talking local on 20 and 40 meters..

[wavrider]

http://www.dx-antennas.com/Height versus take off angle.htm

good reading on height of dipoles TOA

http://www.hamuniverse.com/wb4yjtdipolepatterns.html

,25 WL AGL is the NVIS cloud warmer,,notice the only lobe going to the clouds.
Whoever posted height is might for local coms on lower bands needs to review radiation pattern vs height AGL.

C&P

The precise height above ground for the very best NVIS performance is not a well-agreed value. Antenna models reported by Jack Swinden W5JCK (and based on work of L.B. Cebik W4RLN) seem to point to best performance on 40-meters at 0.175 wavelength (7 meters, ~21.7 feet) above ground, and on 80-meters a height of 0.165 wavelength (13 meters, ~41 feet). Pat Lambert WØIPL has conducted extensive objective data collection in Colorado and reports an experience of better coverage with a height of only 1/20 wavelength above ground. He notes that noise is significantly reduced as the antenna is lowered below 1/8 wavelength, and that communications with close stations (up to 300 miles away) was greatly enhanced with such low antenna height, particularly using the 80-meter band.

You want NVIS,,keep that wire low to the ground

 

[543_Dallas]

If it means more to you to have a textbook nvis antenna than one that works better keep it low to the ground. I've been there and moved on. I posted the w8ji article because it falls inline with what I have found to be true. and goes against common hambone folklore. My antenna was originally at 20 feet to the apex and now its between 35 and 40 feet. Getting it up above the house and trees helped. I also believe reduced ground loss is responsible for performance gain. Another plus is that I don't turn the television in the living room on and off when I transmit anymore.

Maybe there's something to having a low antenna for nvis work if you lived in the middle of nowhere with with no houses, trees or other obstructions, just flat highly conductive soil. For the majority of the population putting a dipole slightly above the fence doesn't work out as well as it does on paper.

Neither wavrider or road squawker seem to have any first hand experience on the subject. If they do they seem to be reluctant to share it with us. Surely one of them has tried different HF antennas at different heights. Surely they have had hundreds of qso's with different people using different kinds of antennas at different heights and noticed that some just seem to work better than others. Even if your findings were different than mine I could respect that but you're just posting what you've found using google. Scouring the internet and posting other peoples work is a rabbiporkchop debate tactic....anyone remember that hardrock guy? Now that a challenge has been issued let the fishing stories begin.

 

[wavrider]

543

call sign KJ4IIF
I have built different antennas, tried them at different heights.
Written detailed instructions on building antennas and have them published.
Google my call sign.
Yes my QTH is in the country, two mile down a dirt road to be exact.
Zoned AR,,lots of rooms for antennas and experimenting.

NVIS,,75/40 meter fan dipole at 45' to apex.
fed with RG6 Quad coax,,1:1 current balun at feed point.
come on down to 3.865 in the early mornings and see how well a low hung wire works.
Even coast to coast,,
I have experimented with them, built them, many have failed, many have worked.

What works at my QTH may not work at yours.
Physics is physics,, radiation patterns is radiation patterns
Does not matter who you are or what you represent,, Height above ground determines radiation pattern.

Troops in Desert storm had comm problems with their antennas vertical.
They laid the vertical whip horizontal and used the vehicle as a reflector for NVIS comms,,then they were able to utilize radio comms for effective communications.

SO moral of the story is!!!! Been there done that know what worked for me
What works for you may be different than what works for me,, ARRL handbook is a great source of information,, Many engineers and amateurs have tried all those type of antennas before I ever have,,they publish their results. I have yet to build and test an antenna out of the handbook that did not perform as described.

Your type of antenna installation seems to work for you,,stranger things happens,,bees can not fly according to the mathematics of physics

 

[543_Dallas]

There's nothing but static on 3865, I'm late to the party as usual. You and I are at about the same height, you're actually higher. They are low antennas for 75 and 40 meters but they work. If you were having performance issues on 40 (I'll bet you don't) I wouldn't suggest that you lower the antenna.

No argument that height effects the pattern but there has to be some common sense used and you have to keep ground loss in mind. The OP is at 20 feet now trying to work someone across town on 20 or 40 meters. He already has a low dipole and you say no to a vertical because that's for dx. The only options you leave him is a big amplifier or settle for what he has and tell everyone it isn't possible to do better.

 

[543_Dallas]

come on down to 3.865 in the early mornings and see how well a low hung wire works.

You do realize you and I talking would not be local communication and prove nothing about nvis antennas. According to QRZ you are in FL. 922 miles from me. I'd be glad to work you some day but we really got away from the original topic. 20 and 40 meter communication at extremely close distance.

I'm not sure what frequency the military was using in desert storm or how far they were trying to communicate. We aren't talking about mobile communication either so I don't know how relevant desert storm is to this thread.

 

[wavrider]

Relevance was vertical to horizontal for local comms??? within 100 miles,, not going to draw pictures here or come back explain every statement.

