Why I Just Ordered A K1 "Lunchbox" Repeater and a second Baofeng.
I'm an active memeber of the local Skywarn / Auxcomm group in my area. During potential severe weather events, our Amateur Radio net is activated, and the net controller puts out status updates.
If the weather gets threatening enough, Roll Call is held and stations are activated. In our case, the station is the Amateur Radio user that is a member of this group.
I have a problem though.
Our net is not connected to Echolink, so I can not listen in over the internet. I work in a basement, and to make matters worse, my office is in the centermost area of the basement. While it's good protection from weather events, Amateur Radio, or any radio signals just don't get through down there.
In the main basement area that is down a hallway about 100 feet from my office, there are a couple windows, and I've needed to stand right next to them to receive any signals from my local repeaters.
So the problem is that when the net is activated, I have no idea it was, and so I am not very useful to the group because I just won't know unless someone emails. As a side note, I have to rely on Google Voice for calls and texts because mobile phone networks won't even reach my office. It's pretty well sheilded from everything.
The "Lunchbox" HAM Radio Repeater
All the videos on YouTube that I've found show you how to use a K1 Repeater, which is a box with two Kenwood audio connectors, as a repeater.
The general idea is that one of your two radios (Most videos use the cheap Baofengs, as do I) receives the transmission from your handheld while the other transmits back on a different frequency, thus creating a repeater. I have a very different need.
I need to monitor the net when I suspect that Net Activation is imminent. I figure that I can just go down the hallway and check in as active when needed, but I first need to know when they open up the net.
In my case, the repeater will just amplify the reception down the friggin' hallway to my handheld so I can sit and monitor without leaving my office. One way only. Since it might be on for hours waiting for activation in the office, I can leave the radios plugged in. No concern for battery life unless the power goes out, and in every case the power's gone out, it was after the net was activated anyway.
It might be possible to have 2-way communication using this setup. I just don't know because I still haven't received the K1 repeater box, and am not very experienced in radio communications yet. I figure that I will get the one-way transmission setup and working reliably, then tinker around to get two-way running -- if it can even do that.
I have little to no knowledge and am relying on youtube, which doesn't have any videos for my use case, and ChatGPT which isn't really reliable. Better for general knowledge than something this specific.
The UV-5R Repeater Setup
In an attempt to document what I'm doing here, Let's say that my repeater transmits on 145.390MHz (this is what you see on your handheld display). The offset is -0.6MHz (So 144.790MHz receive frequency), and the tone is 100Hz.
RX (Receive) UV-5R
For this radio, I want it to just receive. It doesn't need to transmit (yet). I have the repeater programmed in to Memory #10, but I could switch to VFO mode and enter it manually:
- VFO Mode: Enter 145.390
- Menu Zero: (Squlech) 3 - adjust as needed for your environment
- Menu 7: OFF (Turns of dual channel monitoring)
- Menu 11: (R-CTCSS): 100.0 - yours might be different from mine.
- Menu 25: (Shift Direction) - (minus)
- Menu 26: (Offset) 000.600 for 0.6MHz.
This completes the setup of the receive radio. I'll pop open the dust cover for the headset jacks on the right of the radio, and plug one end of the K1 Repeater box into that, and turn the volume all the way up. It doesn't matter which of the two plugs I use on the K1 as the box is "bi-directional", or can send the audio either way. The only thing that matters is which radio is setup to RX and which is the TX to transmit to my handheld down the hallway on my desk.
TX (Transmit) UV-5R
The transmit radio is responsible for retransmitting the RX radio's audio. In my case, it only needs to transmit with enough power to get the signal through the main area, down the hallway, and into my office. Five watts of power is probably more than enough, and I may be able to run this radio TX on low power.
I'll set this radio's memory #10 to match. Ideally, I will just set all radios to Memory 10 and be up and running, but here's the manual programming for this radio.
- VFO Mode: I will use a random 2M frequency for this example: 144.100MHz. Use a frequency that no one uses in your area.
- Menu 7: OFF (turns off dual channel monitoring)
- Menu 4: VOX (activates TX when it hears the RX radio audio transmissions) 1 for most sensitive
- Menu 25: (Shift Direction) + (you can choose either + or -)
- Menu 26: (Offset): 000.600MHz (TX frequency will now be 144.700MHz since the shift was positive)
- Menu 39: (Roger Beep): OFF - Not used currently, but if I were to transmit back in the future, the Roger Beep would be my confirmation that I was able to hit the Lunchbox Repeater's TX UV-5R successfully.
This radio is connected to the other Kenwood Audio jack.
Monitor (HT on my desk) TIDRadio TD-H3
This is the handheld that sits in the drop-in charger on my desk. It is what I will use for monitoring. Again, I will have everything programmed in to Memory 10 for easy setup, but the VFO settings are as follows:
- VFO Mode: I will listen to 144.700MHz. This is coming from the TX UV-5R directly above.
This is the complete setup for a monitoring-only station, but if I wanted to transmit back, I believe I'd have to transmit on 144.100MHz, and then the RX UV-5R would need to also have VOX turned on so that it could re-transmit my traffic back up to the net. Something like that. It kind of hurts my brain.
Radio Settings Table
| Radio | RX Freq. | TX Freq. | Shift Dir. | Offset | Tone (CTCSS) | VOX | Roger Beep | Notes |
|---|---|---|---|---|---|---|---|---|
| RX UV-5R | 145.390 MHz | 144.790 MHz | - (minus) | 0.600 MHz | 100.0 Hz | OFF | OFF | Receives net repeater, sends audio to TX |
| TX UV-5R | 144.100 MHz | 144.700 MHz | + (plus) | 0.600 MHz | None | 1 | OFF | Rebroadcasts RX UV-5R audio to hallway |
| Monitor TD-H3 | 144.700 MHz | N/A | N/A | N/A | None | OFF | OFF | Desk HT for listening only |
Notes and Thoughts
There are other ways that I could make this happen. I know I could setup a radio's audio to feed into a computer and then I could listen via IceCast or something, but I also like the idea of having repeater capability - even if it's for a limited range. Fun to have.
I have seen comments on the videos I've watched saying that this doesn't work well. For me, I just need it to reach 200 feet or so on listen-only. Never saw a comment saying it wouldn't receive and retransmit, the comments were always about your outgoing communication back through the repeater.
Why didn't I just setup an antenna with a really long lead? It's work. The less they see, the better. I'd need at least 250 feet to get the antenna to the window. Don't think the boss or IT would like rogue lines.
The K1 Repeater box is due in tomorrow. I'll do a setup and see how it works.