Even though portable SW radios have come a long way in recent years and using one outdoors with a well planned antenna can sometimes bring surprising results, I don’t want to deal with their fiddly buttons and tuning limitations for this years summer field days, so instead one of my pair of Realistic DX394’s is making its way out of the house for the first time.

Although its a little on the bulky side, there’s thankfully not much weight to it and don’t see a problem once its thrown (carefully) in with all the other camping gear.

Powering the DX394 for a Few Hours

The DX394 can either be powered from the mains or a 13.8 volt DC socket on the back panel of the radio. Working up a cheap battery pack wasn’t that difficult with all the bits available from my local (and hideously overpriced) electronics store.

Could have lugged along a nice tidy Yaesu battery to do the job, but once that’s gone flat there’s no chance of charging it while sat on top of a mountain late at night and they do tend to weigh a lot, so using a bunch of AA batteries makes its quick enough to swap them out once they’ve been eaten up.

dx394 portable battery pack

13.5 Volt(ish) Battery Pack

Initially I tried the radio on 12 volts only, just to see how it would preform. Everything seemed to work OK but didn’t want to take the chance that once the battery voltage slips below that 12 volt mark things may well go down hill.

For some reason it does seem weird making a portable power source with an odd number of batteries and provided it keeps the radio going for at least a few hours, it would have done its job 🙂

Fancied getting hold of a dummy battery to fill the last space in the holder and even after explaining the concept to the slightly clueless shop workers in the limited local electronics store, they still couldn’t get their collective heads around it (amusing and annoying at the same time).

Got around the missing battery in holder by running a wire wedged under the last cell to where the PP9 connector joins the pack.

I could have broken out the soldering iron and tacked a permanent wire, although these holders are pretty flimsy when it comes to heat and I may want to use it for something else down the line.

Extending Battery Life

The stated current is only 450ma and this can always be kept to a minimum by turning down the display brightness and eliminating one of the biggest current drains on portable radios by using headphones instead of the (power hungry) built in speaker.

Result!

Surprisingly the current drain when run in the state listed above is only 125-130ma!. Interesting for such a big radio and good news for me as its not going to chew through the battery pack too quickly.

Have a nice quality pair of Sennheiser in ear headphones with the bit that fits behind the ear (so I don’t have to keep messing around putting them back in every 5 minutes) and provided I’m prepared to sit in the dark, having the display back light turned right down isn’t going to be a problem.

sennheiser in ear headphones

Great Sounding Sennheiser in Ear Headphones of the Non Falling Out Variety

Dealing with the Power Cord

There’s enough wire being loaded into the backpack with the addition of a homemade (and highly experimental) 160 meter longwire and could really do without having to work around the mains flex attached to the radio.

Luckily the flex has already been cut back as I had run out of plug space at some point leaving no choice but to wire a few pieces of equipment into the same mains plug (I know its a bodge!).

Cosmetically the outside case of this DX394 isn’t in the best shape and I can only take blame for some of it. It is however all in working order and was very cheap to buy :). I’m not really hung up on how a piece of radio gear looks provided it does what its meant to do.

realistic dx394 back panel

Good Job Black Electrical Tape is So Cheap!

Did consider taking the mains cable out altogether but this means opening up the radio, which is something I like to avoid as this one has never had the lid off (at least not by me anyways) and don’t like messing around inside shortwave receivers unless absolutely necessary.

Taping the cord flat to the bottom of the radio keeps it out of the way completely, while also making it quick to reattach the other piece of mains cable once the receiver gets back home.

Testing?

Everything tells me that this battery setup should give enough play time with the radio to have a blast and I could always double check by timing how long it all lasts just by leaving the DX394 running at home, but batteries aren’t cheap and chewing through a full set doesn’t seem right somehow.

The addition of an extra set of batteries will ensure a full night of use (especially with the low current drain) with the option to accept extra weight by upgrading the pack from AA’s to heavier D cells if things end too quickly!.

Cautious Waterproofing

The summer months don’t see me using a tent much (bed roll and sleeping bag only) but this doesn’t offer much protection from those freak downpours that the British summer loves to launch at us with very little warning.

The radio will get a good wrap before heading out and suffering carrying the extra weight of a tent means the rains not going to bother me, along with the chance to setup a nice little radio shack high up on a mountain (radio heaven) 🙂

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