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Discussion Starter #1
I just installed my Icom V8000 and I want to know what a good SWR would be? Also, other than adjusting the antenna up and down, how else would you lower the SWR?

Thanks
 

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Your best bet is to take the unit and antenna to a pro and have them tweek and peek it. That way all you have to do is install, with no mods to worry about, and you will have max preformance. Also give them the SWR meter so it is part of the Cal process.
 

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A good SWR would be a theoretical 1:1, but you'll never get that low.

Grounding is very important; use excessive grounding braid/wire to ground the mount.

Make sure it is away from obstructions. If possible, mount it at the back of the bed, so that you aren't emitting right next to the cab. When you tune it, do it away from buildings.

Use high quality cable/components.

Don't coil the excess signal cable.

Install a grounded spark arrestor on the signal cable.

If you are getting really picky, grease the threads inside the antenna mount (if applicable).
 

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Your best bet is to take the unit and antenna to a pro and have them tweek and peek it. That way all you have to do is install, with no mods to worry about, and you will have max preformance. Also give them the SWR meter so it is part of the Cal process.
Wow, you dont have a clue what your talking about do you?
 

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I just installed my Icom V8000 and I want to know what a good SWR would be? Also, other than adjusting the antenna up and down, how else would you lower the SWR?

Thanks
from the above, and since you didn't bother to respond to my question at the end of this post in which i provided all of the info you needed,
http://www.ttora.com/forum/showthread.php?p=781078#post781078
it's pretty clear you don't have an amateur radio license.

jim aka the wrooster
 

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A good SWR would be a theoretical 1:1, but you'll never get that low.
sure you can.

Grounding is very important; use excessive grounding braid/wire to ground the mount.
the OP did not specify what kind of mount he is using. an NMO mount, for example, is inherently grounded. a magnet mount, on the other hand, is capacitively coupled to the underlying sheetmetal. in either case, using a "ground wire" at ~146MHz isn't going to do anything for your SWR. perhaps at CB frequencies, ~27MHz, yes. but not in the 2M amateur band -- it will not help and may in fact hurt the SWR. a properly installed mount with the correct antenna for the application (read below) will never require a supplemental ground.

Make sure it is away from obstructions. If possible, mount it at the back of the bed, so that you aren't emitting right next to the cab.
depending on the type of antenna he chose (again, not specified), this could be worst idea ever. most mobile antennas depend on a suitable ground plane for the best radiating pattern, and also for the best impedance match to the radio. for these reasons, mounting the antenna atop the cab will generally provide optimum range and optimum radiating pattern. if mounting atop the cab is not possible, the antenna MUST be specifically selected as to not be ground plane dependent. a 1/2 wavelength radiating element is typically used in cases where you want to mount the antenna to a bedbar or similar. for 2M applications, this means a 39" or so antenna.

When you tune it, do it away from buildings.
at 2M frequencies (~146MHz), anything farther than about 1 lambda isn't going to make any difference whatsoever. so 2M, approx 6 feet, is all you need to any surrounding structures.

Use high quality cable/components.
AMP or Amphenol, nothing from radio shack.

Don't coil the excess signal cable.
cut off the excess cable. don't worry, it won't screw up your SWR or make you dog go bald. cut off the excess and attach a quality connector.

Install a grounded spark arrestor on the signal cable.
on a vehicle? with a nearby lightning strike, voltage gets induced both onto the antenna AND onto the car body. where, in this case, is "ground"? where are you going to ground the arrestor to? both the antenna and the car body are at the same voltage potential -- therefore the arrestor has the same voltage on both (the signal and ground) sides of it. hence, it does nothing, and can do nothing.

If you are getting really picky, grease the threads inside the antenna mount (if applicable).
?

jim aka the wrooster
 

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wrooster-

Thanks for continuing to put out good information!! Just wanted to let you know that even though there's some misinformation put out there, knowing both what's wrong and what's right is helping me a lot. I also see that you are being very patient with the folks out here that are seemingly defiantly going to break the federal law and not get an FCC Amateur Radio license (the test was $14... took an hour for the whole deal... studying wasn't that bad..no more morse code requirement)... I guess they feel that selectively choosing which laws are o.k. to follow, and which one's arent' is up to them....?

73,

KI6IHV

-Mark
 

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Well, when I suggested to mount it away from the cab (towards the back of the bed) I was under the impression that he didn't want to scar the crap out of his roof with a magnet mount-style antenna. Maybe it's just me, but I have had bad experiences with magmount antennas. Some say that you need to make sure that the underneath of the magmount has some type of protective layer so that it doesn't scratch... this raises another problem.

