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Message |
    
Nightmarenyc
New member
Username: Nightmarenyc
Post Number: 4
Registered: 1-2005
| | Posted on Saturday, February 05, 2005 - 12:04 pm: | 
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Ok guys, I know that this has been discussed before and I have seached but have not been able to find an exact answer. Ok here's the deal. I have the M104 on a 10 ft mast on the roof and am using a Rat Shack rotor to turn it( with a short 16" pipe holding the antenna to the rotor). Originally I had a ground wire to the mast/boom plate, but I noticed I bled somewhat(over tv, white lines that increased with audio). I put the antenna up another 10 feet and it helped a little, but not much. I then removed ground wire from the plate and put it on the mast itself. It helped a bit more, but it's still not completely gone. I then realised that rotor is actually insulated from the mast being that it's made out of painted alloy of some sort. I have the coax (LMR 600) sheild grounded to my ground rod as well as my Browning Mark 3 and my Firebird 500 amp with chokes on EVERYTHING. I also noticed the tvi get worse when I'm pointed West and lessens when I'm pointed East. this does me no good being I line IN NY and all the conditions come from the S/W, West directions. When I had my V 5/8 on the same 20 feet of mast I had NO TVI @ all, so I know it can be done. By the way, this is only when the amp is on. Barefoot I'm ok. What do you guys think? |
Tech291
Moderator
Username: Tech291
Post Number: 57
Registered: 11-2004
| | Posted on Saturday, February 05, 2005 - 6:58 pm: |
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Nightmarenyc,
first 2 questions,what polarity is your m104 oriented and how do you recieve your tv.via cable,dish or off the air antenna?
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Nightmarenyc
New member
Username: Nightmarenyc
Post Number: 5
Registered: 1-2005
| | Posted on Saturday, February 05, 2005 - 8:26 pm: |
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I'm using the M104 flatside and all the tv's in my building are cable. |
Tech291
Moderator
Username: Tech291
Post Number: 58
Registered: 11-2004
| | Posted on Saturday, February 05, 2005 - 11:07 pm: |
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ok,sounds like the cable co.may have some bad connections or your building may have a distribution amp that is not grounded properly. |
Nightmarenyc
New member
Username: Nightmarenyc
Post Number: 6
Registered: 1-2005
| | Posted on Sunday, February 06, 2005 - 12:26 am: |
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Darn. I was considering changin the coax to 9913. I know the Lmr have almost NO loss, but is the 9913 SHEILDED better? You think this may help? |
Tech291
Moderator
Username: Tech291
Post Number: 66
Registered: 11-2004
| | Posted on Sunday, February 06, 2005 - 10:25 am: |
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stay with the lmr if it is in good shape |
Nightmarenyc
New member
Username: Nightmarenyc
Post Number: 7
Registered: 1-2005
| | Posted on Sunday, February 06, 2005 - 1:00 pm: |
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Thanks Tech...the coax in new. I only got it a few months ago. I just wish I could properly ground the antenna. I know whole whole antenna radiates, just wish there was a spot on the thing were I could put that ground wire. |
Dx431
Advanced Member
Username: Dx431
Post Number: 974
Registered: 2-2002
| | Posted on Sunday, February 06, 2005 - 10:40 pm: |
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Attache the ground wire to one of the mounting bracket bolts that holds the ant to the mast. |
Marconi
Intermediate Member
Username: Marconi
Post Number: 355
Registered: 11-2001
| | Posted on Monday, February 07, 2005 - 7:48 pm: |
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IMO, the lack of good lightning protection is why it is not a good idea to have your beam attached to your house.
If you are going to ground the beam, you need to do it right and even then it may interact with your beam a bit. Otherwise the beam does not need to be grounded in order to work. Something might be said about disapating static, but I am still undecided as to how effective that could be.
Attaching the wire to anything above the rotor will require it to handle rotation as well. The wire needs to be heavy in order to provide a good low resistance path to earth and it needs to be insulated properly from the house or anything else it touches on the way.
