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Message |
    
Mscott1212
Member
Username: Mscott1212
Post Number: 50
Registered: 12-2006
| | Posted on Sunday, March 27, 2011 - 3:39 pm: | 
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So I'am thinking of getting a Imax-2000. How is the swr on 10 meters 28.3-28.5 vs cb 1-40 right out of the box? Is there any tunning required to use it on 10 meters?
73's
Cef#1011
Ham#294
From the Great Lakes State
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N8fgb
Intermediate Member
Username: N8fgb
Post Number: 103
Registered: 5-2002
| | Posted on Sunday, March 27, 2011 - 7:08 pm: |
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We trimmed one some to tune it for ten. Don't remember how much. We used a MFJ 259 to tune it.
Rich |
Tech833
Moderator
Username: Tech833
Post Number: 1942
Registered: 8-2002
| | Posted on Monday, March 28, 2011 - 11:25 am: |
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If you cut a few inches off the tip piece, it will tune the whole 10m band beautifully. And, it will still cover 11m under 1.5:1 SWR.
Your radio 'Mythbuster' since 1998
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Mscott1212
Member
Username: Mscott1212
Post Number: 51
Registered: 12-2006
| | Posted on Thursday, March 31, 2011 - 9:37 am: |
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would you say 2 to 3 inches?
73's
Cef#1011
Ham#294
From the Great Lakes State
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Funtimebob
Intermediate Member
Username: Funtimebob
Post Number: 267
Registered: 5-2002
| | Posted on Thursday, March 31, 2011 - 5:14 pm: |
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Just a couple of inches can make a big difference
This post was brought to you By Umpire Cologne.
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Dale
Senior Member
Username: Dale
Post Number: 1690
Registered: 12-2002
| | Posted on Friday, April 01, 2011 - 4:33 pm: |
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i would only cut it in 1/2 inch increments
once its off cant be put back on.whats your swr on 10m now.shouldnt be more than 1.3.1. when i had mine thats what mine was.i used a mfj 259
dale/a.k.a.hotrod
cef426
cvc#64
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Tech833
Moderator
Username: Tech833
Post Number: 1944
Registered: 8-2002
| | Posted on Saturday, April 02, 2011 - 10:57 am: |
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I ended up cutting about 8 inches off to center it in the 10m band. So, assuming you still want to work 11m with it, try half that measurement.
Work in small increments!
Your radio 'Mythbuster' since 1998
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Mscott1212
Member
Username: Mscott1212
Post Number: 52
Registered: 12-2006
| | Posted on Wednesday, April 06, 2011 - 3:21 pm: |
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I don't have one yet. I'am in the process of buying a home. Once I close on the home I will be purchasing the antenna and coax. Does anyone have any thoughts on the ground plane kit that you can put on the imax-2000? The coax I will be buying is belden 9913, anyone have any thoughts on that kind of coax?
73's
Cef#1011
Ham#294
From the Great Lakes State
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Tech833
Moderator
Username: Tech833
Post Number: 1952
Registered: 8-2002
| | Posted on Thursday, April 07, 2011 - 2:51 pm: |
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9913 is great. The CA-400 is better.
There is a huge article here on the Imax GPK with gain and pattern measurements made on an antenna range. It will tell you exactly what the difference of an Imax 2000 with and without the ground plane kit will be.
http://www.copperelectronics.com/discus4/messages/7750/20506.html?1023340740
Your radio 'Mythbuster' since 1998
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Mscott1212
Member
Username: Mscott1212
Post Number: 55
Registered: 12-2006
| | Posted on Sunday, May 08, 2011 - 2:46 pm: |
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So I bought the Imax 2000 with the gpk. I also got LMR 400 coax to use with this antenna. I am still up in the air if I want to cut the antenna so I can use it for 10 meters also. I think I will just test the swr when I get it put together and see how it is first. I have heard reports that some have had swr's below 1.5 right out of the box on 10 meters 28.300-28.500.
