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mikefromms
| | Posted on Monday, July 21, 2003 - 7:25 pm: | 
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I was off today so I got on the roof and took down the AP. I sanded the paint off the Rat Shack pole and just before I was about to put up my ladder the UPS trunk pulled up with my coax. Great! Time to get this long overdue task done.
I installed the very hard-stiff line mini 8 (the latest from Beldon) and stuck the AP up 5 more feet. The first thing I noticed was the swr is 1 or flat on channel 20. It's still not as broadbanded as advertised but I like the improvements. The next thing I noticed was the hears. The improvement in my reception was very evident. Didn't have to listen for long to notice this. Broke 19 and got a good report on my signal. Also talked to some station out a little farther and again good reports. I'm happy with it now.
I'll still be asking questions about other antennas because that is my interest. Love this site and appreciate all the good advise.
I know you guys have waited long enough for me to do this work. The work paid off.
Mikefromms |
Alsworld
| | Posted on Monday, July 21, 2003 - 9:35 pm: |
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Nice to hear Mike. Good (and new) coax always helps, but I don't remember what you ran previously. Doesn't matter. I'm sure that antenna will do you just fine once you bring it to your standards (which you might have done today).
Chances are, once the skip starts rolling you will blow some smoke and be amazed at how good of a job you have done. I'll bet the locals will notice a difference as well.
I'm glad things are going better than initially.
Hey remind me, I still owe you a SWR report if you are still interested with my IMAX 2000. I trashed my GPK after dropping the antenna a few times trying to install it myself in some tough locations. It is no longer on it, although I can still fix and install the bracket once I can figure out how to get myself to the antennas feedpoint (the bracket got beat/bent up, but the radials held up okay). I'm not through yet but am at that point if you want it, I can provide.
Once again, I'm not trying to be a salesman, the company provided me nothing but an antenna and a bill, but for comparison to what Buck provided, maybe it may help someone concerning the broadband issue.
Alsworld |
mikefromms
| | Posted on Monday, July 21, 2003 - 11:12 pm: |
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Alsworld,l would like to see those swr readings on your imax 2000. Be careful trying to get a few more drops performance out of that thing with the gp kit. It's not worth injury or worse. I'll bet that Imax 2000 really smokes out of that pine tree. I'll never forget having a super big stick up in a pine tree. Man, that think could transmit and receive. Too bad the pine beetles killed my tree. What the beatles didn't kill the wind blew over. Those stick antennas walk the dog and cat up in a high tree.
Later,
mikefromms |
Alsworld
| | Posted on Tuesday, July 22, 2003 - 12:31 am: |
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Mike,
tomorrow (Tuesday), I will hook it up and give you readings from 2 different meters. One will be my Dosy 4002 (which always gives me higher readings SWR wise from my....) cheap RipOff Shack $29 Power/SWR meter. I will honestly not go back to Bucks readings until after I post my own to you here. I am curious myself how it will measure out between different antennas at different locations.
In Florida where I just moved from, bandwidth was very good. I am curious to see how these results will compare (I never actually wrote those down) per'se.
I'll give you the straight scoop without any predjudice (sp?), as I prefer to bring out the facts so you and others can form your own opinion. I am curious as well.
It should be posted to the forum by sometime late afternoon PDT, and officially posted whenever the Forum Master or Techs/Moderators approve it. I will post the results (with equipment used) here under this thread.
Shoot, now I'm getting excited! Crazy over some SWR checks huh? LOL!
I concur about the hazards of playing with antennas. I need to secure it better, and would once again like to add the GPK, but at that height, safety is #1. I'm far away from power lines and such, but getting my butt up that high will be done with little risk. I love to climb trees, but these here are not "climber friendly" until you are at 50ft, and I'm not getting any younger. I'll search over time for logger friends, a very tall extension ladder, or maybe meet some of the volunteer firefighters (two blocks down the road) that can show me how to rescure a cat 50ft up in a tree LOL! Practice is everything....
Alsworld |
Buck
| | Posted on Tuesday, July 22, 2003 - 8:07 am: |
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Heck just make a little trip and get Karate...Make him climb it...He's got alot of extra energy to burn
Buck |
Alsworld
| | Posted on Tuesday, July 22, 2003 - 8:14 pm: |
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Mike,
here is my setup and how I got these results.
