The Tale of the Railroad Spectra

batwing4ever · Post by **batwing4ever** » Sun Aug 29, 2004 5:30 pm

This is a short story of my experience with a Railroad Spectra. Perhaps someone can gain some useful information from this about the Railroad Spectra over and above what is on Batlabs.

I picked-up a non-working Railroad Spectra a while back for the proverbial "song" i.e.: "please make this go away." The radio is basically a big box, with a huge control head. Inside there's an ordinary Specta, 74vdc power supply and whole lot of empty space.

I put 74vdc (with a variac power supply) on it and nothing. The same for the 12vdc input.

Long strory shortened; I open the thing up and find the 74vdc supply is toast and that some "genius" instead of replacing the 12v fuse, wrapped it in aluminum foil and it melted the fuse holder.

So after a quick examination I see that the power input to the radio from the power supply is the standard Motorola power connector like you find on the back of a Radius or "ordinary" Spectra with one key difference, the polarity is reversed. OK, so I make-up a power cord for it, put 12vdc on it and VOILA! it works.

At this point it appears that the power supply module is junk and I might as well just dispose of it. WRONG! The 4-pin power connector and the 12 pin accessory connector are attached to the power supply board.

I follow the cable back from the accessory connector and it goes to an IDC header on a different board, so I figured that since I was not using the 4-pin power connector, it would be safe to dispose of the power supply afterall.

So I connect the radio to the RIB and quickly learn that Spectra RSS doesn't work on this radio. So after call to /\/\ I fixed that, for a fee ofcourse. OUCH! The service manual is no cheapy either at $185!

OK, I read the radio with the correct RSS and after some browsing around I come to see that you can program different TX and RX freqs for the same channel, just like any other radio.

When you select a channel on a Railroad Spectra, you specify the TX and RX channels separately i.e.: 01 and 01 to TX and RX on channel 01. So, I think, why not try putting a repeater split on channel 01.

I program in channel 01 with a TX of 146.010 and an RX of 146.610.

I power-up the radio and enter in 01 for both the TX and RX channels and it should (at least in my mind) work on the local ham (146.610/-) repeater. Well, don't waste your time trying this because it doesn't work. That is unless I did something else wrong, which is entirely possible.

There is an interesting feature with this radio, if you key-up with high SWR on the antenna/feedline the radio sounds a "bad tone" and "BAD ANTENNA" appears on the display. It does not however, shut down the transmitter. I guess they figure that if you're dumb enough to continue holding the PTT button down with an audible warning and "BAD ANTENNA" on the display, you deserve to have your radio go up in smoke.

So once I got it working on a ham repeater, the complaints about audio quality followed shortly thereafter. The most common complaint was "you sound like you're in an echo chamber." OK, so a plam-mic is probably in order.

I go to the junk-box and find a Systems Saber SVA palm-mic and after some tinkering with clip leads, I figure out how to hook it up and what do you know, it works. If someone wants the pinouts, let me know.

I mounted a wall mount category 5 network outlet inside the radio where the power supply was and TADA, I have a palm-mic.

A few things that I haven't had the guts to try is to see if the Railroad Spectra radio will work with an ordinary Spectra control head and if an ordinary Spectra will work with a Railroad Spectra control head.

The radio has excellent receive charateristics. I can hear HT's 10 miles away (simplex) with just a mobile antenna. That is ofcourse on the RR band and may not be true on other freqs. If you like to listen to the RR radio traffic, it's great for that.

For ham use, you can only get maximum of 49 repeater pairs in it and you tend to be a "gator" (big mouth and no ears) with it's 45W output power. Several of the repeaters that I can barely hear on this radio, I'm told that I'm in the repeater in question "full-quieting."

For business use, it's a BIG (about 4 times the size of an ordinary Spectra) and somewhat clumsy radio.

Now I know why got it for a song.

