| Author |
Message |
    
Mikefromms
Intermediate Member
Username: Mikefromms
Post Number: 130
Registered: 6-2003
| | Posted on Tuesday, March 30, 2004 - 2:46 pm: | 
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Here's a fun question: If you were already 36 ft high with your antenna and wanted improved performance, which would give you the best efficient improvement taking into account all factors like interference, cost to improve, but let's say a pine tree would be your tower, etc.--would it be an amplifer or add 40 ft to your antenna's height? Which would you chose and why?
mikefrommms |
Tech808
Moderator
Username: Tech808
Post Number: 1988
Registered: 8-2002
| | Posted on Tuesday, March 30, 2004 - 5:52 pm: |
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If I had it at 36' I would raise it to 54' or 72'
This would allow me more room for other antennas below it. 
Cost & Performance wise an Amplifier with a good 27 to 30 db Pre-Amp is the way to go.
It would save lot's of Money and Time. 
The Higher you go the More chance of Problem's, ie: Wind Damage, Coax, Guy wire's and Cost all play a major part.
Lon
Tech808 |
Simpleman
New member
Username: Simpleman
Post Number: 9
Registered: 2-2004
| | Posted on Tuesday, March 30, 2004 - 5:57 pm: |
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A amplifer. Why because it would take along time for that pine tree to grow another 40 ft. |
Ca346
Advanced Member
Username: Ca346
Post Number: 669
Registered: 8-2003
| | Posted on Tuesday, March 30, 2004 - 6:24 pm: |
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Raise it!!!!!!! |
Highlander
Intermediate Member
Username: Highlander
Post Number: 476
Registered: 12-2001
| | Posted on Tuesday, March 30, 2004 - 7:18 pm: |
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If I knew that the supporting structure were sound, I would definitely go for the increased height over an amplifier. Mainly for the benefits on the receive side, but the transmit would benefit equally. A receive amp only takes you so far--It can't amplify a signal that the antenna doesn't "see", and they mostly just amplify the noise floor anyway. I also wouldn't get hung up on the height being a multiple of a wavelength or a half-wavelength---just get it as high as it can safely be supported, and forget that wavelength mumbo-jumbo. |
Boxcar
Intermediate Member
Username: Boxcar
Post Number: 261
Registered: 4-2002
| | Posted on Tuesday, March 30, 2004 - 10:00 pm: |
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What's the highest you guys have ACTUALLY seen an antenna tower for 10/11 meter use?
 |
Ozzie
Intermediate Member
Username: Ozzie
Post Number: 158
Registered: 11-2003
| | Posted on Wednesday, March 31, 2004 - 8:54 am: |
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Raise the antenna and use good low loss coax. Yes the amp with give you more oompf (a technical term) on transmit BUT the extra height works on both transmnit and receive. Of course you could always be greedy and do both. |
Ryan
Member
Username: Ryan
Post Number: 86
Registered: 11-2002
| | Posted on Wednesday, March 31, 2004 - 10:01 am: |
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i say live a little, do both. or better yet, get a big trucker phasing harness, build two dipoles, tune them, and stack them for lots of gain. |
Pp1616
Member
Username: Pp1616
Post Number: 71
Registered: 2-2004
| | Posted on Wednesday, March 31, 2004 - 4:03 pm: |
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highest in person that i have seen 100-118ft had a light becon on it off the east cost line up here in ri used to talk to the guy all the time.. |
Taz
Senior Member
Username: Taz
Post Number: 2652
Registered: 11-2001
| | Posted on Wednesday, March 31, 2004 - 5:46 pm: |
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Ive seen them very high, hows 150´ sound? Anyhow, I would most definetly add height before you get an amp. |
Mikefromms
Intermediate Member
Username: Mikefromms
Post Number: 131
Registered: 6-2003
| | Posted on Wednesday, March 31, 2004 - 7:04 pm: |
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I'm leaning toward the height. For the record. There are several guys here in my part of Mississippi with antennas 120ft and 140+ft. These guys don't require amplifiers.
I'd like to put an antenna in the top of a pine. I'd use the best coax I could find. It would be worth 500, maybe $600 to me.
mikefromms |
Ca346
Advanced Member
Username: Ca346
Post Number: 676
Registered: 8-2003
| | Posted on Wednesday, March 31, 2004 - 10:02 pm: |
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I talked to one of them last Summer. I thought he was using an amp. Then he said he had a 120ft tower and a 4 element beam. He was blowing my socks off here in California. |
Mikefromms
Intermediate Member
Username: Mikefromms
Post Number: 135
Registered: 6-2003
| | Posted on Saturday, April 03, 2004 - 8:16 am: |
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Well, within the hour the work will begin on putting my Thunder 8 in the top of a pine. I lowered the antenna and tuned on it some more yesterday evening. I bought a 8 ft ground rod and a lot of copper wire for grounding and clamps. I should be up in the 70's in height when this is done.
Strange comment from a guy who said he was in radios at the Home Depot yesterday: he said by installing a ground rod I was actually inviting lightning to strike my antenna. I was turning it into a lightning rod. He tried to tell me the antenna didn't need to be grounded. I told him I didn't want to argue with him (or words along that thought).
