I live in a valley. Some say it’s a Grand Valley. I didn’t necessarily choose my homestead based on the radio horizon. I live fairly close to several high mountain top repeaters, but there are hills and other obstructions in the way. Even if the land was flat between here and there, I’d still need more than a few watts of power from a handy-talkie (HT) to have a clean signal into the more distant repeaters. And then there’s simplex and data modes. Fact is, the west is just bigger and you need a big signal to get out. So the small HTs I was used to back east don’t cut it unless you’re in Denver or Salt Lake City, and even then only if you’re fairly close to the foothills and don’t have skyscrapers blocking you.
But my home station is pretty powerful. The primary radio is my old IC-9100 DC-to-Daylight radio from the early 2000s. It puts out 100 Watts on 2 meters (although I usually run a lot lower than that - power supplies groan when I run full power and we’re only supposed to run as much power as necessary), but 25-50 watts is more than enough to hit most repeaters with a directional antenna. Problem is, it’s in a rack in my shack. So if I want to use it, I have to be sitting in the shack, next to the radio, tethered by a curly microphone cable. Not the best situation if you’re just listening in case someone wants to strike up a conversation. You’d need to be glued to your seat waiting for a call. Even worse would be if there’s a call for emergency assistance and you stepped away.
What if there was a way to carry a speaker and mic around the house with you? That way you could be doing other things while monitoring the local channel. If you heard someone calling, just pick up the speaker-mic and start talking.
There are several ways to accomplish this. The most common is to ditch the radio and use the Internet. If the repeater is running AllStar or one of the digital voice variants, it’s a simple task of setting up a very low power transceiver (AllStar node) in the house, then connect to the repeater(s) over the internet. Now your little Baofeng radio can talk all over the world, sort of. It’s not really the same, more like a radio “last mile” setup. Like your mobile phone connected to a “tower” your radio becomes part of a system that includes a base radio, Internet backhaul, lookup servers, super nodes, etc. And like the mobile phone networks, it is very spectrum efficient due to the very small area covered by the hot spots. Most all radio hotspots operate at under 1 Watt with really poor antennas, so everyone could probably just use the same frequency and never interfere with each other.
However there are problems with this setup. Primarily, it is completely dependent on the Internet backhaul to get out. You’re also locked into whatever network you happen to be using, AllStar, DMR/Brandmeister, Traditional D-Star repeater linking, IRCDDB, Yaesu System Fusion, D-Plus, etc. I’m sure I’m missing a few too. None of them interoperate easily. So you either end up with 10 different radios and hotspots or just live with whatever mode you bought into. And you’re running equipment that will never have much reach because of the low power levels, so if you do need to contact the outside world via high power repeaters, you’re out of luck.
But what if you turned the radio around? Instead of using a set of small transceivers you used a high power transceiver that is remote controlled? Over the years “remote ham radio” brings up visions of a remote controlled shack, set up in an ideal location for HF, with a good Internet connection and plenty of remote controlled equipment. Hams log into a PC at the remote location and operate from home. These setups can get very elaborate, with antenna switching, high power amplifiers and high end radios, all remote controlled and with lots of status monitoring and feedback.
But that’s largely overkill for this sort of activity. I just need something that can stream audio around the house. Back in the day, Kenwood created a voice and remote system called Sky Command that let you control a TS-2000 radio using a TM-D700 mobile and TH-D7 handheld. It required a TM-D700 connected to the TS-2000 and the operator would run the system using a TH-D7 or TH-D72. Kind of a pricy solution, given the number of radios involved. And it took Kenwood petitioning the FCC for a waiver to be legal to operate in the US. All so you can get on the 80 meter breakfast net from the kitchen instead of sitting in the shack.
AllStar to the rescue!
As I showed in part one, it’s possible to integrate inexpensive VoIP phones into an AllStar node. Once in place they behave pretty much like that little Baofeng and RF hot spot, but running over WiFi instead of the amateur bands. Adding a radio is simply a matter of configuring it in AllStar as another node/extension. Then all I have to do is dial the node, just like connecting to a repeater miles away. Audio is streamed from a sound card, just like normal, just basically going in the other direction.
But what about PTT? How do you key up the IC-9100 when you want to talk? There are a few ways, but I’d like to keep things simple without having to buy a bunch more hardware. I’m using the USB interface so that means CAT control, not GPIO. AllStar has a way to trigger shell scripts from a sequence of DTMF numbers, so I wrote a script that will put the radio in transmit using HAMLIB, using the same *99 TX and # RX setup that AllStar SIP already uses. Really simple.
Or at least it should be. Turned out to take a lot more trial and error than I anticipated, but isn’t that always the case? These days it’s still so much easier to hack away thanks to ChatGPT. I was able to describe what I wanted to do and it provided fairly complete config files for AllStar, stepped me though setting up a software SIP phone on the Raspberry Pi, and helped me troubleshoot the many problems I encountered. It didn’t do everything, but it does seem to be very well versed in Asterisk and VoIP systems. Here’s a very quick video demo of it working.
So now the wheels start to turn. I could put more radios on my network and just make them more extensions. Maybe even put that SDR dongle on my desk on the network and make lots of audio streams, just dial up the signal you want. Or add different data modems like DireWolf and VARA on their own extensions so they can connect up to different radios. Since the push-to-talk function uses a CAT command instead of a relay, it opens up possibilities for changing frequency, mode, etc with the keypad… which means I could create complicated sequences in the handset’s directory (for example, have an entry to “call up” the HF hurricane net on 14.325, or tune to the Colorado Connection memory channel). And the best thing is it makes it easy to carry a “radio” around with me that sounds good so I don’t have to sit at my desk all day.
Anyway, lots more to come with this.