Radio is a Magnum Delta Force run off an Alinco DM-330MV 30A power supply. A three foot RG-8 jumper going to the Dosy Meter. Another three foot RG-8 jumper going to a Vectronics Low Pass filter. From there is 125 feet of Davis RF ‘BuryFlex’ double shielded low loss coax to the antenna. The antenna feedpoint is 55ft above ground, putting the tip roughly at 79 ft high. No Ground Plane Kit is installed at this time
As of now, this is a rough setup. Nothing is grounded yet (either the antenna or station equipment). That "may" help future readings. Also, this Dosy meter will not calibrate for the SWR setting unless I am at 4.5 watts minimum. All of these readings were taken twice. One pass through where I would set the dead key at 4.5 watts on every channel, then read the respective SWR. I did exactly the same on the next pass. I then switched meters to the RS meter. Once again for consistency, I kept the radios’ power at 4.5 watts on each frequency, then read the SWR, then repeated the whole thing in order. The results are interesting and not real consistent between meters, especially at 28.765, 29.215 and 29.965.
It does appear that the GPK made a difference from previous installation and location, as I used to be able go higher in frequencies with better SWR readings, and my lower frequencies would approach 2:1 at the bottom. With it removed, that might explain it. Or, the adjustments might have shifted upon installation.
Here it is. All numbers are compared to ":1"
| Frequency | Dosy Meter | RS Meter | | 25.165 | 1.25 | 1 | | 25.615 | 1.4 | no movement | | 26.065 | 1.6 | 1 | | 26.515 | 1.4 | 1 | | 26.965 | 1.6 | 1 | | 27.205 | 1.6 | 1.2 | | 27.415 | 1.6 | 1.35 | | 27.865 | 1.15 | 1.6 | | 28.315 | 1.25 | 1.5 | | 28.765 | 2.7 | 1.3 | | 29.215 | 2.85 | 1.85 | | 29.965 | 1.8 | 3.1 |
Alsworld |
Kc0gxz
| | Posted on Wednesday, July 23, 2003 - 1:47 am: |
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Alsworld
Wouldn't you suspect that there may be a possible problem with your Dosy if you have to use 4.5 watts to get it to calibrate?
That wouldn't stand well with me.
Jeff, kc0gxz.
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Highlander
| | Posted on Wednesday, July 23, 2003 - 8:32 am: |
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Alsworld,
The tree might be messing with it a little.
When mine was in a 50 foot pine tree, it favored the lower end of the band a little, too.
I just moved my rings up a little to fix it. |
Tech833
| | Posted on Wednesday, July 23, 2003 - 12:24 pm: |
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Try it with a Bird meter. The innacuracies between your readings are unfortunately making me believe they are unusable. |
mikefromms
| | Posted on Wednesday, July 23, 2003 - 5:58 pm: |
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Wow, either way you look at this the reading communicate one thing: this antenna is very broadbanded! That is incredible! I can't use mine nearly that low on the band and I can forget about going over 28.500 mhz now to transmit.
Imax is the broadband king.
mikefromms |
Alsworld
| | Posted on Wednesday, July 23, 2003 - 10:36 pm: |
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Yes, to all. The inconsistencies make little sense. I would expect to have the nice bell curve but at this point I haven't achieved it. Like I said, this is a very rough setup, primitive so far (inside the house it's great, but I have been working on a custom window bracket all this afternoon). It is not finalized by any means.
This Dosy has done this since new, giving me higher SWR readings compared to both the radio readings and the Rad Shack meter. Even in my mobile, same higher readings. Interesting though, the RF output readings are almost identical. This is with both my Delta Force and Lincoln, in either the mobile or base setup. Same basic readings no matter how I switch the radios around.
Also, I have seen many other with these meters that say theirs do the same concerning about 4.5 watts to calibrate. It does not make it right, but with as many with this same "discrepancy", I considered it 'normal'. Don't have that problem with the RS meter.
As I continue with my setup, I at least have something to base it to. In Florida, my antenna stuck out of the top of the tree in the air, here, I have much more tree above the antenna.
