I’ve been talking about field operations and a back-pack preference for all radio equipment since I’ve started documenting my journey on this site. I’ve finally managed to start putting things together for such an operation for myself¹.

And as always, here is the TLDR; version:

• What is in the bag
• Objective(s) I had for the operation
• Field site and the challenges
• Learnings from the testing
• Next steps before I head out

Criteria for the go bag!

• Back-pack, not more than 20l and I should be able to carry it on hikes/treks
• Flight-safe, as I can then carry it with me on different trips
• Self-contained
• Needs to be QRP!
• Back-ups for radios and antennas
• Single man deployment

What is in the bag?

Without much ado, here is my current version of the bag²:

What did I want to do?

The idea was to test this backpack version I had assembled for myself and the different components I was carrying,

1. Powering the radios with the power-bank and the USB-C to DC power cable.
2. Home-brewed vertical coil: This is based on SA2CLC’s design and something I wanted to carry when I go to the field as a back-up antenna.
3. Cables for the QMX with iPhone (specifically the data cables) for FT8 operation: QMX is a joy to operate, so I wanted to test if the cables and “camera adaptor” will work with the iPhone that has a lightening connector only.
4. SSB mic for the QMX/zBitx: Based on K6ARK’s design, I home-brewed two different SSB mics for the QMX and zBitx.
5. V2 of the software for the zBitx (both versions of the OS, JJ’s and the version released by Farhan): I flashed two versions of the OS on the zBitx on two different SD cards so I can test them in the field.
6. QRPickle functionality: Given that QRPickle was out in the wild, I thought I must give it a spin.

In addition, I wanted to check if it is easy to deploy this easily in the field.

Where was I?

I hadn’t really chosen the field site based on radio requirements, this was meant to be a weekend getaway of sorts where I happened to carry this bag. I was at MK81fm, which was bang in the middle of three possible sites for activating parks, IN-0041 ⁵, IN-0085 , and IN-0086. This did mean that I could have hiked over to one of the parks on one of the days or attempted a 2-fer in a couple of areas. Exciting times! The beautiful little place we did end up at was bang in the middle of a tea estate, was a fair distance away from humanity, and the right choice for a holiday. However, it was possibly the worst possible place for any radio activity! One portion had tea bushes, and no way to get an EFHW antenna up (I could try the vertical right? We’ll get to it shortly.) with the trees. There was small tight cluster of living areas and not much vertical support around. Here is a short video showing the final deployment of the EFHW:

Results from the field

And here are the results!

Powering the radios with the power-bank and the USB-C to DC power cable.

• What worked:
  • As you can see from the video, I was able to use the radio (individually) with the power-bank.
• What didn’t work:
  • Powering two devices from the power-bank didn’t work as the voltage automatically dropped to 5V instead of the required 9V and 12V.

Home-brewed vertical coil

The current manner in which I had configured the coil and the POTA20 mast I had significant help from my XYL⁶. Here is a picture of the coil and the past together anchored⁷ on a tree:

• What worked:

  • I seemed to have put the parts together! We didn’t have a blow-out.

• What didn’t work:

  • Pretty much everything else!
  • As I said, I needed help to actually fix the mast onto the tree stump. This was mainly because there wasn’t a place where I could actually put up a vertical without any obstructions or open enough space.
  • POTA20 is carbon-fibre and not fibre glass. So it is definitely not a good candidate for hoisting up a vertical radiating element.
  • Given that I wasn’t able to actually use the vertical, I wasn’t able to actually calibrate the coil well.
  • While I was flummoxed with the readings, VU3JIM that it is probably the tree that is causing the weird SWR readings (he wasn’t aware about my mast!), and that is when I realized the mast was the problem.
  • I checked the connectivity of all the solder joints when I came back as well to check if that was an issue too.

  

I guess this was a result of my enthusiasm and completely missing the important detail about propagation properties and materials.

Cables for the QMX with iPhone (specifically the data cables) for FT8 operation

• What worked:

  • Rx worked perfectly fine on the QMX on SSB
  • Rx worked flawlessly on two applications iFTx and FT Ham on the iPhone with the USB camera adaptor.
  • I was able to listen to the morning Belgaum Net on 7,150 kHz and a couple of other consistent chatter or nets at 7,123 kHz and 7,090 kHz. All three were loud and clear (44 to 59 depending on who was speaking) on the QMX with the headphones.

