Emergency shortwave radio help

[jgiercyk]

All - over the years I've collected my share of "emergency" AM/FM/SW radios. You know, the kind with the hand crank and solar panel, able to charge your cell phone when the SHTF. None of them have a jack for an external antenna.

It is certainly possible to lose local AM and FM, and find yourself without power and looking for information on SW. I've got plenty of wires in the air that will get the job done. Is there such a thing as an emergency radio that allows for an external antenna to be used? Certainly there are some portable SWL radios that will do the trick, but their batteries will inevitably fail. I'm looking for a unit that will power itself and receive SWL signals using an external antenna. Any ideas?

 

[N1EXA]

All - over the years I've collected my share of "emergency" AM/FM/SW radios. You know, the kind with the hand crank and solar panel, able to charge your cell phone when the SHTF. None of them have a jack for an external antenna.

It is certainly possible to lose local AM and FM, and find yourself without power and looking for information on SW. I've got plenty of wires in the air that will get the job done. Is there such a thing as an emergency radio that allows for an external antenna to be used? Certainly there are some portable SWL radios that will do the trick, but their batteries will inevitably fail. I'm looking for a unit that will power itself and receive SWL signals using an external antenna. Any ideas?

You mean a crystal radio .

Pete N1EXA

 

[mmckenna]

If the crank radio has an extendable antenna, you can clip one of your wire antennas on to that.
But be careful, usually those radios won't take a strong static electricity hit very well.

There are lots of suitable AM/FM/SW radios that will run off AA batteries. Get a solar charger or an external crank charger. That would open up the radio possibilities quite a bit.

 

[MUTNAV]

If the crank radio has an extendable antenna, you can clip one of your wire antennas on to that.
But be careful, usually those radios won't take a strong static electricity hit very well.

There are lots of suitable AM/FM/SW radios that will run off AA batteries. Get a solar charger or an external crank charger. That would open up the radio possibilities quite a bit.

and you can get a crank charger of whatever quality you want.

Thanks
Joel

 

[MUTNAV]

On the MW ultralight sites, they have plans for modifying a radio to have an external antenna jack, as well as ideas for replacing the normal small antenna in the radio with an external antenna.

Hope this actually helps

Thanks
Joel

 

[MUTNAV]

To be specific

http://peditio.net/utility/pdf/Adding_a_MW_Antenna_Port_to_Tecsun%2520DSP_Ultralights.pdf#:~:text=The%20basic%20strategy%20proposed%20in%20that%20first%20article,receiver%2C%20automatically%2C%20to%20the%20Unlimited%20Class%20of%20Ultralights.

 

[jgiercyk]

Outstanding idea in the long run!

 

[jgiercyk]

You mean a crystal radio .

Pete N1EXA

Yes. excellent direction. I have a few I've built but without a dynamic amp inline they don't do a great job on HF frequencies. But, I like the way you think!

EDIT: On second thought I may give them a try again.....I haven't really used them since the SW stations cut back on broadcasts and I am in a new QTH with new antennas. I'll give it a run....I like this idea a lot.

 

[MUTNAV]

Another option is to actually transplant an antenna, removing the internal loop-stick and replacing it with a larger external one....

With the crystal radios, there are some ideas that can improve their abilities a little.

January 2007 of QST has an article on a very high sensitivity crystal set
There is also (for MW ) the Lynodyne 17

CRYSTAL SET DXing

or for SW also

Build a Crystal Shortwave Radio

If you enjoy that kind of thing.

Let us know what you decide?

Thanks
Joel

 

[N1EXA]

Yes. excellent direction. I have a few I've built but without a dynamic amp inline they don't do a great job on HF frequencies. But, I like the way you think!

EDIT: On second thought I may give them a try again.....I haven't really used them since the SW stations cut back on broadcasts and I am in a new QTH with new antennas. I'll give it a run....I like this idea a lot.

You need a regeneration circuit on the crystal radio to increase the sensitivity.
When you build an hd/sw crystal radio you have multiple tank circuits to increase the gain to the point you drive the regeneration circuit. You can use a high impedance telephone ear piece to listen no need for a powered audio amp.
Long wire is needed to pick up rf energy
To drive the circuit.

Pete N1EXA

 

[Boombox]

You can use radios with no external antenna jack with a longer wire antenna by induction, or the 'proximity effect'. Either loop some of the feedline around or near the radio, or place the whip near the end of the feedline. Or you can wrap the feedline around the radio... Or you can wrap some wire around a round tube (even a paper towel or TP tube can work,.

