WX radio repeater on solar power

iMONITOR

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A couple of solar panels, a deep cycle marine battery, a Raspberry Pi, SDR dongle and a wireless access point back to the house would work. Might cost a couple hundred $ and you would have much more than just a WX receiver.

Maybe a few webcams while he's at it!
 

Spleen

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You will definitely need a directional antenna with a Whole House transmitter. I can't find a review where it worked much past 75 feet...I had the 2.0 version, and that would barely make it from the living room to the can unless you clipped on the illegal-length antenna.


Part 15 FM broadcast transmitter. With a good directional antenna, it would probably reach your house:

12/5 volts DC. Not sure about the ERP limits under Part 15, though.

Beware, there are a lot of non-certified FM broadcast transmitters on Amazon that would not meet the FCC requirements.
 

Twister_2

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If you need to get NWR alerts somewhere that you can't receive NWR (and a cell phone isn't an option), build a 2 meter or 440 amateur repeater and hook up a NWR to the controller. Don't rebroadcast 24/7 but set the alerts to come over the repeater.
 
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NOAA used to send out an alert tone that would trigger older receivers. It's not hard to trick a commercial radio with 2 tone paging capability into recognizing that tone and opening the audio for a set period of time. Then all you'd have to do is feed the audio via IP connection down to your house.
How can you trick a commercial radio into operating that way? I think it would be tricky to set up a computer alert based on something like this but certainly possible.

I would think if you placed a programmed WX alert radio on hill, quiet unless activated. Low power transmitter aiming down into the valley with VOX set on transmit. Receiver would be quiet then you would hear the message just like if the receiver was in the house. You wouldn't have a warble type alert but increasing the volume would work.
So the receiver in the house wouldn't be playing static all the time because the transmitter on the hill is transmitting silence all the time? Since it would be on in the house 24/7, how silent do you think it would be if I kept the volume high enough for an alert to wake me up?

Run a cable up to the top of the ridge to an antenna?
It's just too far all the way up there.

A couple of solar panels, a deep cycle marine battery, a Raspberry Pi, SDR dongle and a wireless access point back to the house would work. Might cost a couple hundred $ and you would have much more than just a WX receiver.
The problem there is practical monitoring and alerting. If I'm understanding correctly this would be a continuous stream of audio over the network. A weather radio will silently wait for an alert on the WX band and trigger an alarm once it is received.

There are some outboard S.A.M.E decoders for broadcasters that can be installed at your home and connected to some "other band" receiver that picks up a relay of the NOAA audio from the hilltop. But they are not cheap and you can hack a cheap NOAA receiver to utilize its SAME decoder and audio circuitry by breaking the discriminator line.

1) At hilltop, Crossband repeat NOAA audio via a low power MURS or 900 ISM band (baby monitor) transmitter. At the house, tap a MURS or 900 ISM (baby monitor) receiver into the audio and decoder line of a NOAA receiver with SAME circuitry. Basically a hack.

2) At hilltop, receive and upconvert 162.5xx MHz NOAA signal to 915 MHz ISM (752.5 MHz LO). At the house downconvert 915 MHz ISM to 162.5 MHz with same 752.5 MHz LO. This will take some skills and hardware. Do your shopping on minicircuits and ebay, get your soldering iron out. You need filters, mixers, amps and a 752.5 MHz oscillator. Easy peasey.
These sound interesting but I don't have the skills to hack an NOAA receiver or design/build an upconverter and downconverter. An outboard SAME decoder could be interesting but I'm not sure if the pieces fit together to allow for silent monitoring from the house.

5) NOAA has 400 MHz link transmitters that are used for the 162 MHz transmitters. If you can tune in one of those links you might make your own very low power 400 to 162.5 MHz repeater NOAA station to service your house.
This is interesting. Why not rebroadcast from the hill on Part 15 FM and do a very low power micro-rebroadcast at my house for my WX radio? I could rebroadcast right up against the radio at some extremely low power. Even better, would it be possible to rebroadcast over a short wire directly to the radio's external antenna input?

If you need to get NWR alerts somewhere that you can't receive NWR (and a cell phone isn't an option), build a 2 meter or 440 amateur repeater and hook up a NWR to the controller. Don't rebroadcast 24/7 but set the alerts to come over the repeater.
This is the practical monitoring and alerting problem if I'm understanding correctly. I think I'd be listening to static all day and night.

Here is the software I was thinking of, that you could provide an audio feed from a remote receiver.

It looks like this is a computer application for taking the WX signal from your radio and alerting you over the internet via SMS or email. There is no cell service at the house but even if there were I don't think SMS is a practical alert mechanism in case there's an emergency at night.
 

mmckenna

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How can you trick a commercial radio into operating that way? I think it would be tricky to set up a computer alert based on something like this but certainly possible.
The NOAA SAME alerts are followed by a 1050Hz tone.
Commercial radios that have 2 tone paging receive capability can be programmed to recognize the 1050Hz.

Setting up the page function on the radio to keep the audio path closed until it recognizes that 1050Hz tone, then open the audio path for a set period of time can do what you want. After the time elapses, the audio path will close back down until it hears the alert tone again.
 

cmdrwill

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Steve08CVPI said:
Run a cable up to the top of the ridge to an antenna?

