Complete and utter waste of time - might as well not have one.
If you insist on using one of these monstrosities it wants to be no more than 5 turns on a 4.25" core.
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Imax2000 swr
- Thread starter Last man standing
- Start date
Complete and utter waste of time - might as well not have one.
If you insist on using one of these monstrosities it wants to be no more than 5 turns on a 4.25" core.
And they're all full of crap.
The site in the following link is the only site you want to take notice of. It is done by someone who is well respected in the amateur antenna world.
Common-mode chokes
A Imax 2k new out of the box has the swr set at a 1.5 this is with the rings in the center of the black section....
To fine tune it, both rings needed to be a little lower in the black, that would have gave u a 1.1 swr or less across the 11m band....Forgot to mention I tuned mine on channel 20....
And on the 10m band up around 28.3250 to 28.500 the swr would have been a 1.3 swr....this is what mine was running 3 years ago when I bought it new, and now on the 11m band swr is a 1.1 or less.....oh yea, and Im running 62ft of RG 213 coax on it..
Tuned my swr the ol fashion way I guess, didnt use a MFJ meter..
To fine tune it, both rings needed to be a little lower in the black, that would have gave u a 1.1 swr or less across the 11m band....Forgot to mention I tuned mine on channel 20....
And on the 10m band up around 28.3250 to 28.500 the swr would have been a 1.3 swr....this is what mine was running 3 years ago when I bought it new, and now on the 11m band swr is a 1.1 or less.....oh yea, and Im running 62ft of RG 213 coax on it..
Tuned my swr the ol fashion way I guess, didnt use a MFJ meter..
Oatmeal, in 2009 a friend loaned me an Imax to test using my Autek VA1 analyzer. The antenna was old, but it was brand new in the box and had never been opened. At the time we were hearing stories that Solarcon had changed the resonant point for the Imax a bit higher...in order to help encourage more 10 meter use here in the US. Other CB operators had been suggesting a difference in length between an Old Imax and a New Imax. I'm not sure this "CHANGE" ever happened though.
As best I can recall we wanted to see if I could tell by doing a bandwidth report, using my VA1, if the claim from Solarcon was true...about their factory setting the tune for use in the CB band at 27.205 mhz like the manual indicates, and if the sweet spot frequency was higher than reported in the manual.
We also wanted to see if I could tell the frequency difference that a 1/4 turn of the rings made to the resonance of the Imax, and if possible how many channels a 1/4 turn made in the process. I never tested beyond this single iteration however.
The Antenna Work Sheet form I used in this case covers a bit more that the CB range only, the frequency step rate is equivalent to 5 channels, and the top curve is results from the VA1 at the antenna feed point, and the bottom line was read thru a working feed line to a Daiwa CN-801H a foot away from the radio.
Here are the two BW curves before and after, moving the rings down 1/4 turn.
View attachment Imax VA1 test.pdf
IMO these reports clearly show the Imax is higher in resonant frequency than Solarcon suggested (27.205) in the manual, and the Z value for the complex impedance is right on the mark near 50 ohms across the entire CB bandwidth. Make you own conclusions about what this tells us.
The data also suggest that the Solarcon matcher is very effective at controlling the resistance (value of R) across the CB bandwidth and for me that is what makes this one so broad banded.
In the real world however, your results may differ.
Well, I'm confused.
It is not much of a distinction, but your first post told us the best SWR you could get was 1.80, and now it is 1.50. I still think an Imax that works right will show a better match right out of the box, and with the rings set in the middle.
LMS, a lot of information and ideas were posted to help you, but did any of this answer your question?
I still stand by my original post #21.
Good luck
Different meter
I bought this one off eBay ,a 3 meter type,replacing 35 year old single meter that was showing 1.9-1.
now to get the rf out the home stereo when it's off .......
I am back to the books on ham testing, and plan to take tech test soon..
There isn't a lot of traffic in the the 28.300-28.500 ssb.?
Where is the most popular call spot ?
I bought this one off eBay ,a 3 meter type,replacing 35 year old single meter that was showing 1.9-1.
now to get the rf out the home stereo when it's off .......
I am back to the books on ham testing, and plan to take tech test soon..
There isn't a lot of traffic in the the 28.300-28.500 ssb.?
Where is the most popular call spot ?
As you are studying for your license, look up solar cycle, that will answer why 10 meters does not have to much activity, but when it does it is a lot of fun.
Cutting the antenna was a major mistake, i would find/replace the top section first to get back to stock. Then, remove the choke......might be giving a false reading. 80+ft of coax to the back deck is overkill but not the main concern, make sure the coax isnt looped or rats nested........straight shot not looped like a garden hose. After fixing the mistakes, ask all your locals if you can borrow more meters?
i would start with properly mounting it. use the c-clamps and bolts ant nuts to mount it
if ya dont have you can find them at radio shack or walmart. next at the very least
mount it to a aluminum pole or perferbly metal one for proper ground.next
buy a 102 ss whip to replace the top section then just use your rings to
fine tune. the rf choke id make it 8 turns 8 inches round diameter then tape
it to mast. put it as close to feedpoint as possible
Big hose clamps
The latest antenna is now 28 ft up on some welded to gather emt conduit and a smaller choke,made from RG 8 stiff stuff, I got in the used 600 3 meter swr meter Friday ,what a piece of junk ,all 3 meters are. Very lose in the housing
I payed 20.00 + shipping for it! I think it going to the range for 10mm glock practice"..........next. Cooling fans for 2970n2 I will make a stand for it with some fans in it
The latest antenna is now 28 ft up on some welded to gather emt conduit and a smaller choke,made from RG 8 stiff stuff, I got in the used 600 3 meter swr meter Friday ,what a piece of junk ,all 3 meters are. Very lose in the housing
I payed 20.00 + shipping for it! I think it going to the range for 10mm glock practice"..........next. Cooling fans for 2970n2 I will make a stand for it with some fans in it