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Nightmarenyc
New member
Username: Nightmarenyc
Post Number: 8
Registered: 1-2005
| | Posted on Monday, February 07, 2005 - 9:40 pm: |
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Thanks Guys. I'm using 2/O welding cable for the ground wire being that's about 80 feet long. I figured that would have been enough no? I did notice that I actually got less bleed with the ground wire off though. I'd hate to take it down, but if I can't get it under control I may as well take it down. I'll just stick with my V 5/8's cause I never had a problem with that. |
Airplane1
Intermediate Member
Username: Airplane1
Post Number: 280
Registered: 5-2004
| | Posted on Tuesday, February 08, 2005 - 8:23 am: |
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How do you ground a beam antenna, I never thought about it till reading this post.
I grounded my Maco v at the base of the antenna with stiff copper wire going down to a ground rod but when I put my beam up I need to find out how to ground it.
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Marconi
Intermediate Member
Username: Marconi
Post Number: 358
Registered: 11-2001
| | Posted on Wednesday, February 09, 2005 - 4:18 pm: |
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Got to ask yourself if electrical energy follows the path of least resistance or not? Then ask yourself what path from the antenna shows the path of least resistance, the feed line or the support?
If the answer is the coax or feed line, then that is probably the point that must be addressed if you want to effectively ground. What can we do there?
Unhook and reconnect to a good earth ground outside of the station in case of a hit. There are other ideas for protection, but even if you do as noted here the power of a direct hit or maybe even a nearby hit can do damage to your electronics via the ground system for your AC power to the station.
Airplane, you might expand on the grounding system you have by further reducing the resistance at the base of the antenna support. The more long rods the better, but you still have to live with the high resistance of the support as compared to the low resistance of the feed line. With a V-5/8 antenna a ground wire directly from the antenna to the ground rod system is practical, but how do you connect an adequate ground wire to a rotating antenna except thru the rotor and part of the mast below the rotor? The rotor also has a wire to the station what do we do about that connection?
Some talk about the use of a device in the coax line that will redirect the energy to a earth ground and save the stuff attached to the TX'r end. Coax can only handle so much current and remain viable. What do you think will happen to a run of coax if it gets a charge from a lightning bolt? It is my opinion that at best maybe the inline lightning arrestor idea might handle a heavy static charge in the air from a nearby hit.
The last coax I had that got a direct hit is probably still flying. Just to be clear, before the lightning hit my Big Stick in a pine tree, the coax was all outside and the end was wrapped around the tree with the end hanging about 2' off the ground. After the lightning nothing was left but a damaged tree, a foot deep trench in the ground running over to my water supply pipe coming from out near the street, cracked sheetrock broken glass all over the house, and every electronic device something wrong. Light bulbs blown, and foul smell was all around. The hair on my head and neck standing straight out, with ears ringing so loud I could not hear on the phone. Our eyes burned from the ozone. It was terrible.
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Airplane1
Intermediate Member
Username: Airplane1
Post Number: 281
Registered: 5-2004
| | Posted on Thursday, February 10, 2005 - 7:30 am: |
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Thanks Marconi but I still dont know the answer to my question.
I was thinking of a flexible strap mounted from the antenna mast to the mast that the rotor is on and then copper wire from there to ground rod.But the ground from rotor mast to antenna mast would need to be very flexible.
I just dont think if I ground the mast the rotor is on the antenna wont be grounded very good because the connection will be throu the gears and that cant be good.
Can anyone tell me how they grounded there beam antenna or antenna mast when it turns 360 degrees?
Or dont I need to worry about this ground connection?
Thanks, Roger |
Tech291
Moderator
Username: Tech291
Post Number: 72
Registered: 11-2004
| | Posted on Thursday, February 10, 2005 - 7:19 pm: |
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Roger,
welder lead would be flexable enough to make the rotor loop to ground your beams
tech291
CEF#291
kc8zpj |
Airplane1
Intermediate Member
Username: Airplane1
Post Number: 282
Registered: 5-2004
| | Posted on Friday, February 11, 2005 - 7:56 am: |
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Thanks Dennis. |