Post by **batdude** » Sun Aug 29, 2004 6:55 pm

everything made has a purpose.

or at least the guy that designed it had SOME purpose in mind.

safe bet is that no one at /\/\ **EVER** thought of using a RR spectra on the ham bands.

therefore, i'd say things are as they should be.

funny thing is, i remember a while back a minty RR spectra brought $700+ on greedbay... of course it was in near - new condition with all the stuff.

the manual you mention is the complete service manual for spectra - about 6 inches thick, with enough data in it to choke even the gutsiest techs (insert nand here) - at least it was when i ordered it 10 years ago for another ham who happened upon the "deal of the century"

LOL

doug

nmfire10 · Post by **nmfire10** » Sun Aug 29, 2004 7:09 pm

I get the feeling I know where this thread is going to go.

jcobb · Post by **jcobb** » Sun Aug 29, 2004 7:27 pm

Nope.

Jack

apco25 · Post by **apco25** » Sun Aug 29, 2004 7:30 pm

Couples thing....

I wouldn't judge a railroad spectra for use on anything other than railroad frequencies.

Do a search, these beasts get talked about a lot.

As Doug said, it was never meant for ham, commerical or public safety use.

Its big because its supposed to be in a locomotive cab which is huge. It also had to conform to the "clean cab" specs as well as offer run through capability on any railroad. The radio was designed to use headsets, mics, phone handsets or hands free mics - its also noise cancelling (ever been in a locomotive cab?)

That's why the 99 AAR channels are presets with independent tx/rx selection. Same goes for the programmed channels.

I guess screwing with a railroad spectra is like trying to get a spark gap transmitter to work C4FM

Josh · Post by **Josh** » Mon Aug 30, 2004 2:27 am

I'm surprised that you can get as good RX as you claim.

I have a railroad spectra right now, acting as a paperweight, and its receiver totally sucks. I miss a lot of stuff.

I have an older MCX100 loco radio, and while it is no RSS programmable or anything on those lines, it works much better. I think you should try using another mobile (non spectra) radio for RX and see if you get better performance afterall (I think you will).

-Josh

larryepage · Post by **larryepage** » Mon Aug 30, 2004 1:31 pm

My experience with RR Spectras has been very different from the ones reported here...

First...the radio can handle 99 simplex or repeater pairs. The key is to use the "Home mode," which group transmit/receive pairs nicely and conveniently.

If you are receiving complaints about your transmit audio, I'd look at the RSS service parameters. I have used a RR Spectra sitting on the transmission hump while operating mobile (using the built-in mic) and gotten excellent reports on my signal quality. Double check the microphone mount and make sure there is no gunk blocking the microphone port. These mount with foam and other material that can get dislodged and influence your audio.

Remember that locomotive cabs can be very hostile environments and that train crews are not always the most knowledgeable radio operators. By the time RR radios become available, there is sometimes not a lot of life left in them. Southeastern railroads in particular seem to generate very much abused radios to the surplus market.

My experience is that properly aligned RR Spectras should easily transmit at 40 watts all day long. Setting them higher is usually what leads to the fried power converter. The higher current drain at 50 or 55 watts may not hurt the transmitter, but it just bakes the converter. (50% more current is required at 50 watts than at 40 watts, and if you go to 60 watts, the current is more than doubled from 40 watts.)

I'd suggest that unless you are totally discouraged that you keep working with your radio. It should do much better than what you describe, on both the railroad channels and 2 meters. Remember also that the RR Spectra has a 20 watt audio system, so it can be a good choice for a receiver that can be monitored by multiple folks.

If you decide to give completely up, I might be interested in having one more radio that I don't really need.

Regards,

Post by **batdude** » Sat Sep 04, 2004 5:59 pm

THE DEAL OF THE CENTURY

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 09998&rd=1

kf4sqb · Post by **kf4sqb** » Tue Sep 07, 2004 8:23 am

Yeah, if you decide to give up on it, I would love to have one. As far as the fried power supply board goes, there are other causes than just transmitters turned up to high. Most railroads use a very large arc-welder (about 400 amp capability) to "jump-start" a loco with a dead battery. Needless to say, this can cause quite a transient throughout the whole electrical system, which isn't very nice to the power supply board. As stated earlier, they are "application specific", and therefore may not work properly for different applications. The noise canceling on the panel mic is unparrelled, and that may make you sound funny to people who aren't used to it. The control head from a regular Spectra, I would not think would work on a RR model, due to firmware differences. This is not a "regular" Spectra in there. It has extensive firmware differences from the normal Spectra. On a final note, considering that the RR Spectra is tuned to operate in app. the 158-162 range, I find it impressive that you have any reccive to speak of in the 144-148 range.