the wireless digital access to the world-wide D-Star repeater network

A Hot-Spot is a radio station which allows access to a network, well known from WLAN technologies.

D-Star uses repeaters which are linked via the internet. This hot spot board is also connected to the internet (via a PC) and cann access any D-Star Repeater running the d-plus software (which are most of them).

On the other side the hot spot is connected to a transceivers which must have a 9k6 connector.

When the linked D-Star repeater transmits voice, then this digital voice is also transferred through the internet to the hot spot. The hot spot sends this signal to the transceiver which transmits it on any legal simplex frequency. Using a usual D-Star radio (i.e. the IE91 or others) we can hear this transmission.

This is very interesting if a station wants to speak on a D-Star repeater which is out of range for direct qsos. This makes the hot spot ideal for areas without D-Star repeaters.

I'm using the hot spot primarily for QSOs at home with the IE-91. I can only access a D-Star repeater with very big antennas. There is no chance to use a hand held transceiver. The hot spot solves this problem. 

Where to get the hot spot:

PCBs and programmed PICs are available from Satoshi 7M3TJZ/AD6GZ , the inventor of this perfect development: http://d-star.dyndns.org/rig.html.en
Simple write an e-mail to Satoshi with an order for boards and you will receive the boards in a very short time for a good price. You will also receive a special internet page showing all required information to build  the hot spot.

Additionally you need the PC software which talks to the board and links it to a D-Star Repeater. This software was written by Mark, KB9KHM and is avialable for download in the yahoo group: gmsk_dv_node.

This is a short report how I built this hot spot:

This is the component side of the hot spot board. The big chip on the left is the CMX589A GMSK modem chip. It is available from electronic distributors. In Germany I got it from SE-Elektronik. 
I have connected the hot spot board to an old Standard C5608 transceiver which was extended with a 9k6 access (see this link).

For best performance I did this modifications on the hot spot board:

remove C4 (330p)
mount 100nF in series with pot VR1 to block DC voltages from the transceiver
R8 = 100 kOhms
set VR1 to get 100 mVpp at pin 7 of U3
set VR2 to get 100 mVpp at pin 1 of U3
C10 = 47 uF

This is the solder side. You can see the additional 100 nF (SMD) capacitor.


The board connected for testing:


I built the hot spot board into a metal case. This is important since the board radiates on the crystal frequencies and harmonics.

I always use chich plugs for all signals. This makes it very flexible if I want to connect the devices in different ways without the need of soldering cables.


Front and rear side of the ready built hot spot:


Here it is, ready and fully operational together with the Standard C-5608.