Barry, With all due respect, I think the appropriate response to your statement is: "Not necessarily."
The typical Motorola Micor 100 watt repeater station will have the duplexer at the very bottom of the cabinet, with the power supply just above it. Then follows the unified chassis, and finally the 100 watt PA at the top. While your desire for cooling fans is well-intended, I daresay that the vast majority of 100 watt Micor stations- many of which remain in service today- are cooled solely by convection, and they seem to survive without fans. Let us keep in mind that fans do not "cool" anything; they simply move air around. If the ambient temperature in an uncooled transmitter shack is 120 degrees Fahrenheit, the fan will simply raise the temperature inside the cabinet to 120 degrees F- which might be higher than the temperature inside the cabinet if no fans were used. 73, Eric Lemmon WB6FLY -----Original Message----- From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of Barry C' Sent: Saturday, November 24, 2007 3:37 PM To: [email protected] Subject: RE: [Repeater-Builder] 19" rack positioning question Just remember heat rises so the hottest items usually go high in the stack , assuming you have a top mounted fan. ________________________________ To: [email protected] From: [EMAIL PROTECTED] Date: Sat, 24 Nov 2007 18:50:41 +0000 Subject: [Repeater-Builder] 19" rack positioning question In the sprit of the only stupid question is the one that goes un- asked. Here goes: I have a Micor UHF repeater mounted in a 46" x 19" cabinet. It is now a ham band repeater that I have added a new NHRC-5 controller and IRLP interface. The modules are mounted as follows: Top: Custom built 12V PA cooling fan rack controlled by the NHRC-5 aligned with the top door vents. 75W PA Transmitter/ Antenna Network Control module (mostly empty now replaced with NHRC-5 and mods from this site) Receiver module Massive TPN1110B power supply 4" space Bottom: WaCom duplexer cannisters (4) I would like to put the power supply on the bottom so that it aligns with the vents in the cabinet doors and I can add some fans to cool the transformer (you can cook a grilled cheeze sandwitch on it) An added plus is that it will make the cabinet more stable with the weight on the bottom. Is there any issues mounting the duplexers between the receiver and the power supply with the powersupply on the bottom. I hate to move things around and have problems. And yes I will get help to lower the power supply and save some digits. I know the best solution is to replace the powersupply with a more modern one. I plan to do this when funds are better. When this time comes who makes the best replacement powersupply unit? (ok two Questions) Thanks gang Bill N5ZTW ________________________________ Sell your car for just $30 at CarPoint.com.au. It's simple! <http://a.ninemsn.com.au/b.aspx?URL=http%3A%2F%2Fsecure%2Dau%2Eimrworldwide% 2Ecom%2Fcgi%2Dbin%2Fa%2Fci%5F450304%2Fet%5F2%2Fcg%5F801459%2Fpi%5F1004813%2F ai%5F859641&_t=762955845&_r=tig_OCT07&_m=EXT>
