FX-4CR HEATSINK

There's been some discussion on various platforms suggesting concern over the FX-4CR's operating temperature, even though I've never heard of anyone suffering any sort of failure, so I do believe that these concerns might be a little irrational (but that statement might come back to bite me, lol).

Having said that, I've been guilty of similar worries with my Expert Electronics ColibriNano, which runs incredibly hot! I was so concerned that I wrote to EE seeking some reassurance and I was told very clearly that the unit is designed to cope with those sort of temperatures. Nevertheless, I decided for the sake of longevity, I would fit some heatsinks and after completing the task, I felt much better. The ColibriNano ran cooler to the touch.

So with that little success, I thought I'd do the same to my FX-4CR. Opening up the case, you can see that there's a large aluminium heatsink plate in the middle of the radio and the high-temperature components press directly against it to help dissipate the heat.

The hottest part of the radio is the very top (and slightly to the right side). This makes sense when you consider the location of the PA and so I decided to attach my heatsink there. It was a very simple matter to remove the top and rear covers, allowing me to apply a bead of thermal-paste to the internal heatsink. The parts circled in yellow are the areas requiring the most cooling.

With that job done, it was just a case of reassembling the radio and then applying the external finned heatsinks. I applied a couple of dabs of thermal-paste to the underside before spotting with high quality superglue, being careful not to get the glue on the rear edge (or I'd effectively be gluing on the rear cover, lol).

When the job was done, I ran the radio for 30 minutes or more, repeatedly sending a CW message into a dummy load at 20W. At the end of it, the radio felt pretty warm to the touch but there was nothing to worry about at all, so I'm 100% happy that there would be no issues with overheating at the power levels I normally work at.

I guess time will tell.

73, Tom, M7MCQ.

SPECIAL EVENT - BOTA 2023

My friend Phil (G7TVB) invited me to participate in the 2023 BUNKERS ON THE AIR event and although I had some personal issues which were causing a great distraction, I managed to activate two bunkers (ROC Posts B/G-0444 and B/G-0925) just before the time limit expired.

Royal Observer Corps monitoring posts are underground structures all over the United Kingdom and were constructed as a result of the Royal Observer Corps' nuclear reporting role - operated by volunteers during the Cold War.

These bunkers were manned by 3 or 4 people and were basically a rectangular space lined with up to 12” of concrete. This concrete box was approximately 14ft below ground level and had a large mound of compacted earth above its roof. A shaft with a ladder was the only way in and out of the bunker.

The estimated cost of each bunker in 1956 was £1000 and over 1,500 were needed to provide adequate monitoring across the country but as usual, costs escalated and prices rose to as high as £8000! 

The basic rules of the BOTA 2023 Special Event were that a bunker would be deemed ‘activated’ by making at least 25 logged contacts. Because many ROC Posts are on private land, activators were allowed to work as far away as 1km from the actual site.

The event ran throughout the month of October  and although it wasn’t a formal contest, points were available to activators, chasers and SWL’s in order to qualify for a Certificate (PDF).

Personally, I wasn’t interested in gathering points, but since my mate invited me to participate, I thought I should make the effort to activate at least one of the bunkers. G/B-0444 (FORTON) was not far from my holiday home in Scorton, so I chose to activate that one and used my Icom IC-705 with my AlexLoop.

The activation went well but driving winds and looming black clouds forced me to cut the activation short and so I had to return a few days later. This time I went out on my motorbike and used my new FX-4CR radio with a resonant dipole. It worked superbly and the activation was soon completed.

Day 1 Log 

 

Day 2 Log

My second activation G/B-0925 (DUNSOP BRIDGE) was completed in a very short space of time thanks to great band conditions on 40M. Again I used my wonderful FX-4CR, but this time from the comfort of my truck, using a mobile whip on magmounts.

To be honest, I didn’t expect it to go as well as it did because of the antenna (Diamond HF40FXW).  I drove over to Dunsop via the gorgeous Trough Of Bowland and I enjoyed quite a few moments admiring the Autumnal views (despite the miserable weather).

Once I’d spotted myself on the BOTA group page, I very quickly got a little pileup going and before I knew it, the activation was complete! My thanks to all those who made contact with me - especially those who struggled to hear my QRP signal. The little FX was a joy to use and performed flawlessly. 

Day 3 Log

On the way home back through The Trough, I took a few more photos…

Thank you for reading the post. I hope you enjoyed some of the pix of this lovely area.

Feel free to leave a comment below.

73, Tom, M7MCQ.

FX-4CR QRP SDR (by BG2FX)

A CHINESE CRACKER!

