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Base 11m dipole symptoms
- Thread starter Limeybastard
- Start date
Limeybastard, I don't think you've got any "ferrite rings" laying about, have you?
Maybe this document is a bit much, (looks to be) but it contains some knowledge that might help.
(Haven't fact checked or read it)
Maybe this document is a bit much, (looks to be) but it contains some knowledge that might help.
(Haven't fact checked or read it)
The dipole? He has a brand new one.
When I read bob85's post it looks clear to me...
I think you should buy a balun, or build one Limeybastard.
(build one if you have the ferrite)
Or make an RF choke by coiling the coax, as mentioned previously.
So a 1:1 balun?
Yes he bought something that he could build in about 15 minutes and would know how its put together.
I have had several homemade dipoles, some made with Firestik mobile antennas and some with 14 ga. copper wire. Some mounted outdoors and some in my attic. None of these had either a balun or choke, and I have never seen any indication at all of common mode currents. SWR was always rock steady anytime I touched the radio or meter or touched or rearranged the coax. My eyelids did flutter uncontrolably whenever I keyed the mic but that's about it.
Last edited:
Limey
I thought you had the $10 dipole, my mistake,
his other antennas have baluns in the same housing so yours should have one at that price,
i can't find any info that mentions it does like the other antennas which i find rather odd since the balun is a major selling point, it is rated @2kw like the other antennas,
maybe throws a spanner in the works with regards to CMC due to no balun been the cause of your issues,
IF it does have a balun & given no other option i would rather rout the coax nearer to the house wiring than near to one of the dipole legs so that's something you can try,
move your coax so its as far from the legs as possible, or move the dipole legs so they are as far from you or the coax as possible,
try winding a choke anywhere in the coax to see if it changes anything,
try changing the length of your coax with a jumper & barrel connector,
you may just be too close to the antenna to run the amp in the house,
try the dipole with the rig & amp in the truck if your coax is long enough
Good luck
I thought you had the $10 dipole, my mistake,
his other antennas have baluns in the same housing so yours should have one at that price,
i can't find any info that mentions it does like the other antennas which i find rather odd since the balun is a major selling point, it is rated @2kw like the other antennas,
maybe throws a spanner in the works with regards to CMC due to no balun been the cause of your issues,
IF it does have a balun & given no other option i would rather rout the coax nearer to the house wiring than near to one of the dipole legs so that's something you can try,
move your coax so its as far from the legs as possible, or move the dipole legs so they are as far from you or the coax as possible,
try winding a choke anywhere in the coax to see if it changes anything,
try changing the length of your coax with a jumper & barrel connector,
you may just be too close to the antenna to run the amp in the house,
try the dipole with the rig & amp in the truck if your coax is long enough
Good luck
Most of the 'symptoms' I've seen can certainly be 'SWR', or better yet, CMC related. CMC isn't that hard to 'cure', but it does take some effort/experimentation if you don't know what the problem is to start with (as normal as it gets). ... So, in no particular order... Baluns are frequency related, what works for one band may not be 'right' for another. That holds for 'chokes' too, if not more so. ... Home made versus 'store bought'. Biggest difference is in 'looks' and co$t. Either have to be tuned/adjusted for your particular way of mounting that antenna. There ain't no 'one size fits all' that works -well-. (That holds for almost everything, not just antennas.) ... ... So, what do you do? Simplest thing would be to wind a choke near the feed point of that dipole and see what happens. That should at least reduce some of those CMCs. A choke very seldom ever 'hurts' anything so if it doesn't 'cure', it pro the problem just leave the thing there. ... I'm not a fan of baluns in general. They certainly do have uses, but are over rated/used to a large extent. They are frequency related/dependent AND power dependent. You can over power (saturate) a balun. It just depends on how they are made. If it isn't big and ugly it probably isn't 'big' enough. But it says it can handle that amount of power? Manufacturer's claims taste better with lots of 'salt', you know? 'They' measure things under the best conditions. Your set up is very seldom the 'best' conditions, you know? ... ... This is getting too long so I'll quit. Good luck.
Yeah, was hoping at least 300W would work on it without it throwing out those symptoms. The Stryker 955 "bare foot" with same antenna works ok.
There is no mention of balun, because I doubt it has one. I have not had a chance to open it up though. The location of the dipole is about as far as where my magmount on my truck is, basically the driveway, and the dipole is in the attic above the garage.
The thing that scared me was the routing of the coax to the dipole, ideally it would have travelled towards and in between the inverted legs of the dipole, issue I have is there is a few electrical wires on the attic floor taking the same route. So I routed the coax as in such a way, that it was being fed from around the left leg of the dipole but still maintaining a ballpark inverted V with coax in the center of it being plugged in.
There is no mention of balun, because I doubt it has one. I have not had a chance to open it up though. The location of the dipole is about as far as where my magmount on my truck is, basically the driveway, and the dipole is in the attic above the garage.
The thing that scared me was the routing of the coax to the dipole, ideally it would have travelled towards and in between the inverted legs of the dipole, issue I have is there is a few electrical wires on the attic floor taking the same route. So I routed the coax as in such a way, that it was being fed from around the left leg of the dipole but still maintaining a ballpark inverted V with coax in the center of it being plugged in.
Maybe it is too close to the left leg, that combined with no choke, and possibly no balun?!
Indeed, I will try moving it, issue is the coax running in parallel with power lines in there, I heard thats a big no no. Will figure it out when I go back up there. The heat is unbearable inside the attic. And with the fiber glass insulation, f**** me , all is needed a foot wrong and I will be through the ceiling LOL.
If you decide to go back up there, i'd advise waiting until early morning before the attic has a chance to heat up.