i want to make a a-94a/u ptt for saber, can and one tell me details and how to make one
thanks for your helps
saber u-94a/u ptt
Moderator: Queue Moderator
u-94a/u
sorry, wrong type is u-94a/u ptt
please help me if u can thanks a lot
please help me if u can thanks a lot
-
Astro Spectra
- Posts: 669
- Joined: Sat Sep 22, 2001 4:00 pm
This is not as simple as it looks. Not only do you have to get the PTT connections correct there are also the mic and headset impednaces to worry about.
There are three main types of mic impedance specifications - none are interchangeable with each other without specific adapters / converters.
Civil
600 ohm total earphone impedance.
Microphone is ‘100 ohm carbon level’ which is achieved in a variety of ways:
• Old style carbon mic
• Amplified dynamic mic
• Amplified electret mic (as per some David Clark headsets).
Normal feed voltage is 4V at 15mA.
Military
NATO Military Specification
• 150 ohm total earphone impedance
• Microphone is a 150 ohm dynamic microphone (eg M-101/AIC)
• UK NATO plug.
USA Military Specification
• 9.5 ohm total earphone impedance
• Microphone is a 5 ohm dynamic microphone (eg M-87/AIC)
• US U174/U NATO plug.
Note: M-87/AIC is available in 5 ohm and rare 100 – 150 ohms versions. No external markings for each type! M-87/AIC is normally 5 Ω dynamic, noise-compensated, 500 – 4,000 Hz with 1.8 – 4 µV output at 74 dB.
Plug Types
GA Twin Plugs
The mic plug is thinner than the headphone plug. These are commonly used on most general aviation aircraft as well as most Boeing airliners.
UK NATO
UK NATO plug is a short brass plug with 4 contact rings commonly used on all UK Military aircraft and some helicopters. (often denotes military spec headset that is not useable on GA Aircraft).
USA NATO
US NATO plug (U174/U) is similar to the UK NATO plug but has a silver nickel finish to contacts and a smaller body diameter. Used on many helicopters and ground crew headsets.
Note: The U174/U plugs on the ground crew headsets are wired differently to standard aircraft U174/U plugs!
Helicopter Headsets
Civil craft use civil spec impedance/levels.
U-174/U style US NATO plug or U-93A/U plug which mates with U-92A/U socket.
Your U-94A/U is a four conductor socket with PTT compatible with the U-174/U plug. You need to sort out the microphone circuit because none of the aircraft types are likely to work directly with the Saber. The U-174/U does not have a PTT line wired on it, this is the function of the U-94A/U.
The baisc connectoion for the saber are here:
http://www.batlabs.com/saberacc.html
The external speaker connections go the the headset pins - that's the easy part. You'll need to tie the opt select to ground with two silicon diodes to give 1.2 VDC. This keeps the RF on the main antenna while switching off the internal speaker and mic.
On civil rotary craft the headset mic is on pins 1 and 3 (pin 1 is the tip) and the cans are on 2 and 4 of the U-174/U.
You might want also to talk to the ramp avionics guys before going too far down this path.
Without knowning what specific headset mic you are going to use I can't offer any comment on a mic interface.
There are three main types of mic impedance specifications - none are interchangeable with each other without specific adapters / converters.
Civil
600 ohm total earphone impedance.
Microphone is ‘100 ohm carbon level’ which is achieved in a variety of ways:
• Old style carbon mic
• Amplified dynamic mic
• Amplified electret mic (as per some David Clark headsets).
Normal feed voltage is 4V at 15mA.
Military
NATO Military Specification
• 150 ohm total earphone impedance
• Microphone is a 150 ohm dynamic microphone (eg M-101/AIC)
• UK NATO plug.
USA Military Specification
• 9.5 ohm total earphone impedance
• Microphone is a 5 ohm dynamic microphone (eg M-87/AIC)
• US U174/U NATO plug.
Note: M-87/AIC is available in 5 ohm and rare 100 – 150 ohms versions. No external markings for each type! M-87/AIC is normally 5 Ω dynamic, noise-compensated, 500 – 4,000 Hz with 1.8 – 4 µV output at 74 dB.
Plug Types
GA Twin Plugs
The mic plug is thinner than the headphone plug. These are commonly used on most general aviation aircraft as well as most Boeing airliners.
UK NATO
UK NATO plug is a short brass plug with 4 contact rings commonly used on all UK Military aircraft and some helicopters. (often denotes military spec headset that is not useable on GA Aircraft).
USA NATO
US NATO plug (U174/U) is similar to the UK NATO plug but has a silver nickel finish to contacts and a smaller body diameter. Used on many helicopters and ground crew headsets.
Note: The U174/U plugs on the ground crew headsets are wired differently to standard aircraft U174/U plugs!
Helicopter Headsets
Civil craft use civil spec impedance/levels.
U-174/U style US NATO plug or U-93A/U plug which mates with U-92A/U socket.
Your U-94A/U is a four conductor socket with PTT compatible with the U-174/U plug. You need to sort out the microphone circuit because none of the aircraft types are likely to work directly with the Saber. The U-174/U does not have a PTT line wired on it, this is the function of the U-94A/U.
The baisc connectoion for the saber are here:
http://www.batlabs.com/saberacc.html
The external speaker connections go the the headset pins - that's the easy part. You'll need to tie the opt select to ground with two silicon diodes to give 1.2 VDC. This keeps the RF on the main antenna while switching off the internal speaker and mic.
On civil rotary craft the headset mic is on pins 1 and 3 (pin 1 is the tip) and the cans are on 2 and 4 of the U-174/U.
You might want also to talk to the ramp avionics guys before going too far down this path.
Without knowning what specific headset mic you are going to use I can't offer any comment on a mic interface.
ptt
hi, thanks for somany detail info, i am using a lite II headset which had been modified with u-174/u connector, it was made by davies (uk), i did not know too much for this headset, hope it can be use on saber
thanks again
thanks again
-
Astro Spectra
- Posts: 669
- Joined: Sat Sep 22, 2001 4:00 pm
You must have 'interesting' friends.
OK, the Lite II comes with either electret or dynamic mic. You will have to find out which.
It would also help to know the headphone impedance, high 150 or 300 ohms or low about 30 ohms. You can check the headset with a multimeter, you will hear a loud click when you're across the cans let me know what you measure.
The mic is harder to check. After you confirm the headphone connections connect the mic pins to an audio amp and see if you can pick up any audio, if you do then it will be dynamic, if you don't it's probably electret.
[/img]
OK, the Lite II comes with either electret or dynamic mic. You will have to find out which.
It would also help to know the headphone impedance, high 150 or 300 ohms or low about 30 ohms. You can check the headset with a multimeter, you will hear a loud click when you're across the cans let me know what you measure.
The mic is harder to check. After you confirm the headphone connections connect the mic pins to an audio amp and see if you can pick up any audio, if you do then it will be dynamic, if you don't it's probably electret.
[/img]
hi, i tested the headphone i use the multimeter and use the 20k section the meter show 0.01, hope what i did is correct, buy the way, my friend told me that the mic is dynamic mic for sure.
i have modified two u-94a/u already one for big m's talkabout and the other is for prc-126, they r easy, hope u can help me thanks
i have modified two u-94a/u already one for big m's talkabout and the other is for prc-126, they r easy, hope u can help me thanks