I was looking for a lightwight echolink hotspot for within my house. I have one hotspot for DSTAR ( see picture ) but never found a solution for echolink.
On ebay I found the DRA818U ( UHF ) and DRA818V ( VHF). Both transceivers are very small and have many options like CTCSS, SQL pins, serial poort for configuration changes and a good frequency range.
See specs: DRA818U – Dorji
The software I use is svxlink version 14.08. In this version you can use the GPIO pins on the Raspberry PI.
Keep in mind that the DRA818 is working on 3.3V. You can see in my picture below that I use the 3,3V from the raspberry. Please don’t do this on older models of the raspberry PI!
This will fry your raspberry!! Older raspberry’s can only give 50mA!!
On the DRA818 there is also a squelch PIN ( pin1 ). This pin is connected to one of the pins on the raspberry. This is a VERY handy solution for the detection of the incoming signal!!!!
In the past I tried a lot of solutions in svxlink like VOX or CTCTSS. Most of the time CTCSS is filtered in the transceiver and VOX is to slow.
I left the DRA818 on low power. So it will not use more than 500mA an can be powered by the raspberry. If you put it in hight power the DRA818 will be very hot and eventually die. you have to cool the device.
Now I want to make a shield for it so I can put it directly on the raspberry.