Hi Eric, > "Eric Lemmon" <[EMAIL PROTECTED]> wrote: > Skipp, > Interesting account! > Will you be performing an autopsy to determine the exact cause > of failure? I'm curious about how a bad cable on the TX side > caused the RX to be degraded. > 73, Eric Lemmon WB6FLY >
Probably no autopsy... I could speculate (sounds like spock...) but without a lot more work that I really don't want to do right now... we wouldn't ever know the 100% real reason. I do know it's not the first time... skipp > -----Original Message----- > From: [email protected] > [mailto:[EMAIL PROTECTED] On Behalf Of skipp025 > Sent: Thursday, December 28, 2006 9:25 AM > To: [email protected] > Subject: [Repeater-Builder] LMR-400 Cluser $*%& Again > > Re: LMR-400 Cluser $*%& Again > > Here we go again... date line Dec. 27, 2006 > > Trouble call to a high level repeater site yesterday... reports of > a vhf Motorola Repeater not working well... very poor receive. > > Test the Receiver and Transmitter Sections for proper operation. > > Receiver checks pretty good... removed the un-needed problematic home > brew (removed from a...) Motorola Motrac Mobile era receiver > pre-amplifier filter assembly with a bad internal cable connection. > Not the main problem source... just a future head ache. > Some improvement in the receiver section... but not enough yet.... > > Those Motrac era receiver pre-selector amplifier assemblies are > another topic/thread. Onward... > > Transmitter chain/side with matching tpl amplifier and Decibel IMD > panel check out just fine. Put it all back on the Wacom Duplexer > and the receiver sens "turns to butta'" (craps out). > > What are you thinking now..? Duplexer..? > > You would be wrong Mr Microphone. The Duplexer checks out 100% using > various tests ... so what do we have left? Well bartender > we figure one of the cables might be bad... let's see what we have > here? > > Aaaaahhhh....! someone put an LMR-400 coax cable from the IMD panel > to the duplexer. "Shoot that person!" Lucky for Mr LMR-400 man > I don't know who he is... > > So out comes the LMR-400 (appears) factory made jumper and in we > place a 1/2 inch andrew superflex hardline jumper. PROBLEM GOES > AWAY..! The Repeater returns to normal operation... I finish my > coffee (with cream) because the wind is doing 55mph plus outside. > > Within the last year I/we have had at least 3 episodes of LMR-400 > feed-line causing serious trouble on repeater systems. At least two > of those serious problems have started some x-value of time after > the lmr-400 cable was first installed. > > **** > > LMR-400 is not allowed on Duplex Radio Systems within my control. In > fact I try to get it out of antenna systems anytime I see it... > > I hope some of you don't fall for the low cost vs performance sales > line... unless you have the time and resources to deal with un-needed > trouble (self abuse). > > cheers, > skipp >
