DHART Helicopter VT 461.2250 146.2

[jeffkett]

Perhaps our friends up north can confirm. While up in Vermont last week at Smuggler's Notch picked up a couple of helicopter transmissions
on 461.2250 146.2 . ID as DHART 2 , appears they where picking up a patient "covid positive, weight 67 kilos" (hint hint)?
I tracked down a 2014 thread from RR https://forums.radioreference.com/threa ... er.295357/ . Indicating DHART
does cover VT. There is a commercial license on Mt. Mansfield WNRT664 to FleetWave Partners LLP. Would they use commercial business freqs
or could this have been a rebroadcast of the VHF?
Jeff

[ecps92]

Good chance they may rent from an existing carrier as they do that for the Goffstown NH Repeater

Perhaps our friends up north can confirm. While up in Vermont last week at Smuggler's Notch picked up a couple of helicopter transmissions
on 461.2250 146.2 . ID as DHART 2 , appears they where picking up a patient "covid positive, weight 67 kilos" (hint hint)?
I tracked down a 2014 thread from RR https://forums.radioreference.com/threa ... er.295357/ . Indicating DHART
does cover VT. There is a commercial license on Mt. Mansfield WNRT664 to FleetWave Partners LLP. Would they use commercial business freqs
or could this have been a rebroadcast of the VHF?
Jeff

[jeffkett]

I did a little more digging.....this puts them in Burlington, VT

https://www.dartmouth-hitchcock.org/dhart

Why weight in kilos as opposed to pounds? Going over the border?

[ecps92]

Gary or Ed will likely chime in on this, but most medical is based on the Metric system

As to Burlington they [DHART] have affiliated with UVM to have a base in Burlington VT at the Airport
https://vtdigger.org/2018/07/31/burling ... -patients/
https://www.dartmouth-hitchcock.org/dhart

I did a little more digging.....this puts them in Burlington, VT

https://www.dartmouth-hitchcock.org/dhart

Why weight in kilos as opposed to pounds? Going over the border?

[garys]

Weight is recorded in Kilograms, because medications are administered in milligrams or micrograms per Kilogram. Some of them at least.

[VermontCUCV]

I’ve never heard them on UHF except for calling a department that they are assisting— I’ll have to check out that 461MHz frequency.

The unit based in Burlington is tail number N635DH as far as I know.

[VermontCUCV]

It turns out 461.225R,146.2, is quite busy.

Confirmed tones today for HealthNet flights, as well as miscellaneous and even some informal chatter.

I haven’t checked the FCC database yet but a Mt. Mansfield repeater was acknowledged. I’d guess there’s more than one repeater.

[ecps92]

Not sure I understand the "More than one Repeater" comment , can you elaborate ?

It turns out 461.225R,146.2, is quite busy.

Confirmed tones today for HealthNet flights, as well as miscellaneous and even some informal chatter.

I haven’t checked the FCC database yet but a Mt. Mansfield repeater was acknowledged. I’d guess there’s more than one repeater.

[VermontCUCV]

I was hearing traffic from what appeared to be all over the state. Only once did a dispatcher acknowledge that they were using the Mt. Mansfield repeater at that moment. If anyone is keeping track of what calls they toned out, which I wasn’t, I heard that comment around 2330 local time.

I’m not very familiar with UHF propagation from an aircraft, but I’d imagine that more than one repeater would be needed to cover the state.

My only experience with quantifyable altitudes and radio performance involved a 2m frequency and an aircraft flying around 3000 feet. Someone in the aircraft with a 5W HT was able to talk simplex for about 12-15 miles over fairly flat but varied terrain to someone on the ground with the same type of transceiver.

(Here is what I typed originally:)
Thus, I’d imagine that with UHF, in Vermont topography, with each station having let’s say a 1/4 wave antenna and 25 to 50 watts, the maximum distance of a usable signal would be under 75 miles, even with one station being airborne. Just a hobbyist-level guesstimate, not a professional calculation. Therefore the need for more than one repeater to cover Vermont, likely more than one in northern Vermont I’d imagine.

(Upon further reflection:)
All of that may go out the window as I was thinking of antenna height relative to sea level/ground level. The aircraft and the Mt. Mansfield repeater antenna both being at high altitudes certainly would drastically change the performance.

[ecps92]

VT and NH are quite similar and NH only has the UHF to cover the Manchester BASE

It has been awhile since I monitored DHART while in NH/VT but likely Burlington is for the BASE, and the VHF is for when Airborne

Anyone confirm DHART is still active on their VHF ?

I was hearing traffic from what appeared to be all over the state. Only once did a dispatcher acknowledge that they were using the Mt. Mansfield repeater at that moment. If anyone is keeping track of what calls they toned out, which I wasn’t, I heard that comment around 2330 local time.

I’m not very familiar with UHF propagation from an aircraft, but I’d imagine that more than one repeater would be needed to cover the state.

