Hello Howard, Thanks for useful information in your web site www.proaudioeng.com which is interesting (the portable power supply for KX3 looks cool)
I must admit that English is my second language and sometimes I may not choose the right words. I have no intention to bad mouth any specific design / R&D on KX3 heat sinks available in the commercial market. In fact, I eventually bought a KB8UHN heat sink, which is a commercial product, for my KX3. The heat sink suits my purpose of prolong operation in FM mode in 10/6m under full power. As a ham, I trust some of them may like to do their own experiment in building their own heat sinks (since it is not a rocket science). Doing experiment at a fraction of the cost could give some satisfaction to the investigating minds. In my case, I did some experiment on fitting different 'amateur' heat sinks. Clearly, the result was not that successful and I eventually settled down on a heat sink available from the commercial market. I have been adopting that kind of 'experimenting' attitude for ham radio for years, Sometimes, I succeed but there were many times when I completely failed. The most successful experiment in my case is that I found a Panasonic boom headset at US$25 which gave me excellent audio reports so that I eventually sold all my Heils (no disgrace to Heil products). 73 Johnny VR2XMC 寄件人︰ Howard Hoyt <[email protected]> 收件人︰ [email protected] 傳送日期︰ 2014年08月14日 (週四) 1:55 AM 主題︰ [Elecraft] Some "Cool" heat sink info. Hi all, Johnny, VR2XMC wrote: >>It should not?be any rocket science, all you need is a piece of thick metal >>plate >>to suck the heat from the PA transistors and with fins to facilitate air >>circulation. You are right: a thick piece of metal will sink the heat from the PA transistors. But how thick? Too thin and there is little benefit. Too thick and the stored heat in the metal mass actually inhibits recovery time after a heating event. How many fins? How tall? How far apart? And what combination of all of these gives the most benefit at a targeted small size? You are right: it is not rocket science, but a dismissive attitude towards the importance of learning the interaction between the variables leads to some of the poorly-performing (not to mention ugly) designs I have seen hung off of several KX3s. I also happen to agree with Elecraft's design criteria which is the same as just about all amateur-radio gear made: 100% power on CW and SSB, 50% power on digital modes. To upgrade this to commercial broadcast equipment performance of 100% duty cycle in all modes would greatly increase the price and size. If someone wants more power and xmit time in digital they can always buy a heatsink, and the cost of doing so is not added to the KX3 for 90% of the purchasers who do not need it. More info on my website www.proaudioeng.com if you are interested, Howie - WA4PSC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net/ Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
