YAESU PTT splitter - RCA output, INH input

Today's standard is PTT output and input on RCA connector. However, the YAESU TRX does not have these connectors. For many users, it is not easy to connect an external device to the TRX that needs a PTT signal. 

For this purpose, a simple box has been created that contains two separate PTT outputs on RCA and one INHIBIT input. These signals are connected to the MINI DIN connector of the TUNER. The signals for the TUNER are also pass-through and will not restrict its connection.

The box includes optical isolation of the PTT and INH signals.

Two versions are available - they differ only in the INH input. The first version has INH active when connected to ground. In the second (MK2) version, an internal jumper can be used to set when INH is active.

There are links for:

MK1 version with simply INHIBIT

MK2 version with INHIBIT jumper

Main functions

• Adapter from YAESU TUNER connector
• Protecting TRX from accessories - opto isolators
• Minimal delay
• Two independent PTT outputs
• PTT output FET switch - DC 30V 1A
• PTT, INH LED indicator
• INH with Jumper for 3 different states
• RCA connectors
• Mini-DIN 8 1.5m cable included
• 4pcs self adhesive feet pads included
• Aluminium enclosure: W x H x L = 58 x 24 x 50 mm
• 
  

Parameters

• Optocoupler isolators protecting TRX PTT out
• Output FET switch 30 V 1A for each port
• 3 states INHIBIT (internal jumper)
• DC power OUT TUNER PTC fuse 1.1A
• TUNER mini-DIN 8 connector
• PCB size 50x50.4 mm

Inhibit (MK2 version)

• Internal jumper to set
• INH active when grounded
• INH deactivated when grounded
• INH activated by positive voltage

MK2 version with INHIBIT jumper

Example to use INHIBIT

An example with a device where RF power is blocked until PTT feedback occurs. Protecting the connected device (here RX Audite) from transmitting into the RX path.

⚠ NOTE: Both jumpers in right position - second jumper settings at picture - jumper settings.

Example of use with Easy Controller 6-2, where the PTT output from the controller unblocks the RF output from the TRX. This watchdog prevents transmissions where the same ANT would be accidentally selected for both TRX - Manual switching and switching from USB or Wi-Fi.

⚠ NOTE: Both jumpers in right position - second jumper settings at picture - jumper settings.

 4-WAY PTT sequencer

This is simply 4-way PTT sequencer. It is designed on LM3880 IC with fixed delay time 60ms. Outputs are made by FET transistors. When active = connected to ground.

Inspiration a few years ago from Rob N4GA and his article.

Parameters:

- Sequencer delay is fixed 60 ms

- Sequencer from RX to TX PTT IN to: T0 = 0 ms, T1 = 60 ms, T2 = 120 ms, T3 = 180 ms

- Sequencer from TX to RX PTT IN to: T0 = 0 ms, T1 = 180 ms, T2 = 120 ms, T3 = 60 ms

- Optocoupler isolator protection at PTT IN port

- OUTPUTS are open while input PTT is in RX, shorted to GND while input is in TX

- When you need to switch positive voltage (LNA) you can use P-FET switch example

- Input PTT logic: active when grounded

- Input PTT logic current typ. 15mA

- Output FET switch 50V 500mA for each port

- DC power supply 9 V to 15 V typ. 30 mA DC cable connection (included for enclosure version)

Internal board

Board without connectors

Schematic:

Sequencing between outputs:

Positive voltage FET switch  - LNA voltage etc:

You can buy it assembled as a board without connectors or assembled in enclosure at our e-shop

Expert 1K-FA repairing - ATU "smoketron"

   Dan OK1HRA is using Expert 1K-FA PA on OL7M remote. After two burnt AC transformers there was new problem. During RTTY contest PA stopped working on 20m and than also on 40m. There were some smoke as well..  I opened it in the job and ATU PCB was burnt off.

 I cleaned PCBs in isopropanol, change some relays and protect it with Plastik 70 super coating