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Message |
    
26_op_141
New member
Username: 26_op_141
Post Number: 3
Registered: 2-2005
| | Posted on Thursday, February 10, 2005 - 7:20 am: | 
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What is the “recommended” maximum length of coax for 27 Meg installs before the cable gets too much loss:-
RG58
RG8 Mini
RG8
RG213
I’ve tried to find a site with this info to no avail. I know every cable has different losses due to brand/construction but it gives me some idea.
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Tech808
Moderator
Username: Tech808
Post Number: 4791
Registered: 8-2002
| | Posted on Thursday, February 10, 2005 - 10:10 am: |
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26_op_141,
Here is a FREE,
Coax Cable and Line Loss Calculator
That I have used for years now.
Coax Cable and Line Loss Calculator
Hope this helps,
Lon
Tech808
CEF808
N9OSN |
Patzerozero
Intermediate Member
Username: Patzerozero
Post Number: 427
Registered: 7-2004
| | Posted on Thursday, February 10, 2005 - 10:24 am: |
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i suppose 3db of loss is a good place to stop losing power, though i prefer my losses to be as close to zero as possible. so...
avg mini 8 around 3db @ 150'
avg rg 8 around 3 db @ 175'
avg rg213 around 3 db @ 300'
avg rg58 around 3 db @ 75'
that's @ 30 mhz, & like you said, they're all different qualities, therefore these are for 'average' quality/shield/conductor/dielectric etc. some coax is better, some is worse. hope this helps! |
Marconi
Intermediate Member
Username: Marconi
Post Number: 362
Registered: 11-2001
| | Posted on Thursday, February 10, 2005 - 10:31 am: |
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I find that you can see remarkable differences in the 50'-100' range at times.
But, seeing as this factor can vary so much, and because it is always a good idea to check each line, I suggest you get a GOOD non-reactive 50 ohm dummy load that has an RF meter in it. Hook the line from your TX'r to the DL and test the output thru the line. Keep a short run of coax around to test what the output is without a lot of line and always check that first. Then you will know for each line you have and there will be no CB buddy bias in the information.
Plus a GOOD DL is a GOOD tool to have around in this hobby. |
26_op_141
New member
Username: 26_op_141
Post Number: 4
Registered: 2-2005
| | Posted on Thursday, February 10, 2005 - 11:38 am: |
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Thanks guys for your info. The reason im asking is that Ive helped install a Shakespeare NBS2010 for a friend. He is on top of the hill and Im on the bottom and Im outgunning him on virtually all local contacts within a 0-100 mile radius. We both have the same antennas and the heights are more or less the same. Radios are the same too with same output power (ive checked with power meter). The only diffence is that he is running about 100' of RG mini 8 and Im runing a Japanese coax called 5D-FB (see link):-
http://www.alphalink.com.au/~gfs/products/dfb.htm
I know your all going to say location,location,location but its strange my friend is down on all TX signals compared to me and he is some 200' higher than me on the crest of the hill. I wonder if its to do with the NBS2010 angle of radiation and him being on the very top of the hill??
Ive checked his SWR and it reads 1.2 , so no problem there.
I cant think of any other reason why his signals should be down on mine????
Any ideas?
I will try the dummy load for sure. In fact Ive just found out tht my other friend has a MFJ antenna analyser.I'll give that a go and see what it reads.
Will keep you posted.
By the way TECH. What happened to the NBS2010 exposed? Was it ever review by TECH833 in the end? Id like to see the results.
73
Tim
26 OP 141
PS. Spin your beams to England this Sunday at 13.00H GMT. Were hearing skip from USA and Im running a NET on 27.535 USB. All are invited. |
Marconi
Intermediate Member
Username: Marconi
Post Number: 391
Registered: 11-2001
| | Posted on Wednesday, February 23, 2005 - 1:39 am: |
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Well I might agree that location is very important, but I did not say height of location.
If it was all about height, then it would be remarkable if stations in the US Rockies did not dominate the air ways, and they do not.
Being on a hill might mean that the soil around is not too good. It may be as simple as that. Sometimes hills or the location on a hill can be detrimental to good RF.
If you have a mobile take notice of how you come to hot and dead spots in your travels.
Did I get you off your subject, sorry. |
Mikefromms
Intermediate Member
Username: Mikefromms
Post Number: 490
Registered: 6-2003
| | Posted on Sunday, March 06, 2005 - 5:56 pm: |
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I would change the coax. No offense to anyone or any company brand or type of coax but I'm running nothing but at least LMR-400 with factory ends already attached for 100+ runs from now on. Cost is not as much an issue as it used to be with me since I've seen for myself what really good coax can do. One tech told me a couple of years ago if you are having a problem with your system the coax is usually the first place to look for the problem. It is incredible what coax can do for or to a station. That Shakespeare should be walking the dog up there.
mikefromms |
