I bent my coax . . .

[WROG989]

Yesterday, I installed my Wouxun KG1000 G Plus.  Went for a several hour drive today and was disappointed with my range at high power, 50w rated ( no different than my previous 15w radio).  When I got home I was reviewing my install and found that the radio had moved and caused a 90° bend in antenna coax.  Did this permanently damage the coax?  The coax is new. 
 

Thank You!

[SteveShannon]

On 3/23/2023 at 7:08 PM, WROG989 said:

Yesterday, I installed my Wouxun KG1000 G Plus.  Went for a several hour drive today and was disappointed with my range at high power, 50w rated ( no different than my previous 15w radio).  When I got home I was reviewing my install and found that the radio had moved and caused a 90° bend in antenna coax.  Did this permanently damage the coax?  The coax is new. 
 

Thank You!

Maybe. Some coax cables have dielectric that will allow the center conductor to contact the shield. If that happened you’ll probably need to cut the bad spot out and reterminate. 

[WROG989]

Thanks Steve.  Is there a way to know for sure?

[axorlov]

No easy/cheap way to know for sure. The very first test is to disconnect from radio and antenna and use ohm-meter to check for short between center and shield. If there is a short, coax is damaged beyond any hope. You'd need to cut off the damaged section and put new connector.

If no short and the coax is of RG type, not an LMR type, you can try to carefully unbend it. RG has much more robust dielectric. The way to test the coax is to plug SWR/watt-meter and dummy load to the radio, and then put your coax between the radio and meter. If there is a huge difference in SWR and/or watts, coax is toasted.

[BoxCar]

The other point in your post - Increased power does not mean increased range with UHF frequencies.

[WROG989]

Ok, I now know what to do.  Thanks y’all!

BoxCar, there’s so much to learn.  That’s why I’m enjoying this so much. Thanks.

[WRKC935]

SWR meter will tell you if you have one.  If the SWR is high and it wasn't when you did the install it's probably bad

 

[KAF6045]

And after the SWR meter, there are full-up antenna analyzers... Many of those can even give estimates of "distance to [short/open]", without needing a radio or antenna connected.

[tcp2525]

21 hours ago, WROG989 said:

Yesterday, I installed my Wouxun KG1000 G Plus.  Went for a several hour drive today and was disappointed with my range at high power, 50w rated ( no different than my previous 15w radio).  When I got home I was reviewing my install and found that the radio had moved and caused a 90° bend in antenna coax.  Did this permanently damage the coax?  The coax is new. 
 

Thank You!

I'm going to go against the grain and say probably not. I'm assuming it is an RG-58 or equivalent? If so, and is of decent quality, it probably has a solid dielectric which can sustain a moderate amount of abuse and bending. Foam dielectric isn't as forgiving. I'd be more worried about pinched coax with trunk lip installations or coax being pinched my the door for magnetic mounts.

[gortex2]

Just because the new radio is 50 watts doesn't mean coverage is any better than the 15 watt radio. Unless your testing simplex line of site its tough to know if its the radio. I've run the MTX275 in both my jeeps since they came out and have yet to not be able to do what they are for.  

[SteveShannon]

On 3/23/2023 at 7:30 PM, WROG989 said:

Thanks Steve.  Is there a way to know for sure?

If they're touching, an ohmmeter will show continuity between the shield and center conductor. But once you straighten out the coax the short might no longer exist.  If your installation puts the coax in danger of getting bent consider using a right angle coax adaptor:

[WRQC527]

I'm going to toss in one thing here. Some antennas have a matching network in the base that consists of a capacitor, an inductor, or both. So connecting an ohmmeter at the radio end of the coax across the center pin and the shield *may* give you a false short with good coax. This is how both my ham and GMRS antennas on my van work. If you can completely disconnect the coax at both ends,  you will have a more reliable test. Let us know what kind of mount you have. 

[WROG989]

Just an update.

I bought a Surecom SW102-G meter.  With the antenna (Nagoya 72G) at center-back on my trunk lid, my SWR was 1.3.

[WRQC527]

45 minutes ago, WROG989 said:

Just an update.

I bought a Surecom SW102-G meter.  With the antenna (Nagoya 72G) at center-back on my trunk lid, my SWR was 1.3.

My guess is that with a 1.3:1 SWR your antenna and coax are fine. If you can get the antenna on the roof, it may work better. Some of that RF energy may be blocked or impeded by the roof and roof pillars. 

[WRWM999]

On 3/23/2023 at 9:54 PM, BoxCar said:

The other point in your post - Increased power does not mean increased range with UHF frequencies.

Please excuse my newbieness as I learn about all of this stuff. ...but if increasing from  a 5w or 15 W radio to a 40w or 50w radio doesn't increase your range,  what is the benefit of getting a higher power radio?

Thanks!

[SteveShannon]

9 minutes ago, WRWM999 said:

Please excuse my newbieness as I learn about all of this stuff. ...but if increasing from  a 5w or 15 W radio to a 40w or 50w radio doesn't increase your range,  what is the benefit of getting a higher power radio?

Thanks!

Just as too much is made of power output, sometimes we overstate how little it matters. Obviously power matters or we could all get by with 100 milliwatts. 
Higher power, especially a factor of ten does make some difference, but where it’s really noticeable is in signal to noise. You’ll typically receive better slightly audio with less background noise when receiving a signal from a higher power transmitter.  A better and/or higher antenna will do the same thing but helps on reception also. 
The real takeaway is that there are other things you can do that truly will increase range much more than transmitter power output, such as a better and/or higher antenna, or a better receiver. 

[WRWM999]

Thanks Shhannon--you are a fantastic explainer.