If you have some type of protective layer underneath the magmount antenna, then it isn't capacitively coupled to the sheet metal beneath it (also not accounting for the x number of layers of paint).

If it is mounted towards the back of the bed, odds are it is going to be on a bedrail. A bedrail does not provide an adequate ground plane (nor is it a decent grounding point), not to mention if he has some type of bed liner, that's not going to help, either. Thus my advising for excessive grounding braid/wire.

Why a spark arrestor? Although my advice is vehicle specific... the original poster never provided information as to what he was installing it to... ;) Some people swear by them.

Although non-essential, the spark arrestor, tuning away from buildings, and solid contact points aren't going to hurt a soul... It's simply good habits, especially if he has some type of dual-use setup.

And the grease in the mount? I assume you have never driven in rain in which once it gets in the mount, freezes?
 

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Discussion Starter #12
To Answer your question wrooster I do not have an ameture radio licence. I help out with several desert race teams and I need to comunicate with the teams when I'm chasing them. The radio will ONLY be used when I'm chasing for those teams. I know this is not an excuse to not get a licence, I'm just telling you what I'm using the radio for. The teams I chase for already have the radios set from PCI and we'll only use those channels.

I mounted my antenna on my cab, in the same spot you mounted yours. I drilled a hole so my antenna location isn't going to move any time soon. I got my radio from Ham Raido Outlet and the antenna and coax from McKenzies. I'll need to check the specific brand of the antenna and cable. Right now I'm getting between 1:2 and 1:2.5 on my SWR meter, I know the lower the SWR the better, but what is an okay SWR?
 

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To Answer your question wrooster I do not have an ameture radio licence. I help out with several desert race teams and I need to comunicate with the teams when I'm chasing them. The radio will ONLY be used when I'm chasing for those teams. I know this is not an excuse to not get a licence, I'm just telling you what I'm using the radio for. The teams I chase for already have the radios set from PCI and we'll only use those channels.
None of that does anything to change the fact that you are bootlegging on MY ham bands.

Get a ticket BEFORE YOU KEY UP!

KC5WDP
 

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well, i thought about how to reply to this for a bit, but i could not find any better way...

To Answer your question wrooster I do not have an ameture radio licence. I help out with several desert race teams and I need to comunicate with the teams when I'm chasing them. The radio will ONLY be used when I'm chasing for those teams. I know this is not an excuse to not get a licence, I'm just telling you what I'm using the radio for. The teams I chase for already have the radios set from PCI and we'll only use those channels.
you are lazy and arrogant, and unlawfully using amateur radio frequencies. if my buddies and i were out offroading and were interfering with one of your desert races, you'd be on our asses in two seconds about how we (a) didn't know what the hell we were doing, and (b) we should find somewhere else to play since we were interfering with your race. why do you think you should get some kind of special treatment?

I mounted my antenna on my cab, in the same spot you mounted yours. I drilled a hole so my antenna location isn't going to move any time soon. I got my radio from Ham Raido Outlet and the antenna and coax from McKenzies. I'll need to check the specific brand of the antenna and cable. Right now I'm getting between 1:2 and 1:2.5 on my SWR meter, I know the lower the SWR the better, but what is an okay SWR?
that's all very nice but i am not helping you break the law, use frequencies which you are unlicensed for, and use frequencies which you may interfere with other amateur operations.

you have no concept of what a "band plan" is, and why certain frequencies are completely off-limits. your race crew may well be interfering with amateur beaconing operations or perhaps school kids trying to talk with astronauts on the space shuttle or space station. you neither know nor care if that's the case.

so, continue forward on your path to blowing out the finals on your new radio.

jim aka the wrooster
 

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If you have some type of protective layer underneath the magmount antenna, then it isn't capacitively coupled to the sheet metal beneath it (also not accounting for the x number of layers of paint).
that is nonsense.
a capacitor consists of two conductive plates separated by an insulator -- the latter is referred to as the dielectric. in the case of a magnet mount antenna at 146MHz, as long as the thickness of the dielectric insulator is "reasonable", say up to about 0.050" (50 thousandths of an inch, about the thickness of a nickel), there will be good coupling. so, no, a second coat of paint (etc.) is not going to make any difference.

