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Message |
    
Azboatanchor
New member
Username: Azboatanchor
Post Number: 1
Registered: 8-2007
| | Posted on Wednesday, August 22, 2007 - 6:22 pm: | 
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Short story:
40ft rohn 25G tower.
24 ft mast pipe
Max 2000 2 months old.
1/2 inch Andrews Hardline.
Antenna tip is about 86 ft up.
MFJ 259 SWR analyzer used for testing.. Actualy Two different 259s' Also Bird43 meter and various SWR meters.
SWR low point: 27.800 mhz = 1.0/52 ohms.
SWR at CH 1 = 2.2 to 1/ 61 ohms.
SWR at CH 40 = 1.3 to 1/ 59 ohms.
As you can see this will not work for me since my I like to talk down low.
Called Solarcon. Was told to use ONLY 213 coax. This made NO difference what so ever in the match or SWR "Curve".
Then I was told to lower the antenna. This had little effect.
Adjusted rings all the way up and down in short turns. This effected the match but the SWR Curve stayed the same. Please do not suggest turning the rings. THis is not the issue.
Solarcon is no longer any help. THey claim the antenna cannot be bad.
I am tired of hiring the bucket truck to come out to experiment with this darn antenna. The last time we installed a 1 to 1 current balun. No change. Grounds are in place. Please help.. Otherwise the next time I go up in th bucket truck I am going to throw this antenna like an Olympic javalin thrower.
C |
Dale
Senior Member
Username: Dale
Post Number: 1102
Registered: 12-2002
| | Posted on Thursday, August 23, 2007 - 5:37 am: |
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the swr measurement ya posted are they with
the mfj 259.its definately not your coax
cause i run lmr-400 and have good swrs.however
how old is the coax and the connectors.is thier
anything metal nearby?as cthis will effect swrs
dale/a.k.a.hotrod
cef426
cvc#64
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Azboatanchor
New member
Username: Azboatanchor
Post Number: 2
Registered: 8-2007
| | Posted on Thursday, August 23, 2007 - 11:21 pm: |
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Thanks for posting.
Mine is a free standing tower with nothing around it. No power lines. Nothing.
I ran this with brand new Andrews 1/4 heliax. Then I ran this with brand new Half inch hardline. Then I ran this with brand new 213. Its not the coax. Its not the height of the antenna. Its not the 259 meter as I tried two. I have to assume now that this antenna is faulty. This is going to cost $300 to fix because I have to hire a bucket truck.
C |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 2614
Registered: 9-2004
| | Posted on Friday, August 24, 2007 - 12:12 am: |
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im not sure why you think there is a problem with this antenna.
the IMAX 2000 has a 2 to 1 SWR range of about 2mhz.
this is totally normal, and is actually a bit more broadbanded than other groundplane antennas.
you say that at 27.800mhz, the SWR is 1.0.
then at 26.965, the SWR is 2.2
thats almost 1mhz.
if you were to go up to 28.7xxmhz, i bet you would see the same 2.2 SWR, or at least very close to that.
all you have to do is pick the frequency that is right in the middle of the 2mhz range you want, and tune the rings for 1.0 SWR at that freq.
i usually tune my antennas for 27.305 since i like to talk above 40, and hardly ever use the freqs. below ch. 1.
if you say that you like to talk down below ch. 1, then i would say, try tuning your antenna at around 27.115 (ch.13)
hey, then you'd have near perfect resonance on the CEF channel!
i dont think you have an antenna problem; i think you just expect too much from it.LOL
good luck,
matt
anyone wanting a "clean signal", just look to the left and build one of these!!!
