malewithatail
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Post by malewithatail on May 4, 2021 16:37:56 GMT 10
I suggest that we decide on some frequencies to contact each other in the group now, before TSHTF. I realize not all preppers want to, or indeed have the means to become Ham radio operators, so to that end, I am suggesting UHF channel 29, which is the road channel. I also suggest a HF 27 megahertz CB channel, say channel 10 on Australian sets, or channel 14 on American sets. This frequency is 27.125 Mhz. Just remember that UHF CB is primarily a short range (20 km max) method of communicating, whilst 27 megahertz has the potential for around the world range under the right conditions.
Comments please ?
What money cant buy, I don't want !
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frostbite
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Post by frostbite on May 4, 2021 17:23:37 GMT 10
My 27mhz unit is at my retreat, so I will let you know next time I'm there to see if we can hear each other.
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Post by milspec on May 4, 2021 19:24:52 GMT 10
What would be even nicer than a nominated band/freq is an app that would generate authentication tables based on a seed phrase shared by two parties. Whilst far from 100% secure, that would provide a degree of confidence that you're talking to someone in a circle that you know/trust.
I would write the code myself ... except I've long forgotten how to do that 5hit.
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frostbite
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Post by frostbite on May 4, 2021 20:05:18 GMT 10
Milspec, say again in English please.
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Post by spinifex on May 5, 2021 8:32:22 GMT 10
I'm not sure on the relevance of long distance comms. Maybe someone here can sell me on it. Then I might actually get all my HF, VHF and UHF gear out of their dust covered tubs and re-commission it.
When we can't use the normal phone network to communicate ... the usefulness of knowing whats happening far away will be rather limited wont it?
And for short range comms ... do we really want to use a means that anyone with a set can detect and listen in on or potentially triangulate?
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Post by milspec on May 5, 2021 9:32:12 GMT 10
Milspec, say again in English please. Sorry, authentication tables are a mechanism for two (or more) parties communicating via radio to verify that the person they are speaking to is a trusted person. One party requests the other party to authenticate by reading out a code and the other party looks up the corresponding code and reads back the answer. If the other party can't provide the answer you know they don't have access to the authentication table. If they do respond with the correct code they are likely to be one of your trusted parties (unless the authentication tables have been compromised of course) The authentication tables should be regenerated frequently in order to prevent them becoming compromised. Authentication might go like this .... Callsign1... Callsign2 authenticate B6 Cs2 AG Cs1... Cs2 authenticate F9 Cs2 RS Where AG is the correct response for B6 and RS is the correct response to F9 To achieve this both parties require access to the correct authentication table for the current time period. The current time period may change daily or more frequently as agreed. These responses must be delivered within seconds to be considered valid so that the challenged party (CS2) isn't challenging a 3rd party to obtain the correct responses. As for listening in to distant news I would consider that quite important ... it could be a warning of danger coming, it could be positive news to boost morale for your group.
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australia
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Post by australia on May 5, 2021 18:39:19 GMT 10
Hf all the way , dare I say higher powered amateur gear on 27mhz ( tongue in cheek)
That way cb operators can communicate with Amateurs to a degree
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malewithatail
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Post by malewithatail on May 6, 2021 16:52:05 GMT 10
Agree with the idea of coded responses, but I try to operate on the KISS principle, keep it simple stupid. Just passing info that a bad ass group is headed towards such and such probably wont compromise your location in any way. Up until the 1970's, 27 megs was a ham band, and my old Yaesu FT-901D has it fitted as standard, at 400 watts as well. I suggested 27.125 as a liaison frequency, as a lot of 27 meg gear that was crystal locked, is available cheaply now and almost always has 27.125 Mhz fitted as standard. There is nothing to stop you from listening on the ham bands, and there are around many older, analogue tuned receivers that can decode SSB. Kenwood, Tandy etc, and my favorite portable is a Barlow Wadley, XCR-30, crystal locked analogue tuned phase locked loop receiver. It can pick up hams from around the world, just on its inbuilt whip aerial, connect to a decent outdoor aerial and the world is at your fingertips. Other older rigs to look out for are the Tandy DX series, DX150, 160, 200. To successfully listen to hams you need something with single side band capabilities. My first rig used a small oscillator placed next to the radio to resolve SSB, but for less than $100 you can do infinitely better nowadays. (A Barlow though, will set you back considerably more than $100, if you can find one of the 20,000 that were made). Things to look for, obviously, SSB reception, bandspread to make tuning easier, crystal filter, operation from 12 v DC, an RF stage to get decent cross modulation and noise figures, a sensitivity around 0.5 microvolts for 10 db. signal to noise will pick up anything that's above the noise floor, external speaker and/or headphones socket, backlighted dial for night use, line out for routing the audio to your small FM broadcast transmitter or recording, don't get too carried away with dial accuracy, as you want to listen, and will be tuning around rather than staying on a fixed, known frequency. Unless you really know what you are doing, stay away from any valve gear, its well over 50 years old now and most will need an overhaul and at least the capacitors replaced. I know that the old gear is probably EMP/CME proof, but maintenance costs are now high on this type of gear. It also will draw a fair bit of power from a 12 v battery, if it can operate on 12 v dc at all, and is impractical to operate from dry battery's in an emergency. As for direction finding, professional gear is expensive, and amateur gear doesn't work all that well. If you don't transmit, the risk of detection is minimal, except if the Military are after you, and its probably too late to worry at that point anyway. Keep messages to less than 10 seconds or so, and I think the powers that be will have bigger issues to face than a few renegade people on properties that are sharing info that isn't classified anyway. Digital gear is available, but how deep are your pockets ? I think Id prefer to spend that cash on night vision gear instead. (Stay tuned for some experiment's with modifying cheap home security cameras to work in low light, without IR illumination. Teasing eh ?) If anyone want some advice on a purchase, PM me.
If athletes get athletes foot, do astronauts get mistletoe ?
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