MARTA frequencies (courtesy of FCC ULS)

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KK4DUY

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I was being nosy, and put this list together.

This is all of MARTA's allocations, with +5mhz repeater offsets from appearances.

I did NOT include the 800mhz trunking (they have some around 805mhz and 850mhz, approximately) or their point-to-point microwave links (they have several, and I assume these are site-to-site links)

Keep in mind the +5mhz offset is an educated guess. If I'm wrong, then just double the table below, with each duplicate being 5mhz higher than the original (eg 453.700mhz and 458.700mhz)

Note, I have no idea how many of these are actually used or what for. All I do know is that these are active licenses. You are more than welcome to go here and do a search against FRN 0001852656 if you want to see this all yourself or check for any changes.

MARTA - PW - Public Safety Pool said:
453.700
453.725
453.775
453.875
453.925
453.950

MARTA - IG - Industrial/Business Pool said:
452.375
452.425
452.475
452.6375
452.6625
452.675
452.6875
452.7125
452.7375
452.775
452.825
 

MTS2000des

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IIRC the legacy UHF channels are for the bus/train SCADA controls.

All voice activity (including police, rail control, safety, track maintenance, retc) takes place on their Smartzone V4.1 mixed mode 800MHz TRS. I monitor it regularly.

They haven't used the old UHF system for voice since around 2003 when the buildout of the 800 system began. The radiax system for the UHF repeaters were removed in 2004 and replaced with newer radiax and BDA's in the tunnels for 800MHz coverage. FYI it also repeats the ATL DTRS signals too (I've tried it riding MARTA N/S and E/W with my XTS5000).

Many agencies maintain their legacy licenses for backup/aux purposes. The city of Smyrna, where I was born and still live, has active licenses on their old VHF conventional frequencies (including two repeaters) for fire and PD, though they haven't been used regularly since around 1995 when the city migrated to the Cobb trunked radio system.

The police department doesn't even own any VHF radios anymore. The caches of portables were sold at auction in 2000. Mobiles were taken out in 1996, I know, I uninstalled many of them myself when I worked at Garrett Diversified.

The Fire department still maintains VHF radios as part of their mutual aid pact with the Georgia Mutual Aid Group (GMAG). They do a daily radio test on 154.16 at 0730, but that's all you'll hear on there.
 

KK4DUY

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Then how is it that I can hear conversations in Spanish in the vicinity of the North Springs station?

That said I do hear what sounds like SCADA in the area as well, but your claim that it is all in the 800mhz trunks seems off.
 
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MTS2000des

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you do know that there are other licenses on those pairs right? specifically, RadioOne has an analog LTR TRS on top of the SunTrust building, which explains the spanish taxi services, I also maintained a fleet of radios on that system for my former employer. MARTA stopped using them when RadioOne put an LTR system online downtown. Do a search on KelRad on the ULS and you'll see many of those 452MHz channels are also in use by them.

The MARTA TRS is used by everyone for voice communications for the entire system. Spend time listening and you'll see. Do you ride MARTA? All you'll see are XTS5000's by PD and EC&S personnel. Everyone else use a mix of MTS2000 and XTS2500 portables, all 800MHz. The ONLY UHF in use is for SCADA. I can put you in touch with their director of communications if you want more detailed data on their radio use. He even lurks on these forums, maybe he'll pop in.
 

KK4DUY

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you do know that there are other licenses on those pairs right? specifically, RadioOne has an analog LTR TRS on top of the SunTrust building, which explains the spanish taxi services, I also maintained a fleet of radios on that system for my former employer. MARTA stopped using them when RadioOne put an LTR system online downtown. Do a search on KelRad on the ULS and you'll see many of those 452MHz channels are also in use by them.

The MARTA TRS is used by everyone for voice communications for the entire system. Spend time listening and you'll see. Do you ride MARTA? All you'll see are XTS5000's by PD and EC&S personnel. Everyone else use a mix of MTS2000 and XTS2500 portables, all 800MHz. The ONLY UHF in use is for SCADA. I can put you in touch with their director of communications if you want more detailed data on their radio use. He even lurks on these forums, maybe he'll pop in.

Ah, thanks for the explanation. Seems odd to me that they would license out the same frequencies in such close proximity - either that, or my radio's sensitivity is beyond the norm and I'm simply picking things up that the intended devices wouldn't normally be able to do.

I'm still figuring out how all this works.
 

MTS2000des

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Cobb County, GA Stadium Crime Zone
your receiver may be getting images, common problem with scanners and ham radios. Bona fide single band commercial radios are pretty immune to IMD, but then they don't have wide front ends.

most conventional VHF/UHF licensed to metro areas where 800MHz trunking is deployed is quiet. Some prudent agencies keep the legacy repeaters online for backup, explorers, special event radio cache's, or repurposed them. For example the East Point public works department are now on the old EPPD dispatch repeater 159.21, and dropped using iDEN (and paying to do so) when EPPD migrated to the Atlanta analog then digital TRS a few years ago. If more governments would do this, they'd save money and keep redundant radio systems online for their public safety users.

Sadly, many metro agencies put all their eggs in a single basket and often take down old systems long ago. The city of Atlanta still has active licenses for VHF and UHF, but they are silent.
 

b7spectra

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And don't forget about Marietta as they have VHF radios in most all of their patrol cars and STEP uses one of the channels for car2car! They took and moved all their public works to a city owned/maintained VHF LTR system.
 
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