These radios only put out around 3 watts from the factory. Keying the Mike for 5 to 10 seconds (with no modulation) to adjust vr6, with no antenna connected, won't hurt the final. I've had to adjust vr6 on several cobra 29's. Not sure why the factory couldn't take a minute to adjust vr6 properly. I guess they like causing undue grief for their customers. If everyone just used a good external swr meter, they could just ignore the antenna warning, knowing that the antenna system is okay.
I need some help - Antenna Warning on SWR Check
Discussion in 'CB Radio Forum' started by HD_Renegade, Jun 15, 2011.
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Of course with a CB radio having an antenna warning lite blinking all the time probably isn't good. Mainly because when you really have an antenna problem, you won't know it. -
Exactly. That’s what I want to adjust the Vr6 component and get it so if it’s on I know there’s a problem and not train myself to ignore it. I adjusted it once, I think it needs a little more as I noticed I get the antenna warning on a few channels but not all of them.
I bought an external SWR meter Sinai could fine tune, (and see if the internal one was even close) but I think the jumper coax I bought must be junk.
The internal SWR meter tells me I’m fairly low, but the external 1 says I’m high. I suspect the jumper is junk or too short. I ordered a heavier coax, and 3’ long instead of the short thin one I thought would be good enough.
this thing is like 10-12” at most and probably 1/2 the diameter of the coax I bought with my antenna
am I correct assuming that the short thin jumper would give me erroneous SWR readings on the external meter? -
No, not necessarily. The jumper cable length doesn't matter, it's just a matter of convenience to use a longer cable. I like using a 3 foot long jumper cable, so I'm not so close to the radio. I prefer to use rg8x cable for CB. You do need to use a coax with braids that are tight and dense for good shielding purposes.
The internal swr meter in the cobra radios are worthless. Just go by your external swr meter, which is probably telling you the truth about your swr, and that maybe why your antenna warning on your radio is coming on. -
The best I’ve been able to get down to is around 1.6-1.7 on channels 1 and 40, but when I go on channel 20 and check it, the needle barely moves off of 1 at all. Not sure why there would be that big of a difference in the readings.
I did check my coax and mount with a multi meter. There’s no short at all between the center conductor and the fitting or shielding. I definitely have a good ground from the mount to chassis and even battery ground. Get almost a zero resistance reading when I put the leads from the nut on the coax to different spots on the body/chassis, and have tested to a lug that goes to battery ground as well. The antenna is a 3’ firefly. RA930 ProComm right angle stainless steel stud adapter, and a SS3M fire stick medium duty antenna spring. Wondering if I remove the spring if it’ll allow me to get the SWR lower. I have the antenna mounted through the center to the roof of the cab, I thought that was the ideal location. Any suggestions to get the SWR better? I guess in reality, if the meter is correct my SWR is great mid range channels, so I probably shouldn’t obsess about it- just wanted to get some thoughts from others about it. Do those readings even make sense, can there be that big of a difference? -
Part of your swr problem is the 3 foot antenna. You really shouldn't use an antenna that's less than 4 foot. Some antennas are known as broad banded, they give you a better swr reading across the band. The down side to a broad banded antenna is that they aren't as efficient as far as antennas go. They will still work though.mike5511 Thanks this. -
A 102 inch whip is broad banded. How can it not be efficient?
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Finder Maybe To Low. -
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