G&R Tactical
Page 2 of 51 FirstFirst 123412 ... LastLast
Results 11 to 20 of 508

Thread: Let's talk Comms.

  1. #11
    Join Date
    Jan 2007
    Posts
    1,265
    Feedback Score
    0
    Quote Originally Posted by QuietShootr View Post
    Preface: Don't jump in with comments about legality. Assume that when I'm talking about operating outside a ham band, I'm talking about emergency situations, which FCC rules clearly state is permissible (any mode, any power, any method available). This is a technical discussion, not a "OMGWTFBBQ!! The hams are going to DF your signal and come and paste pocket protectors all over your house!, and the FCC is going to burn your house down, fine you, and violate your daughter!" discussion.

    I've been working on this very thing the last couple of weeks.

    The Yaesu FT-897D is (imo) the best reasonably priced radio available for what we're talking about. After a simple modification, it is capable of transmitting 1.8-56mHz with no gaps, 136-173mHz no gaps, and 410-470mHz no gaps. Also, it is capable of USB/LSB, AM, FM, CW, and digital modes right out of the box. It puts out 100w of power on external 12V/23A power, and is capable of 20 watts on optional INTERNAL rechargeable LiPo battery packs. It has two very capable auto-tuners available for it, and they can be bolted right to the side of the rig.

    A homemade dipole antenna rolls up on an extension cord reel nicely, and all this fits in a small ruck. On the internal batteries, you can expect at least 8 hours of continuous operation before you need to recharge (which can be done from 110 or from 12vdc.)

    Couple this with a communication method known as NVIS, or Near-Vertical Incident Skywave, and things begin to get very interesting for the tactical communicator.

    I differentiate the tactical communicator from the ham dork (hereafter TC and HD) because of the following:
    • The ham dork does not necessarily want to talk to a specific station. Normally, he wants to talk as far as possible with little regard for a specific contact, except for wanting to contact someone in a specific country. Oddly enough, they actually have contests to see how many random strangers they can talk to. It takes all kinds, I guess.
    • The tactical communicator wants to talk to a specific station/unit/person. This is an important distinction, because a successful comm shot to a specific station is a much more interesting problem than simply getting an antenna up and talking to somebody.


    Without boring the shit out of you with technical details, just know that there are basically two methods by which radio waves propagate: skywave and groundwave....
    More to follow if anyone's interested.
    TAG for more info that helps me understand all this.

  2. #12
    Join Date
    Jun 2006
    Location
    12S VA 868 817 (NAD83)
    Posts
    1,495
    Feedback Score
    0
    Quote Originally Posted by QuietShootr View Post
    ...Near-Vertical Incident Skywave...
    We had a thing they called a Meteor Burst Transmitter, is this (sort of) the same thing?
    The sun will rise tomorrow; itís your attendance of the event that is uncertain.

    Gun Plumber at Designated Hitter, pet protector and independent consultant to various irresponsible companies

  3. #13
    Join Date
    Jul 2006
    Posts
    4,922
    Feedback Score
    4 (100%)
    Quote Originally Posted by K.L. Davis View Post
    We had a thing they called a Meteor Burst Transmitter, is this (sort of) the same thing?
    Not Exactly:

    http://www.mse-ta.com/meteorburst/me...owitworks.html

    Vs:

    http://en.wikipedia.org/wiki/Near_Ve...idence_Skywave
    My brother saw Deliverance and bought a Bow. I saw Deliverance and bought an AR-15.

  4. #14
    Join Date
    Jul 2006
    Posts
    4,177
    Feedback Score
    3 (100%)
    Quote Originally Posted by K.L. Davis View Post
    We had a thing they called a Meteor Burst Transmitter, is this (sort of) the same thing?
    No. MBTs look for ionized trails of air caused by penetration of meteors into the atmosphere to bounce burst transmissions off of.

    NVIS is nothing more than high-angle HF radio bouncing straight down, instead of skipping horizontally long distances.

  5. #15
    Join Date
    Jun 2006
    Location
    12S VA 868 817 (NAD83)
    Posts
    1,495
    Feedback Score
    0
    Works for me... I did enough of the commo thing to get qualed, give me a GRA-71 and a simple WX report could turn into something very bad
    The sun will rise tomorrow; itís your attendance of the event that is uncertain.

    Gun Plumber at Designated Hitter, pet protector and independent consultant to various irresponsible companies

  6. #16
    Join Date
    Jul 2006
    Posts
    4,177
    Feedback Score
    3 (100%)
    Quote Originally Posted by K.L. Davis View Post
    Works for me... I did enough of the commo thing to get qualed, give me a GRA-71 and a simple WX report could turn into something very bad
    Wow!! Old school!

