| Author |
Message |
    
Torkrench
New member
Username: Torkrench
Post Number: 1
Registered: 12-2004
| | Posted on Monday, December 13, 2004 - 11:20 pm: | 
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I recieved a used Penetrator base antenna from someone today. After putting it at the top of a 27ft pole, driving an 8ft. grounding rod, and connecting the pole to the ground, I am getting a pretty flat 2.9-3 swr all across the band. The radio is a mobile radio running through a power supply. Is there something I'm doing wrong with the grounding of the antenna that would be causing such high SWRs? I've tried raising the antenna, and changing cable lengths with no change at all. My other antenna (2 piece fiberglass) ran pretty constant 1.3 all the time with the same cable and setup. |
Bulldog369
Intermediate Member
Username: Bulldog369
Post Number: 230
Registered: 2-2004
| | Posted on Tuesday, December 14, 2004 - 6:35 am: |
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when you tried changing the coax lengths... how much did you add, or take off? |
Dx431
Advanced Member
Username: Dx431
Post Number: 946
Registered: 2-2002
| | Posted on Tuesday, December 14, 2004 - 11:15 am: |
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Changing the coax length won't change your VSWR.
The wire on the bottum of the ant is part of your tuning of the ant. By spreading those wires will make the ant longer,squeezing them together will make the ant shorter. Same as turning the rings on the Imax or A 99. Try that and let us know if that helps. |
Bulldog369
Intermediate Member
Username: Bulldog369
Post Number: 232
Registered: 2-2004
| | Posted on Tuesday, December 14, 2004 - 3:29 pm: |
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if you add coax that should change the vswr just like on the old big sticks
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Kid_vicious
Member
Username: Kid_vicious
Post Number: 76
Registered: 9-2004
| | Posted on Tuesday, December 14, 2004 - 4:41 pm: |
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i agree with dx431, as frustrating as it is; you've got to take that antenna down and tune it before putting it up in the air.
here's a simple way to tune your ground plane on the ground. if you have a fence nearby, just attatch a pole, (about 6' 6" is best IMO), and put the antenna on that pole, attatch the coax, (whatever length you need, it doesnt matter), and tune the antenna. then put it up in the air.
if you dont have a fence nearby, fill a 5 gallon bucket with cement and put the 6' 6" pole in the center, let it cure, and youve got a nice temporary antenna pole. (dont use it in the wind though!)
matt |
Torkrench
New member
Username: Torkrench
Post Number: 2
Registered: 12-2004
| | Posted on Tuesday, December 14, 2004 - 5:26 pm: |
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I don't see any wires on the bottom of the antenna. It's possible that this isn't a penetrator. It has 3 horizontal wires at the top, and three ground planes at the bottom. The antenna also has no rings for adjusting either. |
Dx431
Advanced Member
Username: Dx431
Post Number: 948
Registered: 2-2002
| | Posted on Tuesday, December 14, 2004 - 6:14 pm: |
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Ok, then what you've got there is an old HyGain CLRII 1/4 wave ant. In it's day, it was a supior ant.
If you have the measurements correct, then the swr should be darn near flat. Try moving the middle section 1/4" at time till you get the desired match you want. |
Torkrench
New member
Username: Torkrench
Post Number: 3
Registered: 12-2004
| | Posted on Tuesday, December 14, 2004 - 9:40 pm: |
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all of the pieces of this antenna screw together with screws, how should I adjust the middle section and what measurments should I have on each piece. there are verticals total. |
Dx431
Advanced Member
Username: Dx431
Post Number: 950
Registered: 2-2002
| | Posted on Wednesday, December 15, 2004 - 1:19 am: |
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Yup, youre right. So then the measurements should be preset.You should have a descent swr like a 1.3. If your swrs are running 2-3, then I would say there is a problem with the ant. Try cleaning each section inside and out where the 2 peices connect to each other and see if that helps, if not then the coil may be blown. |
Torkrench
New member
Username: Torkrench
Post Number: 4
Registered: 12-2004
| | Posted on Wednesday, December 15, 2004 - 2:48 am: |
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I think I may have figured it out. Tonight, my friend and I took the antenna back down and put back up my old fiberglass 2 piece. When we finished, I looked at the tip of the new(old) one and found that the top aluminum piece that we thought was only 2ft long was actually jammed inside of the 2nd piece. When I pulled it out, it extended another 3ft. woah, that's got to make a difference. I'm going to test it and then put it back up. I'll let you all know how it goes. Thanks everyone for the quick responses. Now if I can only figure out why this new amp swings backwards when I modulate. strange stuff... |
Dx431
Advanced Member
Username: Dx431
Post Number: 951
Registered: 2-2002
| | Posted on Wednesday, December 15, 2004 - 10:12 am: |
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"Now if I can only figure out why this new amp swings backwards when I modulate. strange stuff..."
_____________________________________________
Check your deadkey, it may be to high. |
Kid_vicious
Member
Username: Kid_vicious
Post Number: 79
Registered: 9-2004
| | Posted on Wednesday, December 15, 2004 - 11:59 pm: |
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yup, if you have downward modulation out of your amp, then you are probably overdriving it. if its not a high drive amp, turn the dedkey out of the radio down to 2 to 2 1/2 watts. make sure the swing does not exceed 8 to 10 watts. this should clear up your modulation.
matt |
Torkrench
New member
Username: Torkrench
Post Number: 5
Registered: 12-2004
| | Posted on Thursday, December 16, 2004 - 2:15 am: |
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Thanks for the info guys, I played with my Galaxy 88 last night and was able to get the downward swing to stop, but that put my total output on this cheap power meter at like 50 wattts... I've got to get some better meters and maybe try my Cobra 148 again. I'm not too sure about the history of this radio and I don't have enough equipment to work on it. |
Torkrench
New member
Username: Torkrench
Post Number: 6
Registered: 12-2004
| | Posted on Thursday, December 16, 2004 - 9:13 pm: |
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OK Guys, one last post to put this thread to rest. After fixing the length of the antenna and fine tuning it a bit to hit the lower and uper 40 it works great. I had the radio tuned today on a good meter and got the output to just under 200 watts. I made contact with Oklahoma today from CA and all is well thanks for the info guys, I look forward to posting more here |
