+ Reply to Thread
Page 1 of 2 12 LastLast
Results 1 to 15 of 18

Thread: Build your own avionics

  1. #1
    Registered User
    Join Date
    Sep 2012
    Location
    Brookville, NY. USA
    Posts
    1,167

    Build your own avionics

    For those who wish to build their own avionics, this is nice site for schematics.

    S53MV homemade avionics

  2. #2
    Registered User
    Join Date
    Feb 2011
    Location
    Columbus, GA and Albuquerque, NM
    Posts
    1,335

    Re: Build your own avionics

    Integration is not his strong suite.

  3. #3
    Registered User
    Join Date
    Sep 2012
    Location
    Brookville, NY. USA
    Posts
    1,167

    Re: Build your own avionics

    Quote Originally Posted by JamesG View Post
    Integration is not his strong suite.
    Yeah. I can see we can build something much better here.

  4. #4
    Registered User Aerowerx's Avatar
    Join Date
    Dec 2011
    Location
    Marion, Ohio
    Posts
    1,268

    Re: Build your own avionics

    Anything that transmits would be illegal in the USA. The equipment would have to be type accepted by the FCC.

    Now, if you had an Amateur Radio (Ham Radio) license, you could build the radar altimeter to operate on one of the microwave amateur radio allotments. Then it would be perfectly legal (checking for permitted transmission modes first, of course).

    Building your own Comm radio, though, is out of the question.
    ___________________________
    Lost in Thought..Please send help

  5. #5
    Registered User Pops's Avatar
    Join Date
    Jan 2013
    Location
    USA.
    Posts
    1,550

    Re: Build your own avionics

    Years ago, it used to be if the transmitted power was under 50 mw , OK. Don't know about now, it may have changed.
    I made a 3 light marker beacon tester transmitter that is under 50 mw about 30 years ago and still use it. Dan
    Pops

  6. #6
    Registered User
    Join Date
    Sep 2012
    Location
    Brookville, NY. USA
    Posts
    1,167

    Re: Build your own avionics

    Quote Originally Posted by Aerowerx View Post
    Anything that transmits would be illegal in the USA. The equipment would have to be type accepted by the FCC.

    Now, if you had an Amateur Radio (Ham Radio) license, you could build the radar altimeter to operate on one of the microwave amateur radio allotments. Then it would be perfectly legal (checking for permitted transmission modes first, of course).

    Building your own Comm radio, though, is out of the question.
    OK. Fine. I could still build VOR receiver, RDF, CB band radio altimeter(maybe not), and I will have all these integrated with the GPS. In the case of the GPS sat system fails, the pilot still be able to nav as if the GPS is still there.

  7. #7
    Registered User Aerowerx's Avatar
    Join Date
    Dec 2011
    Location
    Marion, Ohio
    Posts
    1,268

    Re: Build your own avionics

    Years ago, it used to be if the transmitted power was under 50 mw...
    Ah, yes. Forgot about that one, Pops. Someone would have to check the regs. You would have to pick your frequency carefully, and I don't know if 50 mw would be enough.

    As I recall, from back in the late 1960s, most of the 50 mw projects that were in the magazines were AM broadcast band 'pirate' transmitters.

    ...CB band radio altimeter(maybe not)....
    I think you would want something at a higher frequency. Just guessing, at 200 MHz or higher. Besides, on the CB band you are apt to enrage a lot of people by causing interference.

    [Edit] Any CB equipment would still have to be type accepted by the FCC, and I don't think a radar altimeter would get very far.

    In the case of the GPS sat system fails, the pilot still be able to nav...
    I used to have around here somewhere that worked even with a complete power failure (yes, I know you would be too busy to navigate, but still...). Let me think, what where they called? Oh, yes...map and compass.
    ___________________________
    Lost in Thought..Please send help

  8. #8
    Registered User
    Join Date
    Sep 2012
    Location
    Brookville, NY. USA
    Posts
    1,167

    Re: Build your own avionics

    I've got something around here somewhere that work even with a complete power failure (yes, I know you would be too busy to navigate, but still...). Let me think, what where they called? Oh, yes...map and compass.
    No IFR when that happens.

  9. #9
    Registered User Aerowerx's Avatar
    Join Date
    Dec 2011
    Location
    Marion, Ohio
    Posts
    1,268

    Re: Build your own avionics

    Quote Originally Posted by Aviator168 View Post
    No IFR when that happens.
    You would also have to ask the FAA about that one.
    ___________________________
    Lost in Thought..Please send help

  10. #10
    Registered User djschwartz's Avatar
    Join Date
    Jun 2008
    Location
    Portland, Oregon
    Posts
    955

    Re: Build your own avionics

    Quote Originally Posted by Aerowerx View Post
    Ah, yes. Forgot about that one, Pops. Someone would have to check the regs. You would have to pick your frequency carefully, and I don't know if 50 mw would be enough.

    As I recall, from back in the late 1960s, most of the 50 mw projects that were in the magazines were AM broadcast band 'pirate' transmitters.
    Definitely not useful or legal for a Comm radio. A comm radio requires at least 1 Watt to be useful. Most handhelds are 3W and panel mounted radios 5 to 10 Watt. A marker beacon is a receiver, not a transmitter.

