Jump to content
  • 0




I recently installed a midland mxt275 with their whip antenna. 

The antenna is installed onto a bare steel tab I mounted onto the top of my aluminum roof rack. 

The radio is wired directly to battery power and ground with a 5A fuse at the battery. 

Using a surecom sw102 meter, I get 1.01 on channel 16 low power, about 5.6w out. Engine off. 

With the engine on, SWR jumps to 2.5ish on channel 16 low power, 6w out. 

Am I missing something?

Link to comment
Share on other sites

3 answers to this question

Recommended Posts

  • 0

Try disconnecting negative from battery and put it to a bolt on the chassis or even a seat bolt. You could be getting noise or feed back from the alternator or some other electronics. 

I have a DC filter coming because I can hear an alternator whine through cb channels. 


Link to comment
Share on other sites

  • 0
6 hours ago, FrostyFruits said:

DC filter

Those have really gone up in price, have used many of them for Icom A110/120 aviation radios, as that connector is also used by that series of mobile radio, with electrical noise being a huge problem with AM radio. Great filter, and does work well. I also add chokes to power cables, a practice that came from Motorola shipping cases of these when doing large projects, such as P25 installations at Public Safety Answering Points (911 Call Centers). That filter should work well to curb much of that noise heard. 

Back when you could still go to Radio Shack, they had a version that was sold for use with CB (AM 23-40 channel) and stereo equipment too, which was larger, cylindrical and comes up in many auction sites, for about the third of the price of the Kenwood version, it works too. Bought many on clearance years ago and used them all over the place.

Link to comment
Share on other sites

  • 0

I moved the ground off of the battery to the chassis near by, started the truck and I’m getting 1.18 on 16 in low power mode, 5.6w, and 1.48 in high power mode, 14.2w. Pretty consistent across the channels and on the repeater channels I’m seeing 1.00 same wattages. 

Thanks for the tip. Simple fix! I also tested my antenna mount for ground for giggles, it’s fine.


Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Answer this question...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...

Important Information

By using this site, you agree to our Terms of Use and Guidelines.