Post by malewithatail on Apr 8, 2021 17:39:52 GMT 10
Below are some of my experiences with different types and brands of radios that I have considered for bugout use.
There are a couple of pre requisites for a radio to be considered for such use. Obviously, the main one is robustness, then comes battery life along with alternative charging methods, and finally, sensitivity and selectivity. Sensitivity means how sensitive the radio is, how well it can receive weak and/or fading signal. Selectivity is how well the radio can separate different stations that are close to each other. We are relatively lucky out here in that we don't have a lot of high power SW broadcasters within a few hundred Km of us, as they have on the continent.
Reliability is also up there, along with size/weight and controls that are not too flimsy to operate, or will break off when used under field conditions. Serviceability is lower on the list as you probably wont have anywhere to carry out major repairs as you will be on the move, hence the reliability factor rates high. However, after an EMP/CME event, all bets are off and unless stored in a faraday cage, the radio will probably not work anyway.
In relation to battery's, I prefer to carry a spare set of AA penlight rechargeables, that suit our torches, and a small solar battery charger. Oh yes, and the torches are bulb types, not leds, for EMP/CME proofness. It is easier to place the battery's in the charger and tie it to your pack in the sun, than it is to hand crank a generator charger, not to mention that most of the hand cranking gear I've seen is pretty flimsy and will probably not last too long under field conditions.
Lets get into a few of the radios I have.
Firstly, a unbranded, cheap shop one that has 8 bands, plus FM. The coverage is not continuous, but it does cover the usual short wave bands. This particular radio has been carried with me on numerous outings as well as in the glovebox of my ute for many years. Even though the dial is broken, and the dial cord broken, it still works and is reasonably sensitive. A good test for a radio is if it can pick up 2CH Sydney, 900Km away at night, at good strength. This radio can, as well as a lot of interstate stations. Short wave performance is adequate for the major international broadcasters, and FM performance is good. I think the radio cost less than $20 when I purchased it. The tuning is analogue, and it has no clock in it. Reliability ? It still works, as bashed around as it is. It takes 2 AA penlight battery's that last almost forever.
Next is the well known Kaito brand. This firm makes several good quality radios. Mine gave good service as a bedside radio for many years, until the clock died, then the digital display died, and finally the radio wont even switch on. Its probably over 20 years old now, so I would class it as reasonably reliable. The radio takes two penlight battery's that last for at least 6 months. It also came with a soft carry/travel case. It is microprocessor controlled, so when something happens to the micro, the radio is useless. Just a note. Most micros have a non volatile memory, E E prom or such as a flash disk has, and this "wears" with use, causing the small capacitor that stores the bit to gradually lose its charge, and eventually the memory gets corrupted. Flash disks will eventually all fail as well from the same process.
Digitech AR1740. Another Jaycar set, It has a clock in it, but is an analogue tuned radio, with a digital display. Its is now several years old and has stood up to the use quite well, apart from the case wearing the paint off. Its reasonably sensitive, just passing the 2CH test. Once again, two penlight batterys power it for a long time.
It has a switchable backlight, very useful in the dark.
The next contestant is another Jaycar set, the AR1733. Its a microprocessor controlled set, featuring 500 memory presets, a clock, alarm, and digital readout. It does offer almost continuous coverage of the short wave bands, as well as long wave (Pretty useless in Australia, but there are some non directional beacons from airstrips audiable). It also covers the FM and air bands, so you can listen to the aircraft traffic if you are near an airport. Its reasonably sensitive, but tends to chew up the 2 AA battery's in a few weeks of use. The soft carry case is thick, and offers good protection from knocks and scratches. It has provision for operation from rechargeable battery's and they can be charged from the USB port on the side. Its is supposed to have some sort of digital signal processing, but the audio is clear enough and it easily passes the 2CH test. Overall, a solid radio, although long term reliability is not known yet, it still has a place in my kit.
