Re: [Elecraft] K2 Buyers remorse
On 2021-08-09 11:10, Phil Kane wrote: For those of us who grew up with dynamotor-powered mobiles. that was a sign that the transmitter was activated! *** Indeed. My first Tiny Linear ( for its day ) project was an ARC-5 transmitter cabinet crammed full of 6LQ6 tubes. I tried it at first without a fan...and it burst into flames! So I mounted a 120v muffin fan right on top, and it ran cool as a cucumber. But loud. REALLY loud. I was much more tolerant of noise in those days. - Jerry KF6VB __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] K2 Buyers remorse
On 8/7/2021 6:35 PM, jerry wrote: Not sure if I'll actually be using this PA... The fan is just so LOUD! It's like a mini turbine engine running on my desk. For those of us who grew up with dynamotor-powered mobiles. that was a sign that the transmitter was activated! My K2 has a muffin fan in top of the heat sink activated by the PTT circuit - serves the same purpose..not loud at all. 73 de K2ASP - Phil Kane Elecraft K2/100 s/n 5402 From a Clearing in the Silicon Forest Beaverton (Washington County) Oregon __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] K2 Buyers remorse
On 2021-08-08 05:57, Mike Harris via Elecraft wrote: Hi Jerry, Yes the little fan is a screamer. [...] blowing down on it at Hi Mike, That makes all sorts of sense. Because the fan can blow much harder on the heatsink than it can suck off of it. The power of sucking is limited by the ambient air pressure, whereas the power of blowing is unlimited. I had a similar issue with my shallow irrigation water well. Needed to clean it out with a water pump. The pump could not suck water out of the well because the water was at 26 feet below grade, which is the absolute max that any pump - no matter how fancy or expensive - could suck upwards. Because the force pushing that water up was just ambient air pressure. The fix was to use a submersible sewage pump and a sandbag. - Jerry KF6VB __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] K2 Buyers remorse
I zip-tied two low speed 60mm muffin fans side-by-side (Globe D24-B08A-04W3-000), stuck tall rubber feet on the face of the pair and sat them atop the the K2/100 heat sink blowing down onto it. Lou W7HV On Sunday, August 8, 2021, 7:22:18 AM MDT, jerry wrote: On 2021-08-08 00:08, Matt Maguire wrote: > The K2 works beautifully with the silent KXPA100, if you make a small > keying circuit: *** Good idea. Actually, I have do have a keying circuit in my QRP K2. Bought it as a kit from W8FGU. Works perfect with my Tiny Linear project. The Tiny Linear has a fan also, but not as loud. I am working on another linear which will have the following characteristics: * 15W in, 600W out * RF deck with a pair of MRF300 LDMOS devices * All band switched LPF. * Monstrous heat sink. * Color touch screen. * Either no fan, or the quietest fan I can figure out. I will have to do it by experimentation - detailed thermal design is beyond me :). The circuit is supposed to be 70% efficient - that means that for 600W out, you put 750W in, and have to dissipate 150W. I have a 1-kW RF resistor that can bolt to a backplate. And I can feed it 86VAC ( for 150W dissipation) from a variac. Getting a little off-topic here. Sorry about that. - Jerry KF6VB __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to louand...@yahoo.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] K2 Buyers remorse
On 2021-08-08 00:08, Matt Maguire wrote: The K2 works beautifully with the silent KXPA100, if you make a small keying circuit: *** Good idea. Actually, I have do have a keying circuit in my QRP K2. Bought it as a kit from W8FGU. Works perfect with my Tiny Linear project. The Tiny Linear has a fan also, but not as loud. I am working on another linear which will have the following characteristics: * 15W in, 600W out * RF deck with a pair of MRF300 LDMOS devices * All band switched LPF. * Monstrous heat sink. * Color touch screen. * Either no fan, or the quietest fan I can figure out. I will have to do it by experimentation - detailed thermal design is beyond me :). The circuit is supposed to be 70% efficient - that means that for 600W out, you put 750W in, and have to dissipate 150W. I have a 1-kW RF resistor that can bolt to a backplate. And I can feed it 86VAC ( for 150W dissipation) from a variac. Getting a little off-topic here. Sorry about that. - Jerry KF6VB __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] K2 Buyers remorse
Hi Jerry, Yes the little fan is a screamer. It's job is to remove heat from within the K2 chassis rather than cool the actual PS transistors. Now to rake over old coals. A few years ago I was providing a signal source, QRSS 30 seconds dot period for a mutual grey line propagation investigation between the Falklands and the UK/EU. The fan became a problem because I left the K2 keying overnight at 20W and the shack is adjacent to the bedroom. The lady of the house was unimpressed. To overcome this I purchased a 80mm square 12V computer fan and experimented with location and orientation to determine the best solution. This is where there is a divergence of opinion. I found that by propping up one side of the fan on a simple square wire loop so that it was 45 degrees inclined to the heat sink and blowing down on it at the location of the PA's I could run the K2 at 30W output overnight and the fan never activated, the heat sink remained cool and was acceptably quiet. Shack ambient about +20C (68F). At that time some hotly recommended that the correct way to orient the fan was to place it directly on the heat sink sucking air through the fins. I tried this but did not find this to be the most effective solution. My logic, if you can call it that, is simply if I am faced with a hot object, say a spoon full of soup, if I want to cool it a little I blow gently on it, not try and suck air from all around it. Whatever, I'm not going to die in a ditch over it. I only used this arrangement for the rather extended duration of the tests. Normal DXing which at the time netted me 200+ DXCC before I built a K3 seldom activated the little screamer. I can email you a picture of the setup if you wish. Regards, Mike VP8NO On 07/08/2021 22:35, jerry wrote: All, Not sure if I'll actually be using this PA... The fan is just so LOUD! It's like a mini turbine engine running on my desk. - Jerry KF6VB __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] K2 Buyers remorse
Jerry: We had turbine generators on our airborne missions in SE Asia a lifetime ago ... 10 KVA but very light, 2 troops could carry one at a moderate trot. We found we could muffle the whine very nicely with sandbags. 73, Fred ["Skip"] K6DGW Sparks NV DM09dn Washoe County On 8/7/2021 6:35 PM, jerry wrote: All, Not sure if I'll actually be using this PA... The fan is just so LOUD! It's like a mini turbine engine running on my desk. - Jerry KF6VB __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] K2 Buyers remorse
While editing, tap DISPLAY to change the KPA100 fan mode: x FAN nor is the normal setting; the fan stays off until needed x FAN LoHi keeps the fan at low speed, going to high if needed x FAN Hi keeps the fan at high-speed at all times in QRO mode -73- FrankKG9H kg9hfr...@gmail.com > On Aug 7, 2021, at 8:35 PM, jerry wrote: > > All, > > Not sure if I'll actually be using this PA... The fan is just so LOUD! > It's like a mini turbine engine running on my desk. > >- Jerry KF6VB > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to kg9hfr...@gmail.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
