Robin Davies G7VKQ was kind enough to give me permission to post thermal images of his FX-4CR, made with an InfiRay P2 Pro plugged into his iPhone.
From Robin:
I received my FX4CR recently, and I have been learning a little about the rig (but not used it in anger yet). As part of my learning I have successfully got the Bluetooth connection to FT8CN working and update to the 1.4 firmware. I have also being playing with some new data acquisition toys (an Openlog Artemis and some thermocouples).
I’ve run this test a few times now and I think my measuring technique has improved - so feel this is the most accurate measurements I have made to date. I ran a soak test this morning with around 55 minutes of calling CQ on FT8 (at 5W) every 30 seconds and then let the rig cool for 10 minutes at the end.
I captured temperature measurements from the back and top of the rig every second, plotted some curves of ambient, rear case temperature and top of case temperature, and took some pictures using a thermal camera to validate the temperature readings.
The rig is certainly hot, but don’t know Yu’s design parameters for the heat sink design and PA temperature. As a reference my freshly poured coffee sits at around 61°C and the hottest point of the rig after 55 mins was 52°C.
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In other FX-4CR news, Yu has released new firmware (available here) which fixes the intermittent loss of sidetone demonstrated in my video here. Unfortunately, the issue of mis-sent characters is still an issue and requires careful adjustment of T/R delay vs. CW speed to minimize - not eliminate - this keying defect.
Yu has also announced that he is offering a 100% refund for those not satisfied with their FX-4CR - quite commendable.
I think a users impression of the FX-4CR will be based almost entirely on which mode they prefer. It seems to be a very capable SSB rig but very poor on CW.
My FX-4CR is on its way back to him and I have already ordered a KX2. The long wait begins...
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A 20W RF radio with a somewhat linear output stage (AB1?) is going to dissipate a few watts. The case temp doesn't tell you too much about the thermal resistance to the semiconductor junctions of the RF devices - those junctions need to stay under a certain temp for long life. So I'm not sure why the case getting hot is a concern - unless it's too hot to touch. The fact that the whole case is the same color (the same temp) in the scans tells me the heat spreads out nicely and maximizes the available surface area for dissipation of the energy. If the thermal resistance to the RF devices was increased, the case would be cooler (time dependant) and the RF junctions hotter - that's bad. Not sure this is an indication of poor thermal design - in fact, I think it's an indication of good thermal design.
ReplyDelete73 Dave kx3dx
Hi Dave - my main concern is not so much the case temperature but the fact that, since the heatsink is sealed within the rig, all components inside the radio are being heated. As hot as the exterior of the case is - very hot if operating continuously for more than 20 minutes - the interior is even hotter. Normally a heatsink draws heat away from the RF devices - in this case, it just absorbs it for a while, then releases it to the case's interior. So every single component that makes up the radio is being heated to 60C or more, including the speaker, the encoders and everything else.
DeleteOne ham operated his FX-4CR (on CW) to the point that it shut down due to heat.
What are the long-term ramifications of that?
73,
John
Very commendable of Yu to give people 100% refunds. He also sent out replacement boards, at his expense, to those who received the first FX-4CRs. In addition, he's working hard to fix all issues with timely firmware updates.
ReplyDeleteThe FX-4CR works quite well in SSB and digital. I believe the CW issues will also be resolved in time.
Now, if only the sBitx developer would also offer refunds or replacement of the early production rigs that need hardware fixes and recalibration after a firmware update. Unfortunately, not every developer stands by his products like Yu!
I agree 100% - Yu is outstanding to deal with...uncommonly so. I look forward to reading (an eventual) review of the FX-4CR in QST and noting the improvements that will take place along the way.
Delete73,
John
I just wanted to follow up about the customer service at HFSignals too. I asked Ashhar, if he would be willing to replace my sBitx V2 with a new production run rig if I paid to send it back and pay shipping on the replacement. He copied the sales guy in the US and Thomas promptly emailed me the US address of where to ship.
DeleteThomas also offered to send me a replacement board so I wouldn't be out any expense, but I opted to ship the old one back and get a replacement. I still offered to pay shipping on the replacement, but it appears they are going to ship it out at their expense.
I must say HFSignals and BG2FX both stand by their rigs and provide excellent customer support. It's been a pleasant experience dealing with both developers, Ashhar with HFSignals and Yu, BG2FX.
Well, seems to be an issue with many rigs, notably also of the X6100 where solutions to cool the rig for FT8 use abound, such as thermoconductive-sticky-taping on additional heatsinks to the back and/or using external ventilators. Kinda beats the purpose of a miniaturized HF rig. Ventilation is not practical for portable ops, but that's simply the price to pay unless you are using class D PAs as in the (tr)usdx and QMX (QRP Labs) designs - both 5W only, and great for CW which is the best mode for portable ops anyway.
ReplyDeleteThanks very much for the excellent documentation on this otherwise fascinating tiny rig.
I think that due to the size of the FX-4CR, many will see it as a great POTA/SOTA rig. The KX2 fits that category as well and was criticized for having ventilation in the form of several openings in the case. Those hoping to use the FX-4CR as a POTA/SOTA rig should do so at 5 watts, using 20w only intermittently. Even at 5 watts, a close eye needs to be kept on the rig's temperature.
Delete73,
John
On another topic, I've now bought my own thermal camera - thanks, Robin! It'll be here Saturday.
ReplyDeleteNice! IMHO they are very handy tools...as is the data logging gear (which I've now used surprisingly frequently over the last few months). Next gadget in the wish list is an accurate low current monitor - most probably the Current Ranger (https://lowpowerlab.com/guide/currentranger/). The downside is it only handles 3A....but the step up to 5A capability is double or triple the price, as you need to an Otii or Joulescope
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