Stand-alone RED system on GSM network - build log

Hello,
My name is Simon and I am a new member here.
I live in Perth, Western Australia which is the most remote capital city in the world, and I am interested in setting up a Blitzortung system in my city.

Unfortunately, the closest receiver to Perth that I am aware of is near Brisbane which is roughly 3700 kilometers away.

As I understand, the Blitzortung system needs at least 3 or 4 receivers spaced between 50km and 300km apart to have any reasonable accuracy.
I would like to set-up a number of receivers around the city and have a few safe locations available to me however there is no freely available internet access at these sites.
For these remote receivers I am currently looking at the feasibility of using the GSM network with either a GPRS or 3G data modem using M2M(machine-to-machine) SIM cards for data access.

Unfortunately, the vast majority of GPRS modems and modules I have found use RS232 communications while the RED system uses Ethernet.
I have found a few Ethernet capable GPRS modems but they are priced in the 'forget it!' range.

While I am very comfortable with a soldering iron(I've had one in my hand since I was 6 years old) my knowledge of networking is extremely basic.
I have found Ethernet to RS232 converters are very common but I get the feeling it will not be as simple as placing one of these in between the RED controller PCB and the GPRS modem.
ie: Antennas ---> Amp Board <---> Controller Board <----> RS232 converter <-----> GPRS modem <-----> Internets <----> Blitzortung server

While I am researching and filling in gaps in my knowledge, I thought I might ask if anyone is aware of any successful stand-alone Blitzortung receivers using a GSM network?

Any assistance would be most appreciated!
Many thanks,
Simon

Forget RS232!

Use some cheap Router where you can plug in cheap 3G-USB-Sticks:

Check local super-markets/discounters for a USB surf-stick with SIM-card included.

Hello Tobi, many thanks for your reply.

I was intending to avoid RS232 where I could, but finding an affordable 2G/3G router or modem with ethernet was the problem. Sierra have a few options but they are around $500 each. ouch!

Thanks for your suggestion too. While doing research I had found your thread:
which at first I dismissed because it seemed to be WiFi only, but after finding a number of threads on Whirlpool(an Australian forum ) that mention the MR3020 and USB dongle modems, I have now revisited your thread to digest it's contents!

My only concern now is the reliability of the USB dongle modems, but I'm thinking I would probably remove the USB plug/sockets and hard wire the dongle.

The prices for the MR3020 and USB dongles are realistic, so I'm now ordering parts to start some testing

Many thanks again,
Simon

Hello Tobi,
Many thanks for your reply.
I sent a reply a couple of days ago but I guess I didn't hit 'submit' :shrug:

Anyway, thanks for the tip! I had already briefly looked at your thread here about the MR3020 in a standalone system before I started this thread, but with only a brief look I discounted the idea when I read it was WiFi.
I have since discovered a few threads about it on an Australian forum, one article in particular is about using the MR3020 with 3G:
I have now ordered an MR3020 and have gone back to your thread to digest it.

I have decided to move away from using 'M2M' SIMS.
While it can be cost effective (as little as $5 per SIM per month) and has all sorts of cool tools, it seems the carriers are pretty strict regarding the hardware used.
The modules have to be approved and certified and even when that certified module is used in equipment, the equipment must also then be certified.
I deal with this sort of thing every day at work, it really doesn't interest me to deal with certification in my spare time!

I'm now looking at using regular data SIM's. These are far more expensive but seems to me I can use any hardware I want.
Best price I have found locally is ~$125 for 13GB of data that lasts 365 days and billed in kB increments instead of MB increments (the standard here)
If my calculations are correct the system will only use around 30MB of data per month, so 13GB is overkill but it is the best I can find locally.


I'm currently working out power requirements, I think I'll need at least a 10W solar panel and two 20Ah LiFePO4 cells.
Early days with much experimentation to be done.

Anyway, impatiently waiting for a reply from the Blitzortung guys so I can purchase the kit and get started with experimenting.

