Review Polmar DB-50M / Powerwerx DB-750X

When I first saw the Powerwerx DB-750X I liked the looks. Because it appeared to be a ‘USA Only’ transceiver I didn’t give the radio much thought; it’s just way too expensive to have one sent to Europe and send it back afterwards. Then the completely identical Polmar DB-50M appeared on the websites of Dutch sellers. It didn’t take long to get a review sample into my shack.

Polmar DB-50M

Anytone, Powerwerx, Polmar, Intek, all the same
I almost forgot that this radio is made by Anytone, and the accompanying memories aren’t good. After opening up the radio there was no doubt about it: this is an Anytone AT-5888UV in a different package. Oh dear. My initial excitement about reviewing a new radio dissipated into thin air.


More model numbers you might run into. Click image to download Anytone FCC Report (PDF)

During the review period my negative feelings towards this radio slowly disappeared. Anytone did something I didn’t expect at all: fix all the initial problems and give other brands a run for their money. From one of the worst Chinese dual-band mobiles to one of the best – Anytone pulled it off.

Basic Specs
•• 10 Memory Banks (with bank linking)
•• 7 Character Alphanumeric Display
•• Power Output: VHF 50 Watts, UHF 40 Watts (4 power levels available for each band)
•• Dual Receive Operation (V+U, V+V, U+U, U+V) with separate volume controls
•• Narrow Band (2.5 kHz) operation for Land Mobile frequencies (FCC part 90)
•• Wide Band (5.0 kHz) operation for Amateur frequencies
•• 750 Memory Channels
•• Dual or Single Display / Receive Modes
•• Large LCD Display with adjustable Colors and Brightness
•• Built-in CTCSS/DCS per channel
•• PC programmable
•• Frequency range (RX/TX): 144-146 MHz, 430-440 MHz (Europe)

For full specs go down this article and download the user manual.

The picture below shows that the PCB revision number is 8.0. The first Anytone sample I reviewed about a year ago was revision 3.0. It’s clear that Anytone’s engineers have been busy. Build quality has improved too.


The Polmar DB-50M / Powerwerx DB-750X Inside.

Look & Feel
I liked the exterior design of the original Anytone, but I like this one even more. The main reason for my preference is the accessibility of the various push buttons. Once you know where they are and what they do you can operate the radio blindfolded. For the rest it’s a matter of taste.

The microphone is rather ugly but reasonably well designed. There’s no lock button, but contrary to Anytone’s first attempt this model doesn’t really need one. PTT is a bit stiff, and you need to press the rubber exactly in the middle. If you don’t, PTT won’t work reliably. There’s also a tiny front speaker built into the microphone which you can activate in one of the menus. Also configurable from the menu are four programmable buttons.

Back Panel
There are two external speaker outputs at the back which can be configured in such a way that each VFO has its own speaker. Nice detail: the cooling fan at the back is pleasantly silent and only kicks in when needed. Also at the back: the (in)famous SO-239 antenna connector and a DC out. Because this connector is not fused I don’t recommend using it, unless you’re 100% sure that nothing can go wrong.

Back Panel

European versions vs American versions
When fresh out of the box the Polmar DB-50M is limited to work within the Dutch amateur bands only. No TX/RX outside the bands, no scrambler, no 2/5 tone generator, no cross-band repeat, no nothing. While I prefer ham radios which only do what they’re supposed to do, Polmar went a bit to far. RX out-of-band for example isn’t dangerous to society, nor is cross-band repeat. To get a better idea of the radio’s capabilities I ‘opened’ it up, basically changing the Polmar into a Powerwerx.

RX Audio
RX audio is fine now. There are no annoying audio artifacts anymore, and base noise levels appear to be more under control. The audio IC and the internal speaker still won’t win any HiFi award, but all in all it’s not much worse than other brands. Tip: put an external speaker on your shopping list.

TX Audio
Complaints, complaints, more complaints. TX audio sucked out of the box. Lots of mid-tones, no highs. The most diplomatic comment I got was “Please take your head out of that bucket.” The problem is easy to fix, but you’ll have to open up the microphone. Do this at your own risk and only if you have the proper tools.

TX Audio Mod
It’s common practice for Chinese manufacturers to solder a small capacitor parallel over the microphone element, in this case an electret. By doing so the higher parts of the audio spectrum will be cut off. The story goes that they do this to compensate for the high pitched voices of the average Asian customer. I’m not sure if the story is true or not, but removing the capacitor does fix the problem. Even my nitpicking friend PA2TSL didn’t complain, but preferred the clarity of the modified Polmar over my Kenwood TMV-71 instead.

Audio Mod

The location of the capacitor to be removed. Click for hi-res version.

I mentioned the problems I have to live with here many times before: there just aren’t many radios out there capable of dealing with all the strong out-of band signals which pound my QTH. My Kenwood TMV-71E for example is of hardly any use on 70cm; base noise is something around S9+60 dB. I can’t even ‘squelch it out’ unless I activate the internal attenuator. This limits the use of 70cm to just a few strong repeaters or local stations.

The original Anytone did a good job here and this new incarnation is as good as its predecessor. Is it perfect? No, I can still hear a few mixer products here and there, but compared to the Kenwood it’s heaven on earth.

Power Output, measurements at 145 MHz:
High: 55.0 Watts
Mid 1: 28.0 Watts
Mid 2: 9.2 Watts
Low: 5.1 Watts

Power Output, measurements at 435 MHz:
High: 39.0 Watts
Mid 1: 20.2 Watts
Mid 2: 8.0 Watts
Low: 4.0 Watts

Harmonic Suppression
All harmonics are on or below the noise floor of the analyzer. Excellent.

Polmar VHF

Spectrum Analysis VHF

Polmar UHF

Spectrum Analysis UHF

Bugs & Flaws
1. Poor TX audio out of the box. Can be easily fixed though.
2. When changing channel spacing, the frequency in the display will be the reference / starting point. If you don’t want to wander off the standard frequencies, set your VFO frequency to something ending in three zeros first.
3. Lacks 8.33 KHz channel spacing for listening to the air band.

Note: the Italian / English manual is confusing at times. It’s also incomplete when you ‘open up’ the radio. Download this one instead.

The Polmar DB-50M was a pleasant surprise. No major bugs or flaws; it’s a transceiver I might buy to replace my Kenwood TMV-71. I already searched for the proper N-connector to replace the SO-239 antenna connector (found one too).

Even when performance is right there are always unknowns, such as reliability in the long run. That’s why I would never order this radio from China, but from a local dealer instead. Warranty is worth much more than a slight price advantage.

The Polmar DB-50M is imported and sold by K-PO (link). Price in NL: € 290,00 including VAT.

Package includes a microphone with DTMF keyboard, mobile mounting bracket, DC power cable, spare fuses, set of screws, Italian/English user manual, plus a separation kit with 3 meters of cable. A programming kit can be ordered separately.