Guest Post: Backpack-Shack radio listening

Many thanks to SWLing Post contributor TomL, who shares the following guest post:

Illustration 1: Main contents

Backpack-Shack radio listening

by TomL

So, the Car Shack idea was good, but I felt constrained by lack of access to better locations to listen to shortwave radio. I took most of the original equipment and stuffed it into a photo backpack I was not using and now I have a portable listening station. Now I can listen in my car or in the field fairly easily.

LowePro350AW – The backpack has three main compartments, integrated carry handles, nice padded waist belt, and a couple of ways to stick a 3/4-inch PVC pipe into external tripod or water bottle pouches. My homemade 14-inch loop antenna with Wellbrook amplifier is light enough to be attached to a 3-foot PVC pipe attached to the backpack. The Palstar preselector (active antenna) and KIWA BCB filter are still part of the portable setup. I added a Daiwa two-position switch to cut out the KIWA BCB filter so I can listen to mediumwave. Power for all these devices are Powerex AA’s for the Sony 2010 and two 12V power packs made from three sets of XTAR 14500 lithium batteries + one dummy AA. I have mounted the electronics and wires using large cable tie-wraps to a 14×10 inch polypropylene kitchen cutting board (sturdy and easy to drill through).

Illustration 2: The electronics board fits neatly into the laptop section of the backpack

Illustration 3: Backpack Shack in operation

Here are some recordings from two test outings around 2100-2200 hours UTC. A local county park (“Forest Preserve”) purposely has few man-made structures (just a trail, picnic shelter made of wood and an outhouse). It is about 15 minutes drive from where I live; the reception is notably clear of local noise. There is an occasional wide-band noise that comes and goes but nothing else I can identify as detrimental noise and it is mostly just a nuisance.

Cuban Numbers station on 11635 kHz:

Click here to download.

VOA from Santa Maria di Galeria, Italy in French on 12075 kHz:

Click here to download.

All India Radio on 11670 kHz:

Click here to download.

BBC Ascension I. on 11810 kHz:

Click here to download.

R. Guinea with music and announcer on 9650 kHz:

Click here to download.

A big downside of the Forest Preserve, like most parks now, is that it is ONLY open from sunrise to sunset and strictly enforced. So, my personal quest for nighttime access to an RF-quiet location continues (I guess I will have to buy/build my own)! It begs for an even more portable setup than this one. That means buying an SDR (with control via a tablet), miniaturizing the antenna, and modifying the lithium power packs to fit in a very small backpack or fanny pack.

If I can miniaturize it enough, I will be able to use common parts of this setup at home, in the car, and at field locations for either mediumwave or shortwave listening. I could then pre-install the unique parts in those situations and just plug-and-play, so-to-speak!

It could be that the continuing tech wave of small, powerful, wide-band equipment is causing a revolution in general. A type of radio revival may be at hand where regional radio starts to take a foothold, catering to a multi-state area and not just to one local metro area – with its one-city mindset and control (Do I really care that the Big City is installing a downtown-only, 12 million dollar bike and jogging connection + hearing endless whining about how bankrupt pensions are putting that County at risk when I never go there and don’t care to?). Portable wide-band radios allow for hours of listening to various types of broadcasts!

An example could be to use digital broadcasts over longwave (somewhere from 150 kHz-500 kHz) which allows ground wave signals to travel hundreds of miles reliably during the day or night without depending on variable skywave propagation. Digital would enhance the listener experience in stereo. It would probably need a narrower type of digital modulation since the current “HD Radio” standard is really too wide and splatters everything at adjacent frequencies. Pure wishful thinking but the technology is available to make something NEW happen!!

Cheers from NoiZey Illinoiz,

Thank you, Tom! You certainly have the right idea: taking your radio to the field! Keep us informed about your progress and updates. No doubt, over time you will discover a year-round spot to play radio in the field!

Spread the radio love

14 thoughts on “Guest Post: Backpack-Shack radio listening

  1. Michael Black

    Wouldn’t some prefer an attaché case for their portable station? A nice one with foam cut so each item firs perfectly.

    Sony sort of did that with the ICF-SW1S, though no place for a better battery.