    I think you would want something at a higher frequency. Just guessing, at 200 MHz or higher. Besides, on the CB band you are apt to enrage a lot of people by causing interference.
    A radar altimeter requires a fairly high peak pulse power. Not practical without an FCC type acceptance. And the wavelength needs to be small compared to the accuracy you want to achieve. So if you want 1 meter accuracy the operating wavelength should be on the order of 20 cm or less. That's a frequency of about 1500 MHz.
    [Edit] Any CB equipment would still have to be type accepted by the FCC, and I don't think a radar altimeter would get very far.
    Children's Band is pretty much useless for anything other than playing "Convoy". Any other use of the band than simple voice communications with type accepted radios is both illegal and pointless.

  11. #11
    Registered User Aerowerx's Avatar
    Join Date
    Dec 2011
    Location
    Marion, Ohio
    Posts
    1,268

    Re: Build your own avionics

    Quote Originally Posted by djschwartz View Post
    A radar altimeter requires a fairly high peak pulse power. Not practical without an FCC type acceptance.
    Depends. You don't need a pulsed signal. You could use a FM transmitter modulated with a triangle wave signal. The difference in frequency between the transmitted and received signal would be directly related to the distance.

    IIRC, early ones (WW2 vintage) used something around 400-500 MHz, I think, but I am not sure what resolution they had.

    If I were to build one under authority of my Amateur Radio License, I would consider the 3.3 GHz allotment with a FM modulated system as described above.
    ___________________________
    Lost in Thought..Please send help

  12. #12
    Registered User Pops's Avatar
    Join Date
    Jan 2013
    Location
    USA.
    Posts
    1,550

    Re: Build your own avionics

    Quote Originally Posted by djschwartz View Post
    Definitely not useful or legal for a Comm radio. A comm radio requires at least 1 Watt to be useful. Most handhelds are 3W and panel mounted radios 5 to 10 Watt. A marker beacon is a receiver, not a transmitter.



    A radar altimeter requires a fairly high peak pulse power. Not practical without an FCC type acceptance. And the wavelength needs to be small compared to the accuracy you want to achieve. So if you want 1 meter accuracy the operating wavelength should be on the order of 20 cm or less. That's a frequency of about 1500 MHz.
    Children's Band is pretty much useless for anything other than playing "Convoy". Any other use of the band than simple voice communications with type accepted radios is both illegal and pointless.
    You didn't read my post close enough. I built a Marker Beacon Tester Transmitter. Small box that would set under the aircraft to test your Marker beacon receiver. Jim Weir ( Kitplanes, RST. ) had a schematic on it back in the mid 80's. Bought the crystal and scratch built it.

    Some of the better handheld radios are 5 watts. My Icom A-6 is 5 Watt. I have a homemade antenna inside my fuselage made from copper foil tape and it works as good as any 5 watt panel mount radio with a expensive aircraft com antenna. Dan
    Pops

  13. #13
    Registered User Aerowerx's Avatar
    Join Date
    Dec 2011
    Location
    Marion, Ohio
    Posts
    1,268

    Re: Build your own avionics

    Using this online calculator, and some reasonable guesses for the numbers, 50 mw should be plenty of power for a 3.3 GHz radar altimeter. I assumed a maximum altitude of 10,000 ft AGL. Received signal was over 3 microvolts. Plenty for todays technology.
    ___________________________
    Lost in Thought..Please send help

  14. #14
    Registered User djschwartz's Avatar
    Join Date
    Jun 2008
    Location
    Portland, Oregon
    Posts
    955

    Re: Build your own avionics

    Quote Originally Posted by Pops View Post
    You didn't read my post close enough. I built a Marker Beacon Tester Transmitter. Small box that would set under the aircraft to test your Marker beacon receiver. Jim Weir ( Kitplanes, RST. ) had a schematic on it back in the mid 80's. Bought the crystal and scratch built it.
    Sorry Dan, I didn't realize you were building a piece of test equipment rather than an operational piece of avionics. I saw "transmitter" and assumed it was a typo. My mistake. And I definitely agree that such a piece of test gear could be a very low power transmitter. And with it used in the manner you describe it would produce no real interference with the actual ILS system, so even if it turned out to be not technically legal, no one would know or care.

    Dave

  15. #15
    Registered User Pops's Avatar
    Join Date
    Jan 2013
    Location
    USA.
    Posts
    1,550

    Re: Build your own avionics

    Quote Originally Posted by djschwartz View Post
    Sorry Dan, I didn't realize you were building a piece of test equipment rather than an operational piece of avionics. I saw "transmitter" and assumed it was a typo. My mistake. And I definitely agree that such a piece of test gear could be a very low power transmitter. And with it used in the manner you describe it would produce no real interference with the actual ILS system, so even if it turned out to be not technically legal, no one would know or care.

    Dave
    I used it for many years in keeping my aircraft IFR rated. Dan
    Pops

+ Reply to Thread
Page 1 of 2 12 LastLast

Similar Threads

  1. [Wanted] Unwanted Avionics
    By avdome in forum For Sale / Wanted
    Replies: 0
    Last Post: June 21st, 2013, 03:07 AM
  2. [For Sale] Avionics and components
    By rforbes in forum For Sale / Wanted
    Replies: 2
    Last Post: December 24th, 2012, 09:53 PM
  3. Avionics Wiring
    By N117FA in forum Hangar Flying
    Replies: 1
    Last Post: October 29th, 2008, 02:17 PM
  4. Regulations on Custom Avionics?
    By Dorfer in forum Instruments / Avionics / Electrical System
    Replies: 1
    Last Post: December 23rd, 2007, 12:56 PM
  5. Avionics up for bid
    By GeorgeD in forum For Sale / Wanted
    Replies: 0
    Last Post: June 8th, 2006, 03:51 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts