TRX-1: Better reception on battery power?

[knitwhit]

So today I turned on my TRX-1 (using an AC adapter as I usually do) and it seemed unusually quite. I powered it off, unplugged it, and turned it back on using batteries and it was locking on freqs. For ex. I hit the WX button on AC power and it would not lock onto a channel and just kept scanning but doing the same on batteries it locks on with no problem. This was all done with the scanner placed in the same position on my end table were it usually sits. I also tried it in a different room and get the same results. Anyone run into this issue before?

 

[ScannerSK]

Yes, I have experienced the same thing with the older however similar GRE version PSR-500 unit. I placed a couple chokes in series in the positive and negative DC power lines between the adapter and scanner and that helped a lot.

I'm not sure whether the noise in my instance was being generated by the AC adapter itself or whether the signal was in the outlet and was being transferred to the scanner via the adapter. In either case, there was a lot of additional white noise when the scanner was powered using the AC adapter vs. when running on batteries.

Shawn

 

[DJ11DLN]

It's most likely the wall wart. I've had a few that caused this symptom with my Pro-18/668. Oddly, the cheaper ones and orphaned cellphone chargers seem less prone to do this than the "good" stuff on the top shelf, or such has been my experience anyway.:roll:

 

[Valeriy]

So today I turned on my TRX-1 (using an AC adapter as I usually do) and it seemed unusually quite. I powered it off, unplugged it, and turned it back on using batteries and it was locking on freqs. For ex. I hit the WX button on AC power and it would not lock onto a channel and just kept scanning but doing the same on batteries it locks on with no problem. This was all done with the scanner placed in the same position on my end table were it usually sits. I also tried it in a different room and get the same results. Anyone run into this issue before?

Well, I haven't a TRX-1 yet (I'm planning to get one in the months to come) but the same thing does happen
to my BCD436HP.
I have verified it beyond any reasonable doubt: when the scanner is powered by an USB cable, either connected to my PC or to a power bank, the sensitivity gets greatly reduced, above all regarding the Close Call Capture mode, which I use heavily.
And yes, I have applied the aluminum-foil fix to the battery bay cover, and put ferrite chokes on the USB cables, but no joy.
For that reason, when I'm not re-programming it, my 436 runs most of the time on internal rechargeable batteries power only.

 

[AC9BX]

This should not be happening. I don't know what type of supply the TRX uses, linear or switch mode. But with a linear supply unless it has a noisy rectifier, which is very rare, it should not make even the slightest radio noise. A switch mode supply however makes tons of it. Proper filtering can eliminate most and even all of the noise. Poor supplies however are notorious for abusing radio reception. A linear supply however can couple radio noise already on your power system through to the attached radio. In either case running on battery disconnects your radio from this interfering signal.
Any number of things today can cause very severe radio interference, washing machines (electronic controllers on modern models), furnace, computers, monitors, TV sets (a plasma TV generates outrageous radio energy), battery chargers, digital picture frames, coffee makers, printers, home theater receivers, some LED and CFL lamps (they have little power supplies inside), and on and on and on. Anything with a switch mode power supply or computing logic device, CPU, microcontroller, is a potential source of radio interference which these days is nearly every electrical item.

 

[SCPD]

Any wallwart is not going to have any filtering in it or full wave rectification,you would need a fully regulated power supply not a switching supply or a stupid wallwart.The wallwart is for charging only.I plug mine into my cable box(samsung/cablevision)

 

[knitwhit]

I did find a little improvement using a 3ft USB cable instead of the 6ft cable I was using for the AC power adapter but battery power is definitely much better reception. Next is to find another AC power adapter and try that out.

 

[majoco]

Get a proper 12volt power supply that will give quite a bit of current say 5Amps continuously and use that for all your 12volt radios. Cheap wall-warts are poorly regulated and have the barest minimum of filtering, both on the supply and the output sides - do the job properly.

I run all my 12 volt stuff from a home-brew power supply that I made back in the 80's! It uses a rewound colour TV transformer, 24,000mF capacitor, 35Amp peak rectifier and 4 MJE2955's driven by another 2955 and a 741 IC regulator circuit. The overload is set for 10Amps which it will supply easily without drooping - most of the time it's passing 3Amps or so and gets barely warm.

 

[AC9BX]

Any wallwart is not going to have any filtering in it or full wave rectification,you would need a fully regulated power supply not a switching supply or a stupid wallwart.The wallwart is for charging only.I plug mine into my cable box(samsung/cablevision)

Yes, no 'wall wart' is going to have any filtering. But a linear one will not (except for some defect) create radio noise. It may well have full wave rectification and some have regulation even if just a simple 7800 series IC, certainly only the more expensive ones. Even diode ringing won't make any significant radio noise, audio yes. But without filtering they may well pass any RF hash that already exists on the power service. And of course if it's a switch mode as most all are today they may generate all sorts of noise either on the output, input, or both.

So, the Nintendo Wii power supply failed, replaced with a $7 direct from China model instead of $50 for the real thing which is highway robbery. Wow does that thing suck, crazy loud radio hash all over HF. I have cell phone chargers that are completely silent, others not so much. The charger that came with my cheapy Baofeng radiates all over the HF bands from the AC input side, which is pretty amazing, it has to get backward through the input cap and rectifier.

Replace your D-Link ethernet stuff with Netgear or somebody. Nice products but notorious for creating radio noise. Some LED shop lights I have make a little hash but not severe. The worst I have is my computer sound card. Fantastic audio but it makes a powerful carrier at regular multiples of the sampling clock frequency all over VHF and UHF, radiates for a block or 2. A Harman Kardon receiver I had radiated on MW and HF from the speaker leads. It was in differential mode so chokes just would do anything. A power surge in a lightning storm took care of that problem for me. Sadly it took the speakers with it.

My goal is to use a larger single supply for all the rechargeable stuff. That's better than a dozen wall warts in power strips anyway, let alone for noise prevention.

 

[jackj]

The almighty dollar is the best indicator of the power supply's quality. If it cost more of them then it is a better supply. If it is cheap and made in China then it is not. eBay deals aren't.

Buy it and try it, if it is noisy then send it back but you won't find a quiet one that is cheap.