Help identify an LV Fed Freq?

[eraweeb]

Can someone please help to identify which Fed agency I am hearing on 409.4 P25 in the Vegas area?

It is obviously a law enforcement channel. Recently I heard suspects being run through NCIC and also they were requesting assistance from LVMPD.

Here is something that is kind of odd. The dispatcher and the units that "she" is communicating with are constantly asking each other to repeat their transmissions due to the signal breaking up or just not being able to understand each other. I am in the far NW part of Vegas using a BCD996T in a ground floor condo with an indoor antenna. I am hearing both sides of the conversations loud and crystal clear!

Go figure!

[Exsmokey]

Originally Posted by eraweeb

Can someone please help to identify which Fed agency I am hearing on 409.4 P25 in the Vegas area?

It is obviously a law enforcement channel. Recently I heard suspects being run through NCIC and also they were requesting assistance from LVMPD.

Here is something that is kind of odd. The dispatcher and the units that "she" is communicating with are constantly asking each other to repeat their transmissions due to the signal breaking up or just not being able to understand each other. I am in the far NW part of Vegas using a BCD996T in a ground floor condo with an indoor antenna. I am hearing both sides of the conversations loud and crystal clear!

Go figure!

This might be a downlink from a VHF repeater or remote base. Sounds like it would be a remote base. If the units are some distance apart the remote base will hear each unit just fine, but the units are far enough to make communication difficult. That is why repeaters are better for mobile to mobile or handheld to handheld communications.

A remote base is just that. It is a base station located on a high point, mountain, building or tower that is then linked to the control location or dispatch via a radio link (usually UHF for the feds), microwave link, or on phone lines. Since you are hearing both sides of the conversation on UHF and the field units can't always hear each other this would probably be a UHF link for a VHF remote base.

If you are hearing the field units, as well as dispatch, clearly on the same frequency there are two possibilites as to system design. This could be a remote base link to a VHF system that repeats the up link on the downlink frequency. The up link would be 9 MHz above the downlink, or 418.4000 in this case. That would narrow down the agencies involved. The second possibility is that the system is using 409.4000 on simplex without a remote base, just a low level base station at dispatch. The DEA uses UHF simplex and for repeaters, while most of the remaining federal law enforcement agencies use VHF.

If you can catch field unit call signs or unit designators I might be able to help. The federal systems I'm familiar with in southern Nevada all use repeaters instead of remote bases, except for the system "hub," so what you are receiving might be unfamiliar to me. The traffic content and locations discussed would also be helpful.

[eraweeb]

Thanks for that good information! I am located very close to Angel Peak which may or may not be a factor.

I found this frequency while doing a Quick Search on 400 to 420 MHz. I am going to put it in my Miscellaneous Bank and monitor it for a while. If I can come up with any more information on it, I'll report back here.

Thanks again!

[ecps92]

Put it in One Radio and then when it's active try these

a.) 162-174
b.) 138-144
c.) 148-150.8

The NPS / USFS use VHF but use UHF as Remote Links [instead of Microwave and LandLines]

Originally Posted by eraweeb

Thanks for that good information! I am located very close to Angel Peak which may or may not be a factor.

I found this frequency while doing a Quick Search on 400 to 420 MHz. I am going to put it in my Miscellaneous Bank and monitor it for a while. If I can come up with any more information on it, I'll report back here.

Thanks again!

[TOUGHLIFE]

Wonder if 409.400 monitored in a non-trunking mode, but P25 format as indicated in the post might not be an additional frequency not showing in the NNSA system active in Southern Nevada which does include some federal law enforcement agency use? Some basic information on this system is showing in the RR DB. Just a thought.

[ChrisP]

If the original poster has the capability of grabbing the NAC from that P-25 traffic, that would help. The NNSA trunked voice channels all seem to be broadcasting a NAC of $264...

- Chris

[eraweeb]

I am using a BCD996T as my primary scanner so I do not have NAC capability. I will however try using 2 radios this weekend and scan the other suggested Fed ranges at the same time.

I will be interested to see if anyone else in the area can identify it. Would also be interested in what kind of reception is experienced in different parts of the valley in order to determine if my close proximity to Angel Peak is a factor or not.

Thanks for all the input!

[eraweeb]

Well o.k., now I’m getting even more curious. his Friday afternoon I left the scanner tuned to 409.4 in manual mode. It’s been well over 4 hours now and I haven’t heard one single transmission on that frequency.

That can only mean one of two things:

Either this unknown entity only uses this frequency occasionally like for very specific purposes, or when I originally monitored it the other day I was hearing an image. I doubt very much if it was an image. There are several reasons why I don't think that it was.

There is only one other very remote possible reason. Perhaps I scared them off of the frequency by announcing it here in this forum. No, I can’t really buy that either!

Well now that I’m committed to this cause, I’m just going to have to leave that scanner tuned to that frequency until I hear a transmission there. Apparently it’s the only way to get to the bottom of it. It’s a tough job but somebody’s got to do it!

[Exsmokey]

Angel Peak has a significant amount of electronic communications equipment on it. I've been up there a few times and got the impression that it is the hub site for many southern Nevada radio systems. I don't think your proximity to it would make much difference as it covers the valley quite nicely. None the less, there is a good possibility that a remote base using 409.4000 is located there.

