RC Field Amateur Radio Weather Station

[rockyboy]

I've been thinking about building a remote weather station for our club's RC field ever since I learned about the Automated Packet Reporting System (APRS) while studing for my HAM Amateur radio license. Rather than try to explain what it is, I'll just let Wikipedia do that..

Automatic Packet Reporting System (APRS) is an amateur radio-based system for real time digital communications of information of immediate value in the local area.[1] Data can include object Global Positioning System (GPS) coordinates, weather station telemetry, text messages, announcements, queries, and other telemetry. APRS data can be displayed on a map, which can show stations, objects, tracks of moving objects, weather stations, search and rescue data, and direction finding data.

APRS data is typically transmitted on a single shared frequency (depending on country) to be repeated locally by area relay stations (digipeaters) for widespread local consumption. In addition, all such data are typically ingested into the APRS Internet System (APRS-IS) via an Internet-connected receiver (IGate) and distributed globally for ubiquitous and immediate access.[2] Data shared via radio or Internet are collected by all users and can be combined with external map data to build a shared live view.
https://en.wikipedia.org/wiki/Automatic_Packet_Reporting_System

However, it's been very difficult with my limited HAM experience to figure out how to tackle this project until I found out that a nearby RC club has a weather station up and running using this technology! They even have the data piped into their club website so anyone can check out the current and historical wind and temperature data https://www.lcaa.org/weather

Knowing that RC people are the most helpful people around, I reached out to their club leadership & HAMs and within a couple of days they had sent me diagrams, parts lists, plenty of feedback on my own ideas, and generally been extremely helpful getting this HAM noob pointed in the right direction!

I've prepared the bones of the plan for club vote next week, and with funding approval will proceed with the build over the next several weeks. For anyone curious, here's a link to the high level plan and a picture of the key equipment diagram:

https://docs.google.com/presentation/d/16USqEwOiILl93buj7HGLl337jmZueOrq5vqBfmsJe94/edit?usp=sharing

Feedback appreciated!

 

[sprzout]

Ok, trying to wrap my head around this:

This system will, using HAM radio broadcasts, broadcast out to different towers, where, hopefully, someone will pick up the signal and then feed it into the Internet for you?

I could definitely see that being a bonus for us, and could potentially convince my club to do the same, but need a better understanding of how things would get the weather station info to the internet, since our flying site doesn't have any sort of power or cables other than those from solar panels...

 

[jhitesma]

Should be a fun project. How far from the field to the nearest iGate? Can you easily hit one direct with low power or will you need to bounce off a few digi's on the way? If you can hit one with low enough power you may be able to get by with a fairly cheap transceiver and decent antenna.

But...even if not....the nice thing is with APRS you don't really need anything fancy on the radio side - just a 2M FM rig. So you can find some cheap options that people aren't using anymore like old HT's or mobiles without CTCSS tones that can't get into repeaters anymore. Or..just get one of those cheap Chinese Baofangs on sale for $40.

Since it's a fixed station that won't be moving...and the igate probably won't be either you can also compensate for a lower power radio with a nice directional antenna. 2m yagi's are pretty easy to make. You can pick up a nano-vna for $50-$70 to help you get it tuned - very handy bit of equipment to have on hand if you're getting into radio...amazing what we can get for so little cost now! I have an older MFJ antenna analyzer that doesn't do half as much as my nano-vna but it still sells for 3x the price.

APRS is a fun rabbit hole to fall into. I had a ton of fun with it about 15 years back. Unfortunately it hasn't continued to evolve all that much since and most of the software available for it is really outdated. Even 15 years ago most people where either using the original DOS based software the original developer creates, or were using a windows package who's developer passed away and kept his code closed so it had no future updates. Now most people seem to just use web-based reporting instead of running anything locally...which kind of defeats a lot of it in my opinion since in an emergency you can't rely on the internet being available. I have the same problem with digital radio...most of the people using it and hyping it rely entirely on IP links. They still promote it as great for emcomm...but they rely on those weak links that won't be there in a real emergency So many people are just used to the internet being always there that they forget just how much infrastructure it requires to keep that link available.

 

[jhitesma]

Ok, trying to wrap my head around this:

This system will, using HAM radio broadcasts, broadcast out to different towers, where, hopefully, someone will pick up the signal and then feed it into the Internet for you?

