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BBT Delivered Hy-Gain Penetrator 500 Today
- Thread starter Eastside
- Start date
does it mention how long the top-hat radials are?Page 4 in my manual shows 22ft from feed to top hat.
No I have not put my P500 up yet......need help putting up my tower.
now i remember your mr suburban the heckler. i remember now from reading other threads on here. ok i understand you have some teenager need to harass people and start sh*t. its just your style so no problem
is the 22 feet just the main vertical radiator pole or all the way down to the tip of the bottom connecter including the bottom insulater?
is it tuned for channel 20? what does only the verticle radiator measure not including the bottom insulator? sorry to keep asking, i just want to get the main verticle radiator tube length right, not including the top-hat radials or the base of the antenna
Cannot say exact size...cannot see how much is inside the insulator.
Doesn't the bottom of the radiator sit on top of the bottom insulator, not inside of it?NB, ES tells us that the bottom section is 72" and my manual shows the length of each of the others. It also suggest to use 2"-3" overlap. Just add it up and you should be able to get real close to the overall. Good enough for government work anyway. The little difference that any two folks could figure might make a bit of difference for the match, but I doubt it would make any noticeable difference in performance... gain, or angle.
After checking some pictures that ES posted earlier, I realized my commets above are not quite right. This antenna has 5 elements for the radiator. Elements 2-5 are fixed set...which is due to the swaging design. The 19' feet overall length in my manual on page 4 may be the right length for elements 2-5.
Only element #1, the top element, is the adjustable part of this antenna. The old SP500 manual would probably give a more accurate idea for building this antenna.
ES, I'm surprised that you didn't realize this while we were discussing the overall length, instead of just telling us it was 22' feet long. The top element can change the overall length by up to about 52" inches.
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When I built my first Penetrator 500, (the original 1975 version) I assembled it strictly according to the instructions, and measured the Z (impedance) according to my MFJ259 analyzer. It tuned to 27.200 (+/-). I then simply shortened the top section, while looking at the analyzer, until I reached 28.800 MHz, my target. At that frequency I was looking at 50 ohms Z, X=1. Perfect.
I highly recommend the use of an MFJ259 analyzer. Well worth the money. Makes adjusting antennas child's play. I will definitely be using it again, when assembling the new Penetrator SPT-500.
I highly recommend the use of an MFJ259 analyzer. Well worth the money. Makes adjusting antennas child's play. I will definitely be using it again, when assembling the new Penetrator SPT-500.
NB, ES tells us that the bottom section is 72" and my manual shows the length of each of the others. It also suggest to use 2"-3" overlap. Just add it up and you should be able to get real close to the overall. Good enough for government work anyway. The little difference that any two folks could figure might make a bit of difference for the match, but I doubt it would make any noticeable difference in performance... gain, or angle.
After checking some pictures that ES posted earlier, I realized my commets above are not quite right. This antenna has 5 elements for the radiator. Elements 2-5 are fixed set...which is due to the swaging design. The 19' feet overall length in my manual on page 4 may be the right length for elements 2-5.
Only element #1, the top element, is the adjustable part of this antenna. The old SP500 manual would probably give a more accurate idea for building this antenna.
ES, I'm surprised that you didn't realize this while we were discussing the overall length, instead of just telling us it was 22' feet long. The top element can change the overall length by up to about 52" inches.
You fellas really get into the the technical aspect of it.
dont the instructions tell you how long to make it for CB? I just want to know how long the main verticle is without the insulator or top-hat.
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VA3ES, did you happen to record what (#1) the top element length was at 27.200 mhz?
And is the overall 19' feet indicated in your manual? And if so, do you remember measuring or using the 19' foot length in your construction for the radiator parts 2-5? If not, did you record this measurement so we can figure what your overall is?
Did you find the perfect match you were looking for at 28.800 or 27.200?
Where in your antenna system (feed line or feed point) did you measure using your analyzer?
ES might find such detailed information helpful in his own construction latter.
I thank you if you can help me with the dimensions for a planned modeling project for the SP500. I want to see if the raised radials makes a difference that modeling might demonstrate.
No.
I can't answer that, as I don't remember, nor did I specifically measure the antenna. I simply built it according to the (1975) instructions (attached below).
Yes for both. It was 51 ohms Z, X=0 for 27.200, and 50.5 Ohms Z and X=1 for 28.800.
Right at the feed point, using a 3' jumper.
If you carefully examine the instructions, you will note that the original length of the antenna is 199-1/8 inches plus the M1 assembly which is 71" bringing the total to 22' 6-1/8" (for 27.200).
NB, ES tells us this is not what he sees in his revised manual. Maybe he will post a copy of his now, since it is obviously different.
I don't see any indications for length/frequency in my manual.
Notice in the text on page 4 & the image on page 5, that it indicates the overall length of all element for the radiator should be set a 19' feet, top to bottom. And, specifically the following is recommended:
This might not be an important issue, but the part above about overlapping by 3" inches would seem to ignore the fact that this antenna is swagged, and that fact alone controls how much overlap there should be. The bottom section may even have a 4" overlap as far as I can tell for the pictures posted.
I question these instructions, and would sure like to see the revised version that ES tells us he has.
View attachment SP 500 manual.pdf