BBT Delivered Hy-Gain Penetrator 500 Today

[Marconi]

Yes. My original P500 was tuned for the CB at about 27.200 +/-. I put the analyzer on it and it read 51 ohms, X=0 or very close to 0. I simply shortened the top section while looking at the analyzer, until I hit my new target, 28.800 MHz. Of course, I had to make small adjustments to the analyzer for it to follow the excursion. At 28.800 MHz, it read 50 ohms (I think 50.5 or 51 ohms) and X=1. Close enough. Somehow, that hairpin is carefully matched to the length to get proper resonance. Since the hair-pin is fixed, and the antenna is designed to provide resonate from 24.8 through 29 plus MHz, it's obvious that the "sweet-spot" is where ever you tune the antenna to.

See above.

Well now I recall you posting your tuning experience earlier, and I think I had the same thoughts back then.

I was thinking the difference in resistance someone might see doing what you did...would show a workable but greater difference however. The reason I had this thought was, I seem to recall a story that I heard about Jay's I-10K design, and how he modified a P500 matcher to be an adjustable tuner instead of fixed, by making both sides of the match point tunable for both resistance and reactance.

If this is not true, then that's one thing, but if it is true...I wonder why he made his matcher adjustable to both sides of the sweet spot?

I guess Jay is the only one that could tell us what was in his mind back then and why he did what he did.

 

[Needle Bender]

didnt someone post back a few months about removing the top-hat from his penetrater and lengthining it the same amount to get it flat again? or maybe that was a differrent forum but i remember reading that it needed the same amount of length added as the top-hat length on one side and the sigma25/8 measures right at 5/8 with no top-hat at all. i wonder what would happen if you shortened the maco5/8 10 inches then added a 10 inch top-hat?

If this is not true, then that's one thing, but if it is true...I wonder why he made his matcher adjustable to both sides of the sweet spot?

I guess Jay is the only one that could tell us what was in his mind back then and why he did what he did.

cool gimick to help sales?

 

[V8Vega]

I just recieved my antenna & the manual shows it to be 19' high. I've read this thread a few times and I have to admit it's way over my head. My question is: Will I be able to dial this thing in on 11 meters? I just run a Tram D201A, so the "broad banded" thing isn't important. I just want low swr's on the standard 40.

 

[VA3ES]

I just recieved my antenna & the manual shows it to be 19' high. I've read this thread a few times and I have to admit it's way over my head. My question is: Will I be able to dial this thing in on 11 meters? I just run a Tram D201A, so the "broad banded" thing isn't important. I just want low swr's on the standard 40.

Should not be a problem. Just build it as described. If you have an SWR analyzer, use it to adjust the antenna to 11M. If not, use your SWR meter to bring it down to the frequency you desire (which I assume is 27.205, the middle of the CB band?).

Just remember the longer the radiator, the lower the frequency.

Once "dialed in", you will absolutely love this antenna!

 

[Needle Bender]

I just recieved my antenna & the manual shows it to be 19' high. I've read this thread a few times and I have to admit it's way over my head. My question is: Will I be able to dial this thing in on 11 meters? I just run a Tram D201A, so the "broad banded" thing isn't important. I just want low swr's on the standard 40.

it should be at last 22 feet tall overall, maybe a few inches more. i think weve shown the 19' measurement to be wrong

it should be real close to this http://www.cbtricks.com/ant_manuals/hygain/model_500/graphics/hy-gain_500_penetrator_1982.pdf

 

[VA3ES]

For CB use, I'd build it to 23', measure SWR and then start adjusting as required.

 

[Needle Bender]

For CB use, I'd build it to 23', measure SWR and then start adjusting as required.

23 feet is longer than even the old 23 channel version http://www.cbtricks.com/ant_manuals/hygain/model_500/graphics/hy-gain_500_penetrator_1975.pdf

 

[V8Vega]

Cool. I thought I may have wasted my money on something again. I'm putting a new roof on the pad in about a week and decided to scrap the Astroplane clone for one of these.

 

[Needle Bender]

Cool. I thought I may have wasted my money on something again. I'm putting a new roof on the pad in about a week and decided to scrap the Astroplane clone for one of these.

it looks like even the new manual that marconi posted a link to contradicts itself says 22 feet on the first pg then shpws 19 feet in the picutre

 

[Marconi]

I just recieved my antenna & the manual shows it to be 19' high. I've read this thread a few times and I have to admit it's way over my head. My question is: Will I be able to dial this thing in on 11 meters? I just run a Tram D201A, so the "broad banded" thing isn't important. I just want low swr's on the standard 40.

V8Vega, when you construct your antenna and get the radiator built, do me a favor. Measure from the very bottom of the insulator (the feed point) up to the top end of element #2. This will include elements 2-5, and according to my figuring it should be about 19' feet tall. Adding the tuned tip #1, should make the total antenna about 22'x" or so...for resonance in the middle of CB. But that is hard to determine with just numbers. It has to be tuned.

I think this might be where the 19' foot number came from, albeit is mis marked as such in my instructions.

 

[Eastside]

Well my manual sez 22ft....and I scanned the pages.

 

[Needle Bender]

I found my calculater and just ran some numbers on it. i see the old penetrater from 1981 is 22 feet 6 1/2 inches but the new one is 22 feet. I was wondering why the diference so i did some calculations. i rememebr reading that the old penetrater is a 64 and the new penetrater is 5/8 so I tried running the numbers and it works out just right.take the old one from 1981 for 40 chanels 22 feet 6 1/2 inches and subtract the 3 inches for the base insulater so you have 267 1/2 inches plus the 10 inches on top-hat or 277 1/2 inches. if you divide that by .9979 for the vf of air you get 278 inches. if you take 278 and divide it by .64 you get 434.4 inches which is exactly a full wave at 27.185. i did the same thing with the new p500 that is 6 1/2 inches shorter but used .625 instead of 64 and got the same number 434.5 so i think the old penetrater was a 64 and the new one is a 5/8 thats why there 6 inches different. i wonder which one works better. maybe someone with both will compare them

 

[V8Vega]

V8Vega, when you construct your antenna and get the radiator built, do me a favor. Measure from the very bottom of the insulator (the feed point) up to the top end of element #2. This will include elements 2-5, and according to my figuring it should be about 19' feet tall. Adding the tuned tip #1, should make the total antenna about 22'x" or so...for resonance in the middle of CB. But that is hard to determine with just numbers. It has to be tuned.

I think this might be where the 19' foot number came from, albeit is mis marked as such in my instructions.

Will do. The new roof should go up in 2 weeks. I'm trying to find one of those fancy analyzers around here to make this easier, but I've had no luck so far.

 

[Marconi]

Thanks for the help V8vega.

This has been an interesting thread trying to figure out if the New SP500 is the same or just similar to the Old Penetrator 500, but how much difference do you think a few inches on one of this type of antennas really makes?

Is it big difference like turning a light switch off/on?

Or, is it just a little difference that would be hard to tell, even at a distance?

I know that modeling will never totally reproduce what might be observed in real life, but my modeling shows little to no difference between a .64 and a .625 wavelength ground plane antennas, and any difference that might be noted at some height...probably wouldn't be noticeable just by operating your radio anyway.

 

[Needle Bender]

i remember reading that a 64 shows a better signal then a 5/8 at 50-60 miles