Many thanks again,
Simon

Edit: I noticed there is a new receiver that went online in Australia in the last day or two.
Brisbane receiver is now no longer the closest to me (~3700km).
The new receiver (Lavington, Albury NSW) is 'only' 2890 km away

Haha! My 'missing' reply has surfaced above my previous reply. I guess it took a while for the mod's to review it

Anyway, things are starting to moving forward

I have ordered one kit from Egon which will be based at home as a base-station/test-rig, more kits should follow after I iron out the bugs for the stand-alone system..
I've also sourced some 2300u ferrite rods(Ferroxcube 3C90) for the antenna, they're on their way. They were pretty cheap too so I ordered enough for 5 receivers(10 antenna's). Though shipping cost twice as much as the rods! ouch.
A roll of 26 AWG enameled copper wire for the antenna's is on it's way.
The TP-Link MR3020 router is on it's way
I already had a spare unused STM32 Discovery board here, but I have three more on the way,
Solar cells are on the way but a battery for solar storage will have to wait until I can get some power figures for the finished setup.
The largest single consumer is likely to be the GSM/3G/4G modem at anywhere from 2 to 4W when transmitting, but I'm hoping average consumption will be much less, fingers crossed.

Have just discovered a new RED document has been released so time to do some more reading

Zitat von MrB

If my calculations are correct the system will only use around 30MB of data per month, so 13GB is overkill but it is the best I can find locally.

Several gigabytes are easily possible, depending on thunderstorm activity and station configuration!

For your pleasant orientation:

TP-Link MR3020 ~ 125mA
Modem Huawei E1752 ~ 75mA
Controller with Display ~ 400mA ( as I remember ~ 250mA without Display )
Amplifier ~ 40mA

125+75+250+40 ~ 500mA at 5V = 2,5W
Step-down converter with 80% efficiency ~ 3,125W ~ 260mA at 12v

I'm not sure a solar panel at 10W is enough -
There is also a loss in battery charger.

/richo

Zitat von tobi

Several gigabytes are easily possible, depending on thunderstorm activity and station configuration!

Many thanks for the information tobi.
I had based my figure on the Oceania network traffic figure. It states "2,750 kB/Day" for the network of 8 stations.
I had figured a worst-case of approximately half that figure for a single station on a very busy day would be a reasonably safe approximation.
You have me worried now! haha

Zitat von richo

Modem Huawei E1752 ~ 75mA

.....
I'm not sure a solar panel at 10W is enough

Many thanks Richo, that is very helpful.
Are you sure of the consumption figure for the modem? Huawei themselves state 2.5W.

Yes I had figured 10W may not be enough, hence why I said "at least 10W", which put another way is '≥ 10W'
I won't be using a 12v Panel, I have ordered individual cells and will be building a custom panel to suit the requirements.

Many thanks for your input, much appreciated

Simon

A bit more information about solar power....

Lightning season for the South West region of Australia extends around the summer months, late November to early March, peaking around late December into January.
Australia has an abundance of solar energy. Mean annual irradiance for the Perth region is around 5.0 to 5.25 kWh/m2 per day. Please compare the following:
and...


During our peak lightning storm season, Summer solar irradiance for the Perth region is approx 8.0kWh/m2 per day. (7.9kWh/m2 for December and 8.1kWh/m2 for January)
Mean number of cloudy days for the summer months (Dec - Feb) is ~5.4 days. (Dec 5.8, Jan 5.3, Feb 5.0 days)

With the information above, I believe that I should be okay with a small panel and large storage battery.
Only testing and time will tell.
I am hoping to have the system up and running and logging data during the coming season.

Zitat von MrB

Are you sure of the consumption figure for the modem? Huawei themselves state 2.5W.

No! I measured TP-Links with and without Huawai, but Huawai was not sending - sorry

/richo

Not much progress to report as I'm still waiting for the kit and a few other bits and pieces to arrive.

The 2300u ferrite rods arrived though, so I started work on the antenna's.

(Photo 1)
I decided to go with the popular 120mm size antenna but the ferrite rods are each 49mm long, so two and a half rods were needed.

(Photo 2 + 3)
I decided to try scribing a line around a rod in my lathe, so I chucked a rod in an 7-8mm ER32 collet chuck and gave it a go.
It worked well, the HSS tool cut a nice line, I thought I'd try another deeper cut and the ferrite snapped cleanly, very easy!

