Category: FX-4C

I didn’t need another new QRP transceiver, but then again I also don’t need to have that second slice of cake for dessert.

<I have no self control>

I pulled the trigger on the Chinese made FX-4C from https://bg2fx.com/ and in only 6 days, it arrived in perfect condition to my home in the midwest US.

This is my initial findings as I just received it this morning.

Unboxing

Opening the box, there is another box. They include a Pelican style case for the transceiver. Note that I included “style” in that description – it is not a case that I would expect to withstand weather and moisture, but the inclusion of this case is definitely a positive. The foam insert is firm and perfectly cut to fit the radio and accessories, though the fit is quite tight and removing the radio can require two hands. That is likely a good thing to prevent it from shifting around in transit and damaging the knobs or screen.

In the box are:

• FX-4C Transceiver
• USB digital cable
• Hand Microphone
• 2 XT-60 Power Plugs (the type used for racing drones and other RC craft)

FX-4C Overview

The FX-4C is a small, CW/AM/FM/SSB/Digital HF SDR transceiver covering 80-10 meters on transmit with an output of 0.1 to 10 watts, and can receive 465 kHz – 50 MHz.

More specifically, it can transmit on 80/60/40/30/20/17/15/12/10 meter bands – 9 in total.

They claim consumption at approximately 2A on transmit and 220mA on receive.

The case is metal, extremely well constructed, and feels like a brick in your hand. The green anodization is actually a nice departure from the ubiquitous black of the ham radio world. All seams mate together very closely, and there are no gaps. The construction really is quite good.

The word that keeps coming to mind is “solid”. Every time I pick it up it just feels sturdy and solid.

Length and width-wise, it is similar in size to the Venus SW-3B at 11x7cm (4 3/8″ x 2 3/4″), a popular 3-band CW only QRP transceiver. It is approximately twice as tall as that little radio though, coming in at 4.5cm or ~1.75″ in height (not including the knobs). Note all measurements are with my ruler, so within margin of error.

The Screen

The TFT screen measures 2 inches and, at least indoors, is sharp and bright.

Outdoors, however, is a different story.

I would say that in shade it is still readable, however in the bright sunshine you really have to find some way of providing some shade in order to really see what is going on with the screen.

I’ve searched the menus and the manual but cannot find any way to increase the brightness. If anyone knows how to do this, please let me know.

Spoiler alert – this is the biggest con so far in what is otherwise a fantastic little radio.

The layout makes good use of the available real estate. Frequency is front and center, with smaller icons that are faded or highlighted depending on state and function.

The bottom half is a waterfall display that does lag slightly when changing frequency, but otherwise performs well for intended purposes.

Features and Specifications

Feature-wise, here is what BG2FX is advertising:

• 2.0″TFT display screen
• Spectrum display and 20 kHz waterfall plot
• Dual VFO operation (VFO A and B) with split mode operation
• Internal USB sound card with serial communication via USB 
• Adjustable DSP digital noise reduction
• Ultra wide input voltage: 9 V – 18 V
• Quick switching among various frequency bands and convenient operation

For specs they show:

• Operating Modes: USB, LSB, CW, AM, FM
• Frequency Steps: 10 Hz, 100 Hz, 1 kHz, 5 kHz, 10 kHz, 100 kHz, 1 MHz
• Antenna impedance: 50 Ohm
• Operating temperature range: -20 – +40℃
• Voltage range: DC 9 V – 18 V (please keep the maximum voltage below +16 V for long-term operation: About 14 V is recommended)
• Weight: (radio only) 0.46 kg
• Filter Bandwidth: 
• SSB: 1.5 kHz, 1.8 kHz, 2.1 kHz, 2.4 kHz, 2.7 kHz, 3 kHz
• CW: 50 Hz, 100 Hz, 200 Hz, 300 Hz, 500 Hz, 800Hz
• FM: 5 kHz, 10 kHz
• AM: 6 kHz, 9 kHz
• Spurious emission suppression: -43 dB
• Carrier suppression: -50 dB
• Microphone impedance: 2.2 k Ohm
• Audio output power: 1 W
• Receiving sensitivity: -120 dBm

CW Operation

CW has become my primary mode, and I rarely if ever use SSB/FM anymore. (I’m not very good, so that isn’t a brag – someone like me shouldn’t be bragging about CW skills – I’m just mentioning that this will be my focus for my initial review)

There are several settings for CW with this radio, with dedicated buttons on the front face to switch between SSB, AM/FM, and CW.