For the reasons I outlined in my previous post I lean toward an answer of this being a simplex system with a remote base, most likely on Angel as you suggest. The question then becomes how the remote base is linked. I would guess by phone or microwave. This is a lot of speculation. Ideally the traffic would be more frequent and you would be able to drive to Angel Peak with a frequency counter to confirm the location of the remote base. Since there is an abundance of equipment on the peak there would be no way to figure out how the remote base is linked.

There could be another answer to how this system works but it doesn't come to mind. The bigger question of what agency this is remains unanswered and giving too much thought to the details of the system design is not likely to narrow down those possibilities.

[eraweeb]

On Monday morning at 8:25 AM, 409.400 came alive again for just a minute.

A female voice put out a call to "923" and "924" and asked for a radio check.

Both units, (male voices) responded with, "Loud and clear."

The female voice answered with, "Thank you!"

That's it. It is now 2 hours later and there hasn't been another single transmission. I'm hoping that maybe someone can identify those unit numbers and solve this mystery!

[AlabamaRS]

A quick google search says...........>409.400Mhz Federal shared

[commstar]

Lacking other replies I'll take a stab at this one. Potentially part of the National Nuclear Security Administration Trunk? That frequency is not listed but 406.4000 is perhaps you are listening to an input.

On that vein, 406.4000 appears to be used elsewhere by the USFS as a link....

Just a guess, not from your part of the world, no personal knowledge.

Best,
Mike

[ecps92]

Why create a new thread, the information is already
being discussed at RR Nevada

[Squad10]

In 1998 Grove Enterprises reported 409.4 being paired with 417.7 (Nevada Net NV079) and used by EG&G Division of URS, a DOE contractor.

[Squad10]

The following appears to be the last published address for EG&G in Nevada:

EG&G
Mailing:
P.O. Box 93747
Las Vegas, NV 89193-3747
Shipping:
821 Grier Drive
Las Vegas, NV 89119
Phone: (702)361-1660
Fax:
(Admin & Purchasing) (702)361-4713
(Executive Offices) (702)361-0932

[wayne_h]

Originally Posted by ecps92

Why create a new thread, the information is already
being discussed at ...

Merged. eraweeb, please stop creating multiple threads on the same topic. Use reply, not create thread. Thanks.

[Exsmokey]

commstar, thanks for the observation and link to the database. 406.400 shows up as an alternate control channel on two sites that could be received from Las Vegas. When not being used as a control channel, this frequency is, of course, a voice channel. However, it is a mystery as to why the responses from mobile units stay on the same frequency. Perhaps the trunking uses the same repeater over and over when there is minimal traffic on the system. The situation does not sound like a trunked system as the two mobile units involved would be able to copy each other dispatcher can copy them both. Since trunked systems employ a separate repeater for each frequency at a site and two units not being able to copy each others traffic that the base or dispatcher can, this is not likely a repeater.

As for being a link for a Forest Service VHF system, this does not match up with the observations made when receiving this UHF frequency. The Forest Service uses repeaters on the Toiyabe National Forest. Mobile units cannot contact the dispatcher on simplex Forest Net. For the reasons outlined in the first paragraph here this is not likely a repeater system. Forest Service traffic would be far more frequent. Lastly, the unit designators the Forest Service uses start with a "7" on the Toiyabe National Forest followed by 3 additional numbers.

The other federal natural resource agencies in the area that might be using a UHF link would be the National Park Service, BLM, and U.S. Fish and Wildlife Service. The first two, as far as I know, don't use a three number series beginning with a 9. Their traffic would be more frequent as well.

I can't tell you much about U.S. Fish and Wildlife designators, but do know that the agency has a VHF system for the refuges adjacent to Las Vegas. I think they use repeaters as well, but I don't remember if this is the actual case. If their system uses a remote base for the known VHF frequency, the VHF is used simplex, and if that remote base is on Angel this would match the observations. Their traffic might be infrequent as well. However, they have areas of some refuges that would be blind to Angel, and one entire refuge, Ash Meadows, that is at a low level west of Pahrump, a location that is entirely blind to Angel. eraweeb, try monitoring 164.425, the USFWS frequency for the Desert National Wildlife Complex. There are Refuge Officers, who attend the Federal Law Enforcement Training Center along with their NPS, BLM, and USFS counterparts. This may explain the NCIC type traffic heard.

[737mech]

This is definitely not NNSA, Not Forest Service, I monitored it today and If I were to render a guess it was US Marshals. If not they are definitely law enforcement that would call in metro support (Narcs, DEA, ATF, HLS, US Marshals, Secret Service) As I said rendering a guess based on limited monitoring.

[joking]

Originally Posted by Squad10

The following appears to be the last published address for EG&G in Nevada:

EG&G
Mailing:
P.O. Box 93747
Las Vegas, NV 89193-3747
Shipping:
821 Grier Drive
Las Vegas, NV 89119
Phone: (702)361-1660
Fax:
(Admin & Purchasing) (702)361-4713
(Executive Offices) (702)361-0932

409.400/417.700 is a freq pair for EG&G that I have listed in some older info - might be worth a try - supposedly they provide support for the Janet terminal at McCarran International as well as the DOE sites and most likely some stuff at area 51

Oops see someone already mentioned this - sorry for dupe - Mod - delete if you wish

[737mech]

No way this is EG&G/URS I overheard a transmission about a car in question downtown and calling in Metro support. See my post above must be Federal law enforcement or a NARC squad.