Hello everyone. I am new to the forum and I’ve found reading many of the threads very interesting. I would like to know how to make a RF choke for my antenna. I am using a Imax 2000 on a lattice tower with no GP radials at the moment, this is going to change soon. How long should I make the choke coils and how many? Also I am in two minds with the GPK for the Imax, your thoughts on this would be appreciated though. The reason I’m in two minds over the GPK is because I'm also considering buying the interceptor 10K, and this antenna already has GP radials. I've also read with interest your idea's on insulating the antenna from the tower, so I’m also going to try this method out. Any help would be most welcome..
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RF choking
- Thread starter delta
- Start date
The size of the coil making up that choke should be such that there is no damage to the coax used to make that choke. Want to make that choke very symmetrical, wind it on a coil form, make it more 'pleasing'? Fine, do so. Rather just coil up a few turns of coax like you would a rope? Fine, do so. Think it would be easier to 'hide' if you wound that choke around the pole that holds up the antenna? That will work too. It really isn't all that critical. Back to the part about not deforming/destroying the coax used by bending it too much.
How many coils or turns in that choke? Depends on the frequency of use. 'More' is better than 'less' to some ridiculous extent. For 11 meters, something on the order of 6 or 8 turns ought'a do it (there's a 'fudge factor' in that number of a couple of turns).
If done 'close' to correctly, the only thing affected by that choke will be what's 'flowing' on the outside of that coax, not what's on the inside (the only reason why it's worth doing at all).
Chokes are NOT fool proof, they don't work all the time. They do tend to at least help, though.
That ought to get you into the 'ball-park'. Finding the right seat is up to you.
- 'Doc
How many coils or turns in that choke? Depends on the frequency of use. 'More' is better than 'less' to some ridiculous extent. For 11 meters, something on the order of 6 or 8 turns ought'a do it (there's a 'fudge factor' in that number of a couple of turns).
If done 'close' to correctly, the only thing affected by that choke will be what's 'flowing' on the outside of that coax, not what's on the inside (the only reason why it's worth doing at all).
Chokes are NOT fool proof, they don't work all the time. They do tend to at least help, though.
That ought to get you into the 'ball-park'. Finding the right seat is up to you.
- 'Doc
As far as the GP kit, fugedaboutit! The antenna was designed to be used as is, and doesnt need anything else to do so properly. It is basically a dipole antenna in itself. IMHO, the gp kits were created to get money from suckers who either dont know any better, or have to have every part sold to have a good station.
Keep the money in your pocket.
JM2CW!
PR
Keep the money in your pocket.
JM2CW!
PR
Hello and thanks for your replies, i've done a search in the meantime and come up with this site on making a All Band HF Air Core
1:1 Choke Balun
BUILD AN AIR WOUND 1:1 CHOKE BALUN FOR HF - THE UGLY BALUN! i hope you also find it usefull.
As for the ground planes on the imax i'm still not sure on what your saying, but i'll bear it in mind. Has anyone else had any joy with the GPK for the imax and what was the results?
Once again thanks guys..
1:1 Choke Balun
BUILD AN AIR WOUND 1:1 CHOKE BALUN FOR HF - THE UGLY BALUN! i hope you also find it usefull.
As for the ground planes on the imax i'm still not sure on what your saying, but i'll bear it in mind. Has anyone else had any joy with the GPK for the imax and what was the results?
Once again thanks guys..
B
BOOTY MONSTER
Guest
if you dont add a ground plane kit to a 2000/99 it will use the coax and/or mast as a ground element . here is an excellent thread about wire weasles adventure/results with adding ground elements to his . highly recomended reading to 2000/99 owners IMO .
http://www.worldwidedx.com/cb-antennas/35992-recommend-ground-plane-kit-imax-2000-a.html
if youre gonna upgrade to jays i10k , i wouldnt waste money ungrading an antenna youre not gonna use .
http://www.worldwidedx.com/cb-antennas/35992-recommend-ground-plane-kit-imax-2000-a.html
if youre gonna upgrade to jays i10k , i wouldnt waste money ungrading an antenna youre not gonna use .
not true,
the imax is an endfed 5/8wave, it does need radials a choke and isolating from any conductive mast to ensure best performance,
imho they are sold without radials at less cost to get money from people who do not have the space for radials or people that do not understand/dont want to understand how antennas and feedlines work,
there is plenty of good information in publications and on the www,
sadly there is 100x more misinformation passed around the www
Delta this Website link you post tells us to use 20+ feet of RG8U like 213 for 27 mhz, it think. They also describe in their image of such a coil with only 7 turns of coax on the forum. That might require a form 10" in diameter to accomadate that much coax the size of RG8/U or 213.
This is quite the opposite from what ARRL Antenna Handbook suggest 6' feet of RG8/U with 6-8 turns for 21 thru 28 mhz. ARRL also suggest 20'+ feet of RG8/U to be used for 75-80 meters. To be fair though, ARRL notes also that "lengths are not highly critical."
How say you, have you tried the Ugly Balun talked about on that site?