Wish us luck today. I'll be even more 10-8 if everything goes well. And, yes, I probably will add that amp later on. Why not?
mikefromms |
Ozzie
Intermediate Member
Username: Ozzie
Post Number: 165
Registered: 11-2003
| | Posted on Saturday, April 03, 2004 - 8:43 am: |
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Mike, the antenna might attract lighting (unlikely) but rather the antenna than the house. Fact yachts use a grounded rod on their mast to protect the yacht from lightning. I cannot recall the formula but for every foot high a lighting rod is the further out from it's base it protects. Unfortunately that piece of information is in one of the books that is somewhere bewteen here and Australia. ARRGGhhhh! Missing books. |
Lowpowerhal
Intermediate Member
Username: Lowpowerhal
Post Number: 181
Registered: 7-2003
| | Posted on Saturday, April 03, 2004 - 3:10 pm: |
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Grounding your antenna will not attract lighting any more than a short tree right next to the house. If you have a tower or push up pole put ground rods away from house. To deflect lighting away from house. I have 3 ground rods running away from the antenna , opposite of the house. If mother nature wants to give you a bolt of lighting she will do it. And radio opperators stay off the airwaves when lighting is around. |
Cm3885
Intermediate Member
Username: Cm3885
Post Number: 317
Registered: 12-2003
| | Posted on Saturday, April 03, 2004 - 7:14 pm: |
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I used to hear the old timers say that putting your coax end in a mason jar is a good idea during a thunderstorm but if you are not home you are kinda screwed.... |
Tech808
Moderator
Username: Tech808
Post Number: 2036
Registered: 8-2002
| | Posted on Saturday, April 03, 2004 - 7:25 pm: |
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Cm3885,
That is what they make the PolyPhaser's for.
Look at the Picture's that I posted of our Set up and you will see the Coax from the Antenna's goes Directly to the PolyPhaser's and then to my MFJ 1700B Antenna Switch .
Check out the Links for them below, And also Check Out the Review that Myself and Tech833 wrote on the PolyPhaser's.
http://www.copperelectronics.com/cgi-bin/checkitout/checkitout.cgi?catalogSTORE:CKIE:prodH00-00002+
http://www.copperelectronics.com/cgi-bin/checkitout/checkitout.cgi?catalogSTORE:CKIE:prodH00-00002+
NO MORE WORRIES AND NO GLASS JARS
Lon
Tech808 |
Dindin
Junior Member
Username: Dindin
Post Number: 44
Registered: 2-2004
| | Posted on Saturday, April 03, 2004 - 10:05 pm: |
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CM3885,back in the 23 channel days I used the mason jar trick but one particularly bad t.storm it didnt help.antenna took a direct hit,welded a direct short in the coax connector,fried rg-8 coax and killed a Midland 13-879b,my first base radio!radio was disconnected from ant and power.also lost a tv in the oppisite end of the house due to proximity strike. |
Cm3885
Intermediate Member
Username: Cm3885
Post Number: 320
Registered: 12-2003
| | Posted on Saturday, April 03, 2004 - 11:32 pm: |
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Well i have an inline surger protector. I wasnt meaning thats what i use (mason jar) but i used to hear the old timers talk about using a jar.
I heard of a guy that had a Galaxy DX 2527 in his closet and a lightning strike hit the pole at the end of his street. The RF in the air from the bolt FRIED his CPU board in the radio and he had to get a new one. The radio wasnt even hooked to the coax -OR- the 120 outlet!!! It was in his closet wrapped up snug as a bug in a rug in the box!!!!!!! Wild! |
Mikefromms
Intermediate Member
Username: Mikefromms
Post Number: 136
Registered: 6-2003
| | Posted on Saturday, April 03, 2004 - 11:47 pm: |
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Well, the antenna is is roped off and a few feet from being mounted. The guys got tired and wanted to finish tomorrow. What a job! The had to cut and cut limbs and twigs and make a path for the thunder 8. In the meantime, I have brought my Astroplane out of retirement. It is on a short pole stuck up in the yard and blowing smoke! I'm getting out and recieving strong signals just a few feet off the ground. Swr? Near flat, barely bumping the needle. I honestly beleive this antenna works better just a few feet off the ground than on top of my house.
mikefromms |
Tech833
Moderator
Username: Tech833
Post Number: 618
Registered: 8-2002
| | Posted on Tuesday, April 06, 2004 - 11:28 am: |
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Boxcar- 400 feet AGL. On top of a broadcast tower. I had a weak moment. It blew down anyway. Dang fiberglass anetnnas..
Mike- The additional antenna height will give you more coverage by lowering your takeoff angle and will also improve your receive by not only getting it higher for more signal, but also further away from man made noise sources near the ground.
An amplifier (assuming we are talking about ham radio here, not CB as it would be illegal), will only gain you some transmit area. It will not help your receive. Ampolifiers with receive preamps also amplify the noise, so do not gain you any coverage for your receiver.
If you lower your takeoff angle 2 degrees, at 50 miles out, that is nearly 13 dB gain. It would take around a 100 watt amp to gain that much. Lower your takeoff angle by 5 degrees (going from 30 to 76 feet with a 1/4 GP) and you increase your gain by 22 dB!! That would take around 650 watts. Unless you plan to buy a 1,000 amp, I would raise the antenna. |
Mikefromms
Intermediate Member
Username: Mikefromms
Post Number: 144
Registered: 6-2003
| | Posted on Thursday, April 15, 2004 - 2:05 pm: |
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I raised the antenna. I've talked 80 -100 miles straight ground waves. I have now encountered a short somewhere in one half of my antenna or coax. What a bummer. Maybe a limb got hung on one of the wires. We'll see.
mikefromms |
