BBT Delivered Hy-Gain Penetrator 500 Today

[gamegetter]

IMO, this Hy-Gain antenna kit and the instructions were always designed to be constructed as fixed-tuned with no tuning instructions included. Hy-Gain either physically marked all the tubing elements and/or indicated in the manual how the exposed lengths for each tube was to be set.

If the parts are pretty close to those in the older kits, then I would use the measurements in the latest old manual for 27 mhz and forget about the reasons and the signage. Common sense should tell us that 19' feet is NOT
correct for this particular styled antenna at 27 mhz, and is closer to 10 meters. If there are legal issues involved in any product, it is normal to be careful, and that too...is a good reason to NOT include any tuning instructions in the paperwork.

If you want to tune it for a different frequency, then you're on you own as to adjustments. A little math, and some "trial an error" should get you close.

words of wisdom...

 

[tvrc18]

I am not sure 19 feet is good for ten meters. I know they are covering there butt and not saying anything about 11 meters. 19 feet may work for the top of 10 meters 29.5 mhz but with out trying it who knows. I am going to shoot for 28 mhz and will try something longer than 19.

 

[BOOTY MONSTER]

maco specs their 5/8 a couple feet short of what what the math says 5/8 (.625) of 36 ft is also .

http://www.macoantennas.net/files/MACO_V58.pdf

FREQUENCY TO LENGTH CHART for V58 26-33 MHz Antenna
THIS CHART MUST BE USED TO SELECT THE OVERALL LENGTH FOR THE ANTENNA.
FREQUENCY OVERALL LENGTH
(MHz) (INCHES)
26.0 249
27.0 248
28.0 232-5/8
29.0 225-3/4
30.0 215-1/4
31.0 209-1/8
32.0 203-1/2
33.0 198-1/4

 

[tvrc18]

Well at 28mhz that is close to 19 feet, just a tad longer. Maybe I will try that first. Checking it at just a few feet above the ground before mounting is not the best way especially in my case. My house and garage are pretty close and I will be between the two. I don't want to get far back from the house because of the power lines are back there.

 

[gamegetter]

could the difference be in the difference in the match types for the two antennas. they are different guage and type.

 

[VA3ES]

I finally had an opportunity to go out into my back-yard to measure the main vertical driven element of my Hy-gain Penetrator (original version). (My antenna is down for maintenance.)

I measured 19' 1" from the top surface of the ground-plane bracket to the tip of the antenna (where the capacity hat is.) Originally, I simply put the MFJ259B on the feed point and simply shortened the antenna until the '259 read "VSWR: 1:1 / 50 ohms / J0. I would recommend doing the same thing - use an MFJ259B to be certain. Failing that, just adjust the antenna for lowest VSWR at the frequency of choice. Also, to maintain maximum band width, use the largest diameter of tubing possible. Telescope the top most tubing into the next section when tuning. The "fatter" the antenna, the greater the bandwidth.

 

[Robb]

Here's a thought:

If you make it the length a 5/8 wave for 11m; then the tuning coil in the base may need to be re-tapped for proper SWR. Given too, is that the ground plane radials will also be shorter for the 10m tuning and may need lengthening as well.

 

[VA3ES]

Here's a thought:
If you make it the length a 5/8 wave for 11m; then the tuning coil in the base may need to be re-tapped for proper SWR. Given too, is that the ground plane radials will also be shorter for the 10m tuning and may need lengthening as well.

Initially, I thought so too. The Penetrator requires no adjustment of the matching network, which is a "hairpin match" or Beta match system. While adjusting my antenna to 28.8, I simply shortened the tubing while monitoring the feed-point with my MFJ259B. When I got to my target frequency, 28.800, the reading was: VSWR:1:1 /50Ω / J0.
Easy-peasy!

Oh, and if the ground plane radials are at least 1/4 wave or longer, they don't need to be adjusted. VSWR climbs only if the radials are too short. I never shortened mine.

 

[BOOTY MONSTER]

im looking forward to the results of this shortened new version of the penetrator compared to the shortened maco or workman 58 that can be had for half the price . it will also be interesting to see the results of their compared durability in bad to very bad weather . i don't recall any complaints about the maco/workmans durability , but im sure theres got to ba a few out there

 

[Meglotron]

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[Meglotron]

so I got to screwing around on the calculator and I think the penetrator might be .64 not 5/8. I took the number for the speed of light 3E10 and divided it by 2.54 for inches then divided it by 1 million so I would be using mhz instead of cycles. When I do the math with 5/8 which is .625 it doesnt work out but when I use .64 it does, if the matching hairpin is a percentage to large for 10 meter tuning.
I got .944 for the percentage of the frequency difference between ch 20 and 28.8, then I did the math with .64 for 28.8 and got 262.5" but I took off 10" each for the tophat and the bottom of the main element that drops below the ground-plain bracket and got 242.5". Then I multiplied by the percentage difference of .944 and got 229" then divided by 12" to get it in feet and got 19' 1" or right where he said his tuned for 28.8 so is it .64 not 5/8?

 

[BOOTY MONSTER]

huh

i just divide 984 by the frequency in MHz and multiply by the fraction of the wavelength that i want . the diameter and the velocity factor of the material also effects the length slightly also FWIU . typically just a few to several inches .

 

[Meglotron]

but he didnt measure the tophat or below the ground plain bracket and the instructions on line show about 10 more inches below it. I dont think the velocity factor applies in air unless you need to split hairs because its like 99.97%. Thats a great doggie picture. Has he tried a stout yet?

 

[tvrc18]

I assembled mine but have not tested it yet. It is like 105 degrees out today and got worn down. I made it 19 feet over all length like the directions so it may be about 10" short of VA3ES mesurment. Do not over tighten the radial hose clamps or they will strip. I replace all 4 with bigger clamps after stripping about half of them. I could still twist the radials so more torque then wap they strip. They are pretty small clamps. Man they thing is tall and wide with those radials sitting out there 105".

 

[Meglotron]

I assembled mine but have not tested it yet. It is like 105 degrees out today and got worn down. I made it 19 feet over all length like the directions so it may be about 10" short of VA3ES mesurment. Do not over tighten the radial hose clamps or they will strip. I replace all 4 with bigger clamps after stripping about half of them. I could still twist the radials so more torque then wap they strip. They are pretty small clamps. Man they thing is tall and wide with those radials sitting out there 105".

What frequency are you going to be using yours for?