| Author |
Message |
    
Jimmy Hooper
| | Posted on Thursday, August 02, 2001 - 7:57 pm: | 
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It seems very few people have heard of this antenna. The best SWR I can get is 1.5 on mine. Anybody done any better?
jrhguitar
(hoopguitar@aol.com) |
vernonott
| | Posted on Thursday, August 02, 2001 - 8:39 pm: |
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When I used to use the 99 I added a three ft. jumper with connector to my 100 ft of coax and got it down to 1.3.You can try 3',6',9' etc.and many times this will bring your swr down.The I-MAX is very popular around here. |
Badintermod
| | Posted on Friday, August 17, 2001 - 11:57 pm: |
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adding jumpers to your feedline does not actually change your swr. You are being fooled into believing what ever your meter reads. |
bruce
| | Posted on Saturday, August 18, 2001 - 1:04 pm: |
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THANK YOU I've been telling people this for the last week ! |
vernonott
| | Posted on Saturday, August 18, 2001 - 9:06 pm: |
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Really all a antenna matchbox is doing is fooling the radio so what difference does it really make .I realize that in the college trained world and in the professional radio technician realm everything is judged by the book ,theory,and parameters proven by science.Now out here in the sticks where we uneducated hicks live the only thing that is important is the way our signal sounds when it is received by our contacts.When my pal thirty miles across the creek at the bend tells me I am loud and clear and sound like I am sitting right there talking to him ,that's good enough for me.Also when my MFJ 259 tells me my system is at 51 ohms and 1.2 SWR I live with it and don't worry about whether it's fooling me or not.73's |
eazyrider955
| | Posted on Sunday, August 19, 2001 - 3:20 am: |
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hay i just found out the star duster is back thats great news to hear its the best annt to have 73 & xrated 88 |
Anonymous
| | Posted on Sunday, August 19, 2001 - 3:23 pm: |
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adding coax changes the reactance and not the resistance. even if you have 51 ohms resistance, a capacitive reactance of just 20 ohms will throw the swr into the red. |
Anonymous
| | Posted on Saturday, September 01, 2001 - 11:56 pm: |
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The true measure of SWR on an attenna can only be made right at the base of the anttena. With this being usually impossible for most people with out the aid of a cherry picker or boomtruck, its becomes important to install the correct lenght of coax so your meter is producing the same reading as if you were checking it at the souce or base of antenna. This is a hard concept for most people to grasp. Find out what type of coax you are using and see how long a electrical half wave lenght is. For standard mini foam its 13'6". The big stuff I believe is 11'4". Keep your coax long enough for use and in multiful lenghts listed above for your type of coax and you can be assure your have a good swr reading at the radio. Thats all there is to it. PS I agree changing coax lenght other than the proper proceedure above will only produce a incorrect reading at the radio. And doesn't really change the attenna at all. Nothing you do to the coax lenght wise will ever change the true swr reading of the antenna you are using. Hope this may help some one. I too agree, if it working great and your are getting out its not broken, don't monkey with it. Daveb |
Bill
| | Posted on Wednesday, January 23, 2002 - 2:49 pm: |
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Anonymous:
I have always cut my base antenna legnths numbers that would divide into 36'0" evenly. I have always heard that 36'0" was a full wave legnth.
I ordered a Imax 2000 from Copper yeaterday and I plan on it being about 45 to 60 ft. at the tip, depending on guy wires. I have 2 sections of Tramax RG-8/u foam 95% shield with stranded center. What legnth would you recommmend if the base of the antenna were set at 20'0", also allowing another 30'0" to get to the radio?
I know that I am not the only one that has heard the theory of cutting coax that will divide into 36'0". I am sure it would work if I had a 36'0" antenna I guess. I am a little confused with a 5/8 wave antenna. Thanks Bill |
Starlighter
| | Posted on Wednesday, January 23, 2002 - 11:38 pm: |
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I have a I-Max 99 which is in storage for the time being while I experiment with a Y-Quad and rotor.I found that by getting a good ground at the base of the mast,you can usually get very close to 1 to 1 SWR.from 1-40.I bought some heavy bare solid copper ground wire from Home Depot and ran a couple of 8 1/2 foot lengths about an inch down in the ground and attached them to a 4 foot copper clad ground rod and ran a short heavy solid copper wire to the mast.Before doing that the SWR was somewhat higher.I only have about 36 inches of topsoil where my antenna mast is so I couldn't use a longer ground rod. I have used this set up with whatever length of coax I had laying around and have moved the mast about 4 times to different places on my property.The coax length never made any difference to me.I use a MFJ-949E Versa Tuner for out of band frequencies but disable the tuner part when on the normal 40. The I-Max is rugged and has always done a great job for a 1/2 wave vertical. I have heard that the 2000 is even better due to being a 5/8 wave unit. |
Bill
| | Posted on Thursday, January 24, 2002 - 12:49 pm: |
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Starligher:
Thanks for the quick reply.
I have ran A-99's with and without the GPK. The SWR's dropped a little and the bandwidth increased a little, but not enough to write home about. At the same time I had a PDL-II set up. I could not tell a lot of difference between the two when the PDL-II was on vertical. I am sure you will enjoy the Y-Quad quite a bit.
Thanks for the information on grounding. I had at one time grounded my PDL-II at the mounting plate, and also grounded the mast at the bottom. Never could tell any difference.
Thanks again for your time.
Bill |