73's
Cef#1011
Ham#294
From the Great Lakes State
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Big_m
Intermediate Member
Username: Big_m
Post Number: 118
Registered: 9-2007
| | Posted on Monday, May 09, 2011 - 2:26 am: |
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The Imax will do 10 (28.000-28.500)- 11 meters without cutting. |
Mscott1212
Member
Username: Mscott1212
Post Number: 56
Registered: 12-2006
| | Posted on Wednesday, May 11, 2011 - 5:10 pm: |
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So I have a 40 foot tower I will be installing the Imax 2000 with the attached Imax GPK. The directions for the Imax GPK says I should have the radials 9 feet away from existing structures for maximum performance. Having said all of that would a 10 foot antenna mast be enough to still get maximum performance?
Cef#1011
Ham#294
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Charliebrown
Intermediate Member
Username: Charliebrown
Post Number: 189
Registered: 10-2002
| | Posted on Wednesday, May 11, 2011 - 9:48 pm: |
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Mscott1212, If you read the article that Tech 833 did you will have the answer you are looking for. I think he told me that 32 foot is the best with the GPK on the I Max 2000. Tech 833 had done some very hard and very good work and you will find the work he had done is dead on the money right. HE SURE DID HELP ME. MY SYSTEM IS DOING THE BEST IT HAD EVER DONE SINCE HE GAVE THE ADVICE. I never had to do any cutting on the antenna to perform anywhere. swr is 1.1 to 1.4 through out. |
Dale
Senior Member
Username: Dale
Post Number: 1706
Registered: 12-2002
| | Posted on Sunday, May 15, 2011 - 10:28 am: |
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id say 10 foot isnt enough. just my opinion.
but sounds like you did great every were else.
the imax should cover 10-11 without any tuning or cutting.even if your swr is higher than 1.5
on 10m just use the tuning rings.lower them
should drop the swr on 10m if needed
dale/a.k.a.hotrod
cef426
cvc#64
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Tech833
Moderator
Username: Tech833
Post Number: 1969
Registered: 8-2002
| | Posted on Monday, May 16, 2011 - 4:04 pm: |
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9 feet from existing structures does not include structure BELOW the antenna, like a tower. They are talking about a garage, building, etc.
Your radio 'Mythbuster' since 1998
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Mscott1212
Member
Username: Mscott1212
Post Number: 57
Registered: 12-2006
| | Posted on Sunday, May 22, 2011 - 8:22 am: |
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Nothing is near the tower. My house is a single story and the tower is mounted up against the back of the house. since I'am new to my neighborhood and there are no amateur/cb antennas in the area I'am concerned about my radio setup causing interference to my neighbors.
I will be hiring a local tv antenna company to attach the antenna with gpk to my tower. I want to have my antenna grounded. What is a low cost/effective way to ground my antenna?
Cef#1011
Ham#294
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Tech833
Moderator
Username: Tech833
Post Number: 1977
Registered: 8-2002
| | Posted on Sunday, May 22, 2011 - 11:30 am: |
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Pound an 8-foot copper clad ground rod into the ground near the tower base. Run a solid copper wire or strap from the base of the antenna to the ground rod. Bond both ends electrically and mechanically.
If you run a legal (unmodified) radio and no illegal amplifier, you should not cause interference.
Your radio 'Mythbuster' since 1998
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Mscott1212
Member
Username: Mscott1212
Post Number: 58
Registered: 12-2006
| | Posted on Sunday, May 22, 2011 - 1:51 pm: |
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I run a Yaesu 857D and a stock like new president washington for my cb base radio.
I also want to get some type of verticle antenna that covers 2,6 and 440. I was thinking about a Comet GP-15.
Cef#1011
Ham#294
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Tech833
Moderator
Username: Tech833
Post Number: 1979
Registered: 8-2002
| | Posted on Sunday, May 22, 2011 - 11:51 pm: |
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GP 15 is a good antenna. It can also be side mounted.
Your radio 'Mythbuster' since 1998
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Mscott1212
Member
Username: Mscott1212
Post Number: 59
Registered: 12-2006
| | Posted on Monday, May 30, 2011 - 12:56 pm: |
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just picked up a LDG AT-200 pro autotuner.
When I get the Imax 2000 with the gpk in the air, hopfully I won't have a high swr on 10 meters without any cutting or turning of the rings. If I do, I guess the antenna tuner will have to earn its keep in my shack.
