Wire antennas height ?

[k8niv]

I've heard forever higher the better, and that 65ft is good for working DX on 40m, well I no this to be true, because I have worked a lot of dx on 40m for sometime now running a EF 4010 antenna, have at the present hanging between 2 tree's transformer side is 65ft and the tail is roughly 55ft, drops a little as it comes across the front yard..

Question I have is, if I was to raise this wire antenna up over say a 100ft, would it still work DX on 40m, and be any better on performance ?

 

[vagrant]

If your current EF is running N/S, you may be better served running another EF E/W and using a switch. You may see several dB difference on some signals.

 

[prcguy]

Higher is not always better and there are specific heights in wavelengths to target different things. For the lowest takeoff angle for DX you want to be at multiples of a half wavelength with the first half wavelength having a slightly higher takeoff angle than higher multiples like a full wavelength or two wavelengths, etc.

For NVIS the maximum gain straight upwards is achieved close to 1/4 wavelength above ground with many NVIS users going much lower to minimize DX signals and noise from distant storms. For 40m a 1/4 wavelength is about 32ft high and most people can find a way to get a wire that high but higher is out of reach for many people.

With all that said my opinion for mounting a multiband wire antenna that covers 80 through 10m would be try to get it about 32ft off the ground. That is the very best compromise for NVIS on 80 and 40m and its also the first half wavelength for 20m giving a good low angle takeoff and also for 10m being about a full wavelength. My main home HF antenna is a 133ft offset center fed for 80 through 10m and I have it about 33ft high. even though much of the signal goes straight up on 40 and 80m I can still work coast to coast DX on 40 and 80 at night and early mornings, so its a real good all purpose antenna.

For those with huge towers, if you can get the horizontal wire antenna up at 133ft that would be the first half wave for 80m and would be many multiples for all other bands making it a DX only antenna. But very few people have the ability to put up a 133ft tower so go with what you can based on the need for DX or NVIS.

 

[k8niv]

Vagrant, I just put my 8010 back up yesterday and it hangs horizontal in a NW to SE directions, transformer side is 56ft high and the tail is 70ft high, this is about the only other direction I can get without crossing the power lines here in my yard, have the lines coming in off the main road, and a service line comes off the pole to the house, all this out side my shack window, noway to get away from it unless I move or bury the lines.....

Prcguy, I was just curious have alot of tall trees here to pick from, but not in all directions, and a fellow Ham operator was talking to me about the height thing.......I no what it's like not having the trees, ect to get much height with, been there myself, just thankful to have what I have here to work with...

 

[Duckford]

I've heard that anything above half wave length will start to destroy your radiation pattern and "shotgun" it into lobes and nulls. 65 feet sounds about ideal for 40 meters. Start going above that and you will probably see a decrease in performance and certain problems.

Why most people say 'you can't get it high enough" is because most people can't get their wires up to 65 feet. Most of them are dealing with 80 meter dipoles or complaining they can't get it higher than ~30 feet where they live. They are referring to compromise heights, not implying that a 10 meter wire dipole is better off at 500 feet above ground instead of the ideal 204 inches.

Indeed, that is one of the potential problems of G5RV and the rest. Set it at 65 feet and it is perfect for 40 meters, way too high for 10 meters, and still too low for 80 meters. Among the advantages of an all band vertical is the fact they don't suffer from this problem like a horizontal does.

Simply put, you are better off with 1/2 wave length and not having deep nulls than you are trying to split up the gain at a higher height.

 

[prcguy]

For harmonically related bands like 40, 20 and 10m, once you get to 1/2 wavelength above ground on the lower band you are multiples of 1/2 wavelength above ground on the higher band and ideal for DX. The higher multiples of 1/2 wavelength like 1, 1 1/2, 2, etc, above ground have progressively lower takeoff angles compared to the first 1/2 wavelength above ground.

I agree that a higher random height that is not 1/2 wavelength related will not give ideal takeoff angles for DX.

I've heard that anything above half wave length will start to destroy your radiation pattern and "shotgun" it into lobes and nulls. 65 feet sounds about ideal for 40 meters. Start going above that and you will probably see a decrease in performance and certain problems.

Why most people say 'you can't get it high enough" is because most people can't get their wires up to 65 feet. Most of them are dealing with 80 meter dipoles or complaining they can't get it higher than ~30 feet where they live. They are referring to compromise heights, not implying that a 10 meter wire dipole is better off at 500 feet above ground instead of the ideal 204 inches.

Indeed, that is one of the potential problems of G5RV and the rest. Set it at 65 feet and it is perfect for 40 meters, way too high for 10 meters, and still too low for 80 meters. Among the advantages of an all band vertical is the fact they don't suffer from this problem like a horizontal does.

Simply put, you are better off with 1/2 wave length and not having deep nulls than you are trying to split up the gain at a higher height.

 

[w2xq]

I've heard forever higher the better, and that 65ft is good for working DX on 40m, well I no this to be true, because I have worked a lot of dx on 40m for sometime now running a EF 4010 antenna, have at the present hanging between 2 tree's transformer side is 65ft and the tail is roughly 55ft, drops a little as it comes across the front yard..

Question I have is, if I was to raise this wire antenna up over say a 100ft, would it still work DX on 40m, and be any better on performance ?

If it isn't broken I wouldn't try to fix it. 😀

If you have a tree that is ~100' why not try something different? Put up a more-or-less vertical wire fed with a matching network on the ground rod near the base of the tree. The low takeoff angle should provide some interesting opportunities at grayline and late at night. I had fun with UA0 contacts over the pole, VKs and ZLs in the early morning hours. If you can manage a quarter wave length for 160m, even if you have to slope it a bit, you might have some fun on the top band. My version of such an antenna was good enough for 160m DXCC and WAS using just exciter power (100w). Good luck.

