Today let’s talk about sustainable output power for grid down ham radio communications. In the video at the bottom of this post, there are two different Winlink sessions. One is PAT Winlink running on a Raspberry Pi, The other Winlink Express running on my Windows 10 Yoga laptop. Both are using the Icom IC-705 QRP amateur radio with ARDOP (Rpi), or Vara (Win10).
Since this channels focus is very much on portable power for off-grid communications, it’s important to point out “We don’t always need to operate QRO!” for regional communications on HF. With good Comms gear, practical experience and constant training with in this case, the Winlink network, we can achieve effective communications, while operating at a sustainable power level.
With the GPS activated, the Icom IC 705 has roughly 300 milliamps current draw. other radios have even less, while some have slightly more. 100 watt radios rarely have efficient receive, drawing more or less one amp just receiving. My Yaesu FT-891 (which is the ultimate portable qro rig for the field), draws about 1 amp receiving. When we use QRP+ (1-20w) or QRO, we have must come up with different power strategies, for each operating style. QRP+ is definitely more forgiving, more cost-effective, but requires a greater investment in operational training. QRO requires a greater investment in power and charging since most QRO rigs take an unsustainable amount of receive current draw, when they aren’t actually doing anything. This is the difference between needing for example of 5 amp hour battery, or a 20 amp hour battery to power our rig all day. It’s also the difference between needing a 60 watt solar panel vs. or eg a 120 watt solar panel. If you’re using a pedal generator it’s a difference between 750 kg calories vs 1500 kilocalories to top up that battery pack. Although we can turn the power down on a 100-watt rig, we can’t turn down its receive current draw. It’s the receive current draw which is actually the slow killer of our portable power strategy.
This is a critical concept we need to understand for emergency communications and preparedness. I’m not saying we shouldn’t invest in and utilize QRO power. I’m simply suggesting we think about it.
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