Not hard to install inline almost anywhere in the feedline, and certainly having it won’t hurt anything. This was just the minimalist in me taking the “KISS” approach.
EFHW
- Thread starter jazzboypro
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I will probably get one and be done with it
G7RUX
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This is really common in installations that have no counterpoise since the feeder screen is forced to become that counterpoise. One can often get away with doing this by using a feedline choke or similar a little way away from the house but a counterpoise of some reasonable size it pretty much required.
In this video, Dave Casler uses the MyAntennas 4010 EFHW as the example and says whether or not you need a counterpoise will be dependent on the length and grounding of your coaxial feed line. In his case it was 50 feet.... and he says the counterpoise was unnecessary.
Thanks for the info. In my case the feedline will be around 75 feet
G7RUX
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At any length at all you will be causing RF on the feeder screen; at reasonable output powers you are likely to have problems with RF getting into the shack. At some lengths things will be better but a hot screen will usually result.
I will be installing a choke and see what happens, hopefully the problem won't be to severe
Choke and counterpoise two very different things. No harm at all in putting the choke in as you plan to do, and should get the common mode currents off the feed line (if there are any in your installation). Casler says it should also give you about a db of noise floor reduction.
K6GBW
Member
I agree with popnokick. I've run several of those antennas over the years and frankly I've never needed to run a choke. I've used a choke on them before, and they are good to have, but unless there is something else going on you likley won't see a dramatic difference. Occassionally, depending on how the coax is run, the shield of the coax can pick up RF and bring it back to the shack. In those cases a good choke is really helpful. Now, if you were running one of the non-resonant wire's that use a 9:1 Unun then you would see a big difference. I had a 53' wire with a Palomar Engineers 9:1 that produced a TON of common mode. I put the choke on the coax at the radio and it helped. I then decided to place it outside the wall of the shack before the coax even came into the room and it made a huge difference. My house is stucco and the chicken wire underneath the stucco actually blocks signals, so putting the choke outside made a difference. But with the antenna you've choosen you should be able to run without it. You also won't need a counterpoise wire with that antenna. I've tested it with and without one and didn't see a difference.
These are good. I have two. I found that if installed at the transformer my EFHW 4010 antenna became useless. Works fine with choke about 10 feet away just before the coax enters the house. I still have RF in the house because I set it up as an inverted L over the house. My EFHW 8010 is away from the house and gives no RF problems.
Reviving the thread, i never got to install the antenna so i am back at it. I am at the point of installing the mast on my chimney and that should be done today. I have everything except the coax because at this point i have not measured how many feet i will need but should be about 75 feet.
The only question remaining is where should i installed the choke. I plan on installing it outside but i don't know if it should be at the antenna end or where the coax enters the house. Any advice ?
Many thanks
The only question remaining is where should i installed the choke. I plan on installing it outside but i don't know if it should be at the antenna end or where the coax enters the house. Any advice ?
Many thanks
No drawbacks at all to having the choke in place before determining if it’s really necessary.
Maybe i was not clear, i do have the choke and i will install it. My question pertains to the choke location. Should i install it near the feed point or where the coax enters the house ?
The purpose of the choke is to keep RF off the feedline and from getting to your radio making the chassis and any connected wires hot with RF. An EFHW operated within resonance has little RF on the coax but used out of band it can get pretty bad. It’s also nice to have a little coax counterpoise on an EFHW so I like to place the choke balun about 20ft down the coax from the transformer. This has worked well for me and I’ve tested it on many band edges with good results. The key is to have a very effective choke balun made with ferrite and not some coax wound into an air choke.
Lou-In-USA
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An EFHW UnUn usually shares the counterpoise lug with the coax shield, so to isolate the shield, you can choke it at the transformer, or at a strategic distance down the coax (a distance of 1/4 wave of one of your bands, or at the entrance of your house. And whereever you put it, you should still have a ground point at the entrance of your house, and choke the line just before your radio since the shield of your cable does pickup RF when it's away from the ground.
Thanks for the info. Installing the choke between 20-30 feet from the feed point is doable in my setup, i will know more when i install the mast tomorrow. The choke i'm using is the one sold by myantennas (there is a link to it a few posts above). The antenna itself will fully horizontal but unfortunately not in a straight line. I still have to decide between a V shape or U shape.
Hello again,
Need some advice here. I will soon be installing the antenna. At some point the wire will need to be attached/supported to a fir tree. I get that i will need to accommodate for the sway of the tree but i'm not sure how i should do it. Any suggestion ?
Many thanks
73 De VA2FCS
Need some advice here. I will soon be installing the antenna. At some point the wire will need to be attached/supported to a fir tree. I get that i will need to accommodate for the sway of the tree but i'm not sure how i should do it. Any suggestion ?
Many thanks
73 De VA2FCS
I tie a 1/4" rope around the tree just above a big branch with a pully attached and enough slack to allow for tree growth. Then I run another 3/16" or 1/4" thick rope from the antenna insulator (far side away from the transformer) through the pully then to a weight made from pouring concrete in a small bucket with an eye bolt sticking out the top.
Tie the weight on so it sits a couple of ft above ground or high enough for when the tree sways toward the antenna the weight doesn't hit the ground. For a 133ft wire antenna about 50lbs of weight is good and for a 64ft maybe 30-40lbs. I use black Dacron rope that has the woven sheath over a bundle of strands, it lasts a long time.
Thanks for the info but i think my question was not clear. I was not talking about the far end of the antenna. The configuration of the antenna will be a horizontal V and i trying to figure out how i will attach the the point where the 2 legs of the V meet to the tree. The pulley solution will be easy to implement for the far end of the antenna.
Two legs meeting the tree sounds like you might be doubling back the antenna on itself. If you put a bend in the wire make it less than 90deg or find another location, running the wire out then doubling back with less than a 90deg bend can really reduce antenna radiation and efficiency.
