Winter is almost over, but it was still <30f outside last Thursday. In order to get a flight in before work, I had to drive out to the airport at 5 AM to plug in the preheater, drive back home (it's only 10 minutes, but still....), and then return at 8 to fly. Leaving it on all the time is out of the question since it's a borrowed hanger and I don't want to push my luck. The alternative of letting the heater run all night the night before would still require a trip out the night before a flight to turn the heater on. If this were 12 months ago, this wouldn't be a problem. You see, a couple of years ago i stumbled across one of these babys: https://tinyurl.com/h4anbkq
Wake up, shoot it a text message, and it turns on any one of three recepticles. Worked great and cost pennies a month! Why am I not still using it, you ask? Because it's a 2g device and as of this past December, the nations 2g networks were largely dismantled it no longer gets service out at the field. TMobile still has their 2g network up for another year or two, and the device works here at home, being closer to town and all, but even here it's spotty. Another downside was that it was only rated for a total of 15a for all three outlets. I never had any problems with my small diy space-heater-turned-engine-preheater, but it was pushing the limits for sure.
Now that N94CR is flying again, it's painfully obvious that I need something similar that works on the current cell networks. Several are available marketed to airplane owners, but the cheapest is almost $300!
And then I found this: https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
$115, and free prime shipping. Purchased it on Saturday and it showed up on Monday. I must have gotten the last one from Amazon because they're out now, but it's available from some import company as well...
Here's what you need to know:
1. You have to supply a sim card. It says ATT, but works perfectly fine with my old T-Mobile sim card. In fact, it works far better with the T Mobile around here... I actually purchased an ATT sim and tried it first, but it kept dropping the signal. Hasn't done that at all with the T Mobile.
2. The power requirements for the board are 12v dc, NOT 110v AC which is what you'll be switching with it. A google search for similar items reveals that there are units available with a built-in inverter (Search for something like "GSM-AUTO-AC"....) Instead of sending it back and ordering one of those, I just dug around in the closet for an old power cord for some appliance that used 12vdc and cut the pigtail off.
3. You have to read Chinese! Not really, but the instructions leave a lot to be desired. For instance, it tells you what the led's are assigned to, but not what their flashing patterns mean! There's also a button you have to push on the device before calling it to put your phone number on the "Whitelist" so that you can then control it. That isn't explained well.
4. The wiring diagram is pretty simple, but requires you to make a few pigtails for power input and output. I chopped up an old extension cord and picked up ends from the local big box store for $10 total. There are two 30amp relays inside, and they can be controlled individually to open and close, and even set to turn on for a certain time limit then off automatically.
5. The device is controlled by text messages which have to be formulated exactly perfectly and are quite obtuse. The good news is that there is a free App for iPhone and Android that makes this quite easy.
I got it built and tested tonight and it seems to be working great here at the house. The real test is how well it picks up a signal at the hanger. Verizon gets fine service out there, so it's promising. Included in the package was an external antenna with about 8' of cable to help locate it for best service. I'm hoping the short one that fits inside the box will be sufficient. With any luck, I'll be able to roll back over and snooze comfortably knowing my engine is warming peacefully as well.