Long range comms

Discussion in 'Survival Communications' started by melbo, Sep 6, 2005.

  1. melbo

    melbo Hunter Gatherer Administrator Founding Member

    What we will need to keep the groups together and planning the same way after moving to the Regional Rendezouz points is Long Range Radios.

    This is best accomplished with HAM HF (High Freuqency) Transceivers. THough 'm not a HAM license holder, I do have a 2 meter handheld. While this is fine to 10 miles or cross country using the Repeater network and EchoLink, Those Repeaters are run with electricity and would more than likely have failed by phase 2.

    New HF rigs are between $600 and $12,000, yes, $12K!

    Older transceivers can be found for around $200 or less. Add an antenna/wire, Microphone, Power supply, w/ a couple Car batteries and a small solar panel for charging an I think it may come in at just under $500 if we get lucky.

    Since most all HAM runs off 12 volt, these could be used in a base station to monitor any traffic around the world and the rest of the States to get a feel for the Situation. They could then be thrown into a truck and driven, (Or on a horse), 20 miles away for a brief, coded transmission to the other group. This could be done on a rolling set of times/days. After transmission, You could simply run back to the Retreat to avoid DF troubles while listening for a response.

    I think that a set of Freq's could be aggreed on and alternates used as well. I think 10,20,30 and 40 would be all that was needed to punch out accross the US.

    I'm trying to find some info on used equipment now. The plus side for us is that HAM radio operators love to get new toys to sit behind so the used stuff get's turned over pretty fast.

    Most poeple have more knowledge than me on this topic. Feel free
  2. ghrit

    ghrit Bad company Administrator Founding Member

    Mostly agree, however. HF will be NFG for our purposes, I think, due to range limitations. 2 meter is pretty good stuff for short range (as you note) but with the repeaters either off line or in the hands of the green meanys, not too much useful to us after the mess beginneth. Same limitations on 6 meter. And also on satellite repeaters, tho' the power won't fail them as soon as on the ground.

    I don't know what frequencies are used by the marine bands, might be worth a check. There are no repeaters at sea, and they do have radios out there. (And no mountains to get in the way of a signal.)

    As you suggest, 10 thru 80 meter bands will probably be our best bet. Note that these are standard bands that the gear is made to operate within. Since we will be illegal as hell anyway, we might slide into something less obvious depending on the gear we can scrounge. Mobile sets, of course, and set up for (if possible) burst transmissions and recorded for later slowing down and reading.

    As you indicate, no transmissions from the home yard.

    All that said, to get things up and running, we will need a couple sets to start, and a couple operators to teach the rest how to use it when the time comes. Meaning it looks to me like a couple licensed hams would be high value ahead of need, at least one in each region They can wash dishes later. Single sideband will also reduce power requirements, as would CW (meaning morse code.)

    Along the same lines, I've seen mobile directional antennas in use. Dramatically reduce power requirements, as well as reducing the exposure to DR detection.

    Just miscellaneous lthoughts.
  3. melbo

    melbo Hunter Gatherer Administrator Founding Member

    I thought and was told that the HF was the one for the distance...?

    Spent a few hours today with the local HAM guru...

    I'm taking your NFG as "Negative Procreating Best"
  4. ghostrider

    ghostrider Resident Poltergeist Founding Member

  5. Minuteman

    Minuteman Chaplain Moderator Founding Member

    I have been doing some searches and this is what I have found out.
    It seems that the 10 and 11 meter frequencys are probably what we are looking for.The 11 meter is your basic C.B. channels but the equipment can be upgraded to give you a much greater range than normal C.B.s.In a SHTF world the FCC regs wouldn't matter.They state now that 11 meter is limited to a certain power and a 155 mi. range.But it is possible to upgrade standard C.B radios,both mobile and base to reach hundreds of miles.

    The next one is 10 meter.This is a license required frequency but can be accessed by regular C.B. radios with only a slight modification.
    The equipment is relatively cheap."Tweaked and frequed" for around $200-$500.
    I am still looking for info on the exact ranges of these types of radios and exactly how they operate.I would think being C.B. they would have no need of relay towers like the 2 meter radios.