  7. #17
    Join Date
    Nov 2008
    Posts
    118
    Feedback Score
    0
    Quote Originally Posted by TheLandlord View Post
    Has anyone factored in comm-gear into their preps?
    What you need before comm gear is a comm plan. Be specific - don't stop at, "Um, I'd like to be able to hear what's going on, I guess, and call for help if I need it." Once you know who you want to hear and who you want to talk to, you can pick gear that best fits the mission.

    RF communication can essentially be broken into two types: line-of-sight (LOS) and beyond-line-of-sight (BLOS). Line-of-sight range is usually calculated by the "four-thirds earth rule:" multiply the distance to the visible horizon by 1.333 to approximately predict a radio wave's unobstructed LOS range. Tree foliage, buildings, terrain, etc, will reduce this range somewhat, depending on the radio frequency and power being used.

    Options for LOS include FRS, GMRS, MURS, any business band, public service, or amateur radio operating at ~50 MHz and up, and the occasional oddball like eXRS. Virtually anything that can be used while mobile falls into this category. (Note that I'm speaking to the Tactical Communicator audience as QuietShootr defined in his post. There are mobile amateur HF rigs that can communicate BLOS, but not with the reliability that a tactical communicator would expect.) Each of these options has strengths and weaknesses, again depending on what your communication plan is.

    Options for reliable BLOS are essentially limited to amateur radio frequencies. Go back and read QuietShootr's post on NVIS for one of the best options. To elaborate on that a little: NVIS only works on frequencies below 7 MHz, and works most reliably below 4 MHz. Although the antennas can be low, they still have to be long - meaning that you can carry a wire antenna with you, but to use it you'll have to stop and set up.

    If one is available, you can communicate limited BLOS on amateur VHF/UHF frequencies using a repeater. A repeater in a good location can allow handheld transceivers to communicate over tens of miles, or even farther with multiple repeaters linked together. If you don't own the repeaters, though, you can't necessarily predict whether they will remain serviceable during a SHTF event.

    Also, if listening is part of your comm plan, consider a dedicated receiver such as a scanner or shortwave radio. Transceivers do not necessarily have the best general-coverage receivers built in.

    How does one power the equipment in the event of disruption to the grid? I've thought about solar panels, but I don't know if they'll pump the juice necessary to power the gear.
    A 12V deep-cycle battery or battery bank with a solar charger is the way to go. The solar won't directly power your high-current transmitters, but it will charge your batteries when you're not using them.

    One more piece of advice: get your amateur radio license, but be wary of the amateur emergency-communication groups such as ARES, RACES, etc. The personality of each local group is different, but many of them focus on augmenting "served agencies" (Red Cross, FEMA, etc) rather than directly helping their local communities be self-reliant in a disaster situation. Those groups tend to have a lot of wannabe G-men and folks who think keying their mic and giving their location will always bring timely help.

    fme

  8. #18
    Join Date
    Jul 2006
    Posts
    4,177
    Feedback Score
    3 (100%)
    Quote Originally Posted by faithmyeyes View Post
    What you need before comm gear is a comm plan. Be specific - don't stop at, "Um, I'd like to be able to hear what's going on, I guess, and call for help if I need it." Once you know who you want to hear and who you want to talk to, you can pick gear that best fits the mission.

    RF communication can essentially be broken into two types: line-of-sight (LOS) and beyond-line-of-sight (BLOS). Line-of-sight range is usually calculated by the "four-thirds earth rule:" multiply the distance to the visible horizon by 1.333 to approximately predict a radio wave's unobstructed LOS range. Tree foliage, buildings, terrain, etc, will reduce this range somewhat, depending on the radio frequency and power being used.

    Options for LOS include FRS, GMRS, MURS, any business band, public service, or amateur radio operating at ~50 MHz and up, and the occasional oddball like eXRS. Virtually anything that can be used while mobile falls into this category. (Note that I'm speaking to the Tactical Communicator audience as QuietShootr defined in his post. There are mobile amateur HF rigs that can communicate BLOS, but not with the reliability that a tactical communicator would expect.) Each of these options has strengths and weaknesses, again depending on what your communication plan is.

    Options for reliable BLOS are essentially limited to amateur radio frequencies. Go back and read QuietShootr's post on NVIS for one of the best options. To elaborate on that a little: NVIS only works on frequencies below 7 MHz, and works most reliably below 4 MHz. Although the antennas can be low, they still have to be long - meaning that you can carry a wire antenna with you, but to use it you'll have to stop and set up.

