User Tools

Site Tools


ubitx:introduction

Introduction to my rig project

I've ordered a uBitx V5 and my project is to make a small go box to be portable with no risk of breaking something on the move.

The goal of this go box is :

  • to be not so big to be carriable easily in a backpak
  • to have it's own energy to last about a day
  • to be also ergonomic and fun to use in the QRA (so, I'll keep some comfortable knobs)
  • to have a connection for a RTL SDR when used at the QRA
  • to be installed in a box with no holes (so you need to open the cap to use the radio, like SOTA boxes for example)
  • if possible and if it's not to big, to be able to carry also small materials like earplugs, mic, notebook + pencil, etc.
  • with an internal speaker which can be switched on or off to be able to share the contacts with my family or friend
  • with USB panel connector to connect CAT on computer a clean way

I'll use this radio at the QRA, but also for SOTA or SOTA like activations (on hills around my QRA for example) and when moving for work (that I do often) to use in hotel rooms for examples.

Box

At first, I wanted to put the whole project in a cookie metal box, because :

  • it's cheap
  • it can be small (or you can find lot of different sizes at the supermarket)
  • it's lightweight
  • you can eat the cookies inside before ;-)
  • it's open source friendly, to keep the philosophy of the global project
  • it can be watertight quite easily (if there are no holes, you can use electrician tape all around the cap to have it protected from water)
  • with a metal box, you can shield the whole radio

I've in first thought thinked about a Pelicase or something like that. It's so badass and look like terrific !

But the main problem is the size of the global case (could be difficult to fit in a bag for a 25x25cm box), heavy (beetween 800g and 1200g for the size I speak about) and could be quite expensive.

After some designs and research, I've found that it will be difficult to put everything in a cookie box. The boxes I've at home are not the good size (too small or way to big).

Finally, I decided to go with a box made from scratch, based on 3D printed parts and also Dibond (PE + aluminium) sheets). You'll find more informations about the enclosure in the right page.

Battery

I've some experience with 18650 lithium cells (I've already built several e bikes with lot of them). It's quite cheap, very reliable, and easy to solder (with a point to point soldering unit that I've built).

Also, you can configure the battery pack shape as you to fit in tiny spaces.

As the ubitx is about 10W output, I think the global power should not exceed 25W when transmitting.

I'll make a 3S battery pack (3x 4.2V fully charged, so 12.6V), and I've ordered 3300 mAh cells. I'm thinking about making a 3S4P battery pack, so the capacity will be 13200 mAh.

It will give about 8 hours of transmitting time with that very simple calculations. It could be maybe a bit overkill but with that you can last a whole WE if needed. Also, you don't have to check everytime before you go if the battery is still OK.

Antenna

The main panel will have a PL259 socket to install all sort of cables or antenna.

At the QRA

I'll certainly use an endfed antenna system, connected with a coax cable like the QRPguys end fed system which is simple : https://qrpguys.com/qrpguys-end-fed-wire-antenna

When moving

I've ordered a Watson ATX Walkabout MK2 which should give me (even it's not the best efficiency) a simple way to connect directly the antenna on the PL259 socket and have it attached to the rig.

Maybe a small tuner for wire antenna like this one if I can deploy wire antenna : https://qrpguys.com/multi-tuner

All the informations here can vary during the experiment time and with design concern. But I prefer to leave the firts ideas here to see the differences at the end !

ubitx/introduction.txt · Last modified: 2019/09/11 23:06 by f4ija