Close. the "someone will pick up the signal" is the bit that's a bit off. Take a look at aprs.fi to see what's currently on the network. You'll see some black diamonds with D's in them. Those are digipeaters - fixed systems that listen for traffic and can repeat it out further and usually send it to the internet. You'll also see a lot of blue WX icons which are weather stations...and a lot of them also double as digi's and igates. (A digi is just a digital repeater - passes signals along. An igate is a digi with a link to the internet to pass data to the internet.)

So in most areas there's enough infrastructure in digi's and igates that you don't have to worry about "someone" picking up your signal, you can direct your signal to a known fixed point. Yes...it could also just get picked up by someone and passed along but generally that's not required in most areas.

 

[LitterBug]

I have thought about putting a station at our field and a webcam. It's only a mile away, so in theory, I could possibly set up a WiFi link to my house using some high gain yagi antennas since there isn't much between me and the field. Too many other forks in the fire though....

It would also come in handy during severe weather spotter events.....

 

[rockyboy]

Thanks Jason!! If you don't mind, I'll be picking your brain about this when I get to the programming stage for sure!

According to the website, our field is 2.3 miles to the nearest active digipeter https://aprs.fi/info/a/WP4BQV-B and just 2.9 miles from a winlink gateway https://aprs.fi/info/a/WC4J-10

I'm hoping a simple mobile whip antenna on the UV-5R at 5 watts will reach it fine, especially if I stick it 15 feet up a pole (the antenna, not the handheld).

But I like your idea of using a simple yagi directional if it needs a little help....

 

[jhitesma]

Yeah you should be able to hit that no problem. I've bounced APRS packets off the ISS with only 5w and a stock antenna...and that's just a tiny bit further than 3 miles

(It's still line of sight though so easier to reach than you'd think...just a matter of timing to catch it overhead and them having their digi enabled!)

Make sure to budget for decent coax to put the antenna up on a pole. At 2m cable losses can be significant with cheap coax. But...only having to get out 3m your link budget should be no problem with 5w. A quick and dirty j-pole antenna may be a bit better option than the stock whip. I've made them out of 1/2" and 3/4" copper pipe (lots of plans on the internet) and they work great and will take a lot of abuse outside. I've also made them from simple 300ohm tv antenna cable then slipped them inside a piece of 1/2" PVC tube to make a rugged little antenna that performs a lot better than a rubber duck. There are tons of easy to make 2m antennas that will give you a bit of a boost if needed....and which will hold up to the elements better than the stock whip. Or did you mean like a car mount whip...those are also fairly cheap and would work well.

I never setup an APRS weather station - just vehicle trackers. And that was 15 years ago so things have changed some since then. So not sure how much help I can be with programming...but feel free to ping me with questions and I'll do my best to answer if I can.

 

[rockyboy]

Thanks! I was thinking a 19" car whip antenna, not the stock rubber ducky - but making a j-pole would be much cooler for the DIY cred!

 

[sprzout]

Close. the "someone will pick up the signal" is the bit that's a bit off. Take a look at aprs.fi to see what's currently on the network. You'll see some black diamonds with D's in them. Those are digipeaters - fixed systems that listen for traffic and can repeat it out further and usually send it to the internet. You'll also see a lot of blue WX icons which are weather stations...and a lot of them also double as digi's and igates. (A digi is just a digital repeater - passes signals along. An igate is a digi with a link to the internet to pass data to the internet.)

So in most areas there's enough infrastructure in digi's and igates that you don't have to worry about "someone" picking up your signal, you can direct your signal to a known fixed point. Yes...it could also just get picked up by someone and passed along but generally that's not required in most areas.

Just checked and it looks like there's two WXes about 1/2 mi. away from the field, on the far side of the freeway, and a digipeater about 1/4 mi. away at the top of a hill/low mountain...I think we should be able to pull something off!

 

[jhitesma]

Copper pipe j-poles are really fun to make. I'd suggest a 3/4" pipe version for a permanent installation since it's got that beefy look going for it I retired my 1/2" one over the summer - it never worked as well and I needed the RF connector off it. The 3/4" one is over 15 years old and still performs great. It's tuned for almost perfect SWR on 144.390 and worked great on my digi when I had one up. Looks like our local APRS activity has really declined though...the big igate appears to be gone and so are most of the digis. Maybe I should set one up again. I still have the TW4000 I used to use for it and the TNC. Dig out a spare RaspPi and I could have it running again.

