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Four_wheeler
New member
Username: Four_wheeler
Post Number: 1
Registered: 1-2008
| | Posted on Wednesday, January 30, 2008 - 10:47 am: | 
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Hello i got a a99 up on a hill behind my house i have 1000ft of rg-6 tv cable running to it my standing wave is 1.2. I have it on a pole hah 10 feet off the ground in the woods. it tx and rx good just about 2-3 db off from what my a99 down at my house does that antenna is about 35 ft off the ground and 160 feet evleation differnce from the antenna on the hill. What i am wondering is what i need to do to get the one on the hill to outperform the one at my house it is a lot higher like i said about 160 feet higher on the hill. but it is low to the ground and in light woods if i would put this in a tree 40 50 feet would that tree interfer with it very much or am i going have to build a tower to get over the trees i just wanting to pick your all brains thanx! |
Tech237
Moderator
Username: Tech237
Post Number: 951
Registered: 4-2004
| | Posted on Wednesday, January 30, 2008 - 12:43 pm: |
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Several things come to mind, including move the hill closer, use better coax such as heliax. Right now most of your transmitted power and received signal is being lost in such a long cable run. RG-6 has 1.5db loss per 100ft (approx), so over 1000ft it has 15db loss, which amounts to a loss of about 80% (approx) of any signal on that run.
If you insist on running such along feedline, try using a 50/400 ohm balun at each end and make the run using 400 open ladder line which has much less loss over long lengths.
The biggest reason that you SWR shows as low is the amount of loss in the feedline.
Simon
Tech237
N7AUS
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Four_wheeler
New member
Username: Four_wheeler
Post Number: 2
Registered: 1-2008
| | Posted on Wednesday, January 30, 2008 - 3:45 pm: |
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yeah i know the long run can't help but some peoples singals improved and others are down as much as 3db. If i had 80% signal lost you would think that no ones signals would have come up at all really it shouldn't work at all but it does okay just wanting to get it off the ground i think the fact that its in brushy woods and that its only 10 feet off the ground hurt it pretty bad its in so much brush right now that u have to get right close with in 10-20 feet just to see the antenna? Just wondering if a tree would work you know halfway up in a tree |
852
Intermediate Member
Username: 852
Post Number: 405
Registered: 3-2006
| | Posted on Wednesday, January 30, 2008 - 4:32 pm: |
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Try doing a search using the topic "tree mount", I came up with 985 post on this subject...some for it, some against it.
Tommy~852~CEF 750
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Tech237
Moderator
Username: Tech237
Post Number: 953
Registered: 4-2004
| | Posted on Thursday, January 31, 2008 - 9:24 am: |
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"yeah i know the long run can't help but some peoples singals improved and others are down as much as 3db."
And how much more would they be up if you did not have such a long cable run??
OK in short sentences. Do no tree mount the antenna. Put up a tower or mast closer to the house that will give you the same height. Cut your coax length down to around 100ft and watch the difference.
Simon
Tech237
N7AUS
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Four_wheeler
New member
Username: Four_wheeler
Post Number: 3
Registered: 1-2008
| | Posted on Thursday, January 31, 2008 - 2:33 pm: |
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a 160 foot tower would take a good bit of money and a good bit of space i'd say...? i talked on it last night and seemed to do just about as good as the one down at my house and the antenna is laying in the brush but there anit no way i am losing 80% of my singal i don't think..?? If i lost 80% my signal you'd think it wouldn't work really at all? seems to work pretty good for laying in the brush alot people are telling me that if i get it up at least 36 feet it will do the trick is 36 feet the magic number...? thanx for your guys input |
Tech808
Moderator
Username: Tech808
Post Number: 15187
Registered: 8-2002
| | Posted on Thursday, January 31, 2008 - 3:49 pm: |
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Four_wheeler,
18' = 1/2 wave length for CB/11 Meters
36' = 1 Full wave length for CB/11 Meters
54' = 1-1/2 wave length for CB/11 Meters
Hope this help's,
Lon~Tech808
CEF#0808/HAM#001/CVC#0002
Tech808@copperelectronics.com
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Tech858
Moderator
Username: Tech858
Post Number: 116
Registered: 10-2007
| | Posted on Thursday, January 31, 2008 - 4:21 pm: |
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Four_wheeler ,
Junk the RG-6 cable as it is 75ohm not 50ohm which is required for use with CB radio , using 75ohm cable might show a good swr reading but don't be fooled by this as you most likely have a very high or very low impedence showing at the radio end which will eventually cause damage to the radio's finals and is most definately causing severe losses in your antenna system . Get yourself some decent low loss cable with airspaced core or as Tech237 said heliax .
