ANTRON 99, SWR, 10 METER adjustment

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darticus

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Got the Antron 99. Seems like a good antenna. Is it normal for weather conditions to change the SWR slightly from day to day? I see SWR changing in good to bad rainy weather. To use the Antron 99 for 10 meters do you have to cut the top section shorter or will it adjust enough with the rings? Any ANTRON 99 INFO would be great! Thanks Ron
 

Skypilot007

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You can't cut the top section or any section of this antenna. You adjust the match with the rings at the base. When I had one of these it seemed to have good swr from CB band thru the top of 10 meters. Never needed a tuner on either band. I have an I-max 2000 now and it is the same way. I don't notice much change in swr with fiberglass antennas when wet or in different weather conditions. My old aluminum antenna the swr would rise slightly when the antenna was wet.
 

LtDoc

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Odd. Wonder why they give 'cutting' options for resonance if you can't cut the thing?
- 'Doc
 

darticus

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I know it has rings to adjust for SWR but the manual says to cut the top 11 inches for 28400 10 Meter frequency. Maybe I'm not reading it correctly. Here is the manual. Ron
http://www.comunicacio.net/eb3tc/esquemes/2008/febrer/A-99.pdf

You can't cut the top section or any section of this antenna. You adjust the match with the rings at the base. When I had one of these it seemed to have good swr from CB band thru the top of 10 meters. Never needed a tuner on either band. I have an I-max 2000 now and it is the same way. I don't notice much change in swr with fiberglass antennas when wet or in different weather conditions. My old aluminum antenna the swr would rise slightly when the antenna was wet.
 

LtDoc

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Length deals with resonance, which those rings have no affect on. The rings only deal with impedance matching. If you cut the thing off, it's a "no way back" sort of thing unless you can add that cut off length back later. It's certainly possible, but not all that easy.
Resonance does make an antenna more efficient. Length is only one way of adjusting for resonance, it cant be either the 'best' way or the 'not so good' way depending on the resulting radiation pattern. for instance, a 5/8 wave antenna isn't resonant at all, all by it's self. It can be made resonant by adding the proper reactance to it, which the typical bottom coil used with them does. The radiation pattern of a 5/8 wave antenna is usually 'flatter' than others, giving a usable benefit.
- 'Doc
 

Skypilot007

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My bad...the A99 I had and the I-max did not come with those instructions for cutting. Please ignor that part of my post.
 

N8DRC

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Got the Antron 99. Seems like a good antenna. Is it normal for weather conditions to change the SWR slightly from day to day? I see SWR changing in good to bad rainy weather. To use the Antron 99 for 10 meters do you have to cut the top section shorter or will it adjust enough with the rings? Any ANTRON 99 INFO would be great! Thanks Ron
Mine does vary on rainy days as well doesn't go up much. My old one I cut the top section for 10 and worked great, the new one I just left alone mainly use it on 11 but do use it on 10 from time to time with the internal Icom tuner..So far I have not messed with the rings...
 

LtDoc

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A change in SWR between nice weather and rainy weather (snow, ice, whatever) is normal. It shouldn't change much, but it will change some with any antenna.
Do you have to cut off that antenna to use it on another band? Only if you want a resonant antenna. Those tuning rings (they only 'tune' the impedance) can compensate to some extent, but that doesn't make the antenna resonant. Want to use the thing on both 10 and 11 meters? Then I probably wouldn't cut it off.
- 'Doc
 

darticus

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Thanks, thats my same results. Ron

Mine does vary on rainy days as well doesn't go up much. My old one I cut the top section for 10 and worked great, the new one I just left alone mainly use it on 11 but do use it on 10 from time to time with the internal Icom tuner..So far I have not messed with the rings...
 
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