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Milkman21218
Intermediate Member
Username: Milkman21218
Post Number: 354
Registered: 1-2004
| | Posted on Friday, August 24, 2007 - 7:31 am: |
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Maybe buying a antenna tuner would help. And it's cheaper than the bucket truck too! |
Dale
Senior Member
Username: Dale
Post Number: 1106
Registered: 12-2002
| | Posted on Friday, August 24, 2007 - 7:48 pm: |
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hmm good point.
dale/a.k.a.hotrod
cef426
cvc#64
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Azboatanchor
New member
Username: Azboatanchor
Post Number: 3
Registered: 8-2007
| | Posted on Tuesday, August 28, 2007 - 1:55 pm: |
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I guess what you guys might have missed is that the rings do not effect the tuning freq that much. I stood on in a Bucket truck up at the base of the antenna and adjusted them in half turn increments from top to bottom. I would adjust and then lower the bucket out of the way and test it. This only effected the impedance mainly. It did shift it from 27.900 to 27.600 at the lowest point. So no matter what I do I cant get this antenna to have low SWR on the 40CH band. My old Army big stick was lowest on 20 for example. This one will not tune down in Freq. My buddys across town is 1.1 on 20 which is his center point. So tuning the rings is out of the question as a cure. 2.2 on CH1 is just to high. Especialy for my modern Mosfet final radios. My old Johnson Viking valiant could care less. It has a tuner built into the transmitter to load the antenna. A tuner is a good idea and I have been offered one by a friend. However. That only makes the Radio happy. It does not fix the High SWR at the antenna. Any more suggestions would be great and I thank you guys for the help. |
Dale
Senior Member
Username: Dale
Post Number: 1111
Registered: 12-2002
| | Posted on Wednesday, August 29, 2007 - 5:27 am: |
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try this'put your anylizer on the frequency
ya will be using then tune for lowest swr.
dont worry about the swr curve im curious as
why yours is so high checked mine my curve is
same as yours however the swr is lower.so
try tuning the antenna for just the frequency
ya gonna use most my swrs are
ch1=1.4
ch.40=1.1
dale/a.k.a.hotrod
cef426
cvc#64
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Marconi
Advanced Member
Username: Marconi
Post Number: 747
Registered: 11-2001
| | Posted on Thursday, August 30, 2007 - 9:13 am: |
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AZ, you are right, I find the same thing, my Imax is not true resonant in 11 meters either. However, the matcher is so broadbanded as to simply not making much difference as far as I can tell.
My Imax is set at 35' and shows X=0, R=51, at 27.700 - 27.900 mHz. This is close enough that the antenna should work as good as it can, even down below channel 1 a ways. I guess we would all like to see our SWR = 1:1, but I suspect that it really doesn't make much difference as to really be able to tell just using our communications to test.
I have an old Ringo style vertical 1/2 wave antenna here (Wolf 50_11M) that is very narrow banded and does not tune up very well even at resonance. That is probably because it has no ground plane attached. It changes tune when I move the antenna up or down just a few feet so I have to tune at installed height or suffer what I get. The antenna also gets complaints from CB neighbors as a bleeder. This one made me a believer in the idea that perfection does not necessarily relate to improved performance. My signal reports using this antenna compared to my Imax at the same height are neck and neck accross the board around me and more often than not the 50_11m out performs the Imax in some directions. So I am a skeptic when I hear guys claim night and day differences among the 11 meter vertials that we talk about.
I know your idea here will get all kinds of objections, but that is my opinion too. With current day transmitters the main thing is that the system load up suffiently. |
Azboatanchor
New member
Username: Azboatanchor
Post Number: 4
Registered: 8-2007
| | Posted on Thursday, August 30, 2007 - 12:59 pm: |
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Ok. It looks like I have found about 10 people with Max 2000's that resonate at 27.800 or there abouts. I found many many more that resonate at CH20. I went to a friends house and checked his.. 1.1 on CH20 with an equal curve. His antenna is years old.. Not sure how hold but one of the originals. Something must have changed inside the antenna to cause this. I agree the antenna works. I just wish it would work better on 26.9150 which is the AM call channel I use. The SWR is 2.4 down there. My johnson Viking Valiant could care less. It has a tuner built in and can tune on a piece of wire..LOL.. But my Solid state base stations and mobiles are unhappy. I Guess its antenna tuner time for me.
The biggest thing that gets me on this deal is I spoke with Charlie at Solarcon. This man designed this antenna. He claims this antenna should be centered on CH20 and if its not something is WRONG. He is very strong about this... He said that if the antenna resonates anywhere other then the center of the CB band, something is not setup right PERIOD. In fact he claims that the antenna wont tune flat at 27.800 becuase of its design.