Yu Hongbo reminds me in many ways of Hans Summers and Boris Sapundzhiev. They are all electronic geniuses capable of coming up with amazing radio designs in compact form factors which perform superbly. They are small scale manufacturers - virtually self-builders! There are no mass production facilities here - these things are put together by hand - by them, without the benefit of a huge assembly line in a factory somewhere.

 

Despite being such incredibly busy people, they also find time to respond to what must be a constant stream of pesky customer queries. Nothing is too much for these people, it seems.

So when I learned about Yu's FX-4CR QRP SDR Transceiver, I was very excited by the idea of trying one out, so I set about finding one and before I knew it, there was one sat in my shack. At the time of writing, getting hold of new stock is like searching for the holy grail! There's a big waiting list. 

Please note that if you wish to order one of these, ONLY DO SO by placing an order directly with Yu! Don’t be tempted to buy anywhere else (unless it’s a second hand seller in your region). Here’s a link to a video of a guy who bought elsewhere…

This is mine arriving at my workplace:-)

The FX-4CR is very compact and will literally fit in the palm of your hand and weighs just over 400g.  Size is so important to me when it comes to a QRP radio and they don’t come much smaller than this, apart from the (tr)uSDX,  which is a great little budget radio, but it obviously can’t compare to the FX-4CR.  It comes in a small Pelican style carrying case which really adds to the perceived value of the kit and demonstrates a high level of customer care (in my eyes anyway).

When you handle the radio for the first time, you are struck by the absolute quality of the build - this thing is beautifully engineered and well thought out. Yu obviously takes great pride in the fit and finish of his products - there are no unsightly gaps between panels. The screen and buttons are all perfectly centered in their case apertures. Even the supplied power lead is top quality and comes with a Velcro-Tidy instead of a bit of twisted wire.

XT60 connector for the radio

The interior of the radio exhibits equally high standards of construction and design. I know nothing about electronics, but I can recognise build-quality and Yu's attention to detail is obvious for all to see. Even the toroids are secured to the pcb with nylon screws - most manufacturers wouldn't even give them a second thought or at best, they'd use a glue gun. It’s built to survive a few knocks and drops.

This amazing little transceiver is a full blown SDR covering 10 bands from 80-6M and is capable of wireless digital operation thanks to built-in bluetooth and soundcard (if you prefer to connect a USB cable to your computer for digital work, you can do that too).

The TFT full colour screen is extremely crisp and sharp but it's not a touch-screen. Even though I have become used to touchscreens, I still don't find it a hardship when it's not available on radios like this - the screen is too small for touch operation anyway and you very quickly get used to using buttons instead.

The radio's panadapter is a really handy tool when out working in the field and you'll be amazed at how readable it all is despite the screen being just 2 inches in size. Needless to say, if you are a person who uses reading glasses, you will need  them when using this radio. 

There's a 48kHz slice of the band on display which makes it easy to spot signals adjacent to the tuned frequency. Please note that none of the photos and videos online express how very usable the screen actually is.

The operation of the FX-4CR is very well thought out and there's little use for the printed manual - it's really quite intuitive (but read the manual anyway lol, because some buttons have hidden functions and are mode-dependent). The buttons are a good size, well labelled and even backlit! The rotary dials have a good feel and are multi-functional as you'd expect. It doesn't take long to learn the functions of the buttons.

Surprisingly, the built-in speaker is really quite good!! It's obviously not bassy, but it produces a very crisp, loud audio which is perfect for outdoor operating. Most radios of this size require an external speaker to be connected, but not this one.

The supplied microphone is good too - small and neat. It's worth noting that the FX-4CR actually has a built-in mic too (in case you one day forget to pack the mic).

The receiver is very sensitive and the filtering is good too. Bear in mind that this radio will almost exclusively be used for outdoor activities which means there’ll more than likely be a great take-off point and a decent antenna - in those circumstances, the FX-4CR will perform every bit as well as any other radio out there. It's only when you wish to detect the most distant and weakest stations that you might wish you'd spent four times as much money on something else.

On the transmit side, you can dial in anywhere between 100mW and 20W output which is amazing for such a tiny radio. On full-tilt, the metal case does get hot and without additional cooling, digital work is restricted to less than 5W - a sensible precaution.

I’m going to fit some heatsinks to the top of the case like I did on my EE ColibriNano (pictured below).  There are rumours that Yu is going to offer some sort of fan kit for the FX-4CR which may allow the radio to use more power in digital modes.

Circles show hot-spot locations

Watching an online video by the popular Temporarily Offline Ham Radio vlogger Steve, it's clear to see that the FX-4CR has a large heatsink plate below the RF PCB and you can see how the heat is transferred away from the PA into this aluminium block. The only criticism is that there's no external heatsinking, but then I've not heard of anyone actually suffering any overheating issues.

