Jim,
And fellow Drake enthusiasts, I will go downstairs later today and get the model numbers of the fans that I use. As a side note, I have a project in progress that will have L4/L4B/L7 power supply fans internal to the supply, for convenience. Quality is indeed important as you mentioned. Both mechanically and electrically. I have some 12vdc computer fans, brushless style, that generate harmonics/hash up to 148 mhz! Try before you buy if convenient. 73, Evan, K9SQG -----Original Message----- From: Jim Shorney <jshor...@inebraska.com> To: drakel...@.zerobeat.net <drakelist@zerobeat.net> Sent: Sat, Jul 17, 2010 10:55 am Subject: Re: [Drakelist] Fan on R4B and linears On Sat, 17 Jul 2010 09:16:50 -0500, Don Cunningham wrote: >Evan, >Would you share the make and model of the fans that work so well for you?? Sounds like something I need to do here. Well, I'm not Evan, but I will share what I am doing with my L-4PS. The larger the fan, the slower (and quieter) it needs to run to move a certain amount of air. Or, the more volume it will move for a given speed. I have a pair of ebm-papst 12 volt fans pulled from server computers, model 4412 F / 2M. They are about 4.75 inches (120mm) in size, and I run the two in series from a 12 volt power source, pulling air OUT on top of the PS. They seem to work very well, and I can't hear them running when I am sitting practically right on top of the PS. I have to check with my hand to feel the air to make sure they are running. They can be "mounted" as Evan describes, or some thin stick-on weather stripping material can be cut into small strips and affixed to the fans. I currently have mine just sitting there with nothing between the fan and the PS, they are so lightweight and made of plastic that they don't scuff. What is probably more important here than the type of fan is the quality. Avoid cheap sleeve-bearing PC fans like the plague, they will die on you. Guaranteed. The ebm-papst seem to be a decent product. Panasonic Panaflo fans are excellent, they seem to go forever. Be cautious of PC fans labeled as "ball bearing", some of the small ones that I have taken apart have a ball bearing at one end of the impeller shaft, and a sleeve bearing at the other. I don't see this as an improvement. The new Sunon "Maglev" design looks interesting and seems to have better longevity, but they haven't been around long enough to make an accurate judgement. And remember to clean the blades once in a while, a little dust can reduce the airflow by a surprising amount. I'm sure Evan will have some great recommendations as well! 73 -Jim -- Ham Radio NU0C Lincoln, Nebraska, U.S.S.A. TR7/RV7/R7A/L7, TR6/RV6, T4XC/R4C/L4B, NCL2000, SB104A, R390A, GT550A/RV550A, HyGain 3750, IBM PS/2 - all vintage, all the time! "Give a man a URL, and he will learn for an hour; teach him to Google, and he will learn for a lifetime." HyGain 3750 User's Group - http://groups.yahoo.com/group/HyGain_3750/ http://radiojim.exofire.net http://incolor.inetnebr.com/jshorney http://www.nebraskaghosts.org _______________________________________________ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
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