• What didn’t work:

  • Tx on the QMX with mic (more in the next section)
  • Tx on either of the apps for FT8, I switched between multiple cables but wasn’t able to pinpoint the issue. I think I should check with a different adaptor probably or maybe think about different way to operate the QMX.

  

SSB mic for the QMX/zBitx

• What worked:
  • Nothing!
• What didn’t work:
  • I couldn’t get either of the mics (slightly different configuration for the zBitx and QMX) to work with either of the radios.

V2 of the software for the zBitx (both versions of the OS, JJ’s and the version released by VU2ESE)

• What worked:
  • It wasn’t very hard to switch between the SD cards in the field for the zBitx.
  • Both the SD cards were perfectly fine in terms of no memory errors/read errors/etc.
• What didn’t work:
  • Neither of the versions of the OS worked in the field for the zBitx, thanks to the QMX I had carried that I was at least able to Rx across the board.

QRPickle functionality

❮ ❯

• What worked:
  • Seamless connection to the phone with the profile being switched.
  • The themes being switched were great, the low light visibility worked well.
  • Brightness adjustment worked well.
  • Sleep worked as intended.
• What didn’t work:
  • I need to add lat-long to the profile viewer/editor.
  • Band conditions was different on on-line sources and what was being displayed on the QRPickle.
  • Boilerplate text when loading POTA/SOTA/etc. information is loading or syncing.
  • APRS messaging was tricky, the messages seemed to go through (as seen in the image above), but wouldn’t be displayed on QRPickle.

Preparations before the next trip

A few very simple things before the next trip:

1. Test any firmware changes before I get to the field, I didn’t really plan this trip well in advance to test new firmware before I went away to the field.

2. Possibly create a working firmware “set” for the radios.

3. Check and double-check the material of any equipment I buy for radio work, does it interfere with signal propagation, conductivity, etc.?

4. Create a QRP dipole that might be easy to use with the POTA20.

5. Either create a (rigid) spacer mechanism for the vertical radiating element or buy a different mast for deploying verticals.

6. I had a really great “tree” available to me for the EFHW deployment, but unfortunately, without the plastic water bottle (the place I was at was in a disposable plastic free zone), and I didn’t have a throw bag/weight. Creating a throw bag that I can fill with rocks/stones at the field site. I have a prototype that worked well, now I need minor changes to it, basically to increase the size of the opening/mouth, reduce the length of the drawstring so it doesn’t catch any foliage up in the trees, better stitches, etc.

   

Bonus

Since, you stayed till the end, remember the community project I talked about earlier? About putting up the antenna? Well, one of the participants, talked about it on Instagram, and I realised that there is a radio audience on Instagram!

As always with my field operations, while largely indoor we did spot the Flameback, Orange Minivet, Brown-capped Woodpecker, Velvet-fronted Nuthatch, Pied Bush Chat, Red-whiskered Bulbul, Indian Robin, Nilgiri Sholakili, Grey Junglefowl, Purple Sunbird, Babbler, Common Myna, Crimson-backed Sunbird, Black-lored Tit, Indian White-eye, Tickell’s Blue Flycatcher, Heart-spotted Woodpecker, Indian Roller, Red-vented Bulbul, Barbet, Tailorbird, Swift, Orange-headed Thrush, Purple-rumped Sunbird, Golden-fronted Leafbird.

Here was my thank you to the folks who helped me finally put up the EFHW:

@online{vu3gljprebac2026,
  author = {Bharath M. Palavalli},
  title = {Preparing a back-pack for field operations},
  date = {2026-06-07},
  url = {https://ham.bharathpalavalli.com/posts/20260611182043-field_oeprations_and_preparing_a_go_bag/},
  language = {en},
  note = {Callsign: VU3GLJ}
}

Bharath M. Palavalli. 2026. "Preparing a back-pack for field operations", 07 June 2026. https://ham.bharathpalavalli.com/posts/20260611182043-field_oeprations_and_preparing_a_go_bag/.