We now come to the homemade radio. Its a 4 transistor, one IC set, with one stage of untuned RF amplification, a regenerative detector, 2 audio preamp stages and a LM386 IC audio stage. It uses standard parts, nothing hard to get and all available from Jaycar, Altronics etc. Cost is about $20 to build, not including the case. The plastic box is actually a electrical junction box and is very robust. It covers all the short wave bands as well as the AM broadcast band. It can easily pass the 2CH test and operates for a long time from a standard 9 volt battery. Bands are switched from the front panel, and the speaker gives reasonable volume. It has an inbuilt telescopic aerial, and provision for external aerial as well as an external coil, to cover the 6 meter and 2 meter ham bands, albeit on AM or SSB only. It will resolve SSB on the short wave bands and is reasonable stable. I have a leather carry case that makes it reasonably weatherproof. It can receive the FM broadcast band, but you must use a technique called 'slope detection' as it doesn't have a limiter/discriminator for dedicated FM use. This involves tuning the station off center of the passband and advancing the regeneration to a level that is almost overload, giving detection of FM. Its quite distorted , but useable. Reliability ? Its almost infinitely repairable, so Id rate it as good. I've used it for a number of years now and its never failed me. Its been on several fire lines during call outs and has stood up well. Its one of a few radio designs that are totally undetectable. All modern radios radiate some RF hash, either from the microprocessor, or the local oscillator. This is detectable up to 100 meters from the radio. As long as you don't advance the regeneration control too far, this radio radiates nothing.
Lastly, the crystal set. This radio is in my bug out bag, ready to go. No battery's needed, no RF radiation, so undetectable, no microprocessor to go wrong, and a cheap crystal diode being the only part that could be damaged in and EMP event. Its disadvantages are that it needs a wire aerial, as long as possible and only operates a earphone. I've built a short wave version with a small transistor amplifier that can run for years from one AA battery, or from a homemade battery. Cost is about $20 from Jaycar, and its about the size of a credit card.
Enough for now, I will post more as I have time.
Almost forgot a classic brand of radio, first appearing in the late 1930's and lasting till the end of the 50's. Good, stable designs using quality parts and fittings, the Zenith Transoceanic range. My model is a 3000, dating from almost the end of the era in 1958. It covers all the major shortwave band, long wave and also FM. It has over 14 transistors and is in a substantial metal case with a swing out drawer that houses the operating instructions and frequencies of various world stations. (A bit out of date after 60 odd years !). It had a leaky transistor, which I replaced with a modern equivalent, but taped the old transistor onside the case for future reference. Apart from that, its totally original, and easily passes the 2CH test. Somewhat heavy at about 3 kg, but built to handle almost anything that comes its way. It uses germanium transistors instead of silicon types, and I think they sound more mellow than modern ones. Its audio stage can fill a house with music and news from anywhere in the world, just on its pull out rod aerial. Battery life is very good, with a set of d battery's lasting months.
There are a couple of pre requisites for a radio to be considered for such use. Obviously, the main one is robustness, then comes battery life along with alternative charging methods, and finally, sensitivity and selectivity. Sensitivity means how sensitive the radio is, how well it can receive weak and/or fading signal. Selectivity is how well the radio can separate different stations that are close to each other. We are relatively lucky out here in that we don't have a lot of high power SW broadcasters within a few hundred Km of us, as they have on the continent.
Reliability is also up there, along with size/weight and controls that are not too flimsy to operate, or will break off when used under field conditions. Serviceability is lower on the list as you probably wont have anywhere to carry out major repairs as you will be on the move, hence the reliability factor rates high. However, after an EMP/CME event, all bets are off and unless stored in a faraday cage, the radio will probably not work anyway.
In relation to battery's, I prefer to carry a spare set of AA penlight rechargeables, that suit our torches, and a small solar battery charger. Oh yes, and the torches are bulb types, not leds, for EMP/CME proofness. It is easier to place the battery's in the charger and tie it to your pack in the sun, than it is to hand crank a generator charger, not to mention that most of the hand cranking gear I've seen is pretty flimsy and will probably not last too long under field conditions.
Lets get into a few of the radios I have.
Firstly, a unbranded, cheap shop one that has 8 bands, plus FM. The coverage is not continuous, but it does cover the usual short wave bands. This particular radio has been carried with me on numerous outings as well as in the glovebox of my ute for many years. Even though the dial is broken, and the dial cord broken, it still works and is reasonably sensitive. A good test for a radio is if it can pick up 2CH Sydney, 900Km away at night, at good strength. This radio can, as well as a lot of interstate stations. Short wave performance is adequate for the major international broadcasters, and FM performance is good. I think the radio cost less than $20 when I purchased it. The tuning is analogue, and it has no clock in it. Reliability ? It still works, as bashed around as it is. It takes 2 AA penlight battery's that last almost forever.