So now I have the man that designed it telling me something is wrong and owners of the antenna saying its working as designed.... hmmm.
Thanks alot for all the help guys! |
Azboatanchor
New member
Username: Azboatanchor
Post Number: 5
Registered: 8-2007
| | Posted on Thursday, August 30, 2007 - 1:54 pm: |
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Ok.. Here is the latest story from solarcon. The antenna is designed to have a 2mhz bandwidth like the guy said above. The original antennas where called I-max2000. THe newer ones are called Max 2000's. Sure enough, on my box it says max 2000. These antennas resonate higher in the band so they could double or tripple the sales. The antenna now works on CB and 10 meter. In fact it also resonates on several ham bands. In other words its now a compromise antenna so two different markets can use them. Thats great for them but not great for me. I can use an antenna tuner to make the transmitter happy but this will induce loss into the antenna system through the tuner. The solution is to install a longer whip. The trouble for me is that I dont know how long of a whip to install. Can someone help me plot this out? My antenna resonates at 27.800. I would like it to resonate at 27.2050. My idea is to get a Fiber glass Firestick or Wilson silver load and adjust it so this antenna is flat on CH20. Otherwise this antenna needs to be replaced with one that is flat where I actualy talk... I want to be prepared because its going to cost me $200 to have the Crane come back out to install the new top section. |
Sonny
Intermediate Member
Username: Sonny
Post Number: 166
Registered: 5-2004
| | Posted on Thursday, August 30, 2007 - 5:44 pm: |
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Anchor the fire stick might work I'll be showing my age but years ago we use to out fire sticks into the Big stick antennas and worked great |
Dale
Senior Member
Username: Dale
Post Number: 1116
Registered: 12-2002
| | Posted on Thursday, August 30, 2007 - 6:37 pm: |
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i did same thing with my a-99.az get a 102 inch with spring and some washers.to get it to resonate like ya want youll need a longer top
section.
1]screw down the spring
2]screw on the whip ,check swrs at YOUR channel
ya desire to talk on
if its still high
3]add a washer between spring and whip,
if its stll high
4]kep adding springs when finally there make sure all connections are tight.i use a cresive
wrech on mine and 1 tug [carefully]
most radio shacks have the 102 whip and spring
in the box with spring should have a couple washers
dale/a.k.a.hotrod
cef426
cvc#64
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Marconi
Advanced Member
Username: Marconi
Post Number: 748
Registered: 11-2001
| | Posted on Thursday, August 30, 2007 - 9:01 pm: |
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AZ, you talk about using a Firestick or a Wilson Silver load to replace the tip of your Imax in and attempt to lower the center frequency.
The Wilson Silver Load may in fact be a true 1/4 wave and if the tip of the Imax is also a quarter wave element then the Wilson and the Imax should act pretty much alike. If the 95" Imax tip is not a 1/4 wave, which I believe is the case, then adding the Silver Load may get you closer to channel 1. This also assumes that adding length to the Imax without changing the matching coil as well, will directly affect the resonance as expected and desired.
The Firestick tip is supposed to be used on the A99 and is probably not a resonant 1/4 wave element either. The tip of the A99 is only 72" and I know it is not a resonant 1/4 wave element in 11 meters. I doubt there is much difference between the electrical length of these tips and they both are way too short electrically.
If extending the length of the Imax will effectively lower the resonance down where you want it, you might have to add as much as a foot or more with the element diameter remaining the same. I seriously question adding springs to add length. The weight up there will be a problem and the hubs will not handle the stress.
If AZ is correct and Solarcon raised the center frenquency, then I believe they would have made the change by a change in the tuner coil and not altering the non-resonant length of the radiator.