Tech858/Jim
MM0TXO
CEF#858
HAM#230
CVC#116
Wavin' a hand at ya' fae Scotland 
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Four_wheeler
New member
Username: Four_wheeler
Post Number: 4
Registered: 1-2008
| | Posted on Sunday, February 03, 2008 - 2:00 am: |
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i priced heliax and it was around 2000 bucks what wire would you ugys suguest?? |
Tech237
Moderator
Username: Tech237
Post Number: 955
Registered: 4-2004
| | Posted on Sunday, February 03, 2008 - 8:39 am: |
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For the distance involved either 1/2" heliax or as I suggested earlier 400 ohm twin lead with baluns at each end.
Simon
Tech237
N7AUS
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Crazy_joker
New member
Username: Crazy_joker
Post Number: 3
Registered: 1-2008
| | Posted on Sunday, February 03, 2008 - 9:37 pm: |
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Every groundplane antenna I have ever seen around here has been in a tree, beams on a tower. There is absoloutely nothing wrong with putting your antenna in a tree, bot the the anntron I used to have and the Starduster I now have were are in trees, they work perfectly with very little swr.
Go go Galaxy and 48!
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Killer
Junior Member
Username: Killer
Post Number: 21
Registered: 1-2007
| | Posted on Saturday, February 09, 2008 - 7:07 pm: |
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Nothing wrong with a GP in a tree but man you got to get rid of the coax!!!!
Is this the same coax you have running to the antenna by your house two? If so you need to change it as well.
Any coax designed to run that far is going to be very expensive. |
Road_warrior
Senior Member
Username: Road_warrior
Post Number: 2124
Registered: 7-2004
| | Posted on Monday, February 11, 2008 - 9:03 pm: |
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Man, that is a long run of the wrong coax. Way to much loss! I've read some very good advice in this post from others. Yes, the cost is high for the good stuff, but, if you want your antenna that far away, you really have no other choices I can see either. Best of luck! |
Mikefromms
Senior Member
Username: Mikefromms
Post Number: 1007
Registered: 6-2003
| | Posted on Wednesday, February 13, 2008 - 12:55 pm: |
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The coax is your main problem; second, ten feet off the ground and surrounded by trees. Solution: Buy a coax equal to 213 or above and put the antenna in the top of the tree. Shoot a rope up there and tie it to the antenna and pull it up. The antron will work suspended from a rope, if you have to do it that way. I know cost is a big factor. As others have said, the tv cable needs to go.
Mikefromms |
Four_wheeler
New member
Username: Four_wheeler
Post Number: 6
Registered: 1-2008
| | Posted on Monday, February 18, 2008 - 4:46 pm: |
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If i pull it up in a tree where would i hook the rope to the top or bottom of the antenna? and just let it dangel? thanx |
Crazy_joker
New member
Username: Crazy_joker
Post Number: 4
Registered: 1-2008
| | Posted on Saturday, February 23, 2008 - 7:20 pm: |
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You have to mount it to the tree. Use part of a push up pole. You can't just tie it to the tree. Tie the rope to the antenna and pull it up.
Go go Galaxy and 48, Jimmie Johnson!
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