New or unlisted EMRC Frequency?

[Spleen]

Caught this one quite by accident this week. 463.1125 PL 167.9 I don't find it in the database.....can anyone concur? I'm receiving this with a Winradio with outside roof antenna and a handhelf PRO-96 with whip in mid-town Bawlmer...

[ocguard]

It's sometimes referred to by SYSCOM as "Med 5.5" because it's halfway between Med 5 and Med 6. It's a low-powered base station located on the University of MD Medical Campus, and is used by EMRC to patch consulting EMS units to Shock Trauma's chief trauma doctor via a portable radio carried by the physician. This way, the chief trauma doc can monitor and participate in a trauma consult from anywhere on campus, and can know to report back to the TRU. Whenever you hear EMRC use the "warble" or "hi-lo" tone to initiate a consult, that is to alert the trauma doc's portable.

[Spleen]

Thanks much OC! I just thought it was strange that a med channel was not only not in the RR database but also no FCC info was present....

[Rburli]

Without getting too picky. The correct nomenclature for the frequency is MED 52. It is the Narrow banded version of MED 5. Information verified with NIFOG 1.3 edition

[ka3jjz]

While not listed in the database, the new channels are listed in the wiki article below (linked in blue)

Emergency Medical Services Radio - The RadioReference Wiki

73 Mike

[ocguard]

Originally Posted by Rburli

Without getting too picky. The correct nomenclature for the frequency is MED 52. It is the Narrow banded version of MED 5. Information verified with NIFOG 1.3 edition

You assume that just because they are using a center frequency half-way between two 25khz frequencies, that it is being used in narrowband. A carrier being narrowband or wideband has nothing to do with the frequency being used -- it has to do with how much spectrum the carrier takes up on either side of the center of the frequency.

Last I checked, it was not being used in narrowband mode. The portables they had for the docs weren't even narrowband capable. The reason it was chosen between Med 5 and Med 6 is because those two med frequencies aren't used in the Baltimore metro area.

Med 5.5 has been in use since long before narrowbanding was popular, and before the narrowband half-step med channels were given official nomenclature.

But thanks for the input.

[Spleen]

Thanks for the info, all. I might have gotten closer on my own had I looked up the frequencies matching Med 21, 22, and 23, all being patched in the Baltimore City trunking system....I usually have those two talkgroups locked out, though, and simply have Med 1 through 10 programmed conventionally...

I'll go out on a limb and assume that all those voice channels in use around these parts are using PL 167.9?

[ocguard]

Originally Posted by Spleen

Thanks for the info, all. I might have gotten closer on my own had I looked up the frequencies matching Med 21, 22, and 23, all being patched in the Baltimore City trunking system....I usually have those two talkgroups locked out, though, and simply have Med 1 through 10 programmed conventionally...

I'll go out on a limb and assume that all those voice channels in use around these parts are using PL 167.9?

All MIEMSS Region III (Baltimore City, Baltimore County, Harford County Howard County, Anne Arundel County, Carroll County, and Cecil County) use PL 167.9 on the MIEMSS UHF system.

I'm not 100% sure I understand what you mean by "the frequencies matching Med 21, 22, and 23, all being patched in the Baltimore City trunking system."

Those jurisdictions having their own EMRC consult talk groups on their respective trunked systems aren't patched to Med channels. They are patched directly to the consulting hospital using tie-lines or microwave intercom. This is a common misconception. In other words, Med 4 (463.075) is completely independent of Baltimore County's trunked system talk group 224 (despite the fact that it is given the label of "Med-4"). Two separate units could use those two separate mediums to consult with two separate hospitals simultaneously. They are not "patched" together to complete a call.

The only med channels/talk groups that are "patched" are the "CALL" channels/talk groups:
MIEMSS Call-1 (a.k.a. Med-9, 462.95)
Baltimore City talk group A-5 CLL21
Baltimore County talk group 221 CALL-1
Harford County talk group A-6 CALL-301
Carroll County talk group 2 EMRC-1
Howard County talk group E-1 CALL-1
Anne Arundel talk group 3-F CALL-1
Cecil County talk group 3 EMRC

And in reality, they aren't even really "patched" together. They are slaved together so that one operator can monitor traffic on all the systems via one port on the console. You won't hear traffic from one jurisdiction on another county's system.

So since each county has 2 consult talk groups, and you add the two Region III UHF med channels, there could be 16 simultaneous consults occurring in Region III.

[Spleen]

Okay....maybe their (Baltimore City trunk) nomenclature confused me. TGs 1776, 1808, and 1840 are labeled EMRC Ch. 21, 22, and 23, respectively. I'd just assumed they were simulcasts of the actual corresponding EMRC channels....perhaps "patch" wasn't a good word.

Again, thanks for helping out on this one....

[ocguard]

Originally Posted by Spleen

Okay....maybe their (Baltimore City trunk) nomenclature confused me. TGs 1776, 1808, and 1840 are labeled EMRC Ch. 21, 22, and 23, respectively. I'd just assumed they were simulcasts of the actual corresponding EMRC channels....perhaps "patch" wasn't a good word.

Again, thanks for helping out on this one....

Ah, I see what you mean. Yeah, I'm not really sure where those labels came from. At work, we refer to them simply as A5, A6, and A7.