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Smokepolejr
New member
Username: Smokepolejr
Post Number: 6
Registered: 5-2004
| | Posted on Thursday, June 17, 2004 - 8:41 pm: | 
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Ok clarify for me I have been told this, I do not think it is correct so I would just like to be sure if I am right or wrong. Does the bands say 11 meter 10 meter ect. Run a different heights above the ground. Now this is what I am told the 11 meter band is like 50 feet off the ground And my antenna must be there to be in the 11 meter band. and so on. OK NO LAUGHING I can find a single bit of evidence to support this. They way I see it if 11 meters only runsat 50 feet above the ground rekon how those signals get down to your car |
Bruce
Senior Member
Username: Bruce
Post Number: 1277
Registered: 9-2003
| | Posted on Thursday, June 17, 2004 - 11:48 pm: |
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Interesting .........
No the number is the LENGTH of the signal in meters WL= (300/f ).......... 11 =(300/27).
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That ELCO Guy (Unregistered Guest)
Unregistered guest
| | Posted on Friday, June 18, 2004 - 1:07 am: |
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To continue the reply of Bruce...
Bands is a term used to describe a group of frequencies. Kind of a verbal shorthand to avoid stating the actual frequency numbers.
The term is used to shorthand conversation in a general sort of way.
It is also used to describe antenna properties such as "the antenna is cut for the 75 Meter Band". You know hearing this its approximate length and the group of frequencies that this antenna will function on.
For more on radio bands you will find a ton more on the subject in the ARRL Handbook.
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Smokepolejr
New member
Username: Smokepolejr
Post Number: 8
Registered: 5-2004
| | Posted on Friday, June 18, 2004 - 5:57 pm: |
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ok lets try it this way are the different band freq or which eevr way you wish to put it run and different heights running pararell with the ground. what I was told is 11 meter band or freq's run at 50 to 60 feet above the ground and say 10 meter band runs at a different height. This is excatly what I was being told. If you have a 40ft push pole with say a antron 99 which is 18 feet the 40 ft pole only goes 38 feet so that puts you at 56 feet and that is right in the 11 meter or cb band. I'm I making any head way. I guess what I really want to know is does say 11 meter 10 meter 2,6,ect run at different levels above to ground at all times. I don't think they do from what i have studied Just trying to back up my own self.they think that the cb band runs at 50 feet to 70 feet above the ground and the others bands run at different heights other than the cb band. so lower some higher. I wished I could draw on here. |
Smokepolejr
New member
Username: Smokepolejr
Post Number: 9
Registered: 5-2004
| | Posted on Friday, June 18, 2004 - 8:18 pm: |
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Thanks guys but really what I think is the feller that has been telling me has fallen off his rocker one to many times. He is just one of those people that has been miss informed. And he thinks he knows everything. He is convinced that the band plan runs along the earths suface and different heights. |
That ELCO Guy (Unregistered Guest)
Unregistered guest
| | Posted on Saturday, June 19, 2004 - 12:42 pm: |
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Antenna Height Tutorial...
To continue Hollows answer, for an antenna to radiate its signal in the proper theoretical pattern it has to be above ground high enough so that the ground does not act a defacto relfector/director. If the antenna is aboeve a quarter wave length above the ground for the frequency in use then the pattern will be fairly pure. If it is half wave length or more above the ground then it will be almost perfect.
If you are running a dipole antenna (a length of wire fed in the middle with coax or ladder line) then you use height to adjust your SWR after cutting the wire to proper length. The distance between the antenna and the earth act to tune the antenna to the proper resistance value at feedpoint.
Now if you want to HEAR more, of course pure height comes onto play. The higher the antenna the more you will hear.
NOWEVER consider this. Once while on a temporary location I had to run a net on the 75 meter phone band/a ham band. I had the room to put up the long wire antenna but no tall towers to put it up high. SO I just hung it up in the air about 10 feet above the ground. A quarter wave length for 75 meters is over 60 feet. SURPRISINGLY over 90% of the regulars heard me without much signal loss AND shockingly my background noise dropped significantly so I could hear stations clearer. True Story. So do not discount the low antenna without first trying one.