If it is mounted towards the back of the bed, odds are it is going to be on a bedrail. A bedrail does not provide an adequate ground plane (nor is it a decent grounding point), not to mention if he has some type of bed liner, that's not going to help, either. Thus my advising for excessive grounding braid/wire.
there is an immense difference between a DC ground and an RF ground. at high frequencies, such as the amateur VHF range (~146MHz), a piece of "ground" wire longer than about 1/20 wavelength (10cm in this case, just under 4") is not doing what you think it is doing -- it is not a "ground".

And the grease in the mount? I assume you have never driven in rain in which once it gets in the mount, freezes?
unlike the 3/8" stud mount typically used on CB radio antennas, the NMO mount typically used on VHF amateur radio is completely watertight (via integral Viton rubber gaskets) and will not freeze up no matter what the weather does.

ps:
i apologize if my reply above comes across as direct. it's not your fault, it's the guy above you.

jim aka the wrooster
 

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Discussion Starter #16
Desert racing in Southern California is a huge sport, it's not just a random group of guys getting together and driving around. These races are put on by well organized groups that cover all aspects of the race, pit location, race course, road crossing, and even the frequencies the race teams can use. Local police, fire, and search & rescue teams give us the frequencies to use for emergencies. Each team has a designated frequency (given to them by PCI/SCORE/other race organizations). The teams I work for already have their frequency set. I’m using my radio to communicate with the teams on frequencies designated by the race organization for them. I’m not communicating on random frequencies, I’m not using my radio outside of the race. If I intended to use my radio outside of the races I would look into a Ham license. The racing organizations care about what the race teams do, that’s why they designate only certain channels for us to communicate on in certain areas.

I’m not trying to be arrogant or lazy, just looking for help with my radio.

P.s. I’ve worked races before where we had other people on the same frequency and we don’t flip out at them and tell them to get off the channel. We don’t even tell people to go somewhere else to “play”. The desert is a huge place and we know that everyone gets a chance to enjoy it racer or not. If people are on the race course that are not racers or a part of the race team we do tell them to get off, but we do that because we don’t want them to get injured or killed. Every injury or death is on step closer to our courses being closed.
 

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Discussion Starter #18
Our race frequency is 153.695MHz, we have 154.600, 166.375, 155.400, and155.970 for an emergency. Most race frequencies range between 150.000 to 155.000 depending on the area.
 

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Our race frequency is 153.695MHz, we have 154.600, 166.375, 155.400, and 155.970 for an emergency. Most race frequencies range between 150.000 to 155.000 depending on the area.
ok, you didn't tell us the whole story. those frequencies are not in the amateur 2M band allocation of 144.000 to 148.000 MHz.

you, or a friend of yours, modified your V8000 after you received it, right?

i'll leave aside for the moment that the V8000 is not FCC type-accepted, and therefore can not lawfully be used outside the 2M amateur band.

i have two Icom V8000's, and am very familiar with these radios from an engineering standpoint. you are going to have somewhat of a difficult time with using the V8000 on the frequencies you list above. the receive side filter is very much optimized for 144 to 148MHz, and therefore receive sensitivity and adjacent channel selectivity will both be reduced on the frequencies you are assigned. on the transmit side, the directional coupler is again optimized for 144 to 148MHz, and therefore output power will be reduced the farther you get from that range.

finally, the frequency span you gave of ~153 to ~166 Mhz will be extremely difficult to meet with just one antenna. you will have to tune the antenna at the center of that range and suffer high SWR at the two extremes. this will of course degrade transmit performance and lead to reduced lifespan of the output amplifier. you must monitor carefully the radio for excess heat at any power output levels above the 10W setting. i would not TX at the 75W setting as the combination of the mismatched antenna and the mismatched TX side filter will lead to catastrophic failure of the RF output transistor.

ps:
there are a a variety of Motorola and Vertex commercial band radios that are much better suited to operation in the frequencies that you were assigned. moreover, they are FCC type-accepted for operation on those frequencies -- in contrast to the V8000, which is not.

jim aka the wrooster
 

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Wow, you dont have a clue what your talking about do you?
Your right. But it's better than no one trying?
Examples:
http://www.ttora.com/forum/showthread.php?t=65169
http://www.ttora.com/forum/showthread.php?t=65118
http://www.ttora.com/forum/showthread.php?t=64827
http://www.ttora.com/forum/showthread.php?t=64687
http://www.ttora.com/forum/showthread.php?t=64686
I can go on with this and make people who know shit look stupid? The point is I tried instead of just not giving a shit. If I have some knowledge I will try and help. If I' wrong than I will admit it!
Something is better than nothing!!!
 
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