Actually, there's more energy available in a 120-degree shift to halt the mechanical reed, than there is in a 180-degree shift. This can be proven mathematically. According to a Motorola treatise published decades ago (I'll post it once I find a copy), Motorola chose the 120-degree shift simply because it was more effective at stopping the reed. Remember, Motorola pioneered the concept of CTCSS. Other manufacturers settled on a 180-degree shift because it was easy, and they needed to rush a competing system to market. No mention was made of reed breakage in these papers.
73, Eric Lemmon WB6FLY -----Original Message----- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of MCH Sent: Saturday, December 12, 2009 9:02 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] RE: 50 Watt Repeater You have to keep in mind that they chose 120 degree shift because they had problems with 180 degree shift breaking reeds. 120 degree shift stops them at a softer rate and increases longevity. The other manufacturers didn't care because they weren't around pre-microprocessor based decoding (they didn't have reed-based decoders), and probably rather liked the idea of making Motorola look bad by breaking reeds in Motorola equipment. Joe M. wd8chl wrote: > Paul Dumdie wrote: >> I have a TKR-750 repeater and like it. My only issue is that I use >> Motorola Portables and keep getting a squelch crash. What have you >> guys setting the setting for the reverse burst at to get rid of the >> squelch crash? >> >> Thanks! >> > > Assuming you mean you have Motorolas that have the switch in software, > Kenwood and virtually everyone else in the world uses 180-degree shift > for rev burst, so whatever that setting is. > Moto uses 120-degree shift, and nearly no one else does. > > > > ------------------------------------ > > > > Yahoo! Groups Links > > > > > ---------------------------------------------------------- > > > No virus found in this incoming message. > Checked by AVG - www.avg.com > Version: 9.0.709 / Virus Database: 270.14.103/2558 - Release Date: 12/11/09 05:06:00 >
