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Author Topic: General Coverage Survival Receiver  (Read 648 times)

swxx

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General Coverage Survival Receiver
« on: August 25, 2017, 09:03:03 AM »
I've been out of the radio scene for 20 or 30 years and I haven't a clue about what radios there are around now, other than the QRP transceivers, which I have researched. So I'm looking for advice here: I have decided the way to go in the absence of a good survival radio, as mentioned in another thread by Gil, that there is not one out there that does ALL the things we would want: 80, 40, 30, 20m at least, on TX, and general coverage at least 5-15 more MHz with wide filter for SSB/AM (even if in SSB). Low current consumption, long life on small batteries, light weight, not too flimsy or prone to breaking.

So I think I need TWO at least: one perhaps the PFR-3b which does 20/30/40m CW and has almost everything I'd need, and a SECOND one for receiving only. Ideally SSB/CW can be as one, no need for AM, so long as the receiver is sufficiently wide. I have NO PROBLEM with a Direct Conversion receiver, in fact, this could be better, as you can hear 3kHz up AND down. I'd want one that does not drift much, is easy for tuning, ie. you don't touch the knob barely and it already shifts 10kc randomly. Low current consumption, light weight, low in price, even a kit that can be built. Not necessarily having digital display, but ideally some way I can return to a frequency.

Any ideas? Do such receivers exist at all, or is everything only amateur radio QRP and QRO transceivers these days?

paul5.wolf

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Re: General Coverage Survival Receiver
« Reply #1 on: August 25, 2017, 10:56:29 AM »
An SDR solution?  I'm not a ham.  But I bought the Air Spy with SpyVerter to get lower frequencies up to L Band.  I have to take the SpyVerter in and out of the signal path.  I got it to play with.  Nevertheless, it might be good to ask around, if you're only trying to receive.  And I would love to hear your decision!  (I'm studying to try testing for zero to extra class right now.)

Sent from my Pixel XL using Tapatalk


swxx

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Re: General Coverage Survival Receiver
« Reply #2 on: August 25, 2017, 11:35:07 AM »
Hi Paul Wolf, yes I'll share what I come up with. For now I have no idea, hoping someone can suggest something for RX. But SDR, I know little or nothing about them, but I'm very mistrustful of new technology where you can't see discrete components and things need software. I want just hard ware. It's same with cars. I don't like new cars, not only coz they look so cheap and cost the earth, all plastic looking, in fact I think they are all plastic, but because you can't fix anything and if that computer breaks down the whole thing stops. I got into what was for me a very modern car, as modern as I'm willing to go a bit beyond my comfort zone, a 1994 car. And I could not get out, the doors and windows would not open. I was stuck in there for what seemed like an eternity and I thought I'd suffocate LOL. I had to press some button to make things work. Why no mechanical over ride. Same with rigs. With old things their quality was built to last, and you could see what was wrong and fix it. Now you have to chuck the whole thing away. I'm not asking for an old RX as those were heavy but even something modern, DC RX with general coverage SSB if possible and hopefully with a minimum of computer in it. The QCX I'm waiting for, seems to have a lot of that in it, but being relatively inexpensive, I'm willing to try and hopefully that will prove reliable.

cockpitbob

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Re: General Coverage Survival Receiver
« Reply #3 on: August 25, 2017, 01:38:25 PM »
Don't be too afraid of the SDR rigs.  They all came about a number of years ago when the chip manufacturers figured out how to make really, really fast, low power analog to digital converters (ADCs) and digital to analog converters(DACs).  It's now a pretty well established technology, and it keeps getting cheaper so more and more people are finding new uses for it.

For Rx, instead of demodulating down from the IF frequency, the ADCs are so fast they can digitize a really wide IF bandwidth, like 10MHz wide, and let software demodulate it down to audio.  One thing this gets us is that magic waterfall display that shows signals exist over a wide range of frequencies.  Instead of having to spin the dial to find who's transmitting, just look at the waterfall.  You can see how busy the band is, how strong the signals are, if they are SSB or CW (you can see the dits an dahs), etc.  For "band awareness" you can't beat a waterfall display.

swxx

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Re: General Coverage Survival Receiver
« Reply #4 on: August 25, 2017, 10:32:24 PM »
True, and for me another very educational post, thank you. I do find listening to SDR this is very helpful. There is a big list at that site: http://30cw.net/websdr and they work very well indeed. My concern I think is a broader one with computer chip/modern technology: how reliable, or probably more important by this I mean, how DURABLE is it. And if the processor goes for some reason, would that not render the QCX inoperable? Let's say we have a real EOTWAWKI event, well, that is irreversible. It will take _decades-if-ever_ to recover from that in terms of technology: so these chips won't be made any more, won't be replaceable, unless you have a supply of them and the means/equipment to replace them with, e.g. portable soldering iron that runs from something you can get hold of.

Will gas still be available? Will petrol be available? What type of batteries will be available? What happens after a month, a year, three years to what you have during your ongoing life in survival in this new world? On your own you are not likely to survive at all well or for long. If you have a skill that is needed, then you become valuable and can team up with others who have skills needed: strength, security, diplomacy, reconnaissance, food sources, health matters, etc.

So if we accept all that as likely picture after TEOTWAWKI then we need to focus on OUR special valuable skill: be it Morse Code, Communication, Radio, or all three. But we will have a big fat Zero Value if we cannot put those things into practice EVEN with the help of others in any new Tribe that forms for mutual survival. So we should probably focus on what it is that we can prepare for that will last for DECADES. If we break this down:

ANTENNAS: this is the EASIEST part. Wire, lasts for a life time and would still be able to be found and won't cost anything, or at most, one who stole all the wire for miles around, can be integrated into the Tribe. But if we have one or more EFHW, a reel of wire, we don't even need coax or feeder to make an antenna.

TRANSCEIVERS: this is not quite so easy. Forget all the FT817 etc rigs, we are talking about very low current rigs. We should not have only ONE such QRP transceiver but several: even separate TX and RX, so that there is some redundancy and over lap, otherwise if something breaks or goes missing, all is not lost. Durability is then the issue: do we have spare components? Can we replace them, let alone find out which one is broken?

TOOLS: What tools do we need that will run for years or decades, without mains powered electricity and without the more finite and limited fuel resources (gas, petrol) e.g.:

SUN or WIND or MUSCLE power: are these not the only things we can look at for power sources? And what of the actual supply of power to the rigs, is that done via rechargable batteries? If so, they too have a limited life span.

BATTERIES: are there not batteries we can make out of readily available natural items in the post TEOTWAWKI environment? No matter they are big and ugly, how were they made in the old days, can we re-learn that skill?

Various surviving tribes around the world will likely only be able to communicate long term via QRP CW, so to my mind, the above are questions. Not how cool a new rig is such as the QCX but will it do the job long term in the above conditions? If not, what will?

RadioRay

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Re: General Coverage Survival Receiver
« Reply #5 on: August 27, 2017, 11:32:33 PM »
In a TEOTWAWKI situation I have two things going for me:

1.  Excess calories stored nature's way.

2. Unusually good looks.



I'm set  ;-)


de RadioRay  ..._  ._
"When we cannot do the good we would, we must be ready to do the good we can."  ~ Matthew Henry

swxx

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Re: General Coverage Survival Receiver
« Reply #6 on: August 28, 2017, 02:55:18 AM »
RadioRay by the looks of it you'd be able to supply a lot of gas! That could be tradeable for other things, the excess that isn't used  :D