Why use 40 meters for local comms,,10 and 12 work fine,,load the wire up and talk.

Or put a fan dipole with those bands on it.

3.865 around 0830 to 0900 Z should hear mouth of the Midwest W9FNB,,or Charles N9CED,, both big booming stations running low slung wire antennas.

Local comms of 40 meters 5 mile apart,,connect to the dummy load run 100 watts,,you might be surprised.

I have talked to New Smyrna beach of my dummy load,,was working on an old FT 101 on the bench and started receiving a loud signal ,,I was connected to my dummy load.. SO I replied to his CQ,,he came back,,go figure

 

[Captain Kilowatt]

At a distance of only three miles I cannot imagine why the OP has a problem communicating. NVIS is not required at that short distance and direct wave aka space wave propagation mode should be more than sufficient. I can work stations at that distance on any band from 160-2m with pretty much nothing for an antenna. In fact even on 20m using a simply wire locals out to 10 miles hammer in. On 80m AM I used to use a 12 watt carrier (50 watts pep) with a low (25 feet) inverted L and work out to 100-150 miles regularly during local nets. Three miles on 20m or 40m should be a walk in the park.

 

[KD2GOE]

It may be the cheep 100 foot run of RG8x my friend got on E-Bay he's using. maybe i can convince him to put some thing nicer down.. like davis bury flex the stuff i am running..
Next time he is on ill ask him to tune in to some one i can hear fine and see how they compare..

 

[Captain Kilowatt]

I doubt it is the quality of the coax but it would be interesting to see how well he receives other stations at various distances. Perhaps he has a short or an open in a connector somewhere.

 

[543_Dallas]

It may be the cheep 100 foot run of RG8x my friend got on E-Bay he's using. maybe i can convince him to put some thing nicer down.. like davis bury flex the stuff i am running..
Next time he is on ill ask him to tune in to some one i can hear fine and see how they compare..

At these frequencies there should be little loss from the coax unless it is damaged or full of water. In that case I would expect the swr to be high though.

Relevance was vertical to horizontal for local comms??? within 100 miles,, not going to draw pictures here or come back explain every statement.

Why use 40 meters for local comms,,10 and 12 work fine,,load the wire up and talk.

Or put a fan dipole with those bands on it.

3.865 around 0830 to 0900 Z should hear mouth of the Midwest W9FNB,,or Charles N9CED,, both big booming stations running low slung wire antennas.

Local comms of 40 meters 5 mile apart,,connect to the dummy load run 100 watts,,you might be surprised.

I have talked to New Smyrna beach of my dummy load,,was working on an old FT 101 on the bench and started receiving a loud signal ,,I was connected to my dummy load.. SO I replied to his CQ,,he came back,,go figure

If you can't tell us freq they were using in desert storm how or how far they were trying to communicate how can it possibly be relevant? You are giving the advice here so those other people's strapping signals are irrelevant. We got sidetracked and now you're too caught up in the pissing match to refocus on the original topic. I was on 3865 this morning in that time frame and heard nothing. You guys are using low antennas just like me and we've established that they are not great DX antennas. I have made contacts with crappy antennas too but that is also irrelevant. I have tried to keep my comments limited to personal experience with local communication on the lower frequencies. You keep reaching out for something or someone to prove me wrong because it doesn't fall inline with what you've read.

 

[Captain Kilowatt]

[QUOTE="543_Dallas, post: 589388, member: 21044"If you can't tell us freq they were using in desert storm how or how far they were trying to communicate how can it possibly be relevant? You are giving the advice here so those other people's strapping signals are irrelevant. We got sidetracked and now you're too caught up in the pissing match to refocus on the original topic. I was on 3865 this morning in that time frame and heard nothing. You guys are using low antennas just like me and we've established that they are not great DX antennas. I have made contacts with crappy antennas too but that is also irrelevant. I have tried to keep my comments limited to personal experience with local communication on the lower frequencies. You keep reaching out for something or someone to prove me wrong because it doesn't fall inline with what you've read.[/QUOTE]

I don't think anyone is saying that low antennas are good DX antennas are they? Maybe I missed it. I hope not because low antennas certainly are NOT good for DX unless they happen to be low band verticals over a decent radial field. Low horizontal antennas tend to have high angle radiation which is poor for DX but reasonably good for regional work out to about 600 and maybe up to 1000 miles on 40m. At that distance contacts are not DX unless one is using the simple criteria of skywave as being DX as opposed to local groundwave communications.

 

[wavrider]

If you can't tell us freq they were using in desert storm how or how far they were trying to communicate how can it possibly be relevant? You are giving the advice here so those other people's strapping signals are irrelevant. We got sidetracked and now you're too caught up in the pissing match to refocus on the original topic. I was on 3865 this morning in that time frame and heard nothing. You guys are using low antennas just like me and we've established that they are not great DX antennas. I have made contacts with crappy antennas too but that is also irrelevant. I have tried to keep my comments limited to personal experience with local communication on the lower frequencies. You keep reaching out for something or someone to prove me wrong because it doesn't fall inline with what you've read.

