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Reviews Categories | QRP Accessories | PAE-Kx31 KX3 Heatsink Help

Reviews Summary for PAE-Kx31 KX3 Heatsink
PAE-Kx31  KX3 Heatsink Reviews: 19 Average rating: 5.0/5 MSRP: $89.95
Description: The PAE-Kx31 gives the Elecraft™ KX3 up to 400% longer key-down transmit time than stock (band dependent) when cooled by natural convection. It is a billet-aluminum piece black-anodized to compliment the appearance of the rig. It is designed for the majority of operators and will allow for greatly extended transmit time in any digital mode or band at the full 10W output. It incorporates several features not found on competing heatsinks:

Designed using thermal modeling software for best performance.
Ratio of base mass to fin area optimized for the duty cycle of digital modes.
Rounded cross-section for no-snag use in fabric cases, and no sharp corners to cut or damage adjacent objects (including humans!).
When mounted on Elecraft™ KX3 along with GemsProducts™ SideKX plates and cover, the combo will fit in a standard Rose’s KX3 case.
Custom-color black anodized instead of powder-coated for superior thermal performance.
Radiusing compliments the design of the Elecraft™ KX3 and the GemsProducts™ SideKX.
It’s design interlocks with and greatly enhances the impact resistance of the SideKX Cover.
Low profile at each end for an interference-free fit with the PAE-Kx35 Mobile Mount (in beta testing).
Optimum compromise for most all operators between stock appearance and enhanced transmit time.
The Kx31 is supplied with correct longer replacement black-oxide stainless steel screws and a packet of heat-transfer grease.
Product is in production.
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K4KRW Rating: 5/5 Jun 11, 2014 16:29 Send this review to a friend
Amazing Quality - In every way  Time owned: 0 to 3 months
What a quality product! The instructions are great. It was packed very professionally for shipment. The amount of care put into this product from end to end is simply amazing. I chose option 3 for installation and it took less than 2 hours (really taking my time). I really like the look of the rig with the new heat sink in place. I think some chrome exhaust pipes would really set it off :-). Thanks Howard!
G7DDN Rating: 5/5 Jun 1, 2014 02:05 Send this review to a friend
Works in the UK too!  Time owned: 0 to 3 months
What a fantastic piece of engineering! Howard, its designer, should be very proud of it.

You really wouldn't know that it wasn't meant to be part of the KX3 itself. The packaging and even the little instruction leaflet (with which I was impressed both for its ease of reading and its quality of print!) both show much attention to detail.

Attention to detail also extends to installation, where no less than 3 different methods are outlined. I went for installation option 1 as I don't do Digimodes very often, I just want to keep my KX3 as cool as possible when in bright sunshine operating CW and SSB. I was becoming irritated with the power folding back in the middle of QSOs when operating in warm conditions. No such issues now!

I chose this heatsink over others not only due to its compatibility with other KX3 aftermarket products like the Side KX but also it's specifications, which Howard clearly explains on his excellent website. For me, the decision was an easy one and has been vindicated upon installation.

Sometimes folk here in the UK are apprehensive about ordering from the US. Not because of the quality of the equipment, but because of the stinging import duties & hidden charges that get added. Thankfully the PAE-Kx31 was only an extra £18 when it arrived. I had some issues with HM Customs here in the UK and though that was no fault of Howard's, he was even able to offer viable alternatives should I have fallen foul of their incompetence!

Order with confidence, especially if you in the UK!
WB0OEW Rating: 5/5 May 24, 2014 21:18 Send this review to a friend
almost 5x longer with Olivia  Time owned: 0 to 3 months
Purchased May 16, arrived May 20, installed May 21 using Option 3 (removing powder coat from rear case). Executive summary: before installation it required 4.5 minutes for PA.I to go from 31 C to 60 C. After installation, same test required 22 minutes.

Test conditions: 5W nominal output, 1.6A @ 12.6V input; 14.09 MHz; tested indoors with ambient temp about 80 F; transmitted continuous CQ loop with fldigi REPEAT macro running Olivia 16-500 into dummy load with SWR 1.0:1.

Definitely pleased.
WW4JF Rating: 5/5 May 24, 2014 20:40 Send this review to a friend
Well made, EZ install  Time owned: 0 to 3 months
This heatsink arrived as promised, well packed and with all the extra black SS screws and heatsink grease pac included. It is an excellent product with a finish that is clean, neat and really well done. The data impressed me and the install was simple and easy. The results are as others have said; it makes a real difference for the heat producing modes. It fits well with the end plates and the Lexan cover and, it will fit in the case Rose makes for the KX3. a good addition to a fine radio.
K3NB Rating: 5/5 May 23, 2014 05:06 Send this review to a friend
Solid, EZPZ install, good insurance  Time owned: 0 to 3 months
I'd considered other heat sinks but there are only two real outright producers of them, PAE and the other guy. The other guy's was a few bucks more and S&H put the price into three digits. I couldn't see spending almost ten percent of the price of the radio for an accessory I would only use occasionally.