PS if you put a low antenna please put it up securely so that people cannot run into it. One part of my wire antenna accidentally broke loos and I ran into it with my head while cutting grass with a riding lawn more. Snap to realaty!!!!!! |
Smokepolejr
Junior Member
Username: Smokepolejr
Post Number: 10
Registered: 5-2004
| | Posted on Saturday, June 19, 2004 - 11:51 pm: |
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Thanks elco guy Hope your head is alright I am still study antennas. And one of the reasons I was asking because of the numerous things I have read about antennas being placed low and seen. The way antennas work and the different ways they work is truely a pretty neat subject to study. Thanks for the info you trust it well be truely absorbed. |
Sarge
Junior Member
Username: Sarge
Post Number: 16
Registered: 11-2003
| | Posted on Sunday, June 20, 2004 - 1:11 am: |
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The guy is either terribly mistaken, or simply does not have "both oars in the water".
As has been mentioned, the references to "11- meters" or "2-meters" concern the wavelength of the signal. It has nothing to do with their height above the ground surface. Radio waves travel all all different heights as they propagate through the air.
The only time "height" might come into the picture is when comparing ground wave propagation to sky wave propagation. When you talk to someone locally, you are using ground wave propagation. Your radio signal radiates out from your antenna and runs parallel to the earth's surface. But when you talk "skip" you are using sky wave propagation. Your radio signal radiates out from your antenna at an angle and bounces off the ionosphere way up in the sky before coming back down to earth far away. This is how your signal can travel far distances - by skipping off the upper atmosphere.
I have seen training films where diagrams were used to show the up and down motion of a radio signal being transmitted. The different frequencies used are displayed by larger or smaller "cycles" of the up and down motion. But it is incorrect to somehow connect these diagrams with the idea that radio signals of different frequencies or wavelengths travel at different heights above the ground.
Check out one of the "Now You're Talking" books or other guides to getting a no-code technician ham license. They have good information on the basic concepts behind how radio signals travel. It can be good reading even if you have no interest in getting into ham radio. Maybe your local library has some books on ham radio that could answer some of your questions. It can be tough to understand some of this electronics theory when you can't see it or touch it.
Good luck and keep plugging on! |
That ELCO Guy (Unregistered Guest)
Unregistered guest
| | Posted on Sunday, June 20, 2004 - 2:02 am: |
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Dear Smokie....
If you are studying about antennas and how they work might I suggest the following books.
The ARRL has their "Antenna Book". This is a big volume on antennas and antenna theory. This book can be found at:
www.arrl.org
The book is not exactly cheap but to compensate they include a CD with some software to take the sting out of the sticker shock. AND the book does contain some useful information on antennas, their construction and radio wave propogation.
Another good book for antenna theory is "HF Antennas for All Locations" published by the Radio Society of Great Britain aka RSGB. I got my copy via the ARRL at the above web address. But if they do not offer it you might do a google search for it.
The thing about antenna books is that old or new any antenna book is worth collecting if for nothing else other than that single wierd antenna that no other book has. The older books are famous for strange looking anennas.
Keep collecting
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Ca346
Advanced Member
Username: Ca346
Post Number: 841
Registered: 8-2003
| | Posted on Sunday, June 20, 2004 - 9:26 am: |
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ELCO:
You better sign up and be a 'real' COPPER member! Just maybe you can straighten this group out! GREAT DISCUSSION... I have the Now You're Talking and the Antenna Book. A tremendous amount of information in the Antenna Book. |
Keithinatlanta
Intermediate Member
Username: Keithinatlanta
Post Number: 259
Registered: 3-2003
| | Posted on Sunday, June 20, 2004 - 1:57 pm: |
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Hey Elco. I like Ca346's idea!! When you post, I always learn. You need to become a member. I know you don't have to be one, but on the other hand, it would be nice.
Thanks for yor input into our forum.
Keith in Atlanta
CEF 150
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Smokepolejr
Junior Member
Username: Smokepolejr
Post Number: 11
Registered: 5-2004
| | Posted on Tuesday, June 22, 2004 - 9:33 pm: |
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Sarge and elco thanks alot, Sarge you put it so well. It is the answer I was looking for Not knocking you either Elco. I am currently studieing for my tech licenses and cw so I am on my way. Thanks Again all of you for thegreat info. |