My only experience with quantifyable altitudes and radio performance involved a 2m frequency and an aircraft flying around 3000 feet. Someone in the aircraft with a 5W HT was able to talk simplex for about 12-15 miles over fairly flat but varied terrain to someone on the ground with the same type of transceiver.

(Here is what I typed originally:)
Thus, I’d imagine that with UHF, in Vermont topography, with each station having let’s say a 1/4 wave antenna and 25 to 50 watts, the maximum distance of a usable signal would be under 75 miles, even with one station being airborne. Just a hobbyist-level guesstimate, not a professional calculation. Therefore the need for more than one repeater to cover Vermont, likely more than one in northern Vermont I’d imagine.

(Upon further reflection:)
All of that may go out the window as I was thinking of antenna height relative to sea level/ground level. The aircraft and the Mt. Mansfield repeater antenna both being at high altitudes certainly would drastically change the performance.

[ScanBoston]

Looks like it might be part of a trunk https://wireless2.fcc.gov/UlsApp/UlsSea ... ey=1780028
from this outfit. https://www.fleetwave.biz/
Search this FRN as well 0021239736 for many more sites and systems across VT
https://www.dartmouth-hitchcock.org/dhart/history

[ecps92]

The Trunked part is/was ruled out due to the use of CTCSS [Not seen in analog trunking]

Looks like it might be part of a trunk https://wireless2.fcc.gov/UlsApp/UlsSea ... ey=1780028
from this outfit. https://www.fleetwave.biz/
Search this FRN as well 0021239736 for many more sites and systems across VT
https://www.dartmouth-hitchcock.org/dhart/history

[ScanBoston]

10-4 then I guess I didn't find a license or the correct one yet.

[jeffkett]

The FCC Gen Men is down once again...I can not use above links to see what license is mentioned,, When I was up in Vermont 2 weeks ago,
I pulled the frequency from WNRT664 somewhere mentioned it was NXDN. Did not get any NXDN on the 461.2250 while up there.
Jeff

[W1KNE]

The FCC Gen Men is down once again...I can not use above links to see what license is mentioned,, When I was up in Vermont 2 weeks ago,
I pulled the frequency from WNRT664 somewhere mentioned it was NXDN. Did not get any NXDN on the 461.2250 while up there.
Jeff

Both the General Menu and ULS are down tonight.

[VermontCUCV]

The FCC Gen Men is down once again...I can not use above links to see what license is mentioned,, When I was up in Vermont 2 weeks ago,
I pulled the frequency from WNRT664 somewhere mentioned it was NXDN. Did not get any NXDN on the 461.2250 while up there.
Jeff

Is there a specific emission designator for NXDN or is it just a generic “narrowband digital voice emissions” type thing?

I’ve been monitoring 461.225 without any CTCSS/DCS programmed for a few hours here and there over the last day or so, and have only heard the analog traffic we are discussing here, nothing digital.

[garys]

NXDN Emissions Designators start with 4K.

Here is a list of all Emissions Designators at Radio Reference.

https://wiki.radioreference.com/index.p ... Designator

Is there a specific emission designator for NXDN or is it just a generic “narrowband digital voice emissions” type thing?

I’ve been monitoring 461.225 without any CTCSS/DCS programmed for a few hours here and there over the last day or so, and have only heard the analog traffic we are discussing here, nothing digital.

[ecps92]

WNRT664 is licensed for Analog FM and NXDN

11K2F2D, 11K2F3E - Analog FM
and
4K00F7W - NXDN 6.25 kHz digital voice and data (IDAS, NEXEDGE)


https://wiki.radioreference.com/index.p ... Designator

Is there a specific emission designator for NXDN or is it just a generic “narrowband digital voice emissions” type thing?

I’ve been monitoring 461.225 without any CTCSS/DCS programmed for a few hours here and there over the last day or so, and have only heard the analog traffic we are discussing here, nothing digital.

[VermontCUCV]

Thank you Bill.

I’ve been monitoring quite a bit lately and finally caught some VHF traffic.

Someone on the helicopter went out of service on the UHF channel. The dispatcher asked him a question and his reply was very broken up— I’d guess that he got out of the chopper and was on an HT at that point. The dispatcher couldn’t copy him. A moment later the person from the chopper popped up on VHF (155.325/141.3) asking if dispatch could copy him then. I heard nothing further. I was in Williston using a 5/8 wave 2 meter antenna while mobile.

[ecps92]

461.2250 146.2 added to the Medical Helo's Wiki

Thank you Bill.

I’ve been monitoring quite a bit lately and finally caught some VHF traffic.

Someone on the helicopter went out of service on the UHF channel. The dispatcher asked him a question and his reply was very broken up— I’d guess that he got out of the chopper and was on an HT at that point. The dispatcher couldn’t copy him. A moment later the person from the chopper popped up on VHF (155.325/141.3) asking if dispatch could copy him then. I heard nothing further. I was in Williston using a 5/8 wave 2 meter antenna while mobile.

[W1KNE]

I moved this to the VT forum. Yes it has some overlap with New Hampshire but it is primarily Vermont.

So here it is.