It's just too far all the way up there.

There was miles of TV coax cable in the foothills below Mt Wilson back in the 60' s.
CATV,
 
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These are the most practical solutions as far as I can tell:

1. Broadcast over Part 15 FM on the hill 24/7 but use a silently monitoring WX radio there as the source so that silence is broadcast unless there is an alert. That way I can leave a regular radio in the house tuned to the Part 15 FM frequency 24/7 but it will only output silence (not static) unless there is an alert.

2. Rebroadcast the full WX transmission from the hill over Part 15 FM and then rebroadcast again at the house over a WX frequency at either an extremely low power or through a short cable into a silently monitoring WX radio right alongside.

#2 requires two rebroadcasts but it puts the WX radio in the house instead of on the hill which would give me better control. I'm guessing it would also be more silent than #1.

Is it possible to broadcast over a cable? The Midland WR400 WX radio has an RCA jack for an external antenna which would be perfect for receiving the signal that way.

If not, is there appropriate equipment for making a micro VHF rebroadcast that only needs to travel a few feet or less?

3. Another idea. The WR400 has an output jack for an external alarm:


I could put a WR400 on the hill and use its external alarm function to trigger a rebroadcast over a WX frequency so that another WR400 in the house could monitor silently until it picks up that rebroadcast. Although the rebroadcast would be over WX, it would literally only happen during an emergency and even then it could be low power and directional since it only needs to travel ~1300 feet to one house with no other structures or public roads anywhere nearby.
 

vagrant

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I currently have a 200,000+ acre fire near me in the same county. Not once have I heard a NOAA alert for it over the radio. There have been progressive mandatory evacuations and zero alerts about that. I RX the weekly alert tests as well as a flood or wind advisory from time to time, so the WX radio is working. The Air Quality Index is over 700 in some places, yet no alert for that. (0-50 is healthy)

Will your local NOAA send an alert if there is a fire? Have you called and talked with them? I plan on contacting my local office to find out why zero alerts via radio.
 

ab5r

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Where exactly do yo live that you are concerned with Fire Alerts? are you in California or where?

I am not positive that NOAA alerts on fire situations......could be wrong though.
 

krokus

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Where exactly do yo live that you are concerned with Fire Alerts? are you in California or where?

I am not positive that NOAA alerts on fire situations......could be wrong though.
NWR is part of the Emergency Alert System, that alert activation would come from state or county EOCs.
 

kruser

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I'm in California so very concerned about fire. I emailed two people here to ask if fire alerts are part of NWR but no response yet:


Any other ideas for getting a definitive answer to this?
There are no SAME message types for Fire specifically so I'd say they don't include those unless they would send them under one of the Unrecognized message types.

 
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I heard back from Cal OES:

"Unfortunately local governments cannot broadcast local emergency alerts over NOAA radio at this time. OEM has been informed that this may change sometime in the first half of 2021, however that is subject to change and may take longer to implement (NOAA radio is a federal program)."

It sounds like there's some hope for next year.
 

vagrant

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When I am up in the forest I monitor Cal Fire, especially the Air Plan freqs in the RR database. That's where I will hear something first as they coordinate tankers for drops pretty quick after dispatch. Actually, you may initially hear dispatch via a repeater as they call up various resources for an incident and provide the location. After that you may hear Air to Ground or Air to Air coordination. Well, you may not hear the ground crews, but you have a better chance to hear aircraft. You could probably rig up some ADS-B monitoring as well, but again you're in a canyon so your line of sight is reduced. Still, you don't know until you try. Review the RR database for Cal Fire and have a listen on the dispatch frequency for your area.

Also, does anyone know if there is a new Cal Fire Statewide Radio plan newer than this 2011 PDF? The sites, frequencies and tones may still be the same. That PDF also provides a map of repeater sites. Find your area and the repeater signal may boom right into your home location. You would hear traffic from dispatch long before you would receive an alert on NOAA and time is everything.
 

RFI-EMI-GUY

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I was surprised that there was no wildfire SAME code in the list I found on Wikipedia. There are a slew of other rarer calamities listed. Evacuation alerts exist in some categories. This seems like a very important discussion to have with your county EM manager. Are evacuation orders being planned through the NWS?

Vagrant has some good suggestions for work arounds.

If you have neighbors about, perhaps you can organize some sort of fire watch network and even get state funds, Are there any fire towers?
 

krokus

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I heard back from Cal OES:

"Unfortunately local governments cannot broadcast local emergency alerts over NOAA radio at this time. OEM has been informed that this may change sometime in the first half of 2021, however that is subject to change and may take longer to implement (NOAA radio is a federal program)."

It sounds like there's some hope for next year.
The feds do very few things quickly. Before trying to get some sort of NWR reception set up, since it will not have what you need, wait for the changes to the program. There is a chance that any changes that do happen, if any do, will take a couple years to implement.

In the mean time, listening to CalFire freqs might be your best option, as others have mentioned.
 

N4DES

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Is it possible to broadcast over a cable? The Midland WR400 WX radio has an RCA jack for an external antenna which would be perfect for receiving the signal that way.
How are you connecting your roof mounted antenna to the Midland receiver now from the 75 ohm coax? Are you not using the RCA port?
 
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