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mobile set up help???

sitting duck 616

sitting duck 616

Active Member
Nov 2, 2013
102
8
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des moines, ia
Merry Christmas my friends hope everyone is having a good time..

I need good advice i just bought some equipment and need help on the monitoring part of the setup ...

This is what i have so far.:

Magnum S-9 350

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Xforce streight 10 pill
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Predator 30k
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Mfj 269cpro..
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Bird-43-----5000watt slug

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lmr240 coax a lot of ground strap ...

please let me know what else i need covered 240 amps 4 batteries in line 900 cranking amps..
 

heavy gauge power and ground wire, #1awg or #2awg at least. Cam lock ends for both the amp and the power, they make brass quick disconnect type that lock together. And a disconnect of some type at the batts. Looks like you plan on putting out some power there. Make sure that antenna tunes well, and do a good job bonding. Good luck and keep updating!
 
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Throw away the amp, don't need it if you install the antenna properly (fixed mount) and do all the bonding on the truck that you should be doing.

http://k0bg.com/bonding.html

FOR THE LOVE OF GOD DO NOT USE THE MIRROR ARMS. They are by far the worst mounting points ever for efficiency. Given that even the 350W barefoot the Magnum produces requires serious attention paid to antenna mounting and grounding, if you intend running the amp and not having the radio or even the truck shut down every time you key up you're limited to hole drilling. A ground strap running to the antenna mount does not come even close to being sufficient.

Its good that you've got the analyser as you'll be able to actually measure the improvements the bonding makes. You install the antenna and find the resonant point where X=0 and also record what the value of R is at that point. You then start adding bonding and without adjusting the antenna, measure where the resonant point is again using the shortest length of coax you can. You should see that it has dropped a fair bit - mine dropped almost 300kHz. The value of R should be a lot closer to 27 Ohms (unmatched feedpoint impedance of a perfect 1/4 wave groundplane antenna) than when you started as well. Once you get to the point that additional bonding isn't making any difference then tune the antenna to where you want it to be.

I run 100W, I work the world with no problem. You don't need any more than 100W. Those who say you do have clearly never installed an antenna properly in their lives. The Magnum puts out all the power you need on its own. Just to put the 350W of the Magnum into context with the 100W I use, to the receiving station the 350W would be barely a S point more on the meter. 1kW is barely 1 S point more than 350W and not even 2 S points more than 100W yet the 350W and especially the 1kW require serious attention to detail in the installation and create specific problems especially with power supply and antenna grounding for an improvement that is probably going to be pointless most of the time. I've seen the same level of transmit improvements just by replacing piss poor antennas or piss poor antenna installations and installing decent antennas and installing them properly. One thing that will do which your amp will never do is improve receive as well and no, a preamp is not a substitute - they make things worse if anything. If your antenna and power wire installation takes any less than two or three days to do you're going to have problems when you key the mike.
 
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Sideways said:
Where do you suggest is the optimal place to mount an antenna on a semi? Top/center of the cab is just not going to happen for most of us because of air dams or your boss just won't let you drill holes in their truck. Is the back of the cab a better option?
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If the air dams are fibreglass there's no reason why you can't mount on the top of the roof and have the whip protrude through a discreet hole in the air dam.

Back of the cab is OK as long as you can get almost at the top of it so as little of the antenna is shadowed by the body as possible. The hood is a good option if its bonded well and the front fenders as a second choice although you want to be doing it on the drivers side for pedestrian safety.

If you can't drill a hole at all then 350W is going to cause problems and running a 10 pill is definitely out. You will not under any circumstances get sufficient grounding for that level of power any other way than drilling holes and using a fixed mount.

Talking of fixed mounts, Breedlove antenna mounts are the best there is.
 
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Now that is one long shaft lol. Nice work 616. Keep at it man. You will be one bad a** mobile station if you do it right. Keep up the good work and hope you have good results with the antenna setup as you will need it for that radio and amp to work right. The magnum s9 by itself will do some damage with the proper antenna system and it appears you are covering that now. Keep up hard work!!
 
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