 

[rockyboy]

Project Update #1

The club approved the spending for the weather station project, so more testing and materials acquisition has begun.

On the hardware side, the weather sensor components from Peet Bros have arrived! The rain sensor bucket is a lot larger than I was expecting too, but it all seems sturdy and of good quality. Also have donation offers of two fiberglass masts (one from our club, and one from the LCAA club that's helping out with the design).

So far I haven't been able to get a succesfull test at the flying field with the lower powered hand-held radio transmitter to send an APRS packet to the network over VHF.

I don't particularly think that's a reflection on the location however, as I also haven't been able to get a success on that with the help of the Alexandria Amateur Radio Club even when I'm standing less than 30 yards from one of their internet gates either. It's got to be something in either the Baufeng UV-5R2 radio or APRSDroid phone app settings, so if anyone has experience in this area please let me know. I've googled and youtubed plenty, and every walk through I've found is either with the older Baufeng UV-5R radio (menus & settings are slightly different) and much older versions of APRSDroid app (menus and settings are way different).

My local HAM club is having an online gear auction and I'm bidding on an older Baufeng handheld model, as well as a more powerful mobile set too - might as well setup my own APRS repeater at home so I can have the whole test suite here rather than needing to drive off somewhere to try new settings.

 

[PsyBorg]

Not that I know ANYTHING about APRS maybe this will help? Im watching it now myself to undestand what you are doing better as the weatehr station seems like a cool idea and or project.

 

[LitterBug]

I have "thought" about APRS, but not very intently. I need to get a feed line up to the discone on the gable so I can pull some data in to one of my SDRs and see if there is anything local. I'm hesitant to invest in much other than FPV/RC gear as far as my HAM license goes at this point. I also have a Baoefeng F8HP handheld which is very similar to the UV-5 that I use for weather spotting.

EDIT: Maybe we should make it a point to try and set up a FT HAM get-together..... Learning for us all! I just ordered a cable and it should be here tomorrow.

2nd EDIT: Discone has been fed, RTL-SDR hooked up. Going to set up a RTL-SDR server. If anyone want's to play with it remote after it is running, Ping me in IM. I probably will not publish it on the RTL-SDR server list till I get a dedicated Rpi set up.

 

[LitterBug]

This is encouraging.... Cheap RTL_SDR dongle on discone and solid APRS signals on 144.39. Now I just need to set up the decoder in SDR#

Cheers!
LitterBug

 

[bracesport]

you guys blow me away - I wish I has studied 'lek-tronics' as a young lad!

 

[LitterBug]

you guys blow me away - I wish I has studied 'lek-tronics' as a young lad!

Uhhh.... I'm probably older than you and just learnin it all myself... Never stop learning! BTW, I am also still 12. I refuse to grow up!

Really cheap to do my last post. You just need a cheap $10 "RTL_SDR" reciever and the free program "SDR#".

 

[rockyboy]

Wwwaaaahhhhh??? I never heard about the RTR-SDL stuff before! This is really cool! El-cheap-o RTL_SDR receiver on order now

This will be perfect to help me figure out what the heck my radio is actually sending out!

Thank you!!

 

[LitterBug]

Wwwaaaahhhhh??? I never heard about the RTR-SDL stuff before! This is really cool! El-cheap-o RTL_SDR receiver on order now

This will be perfect to help me figure out what the heck my radio is actually sending out!

Thank you!!

See... We need a HAM info swap mind meld on here.
I have been decoding and feeding FlightAware with these little dongles for quite a few years. Really wish I had one that went up to 6Ghz so I could test FPV gear.....

I have a more expensive wider band one that lets me look at 10-20MHZ worth of the spectrum at a time. Can see a lot of the local FM radio stations in this screenshot.

 

[bracesport]

@LitterBug - know what you mean, think like a child and remain like a child! I will give you a clue, I had my son at 50 and he is turning 7 next month so hopefully there are many years left to enjoy this great hobby! I am enjoying open TX at the moment, but I enjoy following what you guys are up to!

 

[LitterBug]

@LitterBug - know what you mean, think like a child and remain like a child! I will give you a clue, I had my son at 50 and he is turning 7 next month so hopefully there are many years left to enjoy this great hobby! I am enjoying open TX at the moment, but I enjoy following what you guys are up to!

Ah, you have 4 years more on me then...