Sunday, November 17, 2024

 3-WAY active splitter

This is a 3-WAY splitter with the ability to connect a preamplifier with a large dynamic range and gain up to 18dB. This preamplifier can compensate for split losses. It can also add gain up to 10dB.

Both current and voltage protection are included. The gain of the amplifier can be adjusted from the front panel.

Link to web page with manual

block diagram
Examples

Measurements

 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.






Tuesday, November 5, 2024

 Tropo DX at LoRa APRS 433 MHz






Late October and early November brought exceptional conditions for long distance DX contacts. The result was not only great result of OL7M guys in MMC contest, but also new and beautiful DX on LoRa APRS. 


The longest two-way contact was achieved from Koruna 1100m asl - isn't that even a LoRa 433MHz world record over land?

F4JPO-10 from JN08wt 1057km
F1ZFC-10 from JN09xi 1039km

And stations which heard me:

RIG there is TTGO LoRa32 with around 30mW and home made 4el. collinear antenna. Installed at the top of the tree in 1100m asl. Solar powered with rest LoRa toys. More there.

The conditions also favoured the lower positions. Here are the weather stations located around the hills in my area. One nice DX came through my apartment window. On the 5th floor with a small 3D printed dipole - OK2ZAW-23.
There is a 3D printed dipole, like on the other weather stations as well. They are all solar panel powered and have RF power around 50mW.



And there were also nice DX for YO gateways... like YO2B-10