(Photo 4) Next up was glueing the lengths together, I did this with some expensive epoxy adhesive I have had for years.
I had read about some Ham radio guys using epoxy with great success, so I was confident.
After giving the finished rod at least 24 hours to cure, I was able to exert considerable pressure on the rod without the bond breaking. Good stuff.

(Photo 5) Next up was winding the rods with the copper wire. I've done this many times over the years and it's not much fun.
This time I decided to use the lathe on low speed while I manually feed the wire.
The photo shows a few hand wound turns with a dob of CA (cyanoacrylate) adhesive to hold them in place, then I started up the lathe and wound the turns on.

Continued....

(Photo 6) Winding each complete antenna took no more than 2 minutes and would be even quicker if I used a better adhesive. CA is not ideal for this.
As a kid I used to pull apart anything electronic I could get my hands on and I always used to find a waxy substance on antenna's and inductors in radio's.
Despite looking high and low, I could not find a source for this 'wax'. Standard paraffin 'candle' wax is not suitable for use here as it softens at much too low a temperature, especially here in Australia where the temperature climbs above 40c in summer!
The top antenna has the left side of the ferrite broken, I was pulling too much tension on the wire and it snapped off in the collet chuck, oops!

(Photo 7) For a shield I decided to try using some copper tube. This was held in my machine vise while I cut lengthways with a 0.5mm slitting saw in my milling machine.
The completed shield was then cut from the remaining length of tube, chucked in the lathe and the ends dressed.
Interestingly, while the saw was 0.5mm, the split in the tube sprung open to ~1mm.

(Photo 8 ) I had read somewhere on the internet (probably a Ham site) about shielded ferrite antenna's and it was recommended the shield should have atleast 7mm spacing between it and the windings on the ferrite.
The largest copper tube I could find was 19mm ID. I was hoping to find 25mm but this doesn't appear to be easily obtainable. Maybe if I went to a plumbing supplier.
With 19mm ID and an antenna ~8mm OD with windings, this only leaves 5.5mm spacing.
Will it make a difference to performance? I don't know, but I decided to make another shield using 25mm Poly Pipe (for irrigation systems) with copper tape. It will be interesting to see if there is any difference in their behavior.

All up, it was a reasonably quick and pain-free procedure.
Until next time.
Simon

Not much to report on my progress unfortunately.

My kit finally arrived on Friday 1st Nov.
Remind me to ask Egon about quicker freight options for the next kits

Sadly though, I have been working 12~14 hour shifts so haven't really had any time to start construction.
I hate it when real life gets in the way of fun.

I have checked all the supplied components and nothing is missing or an incorrect value. Good work guys.

I also made another set of ferrite antenna's, this time they are 150mm length.
I'm also planning on making a set of 200mm antenna's, just to experiment/compare with the various sizes.
I will also shoot a video of the winding process on the lathe and upload it to youtube for anyone interested.

Hoping to find some time soon to get started!
Until then.

Edit: I, I, I, I'm, I .... Not sure how else to start a sentence!

Well, I've managed to find a few spare hours here and there thru the week (other than work/sleep) and have managed to complete the boards.
The system is up and running!
Station ID is 844:

At the moment it is in it's raw form on my test bench, just bare boards and cables, no enclosures, no external antenna(GPS) and not mounted anywhere.

There's not really any other stations within any decent distance from me, and there's not a lot of lightning activity around me at the moment(closest active cell is ~1700km away)
So it's hard to tell if I'm mainly picking up noise or if I'm actually picking up any real signals. Those signals I am getting are obviously not getting confirmed by (or confirming) any other stations

Oh well, early days.
Here's hoping the three of us in Australia have got the ball rolling to encourage more participants!

> Here's hoping the three of us in Australia have got the ball rolling to encourage more participants!

Pokes head up!
Hi Simon, I'm in Perth too - I still have an older model but not got round to reconnecting it since i moved over here - I have a few mods to make (I want to pull off the serial at low level before the max232 so I can connect to a small embedded box. Secondly I need to screen my ferrites - it's a bit electrically noisy here in Bateman

Hopefully 'soon'