    Also it appears that the "meter" is relative to range.Actually based on the length of the particular wavelength.35' = 11 meters.So the lower the meter # the shorter range.If anyone knows someone who is into amateur radio you might ask them about these radios and thier capabilities.But be warned it appears that there is a lot of animosity between the licensed hams and the unlicensed CBers.


  6. ghrit

    ghrit Bad company Administrator Founding Member

    Approximately --- :D
  7. melbo

    melbo Hunter Gatherer Administrator Founding Member

    The High Frequency (HF) band is the ranges of frequencies between 3 to 30 MHz. HF radios usually include a frequency range of 2 to 30 MHz.

    Single Sideband (SSB) is the term used to describe the method of compressing the transmitted information, voice or data, into a compact signal. This has the benefit of reducing the power required to send a signal over a certain distance. This form of transmission uses only half of the radio bandwidth that AM radios use (double sideband). Since only one sideband signal is transmitted, SSB allows more channels for communication within the HF spectrum.

    HF SSB radios are primarily used for long-range communications where distances of 3000 km and more are possible. Obstructions such as buildings and mountains have little effect on long-range communications. HF radio can cover such large distances because of the way that the transmitted radio signal propagates.
    HF radio waves are propagated simultaneously by ground, direct and sky waves.
    Ground wave

    The ground wave travels near the ground for short distances, typically up to 100 km over land and 300 km over sea. The distance covered depends upon operating frequency, transmitted power and type of terrain.

    Direct wave
    The direct wave travels in a direct line-of-sight from the transmitter to the receiver.

    Sky wave
    The sky wave is the most important form of HF propagation. The radio wave is transmitted toward the sky, where it is reflected by the ionosphere to a distant receiver back on Earth.
    The reflective properties of the ionosphere change throughout the day, from season to season and yearly.
    Frequency, networks and scanning
    Frequency, distance and time of day

    The amount of reflection of the radio wave will depend upon the frequency used. If the frequency is too low, the signal will be absorbed by the ionosphere. If the frequency is too high, the signal will pass straight through the ionosphere. Within the HF band, low frequencies are generally considered to be in the range 2 to 10 MHz. High frequencies are above 10 MHz.

    A frequency chosen for daytime may not necessarily be a suitable frequency for nighttime use. During the day, the ionosphere has many layers. These layers absorb lower frequencies and reflect higher frequencies. At night, the ionosphere becomes very thin. The low frequencies that were absorbed during the day will now be reflected. The high frequencies that were reflected during the day will now pass straight through the ionosphere.

    Summer HF communications usually operate on higher frequencies that are used in winter over the same distance. Solar activity varies over an eleven year cycle with the peak of activity requiring the use of higher frequencies.

    It is important to remember that you may need to change the frequency to achieve the best communication. It is usual practice to provide three or four channels per network to give a frequency spread to suit all conditions throughout the day.

    The general rules of thumb for HF communication are:
    The higher the sun, the higher the frequency - The further the distance, the higher the frequency
  8. melbo

    melbo Hunter Gatherer Administrator Founding Member

  9. melbo

    melbo Hunter Gatherer Administrator Founding Member

  10. ghrit

    ghrit Bad company Administrator Founding Member

    Bump. We've learned a bit since '05, but the thinking was started even then.
  11. BTPost

    BTPost Stumpy Old Fart,Deadman Walking, Snow Monkey Moderator

    It is nice to see that Monkeys were thinking, correctly, even back in the day.... HF is where our Monkey Comms need to be looking.... and just a NOTE Here, Field Day is THIS WEEKEND.... So for the Licensed, lets do some communicating, and for the unLicensed Moneys with Radios, They can do some listening to see what this Radio comms thing, is all about.... For Listening you do NOT need a fancy antenna, just about any length of plain OLD Wire will work, for an antenna, and tune around the HF Ham Bands and see who you can hear..... ......
  12. ghrit

    ghrit Bad company Administrator Founding Member

    I'll be dropping in on the local club's field day location and picking some brains. Recommend that those getting interested do something similar. Most, if not all, clubs do something similar for this annual event.
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