Hello there Marconi, No i have not tried out this choke method yet. I only found it the day i posted it on here and thought you guys might also be interested in reading it.
I think i just might go ahead and buy the i-10k and use a choke when i put it on my tower. The reports look good and the build quality also. I hold a ham licence so i guess i could use it on HF with my ATU, I'm only a 2E1 licence. I've had the I-max 2000 for about 10+ years and fancy a change. Do you think the I-max 2000 with a GPK and a choke would perform as good as the I-10K?
Thanks for your time guys..
Thanks Booty Monster i read that thread, hmm very interesting indeed. I'm very interested in Jays i10k though. What are your thoughts on this antenna compaired to the i-max 2000?
thanks guys..
delta,
im up in yorkshire and have tested my i10k against my imax (without radials) same pole/coax/height, the i10k is stronger and much better performance than the imax without radials,
also tested against my sirio 827 and tested my buddies i10k against his 827 same pole/coax/height, i10k wins again and its MUCH more durable.
im up in yorkshire and have tested my i10k against my imax (without radials) same pole/coax/height, the i10k is stronger and much better performance than the imax without radials,
also tested against my sirio 827 and tested my buddies i10k against his 827 same pole/coax/height, i10k wins again and its MUCH more durable.
Aww thats fantastic news Bob, top stuff! I was concidering buying the GPK for the i-max but i feel like a change to be honest, ive had it 10+ years. So what do you mean by stronger, do you mean like as in rx and tx? Tell me more.. Can i also be nosey and ask how much it cost in in total as i've worked it out to be £360 inc shipping and duties, vat etc. The duty office gave me a code to have put on the package too. Is this twig worth the huge cost over the likes of imax 2000's and sirio 827's etc?
Cheers, Delta
Delta, I believe that the condition of soil affects all antennas, but in the case of the 5/8 wave this negative affect is greater with 5/8 wave antennas in particular.
I also believe there is a lot of confusion about the issue of vertical antenna gain because of the report listed below which shows the typical gains that are talked about, but in such conversations no consideration is ever made of the fact that this report was generated over an infinite conducting ground plane. This error in understanding as to what is being shown in the graph completely ingnores the realy life effect of Mother Earth on communications and under reasonable testing over real earth all of these antennas will produce very nearly the same gains.
So, the Imax antennas I have installed do not do very well here at my location. Plus I have tried many different heights trying to see if the Imax will do better, but no-way-no.
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My two cents worth,
Like BM said, if your going to buy an I-10K, don't waste your money any further. As for the IMAX 2000, I just bought one, is it ten years old already? If I would have known that, I would have just bought something else. As much as I know, You cannot even compare the I-10K at all to the IMAX 2000. In other words, The I-10K is about the best you can get besides a beam or 3/4 wave maybe. Compared to the I-10K, Or one of Big Hairs antennas, The IMAX 2000 is crap. LOL! And I own one, that's the sad part.
But all is not lost, I too am going to build a 1:1 Current Balun, add a premium run of Coax, something along the lines of RG214 or so, double braid or RG-213 or even LMR-200 for that matter and I'm also going to throw down & get the GPK as well.
I guess the saying is true, "you get what you pay for" So go ahead & get the 10K & take down the IMAX. As for me, I kinda like my IMAX in spite of it's downfalls. But I'm going to make the best of it. I've also heard that Big Hair's antennas can upgrade your IMAX's coil to a bigger thicker coil & they offer a better ground plane kit than the cheap ones you see on Ebay. It's all in what you want to do. Whatever it is, do it, and do the most with it. I just may have my IMAX upgraded. Mmmmm gotta check my funds first. You know what they say, money talks but BS walks.
Like BM said, if your going to buy an I-10K, don't waste your money any further. As for the IMAX 2000, I just bought one, is it ten years old already? If I would have known that, I would have just bought something else. As much as I know, You cannot even compare the I-10K at all to the IMAX 2000. In other words, The I-10K is about the best you can get besides a beam or 3/4 wave maybe. Compared to the I-10K, Or one of Big Hairs antennas, The IMAX 2000 is crap. LOL! And I own one, that's the sad part.
But all is not lost, I too am going to build a 1:1 Current Balun, add a premium run of Coax, something along the lines of RG214 or so, double braid or RG-213 or even LMR-200 for that matter and I'm also going to throw down & get the GPK as well.
I guess the saying is true, "you get what you pay for" So go ahead & get the 10K & take down the IMAX. As for me, I kinda like my IMAX in spite of it's downfalls. But I'm going to make the best of it. I've also heard that Big Hair's antennas can upgrade your IMAX's coil to a bigger thicker coil & they offer a better ground plane kit than the cheap ones you see on Ebay. It's all in what you want to do. Whatever it is, do it, and do the most with it. I just may have my IMAX upgraded. Mmmmm gotta check my funds first. You know what they say, money talks but BS walks.
choke
take pie thats 6.28 times freqency times henerys and you get your ohms at that freqency that should give you a starting point.
take pie thats 6.28 times freqency times henerys and you get your ohms at that freqency that should give you a starting point.