Next is the well known Kaito brand. This firm makes several good quality radios. Mine gave good service as a bedside radio for many years, until the clock died, then the digital display died, and finally the radio wont even switch on. Its probably over 20 years old now, so I would class it as reasonably reliable. The radio takes two penlight battery's that last for at least 6 months. It also came with a soft carry/travel case. It is microprocessor controlled, so when something happens to the micro, the radio is useless. Just a note. Most micros have a non volatile memory, E E prom or such as a flash disk has, and this "wears" with use, causing the small capacitor that stores the bit to gradually lose its charge, and eventually the memory gets corrupted. Flash disks will eventually all fail as well from the same process.
Digitech AR1740. Another Jaycar set, It has a clock in it, but is an analogue tuned radio, with a digital display. Its is now several years old and has stood up to the use quite well, apart from the case wearing the paint off. Its reasonably sensitive, just passing the 2CH test. Once again, two penlight batterys power it for a long time.
It has a switchable backlight, very useful in the dark.
The next contestant is another Jaycar set, the AR1733. Its a microprocessor controlled set, featuring 500 memory presets, a clock, alarm, and digital readout. It does offer almost continuous coverage of the short wave bands, as well as long wave (Pretty useless in Australia, but there are some non directional beacons from airstrips audiable). It also covers the FM and air bands, so you can listen to the aircraft traffic if you are near an airport. Its reasonably sensitive, but tends to chew up the 2 AA battery's in a few weeks of use. The soft carry case is thick, and offers good protection from knocks and scratches. It has provision for operation from rechargeable battery's and they can be charged from the USB port on the side. Its is supposed to have some sort of digital signal processing, but the audio is clear enough and it easily passes the 2CH test. Overall, a solid radio, although long term reliability is not known yet, it still has a place in my kit.
We now come to the homemade radio. Its a 4 transistor, one IC set, with one stage of untuned RF amplification, a regenerative detector, 2 audio preamp stages and a LM386 IC audio stage. It uses standard parts, nothing hard to get and all available from Jaycar, Altronics etc. Cost is about $20 to build, not including the case. The plastic box is actually a electrical junction box and is very robust. It covers all the short wave bands as well as the AM broadcast band. It can easily pass the 2CH test and operates for a long time from a standard 9 volt battery. Bands are switched from the front panel, and the speaker gives reasonable volume. It has an inbuilt telescopic aerial, and provision for external aerial as well as an external coil, to cover the 6 meter and 2 meter ham bands, albeit on AM or SSB only. It will resolve SSB on the short wave bands and is reasonable stable. I have a leather carry case that makes it reasonably weatherproof. It can receive the FM broadcast band, but you must use a technique called 'slope detection' as it doesn't have a limiter/discriminator for dedicated FM use. This involves tuning the station off center of the passband and advancing the regeneration to a level that is almost overload, giving detection of FM. Its quite distorted , but useable. Reliability ? Its almost infinitely repairable, so Id rate it as good. I've used it for a number of years now and its never failed me. Its been on several fire lines during call outs and has stood up well. Its one of a few radio designs that are totally undetectable. All modern radios radiate some RF hash, either from the microprocessor, or the local oscillator. This is detectable up to 100 meters from the radio. As long as you don't advance the regeneration control too far, this radio radiates nothing.
Lastly, the crystal set. This radio is in my bug out bag, ready to go. No battery's needed, no RF radiation, so undetectable, no microprocessor to go wrong, and a cheap crystal diode being the only part that could be damaged in and EMP event. Its disadvantages are that it needs a wire aerial, as long as possible and only operates a earphone. I've built a short wave version with a small transistor amplifier that can run for years from one AA battery, or from a homemade battery. Cost is about $20 from Jaycar, and its about the size of a credit card.
Enough for now, I will post more as I have time.
Almost forgot a classic brand of radio, first appearing in the late 1930's and lasting till the end of the 50's. Good, stable designs using quality parts and fittings, the Zenith Transoceanic range. My model is a 3000, dating from almost the end of the era in 1958. It covers all the major shortwave band, long wave and also FM. It has over 14 transistors and is in a substantial metal case with a swing out drawer that houses the operating instructions and frequencies of various world stations. (A bit out of date after 60 odd years !). It had a leaky transistor, which I replaced with a modern equivalent, but taped the old transistor onside the case for future reference. Apart from that, its totally original, and easily passes the 2CH test. Somewhat heavy at about 3 kg, but built to handle almost anything that comes its way. It uses germanium transistors instead of silicon types, and I think they sound more mellow than modern ones. Its audio stage can fill a house with music and news from anywhere in the world, just on its pull out rod aerial. Battery life is very good, with a set of d battery's lasting months.