penetrator 500

[Dr_DX]

A couple of other observations:

You are missing a nut between the center radiator and the matching rod.

The stud that is coming out of the base that both the shorting rod and matching rod connect to, the connection order should be nut, shorting rod, matching rod, and nut - yours is reversed.

Also, you have a hole in the center radiator. You can see in Whiteastro's picture that he has a screw in it. It needs to be sealed so rain water can't get in. If it does, it becomes trapped and it will play hell with your SWR.

 

[Dr. Frankenstein]

Not to start an argument...... throughout the years this antenna has been made and used by many on 11 meters, but then in the early 80s, all metal construction CB antennas were deemed illegal but have and are still made for 10/12 meters as stated in the ad for the antenna.

I know that, for years, no matter who sold the antenna they have always stated the same thing, "This antenna is illegal for 11 Meters use.", even though the antenna was originally made for CB use.

If you want to read it the reason for being illegal is all here:

16 C.F.R. PART 1204—SAFETY STANDARD FOR OMNIDIRECTIONAL CITIZENS BAND BASE STATION ANTENNAS :: :: Title 16 - Commercial Practices :: :: :: :: ::

law.justia.com

As time went on, the only thing that changed in the SPT-500's design was the matching section (it kept getting shorter), as was the wording for the description of the antenna due to being made of all metal (for 10/12 meters).

The SPT-500 Penetrator is made by MFJ (HyGain) and in their "description" on their website, it states "This antenna is illegal for 11 Meters use." can be seen below:

https://mfjenterprises.com/collections/antenna/products/spt-500#description

Looking at the drawing on the 1st page of the antenna manual, from the HyGain site, the matching rod was the original design. The matching rod has not looked like that in years and now they have changed it completely. Also, the new instructions show the new design of the matching rod, and that the length of the antenna is supposed to be 22' tall, not the original 22'6" tall.

The manual for the SPT-500 at the MFJ site is the most updated one, more so than DX Engineers, and it shows a ground wire from the antenna to a grounding rod in this new manual.

So could it be that the SWR problem is due to the new design of the matching rod? The only way to tell what your problem is would be with an antenna analyzer to see where the actual resonant frequency is.

If the matching rod is the problem then maybe MFJ hopefully still sells the original parts needed (one each of the following); matching rod 170774 (not 170477-1), bolt 526530, and rod support 463642 which should be the cure.
1-800-647-1800 for MFJ

Unless you are the only person having this problem...........
or is there someone else on here that has this same design SPT-500 and that also has or hasn't had this problem?

I don't like the new matching rod design............

73

 

[whiteastro]

I only bought my Hygain Super Penetrator SPT 500 from DX Engineering maybe 3 years ago so it should be the same one MFJ markets today for 10 & 12 meter. There is also several sets of instructions out there with different finish lengths for 11 meter and one states 22' 9". There is also many people who have had the rain shorting problem as me so I searched for solutions online and there is posts in here of a guy making his own top insulator which worked for him. His post prodded me to put my thinking cap on and make my own short-cut solution which worked well. I would still be using the SPT 500 today ( which worked well ) if experienced forum members didn't convince me that the M400 Star Duster wasn't a better antenna for this lousy deep narrow valley. The penetrator is tore down and waiting in my garage to be erected when I move out of here because It Worked Well. As pointed out by Dr DX I would take a second closer look at the Matching device assembly and make sure it is correct. We all get excited to try a new antenna which leads to Hurrying and we can make mistakes. ( just a possibility )
I put mine up with simple home owner grade stuff & it worked well. Wish I could be there to help the young Ladd. Good luck And Happy DXing

 

[Greg T]

Im beginning to think ive got a bad match meter, too bad ...its new and cost 85 bucks. But when I wiggle the coax behind it it changes....neither change being a good match. Due to inexperiance, Im wondering.....the match meter has a high setting and a low setting. Im using the low power setting for the most sensitivity and im using a tiny stock cobra 40 channel cb for test rig. I wouldn't dare put my new radio on it which can do a few hundred watts.
My new radio is rci69ffb4 Ranger. I stupidly bought two of them. One for the mrs mobile and one to set up as a base station. Then I picked up a huge yagi beam antenna at a sale, only to find it would have to be hacked up for 11 meter....nope....not going to commit that sin. Save it for later. Then bought the penetrator from dx engineering and either its defective, assembled wrong, or that match meter is bad. Everything is brand new. Can I post pictures on here? Perhaps you could inspect my assembly? Ive pretty much given up and have tried all the reccomended lenghts including yours. Cant even get on the map with the match meter. p.s. now Ive gone and bought an antenna tuner, it will be here ina few days. But you have to at least be in the ballpark before you run this antenna tuner.

I would like to know what meter you have. Is it a cross needle? If so, you must read the meter in low scale, and if there is a setting for average and PEP, use the AVERAGE mode. Also, you read those meters where the TWO NEEDLES INTERSECT, not the tip of the reflected needle.