    Collins sold a suitcase for carrying the KWM-2, and a portable power supply. I did see the suitcase up close once, it didn’t look like anything special.


      1. TomL

        Yes, I like very much this SDR setup and it is a great detailed article. I think we need more detailed articles to inspire people to experiment more and try their hand at it.

        I am looking for something more portable I can wear on a belt. I don’t like to carry a briefcase when hiking/walking, not good for my back.

        1. London Shortwave

          Thanks Tom, and you’re right – it certainly isn’t the most portable of set-ups, especially for hiking. I’m looking forward to reading about your future solutions to this issue! Many thanks and 73s.

  2. Jim

    Maybe a nearby state park that has overnight camping? We are lucky here in East Tennessee to have access to the Foothills Parkway of the Great Smoky Mountains. Plenty of pull-offs for both star gazing and dx and open 24/7. And a lot of nearby state parks if you want to do proper overnight camping.

    1. TomL

      I have tried camping successfully but did not like the cold weather and trips to the bathroom! I will be looking to miniaturize things even more….

  3. TomL

    This was the main inspiration for the homemade loop but he uses 1 meter aluminum straps, very heavy and he welds it together: New Homebrew Magnetic Receive Loop at VE1ZAC.htm

    I just used thin copper sheet and added one extra loop to increase the spatial window or capture area. I just guessed at the spacing between them making it proportional to the design above.

    I actually would rather not have to carry it around, so it may stay home to use on mediumwave. I am looking into a creative, portable use of the DEGAN DE31MS loop antenna but I may use the same Wellbrook amp……

  4. TomL

    Thanks for posting. The next step will be for a fannypack with an SDR and small antenna. I don’t want to be tied to an antenna thrown into a tree. I want to be able to walk and hike while I listen, literally a portable setup anyone can use. I just don’t have the money yet for getting a tablet or PC too to run the SDR. But the battery packs can be small enough and the SDR’s have all the features needed. Looking into the SDRplay2 or the AFEDRI, among others.

    As far as longwave, that was just daydreaming about something as ubiquitous as mediumwave and FM but at a frequency range that has stable propagation characteristics for daytime and nighttime usage. Technically it should work but whether there is political will to make it happen is another story. Vested interests would also not be happy with losing customers to something freely available without a monthly fee to charge…… makes everyone dependent on their choice of news and entertainment for us.

    1. Kire

      I like your wish about longwave broadcasting. Though there are many pessimists who know much more than I, and say shortwave is dead, I feel shortwave is the only hope for radio. So many kids(and adults) I know do not listen to radio anymore because there is nothing to interest them, Its almost all politics, religion, or music that we’ve heard a million times before. Low power FM is limited to a tiny audience. The internet is, well its the internet, not radio, you’ve got to pay for it.
      My Christmas wish is for a shortwave station, located somewhere with abundant cheap electricity, some decent financial backing, some good high KW transmitters and enough radio host/engineers to provide something that we wouldn’t want to miss.

    1. TomL

      This previous post has better pics of the loop antenna which uses 14″ quilters loops from any craft store.

  5. London Shortwave

    Greetings from a fellow field SWLer! You have a wonderful set-up, I especially like how you designed your own loop antenna that’s more portable than the original Wellbrook loop yet uses its broadband amplifier. Congratulations on all the catches, especially the Cuban numbers and the transmission from Guinea. Best wishes and 73s.

  6. Edward

    Hmmmm “digital broadcasts over longwave (somewhere from 150 kHz-500 kHz)” Good use for that spectral wasteland. but would be concerned about locking it up to rent seeking “pay radio” schemes like XM and dish etc. Maybe we should carve out a ham band in there somewhere.

  7. John leonardelli

    What a great kit for portable SWLers. Who says all the ham radio mountain toppers and picnic table operators have all the fun. Good to see great use on the “high end” accessories that make a big difference in receiving signals. I would have been happy after the cuban logging and deemed the outing a success. I have had great success using my metal coffee thermos as a ground/counterpoise which has helped improve readability at times and the DC version of the Autek Qf-1 filter. Hurry up on Radio Australia loggings


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