Wednesday, May 19, 2021

Tiny thermal printer for EmCom

The problem: During an ARES activation, passing Winlink messages for a local hospital, we have no way to print the relies for the hospital staff. We were not allowed to log on to the local LAN and use the hospital printers. We thought about bringing our own printer, but some of our stations were running on battery power or were mobile. Additionally, ink notoriously dries up in a few weeks without use which meant buying new ink (up to $30) for each drill. 

The Solution: I bought a tiny portable thermal receipt printer on Amazon for around $40. It operated on 9 volts and includes a 1.5Ah Li-ion battery. It's supports Bluetooth, but so far I've only gotten it to work via the USB cable on Windows. It uses thermal printer rolls which are 58mm wide. It's certainly not large, but very readable. Best of all...no ink or ribbon. The only consumable is the paper and it has a long shelf-life as long as you keep it away from high heat or direct sunshine. 

I charged the batter by connecting the power cable and installed the printer driver (POS 58) which came with the printer. I connected the USB and it found the printer. One issue was finding a paper definition in the printer setting that worked. I finally found "ZPrinter Paper (58mmx3276mm)" which worked well. I believe I had to install the printer driver for the ZPrinter to get this option.

I then exported my Winlink message to a text file and opened it in Notepad. I set the left and right margins to the minimum, the top to 1.0 and the bottom 0.0. Then I set the font to 9pt. Arial which seemed to be a good compromise between readability and size. The best thing is these settings carry over even after closing notepad. Then I simply printed the message and tore off the receipt. See the video for a look at the process. 

UPDATE: With inflation, the price of most of these types of printers has gone up. I've foundone that is still around $45 (see affiliate link below). 





Tuesday, March 16, 2021

QCX-Mini and a Keyer

So after a club member teased us with a great demonstration on QRP CW, I ordered a QCX-Mini from QRP Labs. It took awhile to arrive (was out of stock and had to wait for the new batch to be manufactured) but once it got here, I was pumped! Spent about three nights putting it together, taking my time to make sure everything was correct. And it tuned up wonderfully!

Next, it was time to find a key. I prefer iambic keyers but the only one I own is chrome Bencher set of paddles. It's just too heavy for a backpack radio like the QCX-Mini. So, I cruised the web and found a nice design on Thingverse. I fired up my 3D printer and went to work. I used the "mini" version which is very small. After a couple of days of fiddling with the fine-tuning, the keyer seemed to work well. I used magnets instead of a metal spring and it has a fairly nice feel. I built a 40m End-Fed Half-Wave antenna and picked up a neat 3Ah 12V Lithium-Ion battery pack recommended by a guy on Reddit. 

This past weekend, I took it along with the QCX-mini out on the trail during a trip to Arkansas. We got caught in the rain, so I didn't have a lot of time to use it, but I did send CQ for a little while and was very pleased.