WRQJ559

My callsign being 559 makes the 5 by 9 terminology quite confusing. I usually try to report by telling them how their volume, signal strength, and background noise comes in. Also too many people lie about "loud and clear" when someone actually sounds weak. Better to be honest so they know and can fix it.

Also curious of your testing results with this antenna. I like the idea of an even more compact antenna for use with my chest harness when skiing so I can keep the 935G plus under my jacket protected from the elements. So long as similar performance to the stock antenna is maintained.

@WRXP381 I would be curious to know if you agree that the noise sounds like injectors. After listening to the noise sample recordings on K0BG.com blog this seemed like the closest match. Here is my latest test recording: https://drive.google.com/file/d/10Oloo84FDnbdT4lqvJUbHP1CqDySZJ-G/view?usp=drivesdk

Yep, I should probably inspect and clean each ground strap and the connections to the alternator at a minimum. It should be noted the noise isn't extreme and I can functionally communicate using the radio it's really just an irritation. Also the leads are connected positive to the battery post and negative to the same location on the inside of the engine bay as the negative battery cable so as not to bypass the ford BMS hall sensor. But yeah, even bypassing that common ground and going straight to the negative post didn't stop it. I did clean up the strap connections from the body to the frame on the passenger side really well because of the easy access and that one is known for corrosion issues.

Update: My final solution was to throw a 30ah eco-worthy lifepo4 battery under the seat and now I have excellent quieting on transmit. Complete power isolation from the vehicle is the ticket. After extensive A/B testing with the various common easy solutions for filtering the DC power nothing ever stopped it and I had a lot of false positive placebo effects going on with various attempts. One thing that did seem to knock down the harshness of the buzz was putting x2 2200 micro farad capacitors in parallel after an mfj1142 filter (only used the filter to provide some resistance for testing, it didn't work by itself) The capacitors smoothed out the tone some. I could potentially continue to experiment with capacitors and target specific frequencies if I were to figure out the specific frequencies of the noise using an oscilloscope. But I'm so happy with the lifepo4 performance I may not pursue it further unless I get bored. Stuff I thought about trying but didn't: - Making my own power leads with heavier gauge wire as the theory is that voltage drop can increase conducted noise. Just didn't feel like re-running wire. - Further troubleshooting and cleanup of the various DC grounding points on the engine and frame (I did try HF style RF bonding of the hood and exhaust, which doesn't seem to matter for conducted DC noise for UHF, wasted effort) - The extreme of replacing injectors and injector harness. Nah, they work.

I think you're exactly right. Midland's primary customers are not those who care to know this level of detail. They are overlanders and off-roaders looking for an easy to use radio that you don't have to program, is largely plug-and-play and just works. The customizable feature rich Chicom products are for us basement dwelling nerds that use chirp.

I purchased my MXT275 in May 2022 and it had the latest version of the firmware which is wideband capable on the repeater channels. You can find out what version you have by resetting the radio and watching the version pop up on the display. The latest is R9 for wideband support. This applies to the usb-c models only.

If you go Lifepo, go big, I tried my kg1000g+ on my little 10ah lifepo4 and it would shut off at high power when transmitting. On medium it worked fine.

I have the KG1000G plus and it's a fantastic radio. I am running it in the truck and as a base station. It's a superheterodyne radio. A quality unit that is comparatively expensive for what it does. But I also just ordered a Btech GMRS-50V2 to go in as my permanent base station radio because of a couple of features that I like about it. Number 1 is the quad watch feature for monitoring 4 channels simultaneously without scanning and Number 2 is the RJ45 to K1 splitter for the hand mic. I wanted that flexibility for recording nets and other things. So even though it's a system on a chip and supposedly inferior to the wouxun, for my needs as a base station it will work great. A repeater net friend has one and sounds great on it. He did have to turn up the mic gain on it out of the box.

This will be my next step should all else fail with bonding and ferrite use. I was discussing dc to dc isolator devices with an electrical engineer friend today that should "nuke the noise from orbit, it's the only way to be sure". [emoji3]

More data points gathered today. Trying to isolate the problem area I hooked up my mobile radio to a separate power supply (in this case a dakota lithium battery). With the truck running there is zero noise on transmit. Again proving (I think) that antenna is fine, but power is noisy. I also did a second experiment, this time I hooked up the radio to truck power but ran an alligator clip test lead wire from the radio body to the seat bracket. The noise reduction on transmit was significant. Not eliminated but significant. Might try this same experiment again but with a wide braided bonding strap and see if even more noise is suppressed. This method combined with a toroid on the power lead might lick it. Just waiting for the toroid to arrive. What conclusions would you make based on these experiments?

Good call on inspecting the block ground strap, stuff is getting crusty under there on an 11 year old truck. My coax is usa made rg58, 12 feet long. Marked pro58au on the jacket. It's strange that when I use the handheld on that antenna, even with the truck running no noise is there on transmit. It's only my mobile radio on the truck power wiring that gets the RFI.

I have been struggling to suppress injector background noise (low pitched buzz that changes intensity with RPM increase) on my 2013 F150 ecoboost (steel body) that occurs only on transmit. No noise on receive. My antenna setup is a midland MXTA26 mounted on a comet nmo front fender mount using pro58au coax cable (USA made). SWR reads about 1.0 to 1.5 depending on frequency. My radio is a wouxun kg1000g plus and I used the factory provided wiring harness run from the battery through the passenger fender cavity away from vehicle harnesses down under the passenger footwell to the wiring access hole under the footwell carpet. Positive is at the battery, negative is at the same grounding point on the inside fender that the negative battery cable attaches to so the ford BMS hall sensor is not bypassed. I used quality copper crimp on terminals at both points. My first effort to suppress it I tried cheap Amazon ferrite beads of unknown mix on both antenna coax and power leads. They helped some but didn't solve it. I returned them and ordered the Palomar engineering troubleshooting kit beads containing mix 31, 75, and 61 covering a lot of frequencies. This kit hasn't arrived yet. I also tried putting a Powerwerx LF-1 DC noise suppressor on the power cable and it had no effect. Returned it. Thinking I have a ground loop isolation problem I then proceeded to place bonding straps on each hood latch and also at 3 places along the exhaust (exhaust tip, between muffler and catalytic converter, and before the catalytic converter with no effect. One item of interest. I connected my handheld kg935g to my truck's antenna coax with so239 to sma adapter and when that radio transmits with the vehicle running, the ignition noise on transmit is not present. So it appears to be on the power side. So my question is this, which ferrite mix is likely going to be most helpful out of the 3 types I have coming and given my symptoms would I want to target the DC power only or would it also be smart to choke the coax with multiple turns as well? Also, would it be worth my time to continue trying to bond more truck body parts? And lastly, could having an older battery with decreased cold cranking amps be contributing to my issue due to voltage drop even though when running the truck is on alternator power? And related to that, should I think about moving up to 10 AWG wiring making my own harness instead to help with voltage drop?