Bob, Let's not denigrate switching power supplies as a class, just because of a few bad apples. Switchers-as a class- are more efficient and reliable than linear supplies. Sure, there may a few brands out there that are spur generators, but not the top-of-the-line switchers from DuraComm, Samlex, Astron, Astec, AEG, and others. QST Magazine has reported on a number of switching power supplies and found that the better brands produced no detectable interference in the HF bands- which are far more vulnerable to spurs than are VHF or UHF repeaters. See the product reviews in QST issues of January 2000, September 2000, July 2006, and August 2009. I rest my case.
73, Eric Lemmon WB6FLY -----Original Message----- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of n...@no6b.com Sent: Sunday, February 28, 2010 8:31 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Micor Stock Power Supplies At 2/27/2010 09:56 AM, you wrote: >I have been following the 9.6 Volt Micor Voltage information. One post >indicated that if one were to replace the Stock MICOR Supply with a >switcher and add the 9.6 Volt circuit, the monthly electric bill to run >the repeater could be significantly reduced. Is this due to the fact that >the switcher, in the standby mode, draws much less current and therefore >cost less to operate or is it this combined with efficiently when the >repeater is in operation. I have stock MICOR and MASTR II Supplies and >would like your expertise on the merits of replacing them with one large >switcher or a couple switchers. As always thanks in advance for your input >and sharing your experiences with us. A local multi-band repeater system is having IMD problems, & requested a CTCSS change to resolve one of them. After describing the "sound" of the low-level (~-70 dBc) spurs I'm seeing a few hundred kHz either side of the 440 output of the system, the owner told me that the IMD hitting his other inputs sounded the same. I asked if he was using a switching supply to power the system & he said yes. I recommended that he replace it with a linear supply; I suspect that will solve all of his IMD problems. Will let you know... Bob NO6B