 

For the CW operator, you may want to know that only semi breakin is available, but on the plus side, the filter is good and the T/R has full adjustability. Early production models had some hardware and firmware issues affecting CW operation which resulted in Yu offering full refunds or free replacement PCB’s. Thankfully, all that is behind him now and he has to be commended for not shirking his responsibilities.

I’m not a morse man, so I can’t comment further on the radio’s performance in this mode. I have just bought a paddle to start the journey, but it’s going to be quite some time before I’ll be on air,😂. 

To be honest, for digital and CW work outdoors I would much more likely to be found using a QRP-Labs QMX or QDX, so the FX-4CR’s performance in these two areas is not as much a concern to me as it might be to you. 

Okay, so everything's quite positive so far - what about the negatives? Well for comparison I may sometimes refer to the Xiegu X6100 because it's a similarly priced HF radio and I've owned one. 

Some people will complain about two specific things about the FX-4CR - no internal battery and no internal tuner. Internal batteries are little more than a convenience to me - I almost never use them except for just playing around at home looking through the settings or using a radio for morse-practise without transmitting. When I go outdoors to play proper radio, I always use my 13.2V Lifepo4 battery. The X6100 has batteries built-in but they don't last two minutes and there seems to be an issue with the BMS which makes the whole thing a bit of a faff.

The lack of a tuner is perhaps a more valid complaint, but then again, my £1400 705 doesn't have one either! And let's face it, most internal tuners are pretty poor anyway, so a few years ago I invested in a tiny 20W Elecraft T1 ATU and that has always been my "go-to" tuner for any outdoor activity. It's super fast, super light and could tune a string vest.

Onto the testing. Connected to an EFHW at home, it was an absolute doddle to pull in signals and get 55-to-59 reports from operators across the globe on just 10W. People were impressed with the modulation and were even more impressed when I asked them for a second report on 5W with barely any change to my signal. This is exactly what I love about QRP transceivers - making great contacts with people who themselves are often using 100-1000W. My IC-7610 is virtually an SWL station these days, lol.

Out in the field, the FX-4CR continued to please. I took it to the site of ROC B/G-0444 to continue my BUNKERS ON THE AIR activation from last week. I'd previously used my IC-705 with an AlexLoop, so this time I thought I'd use the FX-4CR with my SotaBeams 20/40 Linked Dipole. The noise floor was ZERO!! It’s so quiet around here.

The dipole is simple and quick to erect using a TACTICAL-7000HDS mast and within minutes I had spotted myself and was managing a mini-pileup with the FX-4CR easily pulling in signals and earning me a long string of complimentary reports.

 

During the activation I was trying to find things about the radio which annoyed me, but I just couldn't. It's pretty much perfect for me. The only thing that I would love to be added is a 500Hz Tuning Step. So many operators work in-between a 1kHz frequency for some reason and the 500Hz step makes it sooooo easy to flick through the band. Please, please add one Yu 🙏

Once the Bunker had been activated, I relocated to an area on the edge of the Forest Of Bowland which gave me a good height advantage and provided a take-off toward the west.  From here I sought out some proper chinwags to see how well the radio coped with extended TX. Everything went perfectly well and although the temperature of the case climbed, it remained "comfortably warm" - certainly no hotter than the X6100 under similar loads.

 

 

At the higher location I was going to transmit some "CQ TEST M7MCQ" morse messages and see how far my signal was reaching on PSKREPORTER. Unfortunately, the FX-4CR doesn't let you store messages in memory, so I had to use my paddle to do it manually. Maybe message-storing could be something to add to the next generation models?

The radio performed really well as a QRP Field Rig and not once did I think "Oh I wish I'd brought my IC-705 instead".  Okay, so the 705 has a bigger screen and VHF/UHF but it's 3X more expensive and it’s over twice the size.

This fabulous SDR radio costs around £500 and as I've said before, you cannot pay Ford prices and expect Rolls Royce performance! But you can expect high quality and superb value for money - and that's exactly what you get with the FX-4CR. It’s a fun radio and you feel like you're a part of a great adventure with Yu in the background, constantly looking to make improvements through firmware upgrades. He listens to his customers and responds to their comments and suggestions wherever possible.  

For a stand, I used some self-adhesive pop-out stands from Amazon. I've used them on all sorts of radio gear (and other) and found them to be reliable and strong.

Needless to say, any little niggles tend to annoy some people and they want fixes now, now, now, so you'll come across the odd keyboard warrior who blows things out of proportion. You only have to look at other independent radios such as the superb RGO ONE,  QDX  or tr(u)SDX which have all been 'works in progress' and have grown into something far greater than how they originally started.