Hmmm DX is not the topic,,NVIS IS

NO nvis above 14 MHz,,does not leave much to the imagination about what freqs were used for comms in the Storm.

What is the size of IRAQ?? Smaller than Texas,

Surely you are capable of independent thought or do you need to be spoon fed every small detail?

I am not have a pissing match with someone that does not understand how a urinal functions.

I am not reaching for anything,,perhaps you should be reaching for the ARRL antenna handbook,,try doing some reading to put with your personal experience.

If you could not hear anyone on 3.865 it leads me to believe you have issues with either the antenna or your receive, or both.

The advice still stands,,low antenna high angle of radiation good NVIS antenna.

Nothing wrong with a high antenna,,but with height you start getting nulls in the radiation pattern as well as receive pattern.

The nulls is where the concern is,,at the right height there may just be a null in the pattern to the location you are trying to communicate with.

Have a good day and enjoy the hobby as best as you can.

 

[543_Dallas]

Captain

I suggested the OP raise his antenna higher than 20 feet to see if it would improve their 3 mile communication. Waverider says a low antenna better for local communication and that's a bad idea. Waverider then challenged me to tune in to his local frequency so he could show me how well his low antenna works. Im over 900 miles from waverider so I don't see how that test is relevant here. I can understand the confusion.

Hmmm DX is not the topic,,NVIS IS

NO nvis above 14 MHz,,does not leave much to the imagination about what freqs were used for comms in the Storm.

What is the size of IRAQ?? Smaller than Texas,

Surely you are capable of independent thought or do you need to be spoon fed every small detail?

I am not have a pissing match with someone that does not understand how a urinal functions.

I am not reaching for anything,,perhaps you should be reaching for the ARRL antenna handbook,,try doing some reading to put with your personal experience.

If you could not hear anyone on 3.865 it leads me to believe you have issues with either the antenna or your receive, or both.

The advice still stands,,low antenna high angle of radiation good NVIS antenna.

Nothing wrong with a high antenna,,but with height you start getting nulls in the radiation pattern as well as receive pattern.

The nulls is where the concern is,,at the right height there may just be a null in the pattern to the location you are trying to communicate with.

Have a good day and enjoy the hobby as best as you can.

I'm not telling the guy to buy a 100 ft tower. Why do you even bother having the 40 meter wire on your fanny dipole at 45 feet? Isn't that too high? His fanny dipole is for 20 meters also. Since you say there is little nvis propagation why not raise it up?

Frequencies below 14 mhz leaves a lot of possibilities. 40, 80 and 160 all are very different at different times of the day. Iraq is a small country, so what? The OP is asking about 3 miles. You still don't know what freq they were using, what the band was like at the time of communication or how far they were trying to communicate. It was a bad reference but instead of moving on you would rather insult me.

Experts like yourself are why I prefer AM. You aren't heard there. The coax you swiped from the direct tv guy would turn into a long fuse with enough carrier to get you above the static level this time of year. I build a remote balanced tuner and use the same wire on many bands. You use a fanny dipole fed with tv coax and say it's better than what you've built in the past....yep I'm the idiot that needs to be spoon fed.

 

[wavrider]

Storm was known as the first satellite comm war,,most of the coms were used were uplinked and down linked via sat comms.

when the sat comm failed due to software or hardware issues then HF was the standby for comms..data link etc.

Why only 45 feet? because I am in the lightning strike capitol of the world,,why tease mother nature.

I really do not see where you gave anyone any advice on your posts.

I do believe you said I have not built any antennas myself or used anything I have built.

Op asked for reliable comms in short distance,,NVIS cloud burner,, worm cooking,,low slung antenna is what works.

Spoon feed may be to complicated for you,,perhaps you may still be on the bottle.

Not an expert,,just have over 35 years in the communications field.
opinions are like assholes,,everyone has one,,

Unless you have references to back up what you are attempting to advise someone to do then you are doing nothing but wasting bandwidth and time.

But I do find your lack of knowledge amusing and a little entertaining but alas it is hard to have a battle of wits with an unarmed person.

Go back to your AM side where you can flaunt the fact you guessed a few correct answers on your FCC exam and they awarded you a license.

When you come on a forum and start slinging shit don't get your feathers ruffled if it gets slung back at ya!!

 

[KD2GOE]

I suggested the OP raise his antenna higher than 20 feet to see if it would improve their 3 mile communication. Waverider says a low antenna better for local communication and that's a bad idea. Waverider then challenged me to tune in to his local frequency so he could show me how well his low antenna works. Im over 900 miles from waverider so I don't see how that test is relevant here. I can understand the confusion.

at the moment that's not going to happen any time soon 20' is his limit.