Delta Charlie Four Lima Whiskey – DC4LW

I wanted to take part in the Berlin UrbanHamRadio activities with my own equipment. But I did not want to buy a new TRX for portable usage. My iCom IC-7000 is more or less portable – at least it fits in my backpack and can be powered with 12V.

After some research I found out, that I can use it with a standard Lithium-Polymer (LiPo) cell for RC racers. It costs about 50 EUR and if you don’t own a proper charger, you need to buy one as well (and a LiPo carrying bag). It’s a four cell LiPo with 14,4V voltage, which I can directly insert to the IC-7000 (it works best with 13.8V±15%, so from 11.7V up to 15.8V).

The LiPo is equipped with an EC5 plug, so I soldered the proper pins to the power cable for the IC-7000. The good thing about this LiPo: it can release up to 20 times its capacity as current. This is a 5Ah battery, so it can provide up to 100A for a short period of time. With RC racers this is needed for the start-up momentum. But I can also have some advantage during TX, when I want to use up to 100W of the TRX. Although the IC-7000 drains up to 22A at 100W transmit, I’m far away from any unsafe usage.

Talking about battery drains. Unfortunately the IC-7000 is equipped with a bright LCD and a lot of circuits. It’s far away from low power consumption. In idle receive mode it drains about 1.5A. With a battery of 5Ah I can use that for a bit more than 3 hours. Time drops rapidly with every transmit.

But it was time enough for several nice afternoons in the park! The small LEDs on the battery pack signal the remaining capacity. And we were lucky enough to bring a second battery pack just for the single time, when we wanted to end this QSO with Cornwall.

Unfortunately all the needed equipment is not portable enough for climbing on mountains. I need at least the IC-7000 (2.5kg), the battery pack (500g), the power connector (500g), probably the external tuner (700g), antenna and cables (4kg). So already about 10kg of stuff. But it’s okay for the city and carrying around on my bike and having a nice Sunday afternoon in the park!

We are ham radio operators living in a metropolitan area.

We don’t own land, a garden, a house or even a car.

We can’t build large antennas for permanent usage.

We have to struggle with the QRM (interference, noise) from the city.

We work with almost QRP (reduced power).

We love HF bands and the greyline.

We carry our ham radio equipment in our backpacks to high locations inside the city.

We are visible to citizens, strollers and joggers.

This describes our ham radio activities. We is a group of several ham radio operators living in Berlin, who meet each other spontaneously in the evening after school, university, work or at weekends for some activities. There is no fixed place where we just can use our equipment. This needs to be carried to the destination. Each time we have to build up the antenna and the TRX.

Thanks to recent transceiver technology and high power rechargeable batteries it’s possible to carry HF equipment in an average backpack. Berlin features several parks with hills inside, which are perfect for a temporary ham radio session. A GFK pole is a great helper for the antenna. A TRX with filters is also highly suggested. Nice to have is a tablet PC with data connection for DX-cluster access and logging.

We were amazed, that we can work all Europe and even transatlantic SSB-connections to the North-American east coast – with 10W output power reduced by cables and couplers. And we get in touch with interested persons who ask what we are doing. Sometimes this results in interesting stories from their own past.

As we meet spontaneously, we most probably will just give a shout out on Twitter with #BerlinUrbanHamRadio. Feel invited to join the group or start your own Urban Ham Radio session!