Note that there is no CW decoder, so no crutch if you’re just getting started. 😉

You can switch between Iambic and Manual, including switching dit and dah sides of the paddle. The screen even uses a dot-dash and dash-dot to indicate the configuration it is set to use.

Filters can be changed to values of 50MHz, 100Hz, 200Hz, 300Hz, 500Hz, and 800Hz.

Sidetone, volume, wpm, and delay can all be adjusted via the menu or by pressing the AF knob and turning it to the desired level.

In the brief time I have had this (today so far – looking forward to tomorrow and beyond), I’ve called CQ and attempted to answer someone else’s CQ, but no contact.

Yet.

Operation was intuitive and I didn’t have to hunt through many menus to get transmitting.

Feeding the Beast

This transceiver bucks the trend of using barrel connectors or even Anderson Powerpole type connectors in favor of XT60.

It represents an odd choice given the prevalence of the former two in ham radio circles, but as I thought about it more and more it made a lot of sense.

Bioenno type LiFePO4 batteries with Powerpoles are amazing, but very few companies create batteries with that plug as standard.

In the remote controlled hobby arena (think RC cars, planes, etc.) that plug type is a standard, with many companies offering LiFePO4 and LiPO battery packs with that connection.

And they can generally be found fairly cheap in comparison – though you do get what you pay for in my experience in that world.

BG2FX does include two plugs that can be soldered to any connection that you want, and I did create a XT60 to Powerpole adapter that works quite well and allows me to use multiple battery types.

Some, however, may find this off-putting and disagree.

Such is life 🙂

Documentation

This is an area where some Chinese manufacturers really struggle. English is a really difficult language, an as someone who learned Mandarin in early adulthood I believe it can be especially difficult for some Asian language speakers.

I’ve taught English as well – it is pretty messed up as far as languages go.

The creators of this radio, however, have done a great job. The manual (link) is well written, easy to understand, and is laid out in readily consumable manner.

I’m really impressed with the time they put into writing and insuring that it would match a native-English speaker’s expectations in the use of words and grammer.

Well done!

Conclusion

The closest transceiver to this in my mind is the wonderful mcHF by M0NKA. Both are QRP rigs that cover the HF bands and are multi-mode. Neither has a built-in matching unit (ATU) – though you can get one for the mcHF, neither has a built-in battery, both have similar screens.

The FX-4C has a much sturdier metal case in my opinion. It also comes with a handheld microphone and the foam-lined storage case.

The mcHF seems to have more settings and options, but that can be a double-edged sword. Navigating those options in the field can be more cumbersome. I really like my mcHF, so these are more 1:1 observations than criticisms.

This is not a cheap uSDX style clone that shows up all over eBay. I believe this to be a well thought-out radio with a lot of features in a small, sturdy package.

As noted, the screen does leave a bit to be desired when used outdoors. I’m going to play with it a bit more before completely writing it off, but that is my one big nit to pick since first powering it on.

Price-wise it isn’t cheap, and that is likely a turn-off for many folks. It is about $100 USD less than a Xiegu x6100, which does have an internal battery and ATU. But I generally carry a resonant antenna and my own battery pack anyway, so those aren’t “make or break” sets of features for me.

I need more time on the air with it – like I said I wasn’t successful in my contact attempts today. But then again, I’ve only had it since this morning.

So why am I writing this review without having more time with it?

Simple.

I am excited about the potential this has and will do follow up posts as I gain more time and experience with it in the field.

I’ll take you along with me on this journey, especially now that the snow is gone and the weather is warm.

Time to get outside!

Update – May 23, 2022

So I’ve now had a few days to play around more with this rig. All in all I’m still quite happy with the purchase.

A couple of minor nits to pick:

• Changing bands resets the mode to SSB every time – this means that changing back and forth between bands is a two step process where you first change the band and then set the mode if you’re not using SSB (such as CW)
• Actually it is a 3 step process since you also have to set the CW mode back to Iambic (assuming you’re not a straight key user)
• All other buttons have a momentary press action…except MENU – that button requires a long-press in order to activate the menu (minor nit, but worth noting)

Given the fact that this is largely developed by a single individual (BG2FX), and that he has included firmware upgrade options and I’m anticipating will continue to create new firmware versions, I’m looking forward to seeing what updates come down the pipe.

Nothing here is a deal breaker to me – the SW-3B has some similar behavior when switching bands, etc. – but noting here my experiences as I move along.

Thanks!