The reason described by AZ for the Solarcon change makes total sense to me. Sounds like something they might do as a business decision. |
Marconi
Advanced Member
Username: Marconi
Post Number: 750
Registered: 11-2001
| | Posted on Thursday, August 30, 2007 - 10:27 pm: |
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AZ, you indicate you have a Viking radio with a tuner. If it will go down to the freq you want to work, why don't you go there and tune for low SWR and have someone check your signal that is close by, but not so close that your bury their receive meter. Then detune the tuner to show an SWR of whatever you antenna is showing without the tuner and then check the signal again. This will tell you if SWR makes a big difference to your signal to that station. |
Kirk
Intermediate Member
Username: Kirk
Post Number: 340
Registered: 6-2002
| | Posted on Friday, August 31, 2007 - 6:36 pm: |
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Hey Az- I read your post and just happen to look at my box and it also says "Max 2000." When I bought it 4 1/2 to 5 years ago I thought I was getting an IMAX. At least that's what I ordered. Anyway, I was astonished to see that I have what you describe...however...mine resonates nicely at 11 meters as it was shipped. So either a.) I have an IMAX that came in a Max box or b.) They have made changes as they have went with this new design. I have never tried mine in any other band than CB but now I am curious of where else this thing will resonate. Good luck with your fix. I never liked antenna tuners as I gather you don't either.-- |
Johhn
Junior Member
Username: Johhn
Post Number: 38
Registered: 8-2007
| | Posted on Tuesday, September 04, 2007 - 9:22 am: |
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O.K. John in Texas: my swr's on my Madison base are 2.2-ch28 lower or 26.835mhz. 1.6-ch28 high or
27.735mhz.all is grounded My antenna is a 5/8 wave ground plane rad.shak. It is 1.0-ch28normal.Band a.m. as long as my ant. warning light don't come on we are good..johhn cef 938 |
Azboatanchor
New member
Username: Azboatanchor
Post Number: 8
Registered: 8-2007
| | Posted on Tuesday, September 04, 2007 - 1:59 pm: |
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I tried the antenna tuner Kirk. It lost 1 su TX. No matter how I tuned it. SO yes it made the radio happy but it also realy hurt my performance. The older Max and I-max antennas are made for 11 meters. Later ones are a compromise design for 11 and 10 meters. Nothing is wrong with my antenna. Its just not optimal for CB band. I dont suggest a CBer buy this antenna. He wont be happy if he talks on the lower portion of the band. Next month we are cutting my tower down and installing a Hinge plate so I can crank my tower over. When that happens this antenna will be cerimonisly Destroyed! I am going to put my Sigma 4 aluminum 3/4 wave antenna back up. It tromps the Max2000 anyways. |
Johhn
Junior Member
Username: Johhn
Post Number: 40
Registered: 8-2007
| | Posted on Wednesday, September 05, 2007 - 8:56 am: |
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What I'm trying to say is if I was trying too,
operate on 28.7 my cb is 11 band match,my swr would be above 2.6 for that amount of curve.
I can expect so much. (second antenna).for lower band. I would not have mine that high in the air
At some time you got to work on it. 2.2 on low.
Is it worth lowering?you match low what will high bee ? I think 2.2 is fine 1.0 center 20a.m |
Hyperno_1979
Intermediate Member
Username: Hyperno_1979
Post Number: 413
Registered: 12-2005
| | Posted on Saturday, September 08, 2007 - 12:01 am: |
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Just erected my Max 2000. Checked the swr and the needle did not move on 27.355. What i'm worried about is that after having aluminium verticals since day one, the amount of flex in these things. I mean it wobbles up there more than Oprah during an epileptic fit! My old girl has lasted over 10 years, can i expect the same out of the Max?
CEFFFCEF
Bob
CEF703/CVC26
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Hyperno_1979
Intermediate Member
Username: Hyperno_1979
Post Number: 416
Registered: 12-2005
| | Posted on Sunday, September 09, 2007 - 5:07 am: |
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What i should also have added....1.2 on 27.115, 1.2 on 28.360. But i'm starting to have 2nd thoughts about this thing.....seems as deaf as a post. I normally get ground wave from 130km away with my old Megatron......zip with the Max, except for S5 white noise on the Madison, S7 on the Icom. Hmmmmmmm.
CEFFFCEF
Bob
CEF703/CVC26
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