I have also been told that the Imax 2000 will tune to other HF bands with a tuner but having the gpk installed makes it harder to get a good match.
Cef#1011
Ham#294
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Tech833
Moderator
Username: Tech833
Post Number: 1988
Registered: 8-2002
| | Posted on Tuesday, May 31, 2011 - 1:00 am: |
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If using the Imax 2000 on other bands (like 20m), you need to have the tuner installed as close to the antenna as possible. Preferably, right under it at the feedpoint. Otherwise, cable losses (and hot spots) will occur.
If just using it on 15-10m, then no problem.
Your radio 'Mythbuster' since 1998
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Cactus_29
Junior Member
Username: Cactus_29
Post Number: 25
Registered: 12-2009
| | Posted on Tuesday, May 31, 2011 - 6:23 pm: |
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I don't know if this helps but my VSWR with a Imax 2000 and ground plane kix right out of the box with LMR240 reads as follows.
Antenna mounted on 60 foot tower
21.300 FM 10W 1.6
22.300 FM 10W 1.1-1/2
23.300 FM 10W 1.1
24.300 FM 10W 1.3
27.300 FM 10W 1.2
28.500 FM 10W 1.3
29.900 FM 10W 1.5
I guess I just got lucky.
Tested with Diamond SX-600 |
Dale
Senior Member
Username: Dale
Post Number: 1715
Registered: 12-2002
| | Posted on Tuesday, May 31, 2011 - 9:06 pm: |
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ya i agree i checked mine with mfj 259
and it will easily cover 10-11 meters
without cutting or retuuning rings ir tuner
dale/a.k.a.hotrod
cef426
cvc#64
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Mscott1212
Member
Username: Mscott1212
Post Number: 60
Registered: 12-2006
| | Posted on Saturday, June 04, 2011 - 9:55 pm: |
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Thanks for all the info. With any luck I will have it up in the air by the 4th of July.
Cef#1011
Ham#294
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Mscott1212
Member
Username: Mscott1212
Post Number: 61
Registered: 12-2006
| | Posted on Thursday, June 30, 2011 - 5:14 pm: |
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So my tower has major cracks on the legs and lower sections. Not safe to climb. So now I have to put a tripod on my roof. The tallest peak on my roof is about 20 feet high. I will be getting a 10 foot tripod with 10 feet of mast. I estimate my imax 2000 will be around 58 foot to the the tip. Not as high as I would like but its the only way to get on the air without buying a new tower which I don't want to do.
Cef#1011
Ham#294
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Sitm
Intermediate Member
Username: Sitm
Post Number: 454
Registered: 1-2004
| | Posted on Friday, July 01, 2011 - 9:43 am: |
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There are antennas that perform better at that level than the Imax if below one full wavelength. I believe that there is an very well written article here on copper forum in regards to this issue.
If nothing else you definitly need radials at that heights to reduce the loss of ground affect on your radiation patter or lobe. The radials will maximize your take off angle if you are below one full wave lenght (33.5ft).
please see this thread on copper forum
http://www.copperelectronics.com/cgi-bin/discus4/discus.cgi
Copper Electronics Omni/Vertical Antenna Suggestion Guide
by Tech833
very informative thread in fact one that I have in my study guide at home due to the information that is in the article.
73 |
Mscott1212
Member
Username: Mscott1212
Post Number: 62
Registered: 12-2006
| | Posted on Monday, July 04, 2011 - 7:21 pm: |
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I guess the guy I had come out didn't want to climb my tower. I had someone else come out and they went to the top fine. This guy has to add some extra mast to my tower due to the way the Imax 2000 mounts. I have a small copper J-pole antenna he will mount on the tower as well.
I had the Imax leaning against the back of my house on Sunday and made some contacts on 10 meters. The guy is comming this Wednesday to put it on the tower. The swr was lower on 10 than Cb right out of the box? I turned the rings towards the bottom, it made some difference but not much. I hope when its in the air I will see better swr results. Swr on 10 was 1.1, CB was 1.5 on 40 and 1.8 on 1.
