M-8 Cars - Delivery and Acceptance

> 50% of weekend service? Wow this is coming fast!

#9206 leading with six cars and #9132 trailing went by South Norwalk, CT late this morning at 11:18 AM on a deadhead to New Haven.

nope all those are in service cars, highest in service is 9222/9223

Unless I misread (possible), saw 9232/9233 on a revenue train last week.

I think you mis read, currently 126 cars in service highest number beenin 9225

9225 is the highest number I can look up in the TMIS system.

Radioman - What's your take on the radios in the M8's? Channel 2 seems like it's always out of squelch. Channel 1 and 3 are much better. Also whenever you're talking into the radio whether the sash window is up or down sounds like an echo chamber. Can't tell you how many times the RTC's request for a repeat in the transmission due to the radios in the M8's. Just curious.

As far as the squelch, we always have had problems because of switching power supplies in the trains and from out side sources causing interference. We just received 53 replacement radios for the M-3's that won't narrow band, and I made sure they were reprogrammed for a higher squelch setting to try and minimize the issue. For the complaints about transmiting, I havn't listened to any M-8's on the radio so I can't say for sure, but if history repeats itself the gain of the microphone circuit through the common control head (radio P/A intercom) is set too high. Reprogramming the radio my help, but other measures need to be taken to minimize the too much gain issue, but on another note those radios havn't been narrow banded yet, (should have been done by Kawi) so that may take care of it also.

its not the power supply, the software on channel 2 is set wrong, channel 2 has always been a birdy channel and even on older radio's squelch had to be turned up to suppress the interference.
In software settings each channels squelch can be set, there are 3 settings, tight - normal - loose. channel 2 should be set on tight.
it really does not matter much what radio software is used but same 3 choices exist in Motorola, Harris, GE etc.

Dutch
Unless you worked on the mitigation program to eliminate the noise issue with the radios, I don't think you are putting out good information. The issue with Chan 2 and to a lesser extent 1 and 3 is switching power supplies both on the train and outside, as well as other noise sources. The power supplies of the M-7 series had to be modified after delivery to lessen the problem (M-8's were done by design before delivery), and as I said there are all kinds of noise out there and we found multiple instances of switching supplies on the train not just the one for the radio and on the platforms (from the signs) laptop's and desktop computers causing noise issues.
Yes the older radios in older cars were also subject to the interference, since they were receiving it, but mainly and especially when parked near a M-7 (We get calls on this daily). I spent a considerable amount of time researching and doing field tests with a spectrum analyzer looking for the problem. The solution less we go with a CTCSS tone (not going to happen no other rail road is going to cooperate and program PL in their radio's) is to program the squelch setting for a squelch opening of between .4uv and .6uv of signal. It won't eliminate the problem but it does help.
Also you are not familiar with the GE/Harris radios of the M7/M-8 generation which are M7100 and M7200 and now for the new M2,4,6 retro are M7300 radios. There is only one programmable squelch setting for all channels globally, and I never saw any indication of individual channel squelch setting on Alpha's, Spectra's, Mitrek's,GE Orion's or on any other US manufactured radio.
Due to the nature of the signalling format for PTC there is right now a very extensive RF noise analysis program being done in conjunction with PTC for all our stock. You wouldn't believe the crap that comes out of the cars, loco's and the rails themselves. I am not going to go into detail but something as simple as a door closing bell puts out all kinds of garbage.

Mr radioman so far i have been right about many things, and currently some M-8's are modified , yet your dept. still has at least 100 cars out there that are garbage.
stop the rethoric even the M-2 radio's never got set right after 28 years, one of better qualified radio maintainers wshowed me how out of specs those were.

Frequency 161.280 (AAR 78) is a notorious "Birdie" frequency and even the modern radios can only filter out part of the interference.

John the M-8 Harris radio's (as deliverd) are set Normal for squelch on all channels, they started to correct it, but slower than S**t

as of yesterday 130 cars accepted for revenue service.

You're more reliable than the web-site!