Tech833, wish I had access to a Bird meter, but as of now I don't. With time, and as I meet people here, hopefully that will change. I fully concur that it ranges in too many directions, some low, climbing, dropping, almost like an ocean wave. Not the spread one should expect.
Like I said Mike, I would provide raw data for you to see/evaluate. Obviously this is not perfect by any scale, but it's a true reading of what I'm getting right now. Hopefully as I ground and complete/finalize my setup, maybe I'll see something more 'normal'. I sure would like to get a standard bell curve once completed, and consistency would be a bonus. We'll see.
Alsworld |
mikefromms
| | Posted on Thursday, July 24, 2003 - 7:14 am: |
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That antenna is amazing. Either reading is fantastic because of the bandwidth. I get nowhere near that bandwidth. That is really something for folks to look at when in the market for an antenna.
mikefromms |
Scrapiron63
| | Posted on Thursday, July 24, 2003 - 11:44 am: |
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I've had several new dosy meters that wouldn't calibrate at low wattage, but on most there's an internal adjustment for that problem. And these CB meters don't show a true curve sometime. In my shack I get better readings, from my antennas I have about a 100 ft of coax into the shack, but from the shack to the house, I have another 150+ ft of coax and another switch box plus another meter. I just checked my beam on this radio in the house to compare to alsworld's. At 26.000 it's flat, at 27.500 it's 1.2, at 28.000 it's 1.5, then at 28.500 it goes in the red, 3+. From there it starts up and down, at 29.000 back to 1.2, 29.500 up in the red again, 30.000 back down to 1.2. I don't believe the curves are like that, just a meter not showing true readings. |
Tech833
| | Posted on Thursday, July 24, 2003 - 2:41 pm: |
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With all that coax, you just don't know.
When I sweep an antenna, I use a tracking generator and a bridge, and no coax between the bridge and the antenna feedpoint. That is the only way to get accurate readings.
I did sweep an Imax 2000 once, but forgot what it came out to. If you have the time to search the forum here, you could probably find it. |
Scrapiron63
| | Posted on Friday, July 25, 2003 - 11:58 am: |
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Yep, you can add random lengths of coax and fool most of our "CB" meters. When I put my beam together, I used a MFJ 259 analyzer with a short piece of coax, got the swr flat with 50 ohms of resistance at 27.000, then when I added other lengths of coax, switch boxs, etc, I would make sure my dosy 'liked' the setup. When you know your antenna is ok, by using different length jumpers, you can fool a dosy everytime. What few I-max 2000s I have helped with, didn't require any adjustment, they were fine from the factory, they would go way above and below the CB band with low swr. Don't guess I ever tried the analyzer on an I-max 2000. I did check some A-99s with the analyzer, and found that the SWR might show good with the resistance way high. I've wondered if in some cases where people had tvi problems even with low swr, if maybe the high resistance caused the problem. But then I decided I was too old to think about these things, and sold the analyzer. haha |
mikefromms
| | Posted on Saturday, July 26, 2003 - 12:03 pm: |
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Kc0gxz, Alzworld, Techs, et.al., you have convinced me that anyone needing a new or replacement antenna that will give good performance and broadbanded service should go straight to the I-max 2000. Seems to me this antenna solves a lot of issues.
Thanks for all the swr readings and comments.
mikefromms |
Alsworld
| | Posted on Sunday, July 27, 2003 - 12:58 am: |
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Mike,
just trying to give you the readings from an operators point of view. I like mine, but who is not to say that a homemade copper j-pole may outperform it? For it's price, the IMAX 2000 is a great performer, but I still will bet that the Shakespeare ABS is a great one too. Too bad more owners aren't speaking up about that one.
I know Bullseye is now on his 3rd Maco 5/8ths and loves it. I know Tech 307 does!
I think because I have always been fortunate to get my IMAX 2000 up at leat 40ft to the feedpoint (putting the top of the antenna between 64 and 79 ft) depending on where I installed it, it has helped form my positive opinion of this antenna. If I had it lower, who knows how the results (and my opinion) may have changed?
Alsworld |
mikefromms
| | Posted on Sunday, July 27, 2003 - 8:49 pm: |
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I have had a hunch the new Army big stick is a giant improvement over the old ones and may be just as good as I-max 2000 but it is not as broadbanded according to advertising and posts here.
mikefromms |
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