Cef#1011
Ham#294
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Mayor513
Intermediate Member
Username: Mayor513
Post Number: 203
Registered: 3-2002
| | Posted on Tuesday, July 05, 2011 - 5:33 pm: |
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Mscott1212: I bet you are just "chomping at the bit" waiting to get that antenna up and in the air! A few days ago, I ordered a Maco V5/8 from Copper Electronics and, while it won't arrive until later this week, I am already getting anxious, lol. The Maco V5/8 will be replacing a Cushcraft AR-10 I use for my beacon antenna on 10 meters. Unfortunately, when I go to talk on the CB channels using that Cushcraft (we use channel 8, A.M. mode here), my SWR meter reads a tad above 4.0:1! Way too high for me. Have fun on the radio. |
Mscott1212
Member
Username: Mscott1212
Post Number: 63
Registered: 12-2006
| | Posted on Friday, July 08, 2011 - 5:59 pm: |
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I sure am. More delays....The guy who I thought could climb my tower won't do it now. I will be looking for a used steel tower to put up in place of the junk Aluminum Tower I have up now. More leaning the Imax against the back of my house on the weekend is in my future. I was really surprised when I found out how much new towers cost. I wan't a 40 foot steel tower. I'm sure I will find one. I have a local Tv antenna guy looking into it for me.
Cef#1011
Ham#294
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Dale
Senior Member
Username: Dale
Post Number: 1735
Registered: 12-2002
| | Posted on Saturday, July 09, 2011 - 11:02 am: |
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why dont ya get a 20 foot mast and put the
imax on that for time being. that will be better than just leaning it against the house
dale/a.k.a.hotrod
cef426
cvc#64
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Mscott1212
Member
Username: Mscott1212
Post Number: 64
Registered: 12-2006
| | Posted on Sunday, July 31, 2011 - 2:00 pm: |
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Antenna is up. Happy radio operator now.
Cef#1011
Ham#294
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Dale
Senior Member
Username: Dale
Post Number: 1746
Registered: 12-2002
| | Posted on Monday, August 01, 2011 - 7:31 am: |
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how it tune for ya?how high?need trimming or not?
glad ya like it
dale/a.k.a.hotrod
cef426
cvc#64
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Mscott1212
Member
Username: Mscott1212
Post Number: 65
Registered: 12-2006
| | Posted on Tuesday, August 02, 2011 - 3:06 pm: |
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It was 1.1 on 10 meters. On CB it was higher on channel 1 it was 2.0 on 20 it was 1.7 on 40 it was 1.5. Since I don't use the Cb as much I found thoose acceptable. I have an antenna tuner and with that I can easily get 1.1 match 1-40 on CB.
I have the antenna with the gpk attached mounted on top of a 40 foot tower. So far so good. I worked some stations in Porto Rico on 10 meters over the weekend with the 857d at 100 watts. I heard a station in Chillie but I couldnt make contact with that station.
On the Cb the local cbers say I am loud and clear and have a very good signal off my Washington base. I did make one contact into Jamaca on 38 LSB with 12 watts, nice.
My next project I want to add either a Maco M103
or Maco M104C to the tower on the flat side for longer distance contacts. Im not sure which one I should go with. I figure if I go with the M104C I would be getting more coverage off the antenna. I have heard you can mount your Imax on the same mast that the beam is on minus the GPK I have on it now. I think that would be cool if that would work for me. I saw Copper sells a rotor that looks like it would work for the M103C antenna. I have no experience with beams, looking for advice on which one to go with. Right now I use LMR 400 on the Imax, Im guessing I would need to get some ultraflex coax for the beam. Not sure if I would need to switch to ultraflex coax to run up to the imax over the beam?
Cef#1011
Ham#294
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Dale
Senior Member
Username: Dale
Post Number: 1749
Registered: 12-2002
| | Posted on Wednesday, August 03, 2011 - 11:59 am: |
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cant say for beam either will work great.
did ya trim the antenna any?or just move the rings some?as for mounting above a beam should
be able to even with the gpk i think...wouldnt see why not.the coax on yor imax is fine.
id use the flexable on the beam..just me
dale/a.k.a.hotrod
cef426
cvc#64
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Tech833
Moderator
Username: Tech833
Post Number: 2014
Registered: 8-2002
| | Posted on Thursday, August 04, 2011 - 10:08 am: |
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Use LMR-400 (or Copper's CA-400) on both, right up to the rotor. Then, to go past the rotor on up to the antennas, use a barrel connector and RG-8 or similar flexible cable. Make sure the LMR cable does not move. Let the flexible cable do all the moving.