Mostly, so far, I've only used the KX3 for local contacts, one trip to Nashville where I made a few contacts using an alpha antenna, and I'm not using digital modes, yet. I'm still on the low end of the ham radio operator learning curve for DX, digital, etc.

So, I happened to have a few bucks in my paypal account from selling off another gadget and figured, why not.

I was worth the wait. Having missed the first production run, I got my PAE heat sink last week. Anodizing was thorough and deep, instructions were simple, easy to follow, hardware included is on par with Elecraft production and he even includes a little packet of heat transfer paste.

Great detail, fit and finish is first-rate, there's even a relief cut for putting on the "Side KX" lexan top.

And it cost less than the competition.

Does it work? From what I can read of other reviews and the Yahoo! KX3 forum reports, yes. Big hunk of stylish aluminum should work well for transferring heat.

Now to get back to figuring out how to get HRD working with Win7 on my iMac OS Mavericks...
N4CW Rating: 5/5 May 22, 2014 14:01 Send this review to a friend
Cures High-Temp Ills  Time owned: 0 to 3 months
I checked out the other heatsinks online and decided on the PAE-KX31 over the others because of its detailed description backing up the design.

I've had problems in the past using digital modes where I transmitted (at 5W output) for several minutes and would get HI TEMP warnings. It was recommended that I not run more than 3W. I was miffed by that. Then the heat sinks came along and I ordered the PAE-KX31. I had to wait about a month for it, but when I got it and installed it (clear/easy directions), I concluded it was a fine piece of workmanship.
After I tested it (testing consisted of running in PSK-D mode, and sending text for a solid 15 minutes at 5W out into a dummy load), the HI TEMP warning never came on. Temperature never went beyond 52 degrees C.
Like the write-up said, this mod isn't for everyone, but it was for me!
WB4SON Rating: 5/5 May 22, 2014 08:58 Send this review to a friend
Excellent Fit/Finish/Function  Time owned: 0 to 3 months
While I love my KX3, I've been disappointed with both the lower power output and thermal drift issues that some extended digital modes like JT65 have caused. Despite performing the extended thermal calibration, I found that I still drifted so much that I couldn't complete a JT9 QSO, and if I raised the power level above 3 watts I would get a High Temp warning part way through the contact.

I purchased a PAE-Kx31 Heatsink after evaluating several other designs. The kit arrived last week and I was surprised at how well the aluminum heatsink was finished (no rough edges, nice black anodized surfaces). I had clearly been designed to be as low a profile as possible, but still offering a good amount of thermal mass and heat flow. The instructions offered three levels of installation from ridiculously simple to the most complex (with the highest head dissipation). I opted for the best performance. It took about 15 minutes from start to stop, and involved removing four screws and two nuts. About 14 minutes of the time was spent scraping some paint off a part of the KX3 enclosure that is covered by the heat sink to improve the heat flow. Bottom line: if you can open the case to install batteries, you can certainly put this heat sink on the KX3.

As for performance, I am quite pleased. Using the original heat "plate" that comes with the KX3, transmitting at 5 watts for 60 seconds would cause the PA temperature to rise above 60C and cause a thermal "High Temp" trip out. Now at 5 watts the maximum reached after ten 1 minute on/1 minute off cycles was 36C, at least 24C cooler than the unmodified KX3. A similar test run at 10 watts output topped out at 50C.

This is VASTLY better than the stock heat sink, and has improved the thermal drift problems as well. It is also 100% compatible with the SideKX side plates and cover.
NY9H Rating: 5/5 May 22, 2014 07:48 Send this review to a friend
very fine  Time owned: 0 to 3 months
FINALLY bought the sink at QRP FDIM at Dayton....

Put it on last night.

His presentation of time VS temp was the only sales pitch that worked for me. If the others doing this part were wise, they also would do the chart.

It sold me.

The finish is fantastic...
Does integrate well with the Gem Products sidekick & cover.

Not cheap... neither is the kx3
KI7L Rating: 5/5 May 14, 2014 05:49 Send this review to a friend
A really well designed heat sink  Time owned: 0 to 3 months
Love my KX3 but design compromises limit its use for high power continuous operation. Several companies offer replacement heat sinks for the KX3. The PAE Kx31 seem to be the only one that conforms to professional heat sink design criteria and presents actual test data. As an engineer I would highly recommend that potential heat sink buyers carefully review heat sink design criteria, for example on Wikipedia. Installation was straight forward, well documented and heat sink compound was included. Definitely recommend this product.
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