Here's a product on the market - note the FAA L-854 compliance , I like the beefy relays,




This one is rated for 10 A:


this one looks like it's running an Arduino or PIC, with opto isolated solidstate switches.

 

this advisory circular has all the details you need:

https://www.faa.gov/documentLibrary/media/Advisory_Circular/150-5345-49D.pdf

 

I see no legality issue in this application, pilots will be using licensed radios, there must be channels that are assigned to this specific use. The challenge is designing and building a reliable system that is sufficiently hardened.

I do not recall any mention of a user being a pilot. Maybe I missed that part, or perhaps you had a private communication with the TS. Or maybe that is just a guess.

 

I see no legality issue in this application, pilots will be using licensed radios, there must be channels that are assigned to this specific use. The challenge is designing and building a reliable system that is sufficiently hardened.

True story. Well I just want to build a prototype of my own which can potentially be redesigned professionally later and be used as a such hardened system. I want to build my own to check and verify that it can be built using arduino, perhaps DTMF, vhf receiver and transmitter etc... Basicly I want ideas and maybe some help in coding from you guys.

 

Here's a product on the market - note the FAA L-854 compliance , I like the beefy relays,


View attachment 199295

This one is rated for 10 A:View attachment 199296


this one looks like it's running an Arduino or PIC, with opto isolated solidstate switches.
View attachment 199297

Ahh, yes I have seen this systems before. I want to build something easy and similar like this. These systems have been developed over many years and backed up by companies with big pockets. This is something that I dont have. my goal is written on your previous post.

 

These systems have been developed over many years and backed up by companies with big pockets.

I'd suggest you do a Patent search to see if they have any current patents which you might infringe with your project, since they could afford to come after you if they think you're trespassing on 'their' territory.

 

Patents don't really apply until you start to make money off of a product. If you produce one-off for your own use it is never worth the lawyer fees to go after that individual.

 

I'd suggest you do a Patent search to see if they have any current patents which you might infringe with your project, since they could afford to come after you if they think you're trespassing on 'their' territory.

Not going to copy or build excact type of system, mine will be pretty homemade and I do not know which parts or units they used and how it is constructed so I am not worried about patents. If I at a later point construct a commercial product, then it will be someting different. This is a hobby project

 

Side note, I've developed a program for IDEC SmartRelays for airport runway lights (looks for 5 pulses within 7 seconds, turns lights on for 15 minutes, last minute lights flash to let you know they are about to turn off). If you're interested, let me know, happy to share it for hobbyist/not-commercial usage.

I am looking for some way to get analog voltage pulses off of the squelch breaks from some sort of VHF receiver in case anyone has any ideas.

 

A simple and non-invasive means of detecting fairly rapid carrier pulses would be to use the external speaker jack on the receiver along with a high-pass filter. This should detect the noise pulses after the carrier drops, since that noise has a greater high frequency content. At least that works for FM communications equipment. So an FM receiver tuned to the frequency would probably work best. I guess that aircraft VHF communications are mostly AM, but that may be based on old information.

 

Why not use CTCSS boards, then just set the Frequency of the ctcss for tx and rx..

 

A simple and non-invasive means of detecting fairly rapid carrier pulses would be to use the external speaker jack on the receiver along with a high-pass filter. This should detect the noise pulses after the carrier drops, since that noise has a greater high frequency content. At least that works for FM communications equipment. So an FM receiver tuned to the frequency would probably work best. I guess that aircraft VHF communications are mostly AM, but that may be based on old information.

Airband VHF operates on AM, but that's a really interesting concept - never would have thought of that. I'll have to do some testing. What I'm running into in looking at the output is even when there is no transmission (and the signal is squelched), I'm still getting similar voltage/amperage out of the audio jack so having a hard time discerning when a transmission is made.

 

Airband doesn't operate with CTCSS so not sure how that would work. Perhaps I'm not understanding how that would apply. Can you elaborate?

 

Put a ctcss board in the receiver and when you transmit it receives the signal and operates the relay to put the lights on, is that not what you want??

 

Airband VHF operates on AM, but that's a really interesting concept - never would have thought of that. I'll have to do some testing. What I'm running into in looking at the output is even when there is no transmission (and the signal is squelched), I'm still getting similar voltage/amperage out of the audio jack so having a hard time discerning when a transmission is made.

To get anything useful from the speaker connection you will need to look at the difference in the higher frequency noise portion of the signal. When a carrier is present the background noise level drops, of course that is most obvious on an FM communications receiver. If the receiver has a properly adjusted squelch function, there will be no noise present with no carrier present because the output is squelched. Then when a carrier is detected the squelch will open but it will be fairly quiet. Then, when the carrier drops but the squelch is still open there will be a burst of higher frequency noise, in the 3000to 5000 Hz range, and that noise will be silenced when the squelch closes. That burst is referred to as a "squelch tail", and is quite common. THAT is what I was saying could be detected fairly simply.

 

Side note, I've developed a program for IDEC SmartRelays for airport runway lights (looks for 5 pulses within 7 seconds, turns lights on for 15 minutes, last minute lights flash to let you know they are about to turn off). If you're interested, let me know, happy to share it for hobbyist/not-commercial usage.

I am looking for some way to get analog voltage pulses off of the squelch breaks from some sort of VHF receiver in case anyone has any ideas.

I am trying to accomplish what it sounds like you already have done. I put in an emergency heliport recently in my quite rural area. This is a self funded project that I would like to do pilot activation but I have not come up with any affordable answers. I am only half smart when it comes to fabricating but would love to know how you accomplished it and approximate costs Thanks in advance