Your radio 'Mythbuster' since 1998
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Mscott1212
Member
Username: Mscott1212
Post Number: 66
Registered: 12-2006
| | Posted on Sunday, August 07, 2011 - 7:14 am: |
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I didn't trim the antenna, just moved the rings in the up direction. I think I will go with the M103C beam. For what I want it should do the job. I grew up in a town about 50 miles north of where I live now. I cant get the locals up there off the Imax to well. One of the locals up there is running the M103C and I can get him with no problems using the stock Washington base. I also want to be able to pinpoint areas when making dx contacts. Will the rotor copper sells be suitable for the M103C installation on the flat side? Should I leave the GPK on the Imax? I was thinking of taking it off and mounting the Imax as close to the beam as possible. Just my thinking that the beam may act as a ground plane for the Imax?
Cef#1011
Ham#294
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Mscott1212
Member
Username: Mscott1212
Post Number: 67
Registered: 12-2006
| | Posted on Sunday, August 07, 2011 - 8:44 am: |
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I was thinking this rotor might work good for my proposed setup. T40-00004 AR-40 Rotor
[T40-00004] It says its a 5 wire and Copper only sells 3 wire and 8 wire types?
I see copper sells a much cheaper A00-00010 Antennacraft TDP-2 Ant. Rotor. I would be scared I would have breakdowns/malfunctions using this rotor, even if I mounted as close to the tower as possible and used just enough mast to connect the M103C horizontaly and Imax 2000.
Cef#1011
Ham#294
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Tech833
Moderator
Username: Tech833
Post Number: 2016
Registered: 8-2002
| | Posted on Sunday, August 07, 2011 - 12:01 pm: |
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If mounting the Imax on top of the 3 element beam, you want this one- http://www.copperelectronics.com/cart/product_info.php?products_id=1477
If you mount the Imax above the beam, remove the GPK.
Your radio 'Mythbuster' since 1998
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Mscott1212
Member
Username: Mscott1212
Post Number: 68
Registered: 12-2006
| | Posted on Sunday, August 07, 2011 - 8:09 pm: |
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Tech 833 will Lmr-400 ultraflex coax be suitable to use with the barrel connector to go past the rotor to both antennas? I have a 40 ft tower and have 2 50 foot runs of Lmr-400 cable. I was thinking a couple jumpers of Lmr-400 unlraflex should do the trick.
Cef#1011
Ham#294
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Tech833
Moderator
Username: Tech833
Post Number: 2023
Registered: 8-2002
| | Posted on Wednesday, August 10, 2011 - 12:00 pm: |
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Yes, Ultraflex will work well too.
Your radio 'Mythbuster' since 1998
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Gray_ghost
New member
Username: Gray_ghost
Post Number: 1
Registered: 5-2016
| | Posted on Tuesday, May 24, 2016 - 3:49 pm: |
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I have a imax 2000 on my 105 ft tower. I run 7/8 in heliax with a 4ft rg8 jumper at top and a small jumper at house to watt meter. my swr is weird, I have to add a 50 ft jumper at the bottom to get the swr down any. everytime you change the jumper length, the swr is different. the antenna is straight out of the box supposed to be set at factory for 11 meters. I run a RCI 2995DX and when you turn power up swr goes down some, turn it back down and they go up. SWR does the same on my 2517. I used to have a imax up there with no gpk kit and it was perfect, could go all over with great swr. now this new one with a gpk is terrible and I cant figure it out. Need Help !Thanks |
Tech833
Moderator
Username: Tech833
Post Number: 2362
Registered: 8-2002
| | Posted on Saturday, June 25, 2016 - 3:41 pm: |
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Something is amiss.
If changing coax jumper length affects SWR that much, you have some weird reactance at the antenna feedpoint. Make sure nothing is anywhere near the Imax feedpoint. No other antennas, nothing. Hopefully, you didn't side mount the Imax.
Your radio 'Mythbuster' since 1998
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