Thinking about getting an FX4CR as a backup for my kx2. Especially in places where I wouldn’t risk the elecraft. Anyone have one? How do you like it?
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We use one on occasion and love it. The biggest disadvantage is must use a tuned antenna since radio has no tuner. We also use KX2 most of the time. We (W7CBR and I) consider it a worthwhile investment.
Sue
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I’ve had one for a couple of months, but it’s only been used from home so far. It’s going out in the field for an activation in the next week or so. I’m pretty happy with it although it had a few niggles. Firstly, there was a low level background tone on transmit audio. I contacted the manufacturer and they came back with a hardware and configuration fix. The other niggle is 6 metres. It works OK on FM and CW but not on SSB. BG4FX says that there is a software fix for this. Another niggle was an image problem but this may have been finger trouble caused by accidentally accessing alignment mode. It was easily fixed.
I’ve had good audio reports from home and the sensitivity and adjacent channel performance seem great. Transmit power is approximately 20W on all bands except for 10 metres (12W) and 6 metres (5W).
I have 3D printed a battery box for it so that I can operate it hand held.
Cheers,
Glenn VK3YY
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I have an early unit, which has since been upgraded with the latest hardware board. I have used this on a dozen activations or more with good success.
Yu (BG2FX) basically hand designed and built all of these himself. It’s an incredible feat of engineering for one person and I have been impressed, esp. since many (but not all) of the bugs have been worked through in firmware updates and Yu remains responsive to the community. One has to remember that this is not a mass production unit so one cannot expect Yaesu or Icom level support. If you go into it knowing what you are buying into, this is fine however.
The unit has no tuner, so a resonant antenna or tuner is required. Battery is entirely external and uses and XT60 connector, so you’ll need to plan appropriately there with an adapter or choice of battery pack. With all that in mind, you can end up having a number of cables and wires running around to connect everything. In this field this can be awkward but is generally workable.
Reports of my audio quality on SSB have been excellent but the unit can be susceptible to RF getting in and causing interference so I recommend clamp-on ferrites on your mic and antenna cables.
Build quality is rugged. The UI takes some getting used to but is mostly pretty intuitive. Many functions are accessed through either “short press” or “long press” operations on buttons, something to keep in mind. There is an attenuator function, but no selectable preamp. Noise blanker, noise reduction and filtering functions are all available. It has native support for digital modes but depending on your platform, there are issues here (bluetooth seems to work best). Also, the screen is tiny, so if you like large fonts, this can be a challenge.
Overall impressive unit for the price. Very limited availability, however. But what else is new in ham radio?
Jeff (WJ7V)
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I have been watching his website for a few months now, I’m not sure he will be selling any more.
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Do you have bluetooth remote?
What would be really useful via bluetooth, would be being able to key the TX and see the SWR on your phone, when you are down the far end of the antenna.
Can these do an SWR sweep?
Potolab on aliexpress do list them.
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he is making more as we speak, if you email him, he will add you to the pre-order bg2fx@126.com
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Same thoughts here as well Jeff. It is a lot of radio for the buck and it works well enough as a SSB/CW SOTA rig. I use mine with the K6ARK mini-mic (wired like a KX2). The stock mic has as much bulk as the radio itself.
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There is an opportunity to buy an FX-4CR-2 here … without a long waiting time, hi.
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Don’t do it, it’s not supported by vendor. BG2FX direct is the only way to buy them.
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There are other offers like this on eBay.
It looks like these are all Chinese replicas of a Chinese transceiver.
Good to know …
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Exactly, similiar to the trusdx clones. only way to get those is through DL2MAN
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He posts quite often to the FX-4C farcebook page. I think I just saw where he was going to start taking a list, whereas in the past he wouldn’t. There’s a guy out of Virginia that has done a couple of Youtube videos with the FX-4CR. Good to watch if you haven’t seen the rig in action…
Todd KH2TJ
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Jeff, when you say you have an early unit are you referring to the orig FX-4C? Or, an early version of the FX-4CR? Yu was supposed to work on the firmware for the orig FX-4C once he completed the firmware for the 4CR, but I guess that’s been a work in progress 
My FX-4C plays really well on FT8/FT4 via the built in sound card. Just one cable to the laptop. I’ve played around a few times and have had FT4 running off the FX-4C while playing SOTA/POTA off the KX-2.
And in case it wasn’t mentioned before, Yu is the orig designer of the FX-2, FX-4a, and the FX-9a. The FX-2 and FX-4a were sold by LNR…
Todd KH2TJ
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I have a 4CR model. I am aware of the previous versions but have no experience with them.
I need to work on my setup again. I so rarely run digital modes that I’m always a bit rusty. It was suggested that if using a wired setup, turning Bluetooth off is recommended. Have yet to try it.
I managed to get to the front of the queue for a FX-4CR, leaving my order until all teething issues have been ironed out. So far so good, very impressed with this little radio.
Plan is to test this on my next SOTA activations in GM.
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RX power: 2950mW, regardless of supply voltage (i.e. it has an SMPS)
Vmin (rx): 6.5V before reset.
CW-TX 40m: 37dBm (5W) 9V,10V=1.7A, 15V=1.65A. No smps on TX. 8V on CW-TX resets the radio. (K6XX reports the '817 TX current as 1.85@5W 10V, FX4 does not seem to be suffering a penalty @5W for it’s 20W max.)
Off current 0.85mA - enough to flatten batteries in a few months.
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Very useful, so one could hypothesise that an hour of operating with 5W CW:
Radio on: 2.95wh
CW TX 5w, 10% of the time: 17 wh x 10% = 1.7wh
Total 3.7ish watt hours.
That means you should get about 2 hours out of a 1aH 11.7v lithium ion or LiPO !
Hopefully I have that right. It feels very efficient if so.
Might have to test it in the field but I usually operate 10w SSB.
Do you know what SSB draw is ?
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How loud are you?
How hard are you going to set the compressor?
TX Iquiescent=670mA @ 10V, 680mA@12V (ssb TX, no modulation)
My multimeter reads (@10V, CQ-CQ-ZL1THH internal mic,TX_AF_COMP set to “10”) :
2.2A pk and 1.6A Average peaking at 20W on the display.
850mA av. at 5W power level.
As a comparison I have measured an '817 at 20m, 12V:
SSB Iq (0W) 0.556
SSB “CQSOTA” 820mA average, 1.4A max
FM 5W 1.9A
FM 1W 1.1A
RX 331mA
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