Troubleshooting mylack of distance, receivng and transmitting.

[peterblt]

Francis antenna's need 18ft of coax.

[WA4GCH]

Francis antenna's need 18ft of coax.

I hate to tell you this but 18 foot of coax if the antenna is working will do nothing ......

18 foot is the wrong length even if your tryng to use coax to tune it ....and 50 ohm coax is the wrong type anyway ...

[philjo]

Looking at the picture, it's obvious that your problem is the location of the antenna. Too much of it is below the roofline. The truck body is absorbing the radiated signal and detuning the antenna.

Thus is the reason so many antennas are leaned forward. But at the same time it throws your donut thingy off too. Its a catch22

[rabbiporkchop]

[QUOTE=Pmracing;2592237]I have been reading here a while, enough to know that my answer will probably be that I need a better antenna. Talking with other drivers on the road, I am barely getting a mile of range.


I have a Cobra 25 ltd. One year old.

The coax in my cascadia is bad so, when I was only a month into trucking I was sold this antenna setup:

Coax run straight from the radio, along the dash and out the passenger door, about 9 or 10 feet long (I did not measure it). The coax is Tramflex RG-8/x Foam 95% Shield stranded center.





With the velocity factor of your coax being 66% you need 11.95 feet of cable going from your antenna to the swr meter, and another 11.95 feet going from the meter to the radio to get an accurate reading with the cheap meter. After taking measurements you can run any length cable you like. If you had an Mfj-259 it will give you an accurate reading with regardless of cable length.


Mike

[Pmracing]

With the velocity factor of your coax being 66% you need 11.95 feet of cable going from your antenna to the swr meter, and another 11.95 feet going from the meter to the radio to get an accurate reading with the cheap meter. After taking measurements you can run any length cable you like. If you had an Mfj-259 it will give you an accurate reading with regardless of cable length.


Mike

Crap!

what about with this meter? Still not an expensive one...

Workman SWR3P & CX-3-PL-PL


[ame]http://www.amazon.com/POWER-METER-Radio-Watts-Jumper/dp/B002LZB0J2/ref=sr_1_1?s=automotive&ie=UTF8&qid=1337042365&sr= 1-1[/ame]

Mikeeee

[WA4GCH]

Crap!

what about with this meter? Still not an expensive one...

Workman SWR3P & CX-3-PL-PL


http://www.amazon.com/POWER-METER-Ra...7042365&sr=1-1

Mikeeee

I use this one and it tracks my BIRD#43 nicely ...

[mike5511]

There are several threads on here about the Cascadia. First, I had pretty good luck with the Francis 5x5 on the back of the cab. I put the bracket on the air line holder bracket. Only problem was it was taller than the trailer. Good for transmit/receive, bad for hitting things. Plus, I slip seat so running 27ft of coax from the rear of the cab to the dash takes a few minutes longer (plus the need for cable ties) than just running one thru the door.

I have experimented with a similar bracket for the Cascadia. No matter what antenna I ran, I had to lean it forward to get a decent SWR. Except for the antenna I'm running now, Wilson 2000 w/18" shaft, the other antennas, various length Francis antennas and a Monkey Made, had to be leaned so far forward, close to 90 degrees, to get a good SWR that it killed the signal. The antenna I'm running now is leaned forward about 15-20 degrees and I am at a 1.7:1 on 19 and it gets out better than what I've tried so far. Oh yeah, that is with 18' of coax, using 9' of coax raises the SWR up over 3:1, as does 6ft or 12ft. My next test is to use a shaft long enough (will have to make one) to raise the load on the Wilson to roof level, above the door, and attempt to stand the antenna straight up.

Doing some bonding from the mirror bracket to cab then to frame would no doubt help and probably eliminate the need to use a specific length of coax.

I suspect you have a dangerously high SWR currently and that could be a big part of your problem. Plus, most of your antenna is surrounded by metal.

Here is the picture......... finally. (My lean looks greater in this picture than what I remembered when I wrote the above. I also made a mistake when I said 45 degrees......changed it here, couldn't in the first post.)

[MNdriver]

I run a 2012 Cascadia with a stock Cobra 29, a good piece of 18' coax and a vice grip mount on the rear airline swing bar, connected to a 5.5 ft. Francis. SWR about 1.6, normal talk range 4-5 miles. Hears as far as 10-12 miles average. Same results with a 12' piece of coax. Bird perch mount like yours didn't work nearly as good on my truck. Couldn't get SWR down. 5.5 ft. worked way better than a 4 foot.

I did the same thing and am using some RG-58 coax from my 2 Meter rig I had. Getting about a 1.3 SWR and about a 5-6 mile range with it on a 09 Cascadia.

My coax is about 25 feet long too. And home made

[mike5511]

I hate to tell you this but 18 foot of coax if the antenna is working will do nothing ......

18 foot is the wrong length even if your tryng to use coax to tune it ....and 50 ohm coax is the wrong type anyway ...

Everything is a long way from perfect on these new trucks. So coax length does change the SWR. Doesn't solve the problem, but it will change the SWR making it safe to use your radio. You guys that keep scoffing at the coax length thing obviously don't do any installs on trucks with bad rf grounds.

[MNdriver]

Everything is a long way from perfect on these new trucks. So coax length does change the SWR. Doesn't solve the problem, but it will change the SWR making it safe to use your radio. You guys that keep scoffing at the coax length thing obviously don't do any installs on trucks with bad rf grounds.

Yop, don't know squat about doing installs.

Just got a ICOM 2m rig installed in the car. Tried to install my Kenwood TS-480SAT into the truck and the Cobra 18 was not an easy install either.


but hey, using 600 feet of RG-8 coax to 10 or 12 meter bands works pretty slick too.