Fitted with alternative knobs

The great thing about the FX-4CR is that 98% of everything works extremely well and 2% awaits further improvement. The X6100 by comparison  has quite a few serious issues which are very annoying (bluetooth, wi-fi and squelch virtually unusable (and we'll not even talk about those birdies 😮)) plus you have absolutely no confidence in them ever being addressed by Xiegu, which is very poor considering they’re such a big manufacturer and their products are sold by big retail outlets across the globe. When I buy from a large retail outlet, I expect a finished product!!

There's a pride of ownership with the FX-4CR.  Somehow it's more than the sum of its parts. I can't quite explain it - I'm just glad I became part of the club! It suits my modus-operandi perfectly.

So in summary, I very much like the FX-4CR and look forward to being part of its development and growth. I also like that the radio has 20W finals because (to my mind at least) that means I can operate SSB at a full 10W if I need to, without worrying about being at the limit of the PA.

Some features aren't fully implemented yet, but it's early days and no doubt there's a lot more to follow in the coming months.

It's never easy investing hard earned money into a company 5,000 miles away, but when you get assurance from so many other customers that a producer is talented, honest and communicative, it really helps.

We've all occasionally experienced cheap, fake products from China and many people have been ripped off by unscrupulous overseas retailers, but let me assure you, that's not the case when you buy an FX-4CR from BG2FX. Buy with confidence (but only through his website)!

In case you were wondering what the little house-logo was about (which I've embellished here), Yu explained to me that it serves as a reminder of his humble beginnings living in a rural mud house, where everything was a great challenge and it represents the start of his journey to where he is now 💗

Here's a video-review by Bob Nagy...

Technical Specifications  

• Transmission frequency range: 3.5 - 29 MHz, 6M.
• Receiving frequency range: 465 kHz - 50 MHz 
• 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)  
• Power Consumption:  Transmit: (maximum power) ~ 2 A;  Receive: ~ 220 mA. 
• Overall size: length 107 mm, width 65 mm, height 43 mm  
• 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  
• Power range: 0.1-20 W continuously adjustable  
• Spurious emission suppression: -43 dB  
• Carrier suppression: -50 dB  
• Microphone impedance: 2.2 k Ohm  
• Audio output power: 1 W  
• Receiving sensitivity: -120 dBm  

Functional Characteristics:  

• ☆ 2.0″TFT display screen 
• ☆ Spectrum display and 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 
• ☆ CAT control over USB 

73, Tom, M7MCQ.

ELECRAFT’S NEW CW HANDHELD

I read yesterday that Elecraft were releasing a new product and was very surprised to see what it actually was - a handheld!! But not just any old handheld, it’s a CW ONLY handheld and a very odd looking one at that. 

Very unusual and I’m not entirely sure how many buyers there’ll be for it - I reckon it’s gonna be a very niche market. No doubt it is going to work superbly but the appeal will be narrow (I think). Thomas K4SWL and John AE5X have ordered one and I’m looking forward to reading their reviews in due course, but I don’t think this is a radio I’ll ever call my own (not least of all because I’m only just starting to learn CW). 

This radio came as quite a surprise announcement. No one seemed to have leaked anything about it during it's design period (which has obviously taken many months).

UPDATE : 26 Oct : Looks like someone’s happy 😊 

There's one tiny thing that annoys me about Elecraft - and yes it will seem like it's a bit of a silly gripe, but it's a valid one as far as I'm concerned.  When they launched their brilliant (but rather expensive) T1 ATU, they included an interface port which would link up to one of the most popular qrp radios of all time - the FT-817, but they never offered the cable!!  I (and many others) have written to Elecraft Support many times asking about the lead and we always get the same negative response. How difficult would it be for them to have at least released a simple wiring diagram to allow buyers of the T1 to make up their own lead? Moan over.

73, Tom, M7MCQ

AMATEUR RADIO NOTES

 A GREAT HOTSPOT RESOURCE!

I recently thought about creating a post on HOTSPOTS to provide useful information for those new to our hobby but then I stumbled upon a website which does exactly that. And it does it very, very well!

The pages are written by Toshen Golias (KE0FHS) from Colorado and the level of detail is amazing. I'm sure that his work will be of great benefit to those who are new to Amateur Radio and possibly to some of the more experienced hams too.

The only thing that I could personally add to his work is my opinion on the OpenSpot 4PRO which he hasn't had the opportunity to examine yet.

Click HERE to visit this valuable resource.

73, Tom, M7MCQ.