Holy, triple deuce, you've been a little busy! I also found that the old Penetrator 500's were 22'6" but the Crossbow .64 was only 22'. I'll keep working on this 'till I'm at ease. Thanks for your help and time. Have a good one.
Holy, triple deuce, you've been a little busy! I also found that the old Penetrator 500's were 22'6" but the Crossbow .64 was only 22'. I'll keep working on this 'till I'm at ease. Thanks for your help and time. Have a good one.
Reading these posts shows the camaraderie of CB'ers across these United States. The common interest for each other gives the true meaning to CITIZENS BAND.
And people don't think CB type people don't help each other. I've sent a lot of stuff out to people just to help them get on air!! Pay it forward man. And it's good karma!! JMHO. No reason to sit on a pile of things I will never use especially if they can help others with their install. And yes I have met people all along the east coast while traveling for my old profession for 17yrs as a cell site tech. Some of the best people I have ever met! Have a couple of real friends I made up in KY area. Had dinner and all with them. And still speak about daily still by forums or phone. Good stuff man!! Like you said, shows that there are people that still give a shi** about their fellow radio users. Yes there are always bad apples in every bunch, even on the amateur bands. But anyways. To all, have a great day. 73 and God Bless.
222 Daytona Bch., FL.
I'm just a CB'er, what do I know???
222DBFL (10-16-2016)
Hey there,
I realize I'm Just Another Friggin' 0bserver, (in the swamp - LoL)
- but having had NUMEROUS Penetrators in the last 4+ decades, I can tell you this;
OEM, the original 23 ch P500 was designed for perfect resonance at 27.000 MHz, (dead center of the entire 26.0-28.0MHz 11m band) @ 22' 9.5"...
...to the screw on top which held the Four 9.5" rods (10" incl the loop ends)
...because the Penetrator500, (unlike the R/S .64 ) uses a Linear Loaded T-match, which uses the bottom 10" of the radiator, (beneath the counterpoise radials) as part of the matching network.
To have a nice flat SWR on the center of the 40 ch band you'll want to shorten the total length, (from the bottom of the coax connector to the top where the screw is for the top hat rods) to
22 feet, 7.625" WITH Four 9.5" top hat rods.
Goes something like this:
5/8 of a full wave length at 27.185 MHz =
.625 x 11803 (speed of light in MILLIONS OF INCHES per second) = 7376.875
7376.875 x .9979 (VF or Velocity Factor of aluminum in air) = 7361.4
7361.4 ÷ 27.185 = 270.8" minus 2.55" for average circumference of radiator = 268.25" (of aluminum radiator for a typical 5/8, but NOT the Penetrator500).
...continuing, 268.25" minus 9.5" (top hat rods) = 258.75"
258.75" + 12.875" (total length below radials) = 271.625" or 22 feet, 7.625" @ 27.185 MHz total length - from standing it on the ground on it's coax connector and measuring to the "tippy tip top" screw where the 9.5" long top hat rods connect.
On the original P500 the 9.5" top hat rods bent down at ~45° angle.
On the later 40 ch version they went straight out horizontally.
Now, some of the later 40 ch versions had a slightly different match length requiring slightly less (2"-5") length of the radiator so..., "YMMV"!
On my personal 1st Generation OEM Penetrator 500, I drop-kicked the top hat rods and extended the radiator 6.25" to utilize every bit of vertical height for maximum performance, tuned for 27.185MHz.
Without the top hat rods I noticed ZERO static increase, probably since static tends to bleed to ground via the ground shunt part of the matching network connected to both the feed point screw protruding from the bottom insulator and the end of the counterpoise radial to which the shunt is attached. (Some people screw-up when assembling and install the radial in the wrong direction).
As far as increased potential for corona discharge without the top hat radials, I don't run enough power to cause corona discharge, plus the antenna design won't handle the power usually necessary to effect corona discharge.
...not to mention the screw on top would still tend to cause corona discharge. You'd need a smooth, round surface to curtail it, such as the double circle on top of the New Vector 4000.
Hope this might help...
someone,
someday.
73
.
Last edited by JAF0; 10-16-2016 at 04:05 PM. Reason: major syntax correction - LoL
222DBFL (10-16-2016), BOOTY MONSTER (08-10-2017), phantom_tb (10-19-2016)
Thanks for the input JAFO. I went with the 45 degrees down angle for the Cap Hat Radials. Read an article a ham did after doing a good bit of tuning work with the new 500. It was something he suggested doing. I set mine up at 22' 4.5" 'cause I operate above 27.195. SWR's are 'bout 1.25:1 or less the higher I go. Great info, thanks again. 73's
Sorry for the rapid reply...
So I'd guesstimate about 27.500mhz for close to 1.0:1 swr?
The reason I dislike the downward bent top hat rods is because it's inverting the phase of the top 9.5" of the current and tends to cancel about 7" of the top of the radiator current, just below the top hat.
So instead of a full 265" of your 5/8 antenna height you'll end up with only about 249" effective, losing the top 16" which could be adding to the performance in improved receive capture area and overall height, sacrificing that little bit of top current being cancelled.
Last edited by JAF0; 08-10-2017 at 06:09 PM. Reason: Because I can't do anything right the first time. ;)
i prefer full length elements when possible . i also like larger diameter elements simply because the antenna is more durable . FWIU it makes very little to no electrical difference on these simple antennas , but the signal does travel on the surface of the elements ........
Holy Cow on the previous post, LOL. However, my wrong on a previous post. I meant to put 1.025:1 and that carries from about 27.345 to about 27.555. That's the best I see for SWR's. And OMG on the second of your posts. I'm no genius with all this stuff. I do the best I can with what I got and it works. Thanks for the feedback.
Last edited by phantom_tb; 07-27-2021 at 08:46 PM.
Also, I've used this setup with only 200 watts and talked to Australia from here. Must be doin' somethin' right. 73's all.
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