PS, in a major disaster scenario, SW may not be as useful as long distance, night time AM radio for vital news and information.

 

[MUTNAV]

You need a regeneration circuit on the crystal radio to increase the sensitivity.
When you build an hd/sw crystal radio you have multiple tank circuits to increase the gain to the point you drive the regeneration circuit. You can use a high impedance telephone ear piece to listen no need for a powered audio amp.
Long wire is needed to pick up rf energy
To drive the circuit.

Pete N1EXA

Can you go into more detail about how the multiple tank circuits increase gain.

Thanks
Joel

 

[N1EXA]

A basic crystal radio has a coil and capacitor and when it resonates on the frequency it’s tuned for the max signal is
Achieved. The diode will demodulate the audio to the earpiece. But what if you feed the tank circuit through a capacitor to another tank circuit which is tuned to the same frequency you will get more signal.
You can do this in chain of them.

 

[KB2GOM]

The CCrane Skywave SSB 2 receives AM, FM, SW, HF SSB, weather and airband, has an adaptor and socket for plugging in a wire antenna and will run for about 60 hours on a couple of AA batteries. That would be my recommendation for an emergency radio.

My thoughts about it are here: Checking out the new C.Crane CC Skywave SSB 2

My preference for an emergency radio would be to go for the radio performance first and then figure out a way to power it with crank or solar recharging.

You might also be interested in this, regarding "What do you want in your radio kit bag when faced with a longer duration, more severe regional or national emergency?" : The fertilizer hits the fan radio kit

Cheers, Jock

 

[eorange]

PS, in a major disaster scenario, SW may not be as useful as long distance, night time AM radio for vital news and information.

I was thinking the same thing, figuring all the religious stations would just be in nonstop overdrive.

 

[Boombox]

I was thinking the same thing, figuring all the religious stations would just be in nonstop overdrive.

Yeah, and also because I live in an area prime for a 9 point earthquake, something like that would probably take a lot of locals off the air, and the best means of radio information would be MW stations from east of the Cascade Mountain range, or south in California, many of which have great signals to this area.

 

[majoco]

Goggle for: "Kaito emergency radios" - heaps of info

 

[krokus]

Having owned a couple crank radios, including with solar, I can say do not rely on them for long play. It takes a lot of solar, for a couple hours of radio play. It takes quite a bit of cranking, for a few minutes of radio play.

Jock had a good suggestion, get a setup for charging rechargeable AA cells, and use a radio powered by AA. You can stockpile a lot of alkaline, cheaply. (Warehouse club, home center, etc. They can also power small camping lanterns.)

 

[N1EXA]

Yes. excellent direction. I have a few I've built but without a dynamic amp inline they don't do a great job on HF frequencies. But, I like the way you think!

EDIT: On second thought I may give them a try again.....I haven't really used them since the SW stations cut back on broadcasts and I am in a new QTH with new antennas. I'll give it a run....I like this idea a lot.

The MFJ-8100 runs on a 9 volt Battery and can be solar powered - Not a Powerless Crystal radio but A regenerative receiver that uses little
to no power. I run one an listen to WRMI out of Miama on 5.950 Mhz almost every night. I needs a dedicated Antenna tuner and somthing
as easy as a vertical 5/8 Wave Cb antenna. Ive tried a Long Wire and the Impedance is way off for the receiver to function at Maximum Performace.

Pete N1EXA

 

[MUTNAV]

To the original question about connecting an external antenna.

http://peditio.net/utility/pdf/Antenna_Couplers.pdf

Has a good description (with pictures) of some options.

Another idea is a radio using a FET, the one in the following article (reportedly) doesn't require an external antenna for MW, although for a SW variant, an external antenna was used.

http://arrl.org/files/file/Technology/tis/info/pdf/culter.pdf

for headphones, you could try making your own piezo headset or speaker.

I also have to agree with previous posts regarding power sources....

I have to admit though, in concept, the all in one radios like a Kaito KA-600L looks really attractive
(AM/FM Shortwave radio+ a light, and with the addition of some nichrome wire and USB plug- a fire starter, that is power-able by Cranking, Solar, Internal batteries, External source). In reality I'm afraid for an emergency radio, it could fall short. Just improving the power system might be super useful . ie. large solar panel, way better crank generator, better emergency light, (joule thief style). But at least they're easy to throw into peoples bags.

Back to antennas, it might be worthwhile to at least think about "interference reducing antennas" that were simple and intended for people to make in communist countries so that the people there could here western stations despite jamming.

Thanks
Joel