Good luck.

 

[k8niv]

Hello everyone, made a few changes, hoping it didn't mess it up very much, still trying it out as I have the time......have the transformer side its 58ft almost in the top of the tree, and have the tail in a different tree at 80ft up to the pulley, the rope the pulley is on is closer to 100ft off the ground....the other night got a surprise worked Spain off this antenna on 80m band, first time this has happened for me....still have some issues with the swr, I dont own a Rig Expert, or anything like this, never invested in one due to just using it a few times, but maybe I need to, my external tuner handles it but well u no how it is sometimes........tried to adjust the lengths of the wire antena, but didnt get it low as I wanted it just on a few bands..........I have tried to shorten my coax run to the shack but don't think I can any more than I have in which at the present I have a 160ft.......did however ended up putting a cmc choke inline which helped with the RFI I had in the shack........however, really not sure what else I can do about the swr it works well with a ext tuner, but like to have it lower than it is but dont no what else I can do with it...

 

[bearcatrp]

Does thickness of the wire make a difference besides height?

 

[prcguy]

A tiny bit like if you had a 40m dipole made of 24ga wire and compared to another with 10ga wire, the thicker one would have slightly more band width. The NEC has rules for antenna wire size depending on length, you might look that up if you want the antenna to meet code.

Does thickness of the wire make a difference besides height?

 

[bearcatrp]

Thanks prcguy. Had a 60 foot wire up until someone posted about a discone doing just as good. I compared both on same radio and the discone did just as good so took the wire down. Not sure the thickness but think it was 10 gauge. Will have to look at the spool I bought. Was just curious when I read this thread.

 

[krokus]

Thanks prcguy. Had a 60 foot wire up until someone posted about a discone doing just as good. I compared both on same radio and the discone did just as good so took the wire down. Not sure the thickness but think it was 10 gauge. Will have to look at the spool I bought. Was just curious when I read this thread.

The long wire should do better than a discone, in HF. Did you have it connected via a transformer? (4:1, 9:1, etc..)

 

[bearcatrp]

I used the box from a Par end feed antenna. Replaced the wire it came with for a longer wire. About 50 feet in the air. When I had my wire up, using the R75, I compared both to a couple different stations on HF. Was surprised the discone did as well or even better on some stations.

 

[prcguy]

A PAR end fed or similar will probably give more than 10X the signal at all HF frequencies compared to using a VHF/UHF Discone for HF. The thing that drives HF reception is signal to noise ratio and with the wire antenna you will have big signal and big noise with some ratio between them. The Discone will give a much much lower signal level but the noise will be proportional and sometimes lower giving the elusion of better reception and in some cases its more pleasant to hear simply due to the absence of noise. But in the end the Discone will never ever come close to the reception capability of a longer wire antenna.

I used the box from a Par end feed antenna. Replaced the wire it came with for a longer wire. About 50 feet in the air. When I had my wire up, using the R75, I compared both to a couple different stations on HF. Was surprised the discone did as well or even better on some stations.

 

[bearcatrp]

I will put the original wire back on and try it again to see how it goes. Will be a few days. High winds kicking our buts now after the snow storm from last night.

 

[W5lz]

Increasing the height of any antenna will typically increase what you will hear. Unless it starts out really low to the ground, that increase needs to be 'substantial' for it to be noticeable. It "lowers" the horizon and also changes the 'shape' of it's radiation pattern. Is it worth doing? Just depends on how much trouble/expensive it is to do so.
The HF antennas I've had have all been less than 50 feet. If I could do it, I'd double that! I'd also try it at 75 - 80 feet (which in most cases would have tripled it's height). After something on the order of 100 feet I think it'd not be a 'huge' improvement. That includes 'practical' along with 'possible' in defining 'better'. Don't expect a 'miraculous' improvement, but do expect some.

 

[bearcatrp]

Got it up last week. Not the best height due to the weather but about 20 feet in the air. Testing between the wire and my discone and still show the discone as good or a little better on some frequencies. The discone is about 35 feet in the air. Since I just bought a Icom 52A, the loop will have to wait a little bit.

 

[k8niv]

I have put my 2nd EFHW 8010 up in a L shape out front, have the transformer 3.5ft off the ground, also put a ground on it too, and the wire runs up vertical 65ft, and then cross the yard horizontal rest of the length, this end drops some as it crosses the yard, tree it is in just about 30ft tall...
Feeding it with a 122ft of RG 213 coax going to the shack...what time I have had to try it out seems to work pretty well here...it hangs in a N to S directions, no CMC Choke on this one yet so have some RFI in the shack, it appears to affect my desk top computer, which sets on the other side from where my coax comes into the shack....noway to shorten the coax run to the shack, not on either 8010 I have up here.....

 

[k8niv]

Good morning all, I still have the one 8010 up in a inverted L forum it goes up vert 65ft, then out and cross the front yard, and seems to work pretty well, so far, have a ground wire on it, but it seems to have more noise on it on 40m and 80m bands than the other 8010 out in the back yard, is this normal ?.........or does the location there in make a differences.....

I have tried to shorten up the run of coax going to both antennas, due to some loss, but noway to shorten it I see....
Only way I can shorten the 8010 out back is if I hang it n a inverted L forum too....probably shorten it 50ft or so...

Well just going to throw this out there too.....

Is there anyother wire antenna I can go to and better myself without getting a beam for DX ?....