 

[881TX6666]

so....bought another match meter in case this fancy cross needle is lying. Spliced up an old coax to an old firestik and clamped it to my woodstove. Matched it with the new meter and got a 2 with that sloppy woodstove setup. Was hopeful at this point. Decided to brave the cold and the dark with some lights setup. Moved my ground strap on the penetrator as suggested by a helpful fella on this site. Adjusted my penetrator for hours and hours with that new match meter. up and down and up and down. Never could get below a 3. Gave up a couple hours later. Cold, hungry, and depressed. Still cant get an even acceptable match with his antenna. Funny, that garbage setup on the woodstove with the old coax threw a 2. But my new rg8x and penetrator are still threatening to destroy my radio. I give up for the night. back to square 1. Anybody know how to test coax?

I test my coax with an antenna analyzer and dummy load. I have a rig expert. I highly recommend anyone in the hobby invest in one. Well worth the money considering it can save your equipment. After getting mine I’ve tested a lot swr/watt meters and majority of them have been off.

 

[sheldonth]

Sorry Midnight Special,
I have no idea how to do a dummy load. I've given up on this penetrator. Dx Engineering says to contact Hy Gain directly about a possibly defective antenna. Tried to contact hy-gain but it looks like they are under MFJ enterprises? Anyway, I am considering just putting together a di-pole and scrapping the penetrator. I am convinced this antenna must be defective as the SWR never dropped from 3 or over no matter what I did. Admittedly, I did not fiddle with grounding rod, or matching rod. Sadly, the di-pole will not have any height to speak of, just about eight feet high on the garage. But at least maybe I'll get to try out my new radio. I did buy an antenna tuner, but Im stubbornly sticking to getting a fair match first. If I could pay for help, I would. But I live in an area where a ham fella to help me is non existent.

 

[sheldonth]

There must be somebody out there that will help if I pay them?

 

[sheldonth]

Dr Dx, I switched the order on that grounding rod and matching rod as you specified. I cant see what difference that would make ...but willing to try anything. Yes there is a hole that rain could get in. There is another hole below it at the bottom so that rain cannot accumulate in this thing. I will plug the hole after verifying this tube is dry. Still, before I do any modifications, would just like to know the antenna is set up right. I tested the new rg8x for shorts using my multi meter. Its ok. So that's good. I still believe if I had everything right, I would get some kind of ballpark match. 3.2 to 3.5 is very nasty if I'm not mistaken. Like shorted antenna? My battle spirit is recharging and I'm stubborn and want to achieve success with this antenna as others here have. I realize that I probably won't get help from hy-gain as the antenna is 10 and 12 meters only. I did not know this when I let dx engineering pick it out for me. I believe in them, and they probably were getting me a proven antenna for 11 meter. What I didn't know is that it is difficult for a beginner to match this thing. It seems so simple at first. It's just aluminum poles. It doesn't get complicated until you get down to the base radiator pole. I can build computers all day, but I can't match a damn antenna. My antenna tuner arrived yesterday. I'm studying the manual. I've learned (I think), that using the tuner isn't recommended until one is sure the antenna is matched as well as possible and not shorted. I started at 22.9 long on the antenna and worked my way down. A few days later I started at the shortest setting and worked my way up. I tried 103, 105, 108 on my radials. None of this changed my swr favorably, if anything at all. Could it be Im testing this thing too close to the ground? Its only 4.5 feet while sitting on the temporary test pole.

 

[Recon]

I would like to know what meter you have. Is it a cross needle? If so, you must read the meter in low scale, and if there is a setting for average and PEP, use the AVERAGE mode. Also, you read those meters where the TWO NEEDLES INTERSECT, not the tip of the reflected needle.

Bingo!
I think you're on to something!

 

[sheldonth]

Bingo!
I think you're on to something!

On to what? I replaced the new cross needle with a standard style swr meter. still bad.

 

[sheldonth]

Recon, are you saying it might be my proximity of the radials to the ground?

 

[Recon]

Recon, are you saying it might be my proximity of the radials to the ground?

No. My comment was related to interpreting / reading the meter. But, if you have used another SWR meter, I will withdraw my comment.
How many watts is the radio producing?

 

[sheldonth]

No. My comment was related to interpreting / reading the meter. But, if you have used another SWR meter, I will withdraw my comment.
How many watts is the radio producing?

O.K. m sorry guess I didnt refresh this page to see latest comment Im using a stock cobra 4 watt radio for the matching process. The radio I intend to use is a 400 watt. No way its going online until I get a good match on this antenna with the little radio.

 

[sheldonth]

I bought a forward/reverse swr meter and still had a bad match.

 

[Recon]

O.K. m sorry guess I didnt refresh this page to see latest comment Im using a stock cobra 4 watt radio for the matching process. The radio I intend to use is a 400 watt. No way its going online until I get a good match on this antenna with the little radio.

I don't know, but thinking out loud, maybe the problem is with the coax connectors?