    If one is available, you can communicate limited BLOS on amateur VHF/UHF frequencies using a repeater. A repeater in a good location can allow handheld transceivers to communicate over tens of miles, or even farther with multiple repeaters linked together. If you don't own the repeaters, though, you can't necessarily predict whether they will remain serviceable during a SHTF event.

    Also, if listening is part of your comm plan, consider a dedicated receiver such as a scanner or shortwave radio. Transceivers do not necessarily have the best general-coverage receivers built in.



    A 12V deep-cycle battery or battery bank with a solar charger is the way to go. The solar won't directly power your high-current transmitters, but it will charge your batteries when you're not using them.

    One more piece of advice: get your amateur radio license, but be wary of the amateur emergency-communication groups such as ARES, RACES, etc. The personality of each local group is different, but many of them focus on augmenting "served agencies" (Red Cross, FEMA, etc) rather than directly helping their local communities be self-reliant in a disaster situation. Those groups tend to have a lot of wannabe G-men and folks who think keying their mic and giving their location will always bring timely help.

    fme
    This is pure gold, and absolutely true. For a sample of what you need to stay away from, visit http://www.hamsexy.com/cms/index.php . Ham radio, like guns, tends to attract wannabes and douchebags in incredible numbers. You will do well to limit your interaction with them in person to your actual license test. You think gun shows are bad? Visit a hamfest sometime. One major, and annoying, difference between the two crowds is that hams tend to be junior G-men in a big way - they are some of the biggest whiny complainers on the planet, and tend to some really bizarre behavior. See http://www.fcc.gov/eb/AmateurActions...8_07_5111.html or http://www.fcc.gov/eb/AmateurActions...8_07_5107.html or http://www.fcc.gov/eb/AmateurActions...8_07_5109.html .

    In re NVIS; fme is absolutely correct on all counts. The most compact antenna you can carry is an end-fed long wire, and the smallest one I've found usable below 4 mHz is around 72 feet. I use 14ga solid THHN, and roll it on a small extension cord reel.

  9. #19
    Join Date
    Aug 2009
    Posts
    818
    Feedback Score
    0
    My off-road club uses CB to communicate on the trails or I never would have bought one. I did not think I would ever use it other than that, but it is nice to have while driving. They are great for getting traffic conditions/accident info, getting directions if you are lost, calling for help, or just something to do if you get bored and want to chat with random people.

    You can buy them very inexpensively and they work fine if you have it tuned.

  10. #20
    Join Date
    Nov 2008
    Posts
    118
    Feedback Score
    0
    A couple of additional comments -

    I want to clarify that my statement regarding ARES et al was not intended to be a blanket indictment of all amateur radio organizations. The largest ARES group in my area, for instance, focuses primarily on severe weather reporting and has an excellent relationship with the National Weather Service. They perform that function well, and only a few of them on the fringe get really rabid about things like FEMA certs and radio e-mail for the Red Cross. But things in some groups really get off in the weeds, and as QuietShootr said, many of the guys who are heavily into it aren't all that well-balanced. Some of them seem to feel like amateur radio is just waiting its turn to save the world, and that it's every operator's sacred and noble duty to be prepared for that day. By the way, who's bringing the beer?

    Unfortunately, the ARRL (the amateur radio equivalent of NRA) seems to be in the same boat of pushing for integration with government services and "served agencies." They've co-opted the "hero" angle (When All Else Fails... AMATEUR RADIO) and gone wrong-headed in an attempt to attract membership. So in general, the amateur radio "party line" about what disaster communication looks like is probably quite different that what most self-reliant preppers would find sensible.

    There can be some value found in being involved with a local club, though. I've been involved several times when a club has been called on to provide communication support for a community effort like a bike race, marathon, or even an SCCA motorsport event. These events can give you a valuable opportunity to prove your equipment and operating practice in a "real-world" tactical communication scenario.

    Furthermore, if you can wade through the BS at some of the club meetings, you may find that the quiet older gentleman sitting against the wall is well worth getting to know. If it's communications or electronics you're interested in, some of those guys have truly been there and done that, with an amazing wealth of experience.

    So yeah, understand that the culture can be a little weird, but don't throw the baby out with the bathwater. You can be friendly, soak up some valuable tools and techniques, and quietly avoid the Kool-Aid table altogether. Then take home your new knowledge and make it work for you and yours.

    And now for something completely different:
    My off-road club uses CB

    You can buy them very inexpensively and they work fine if you have it tuned.
    How useful CB is depends on where and when you are. If you're close to major trucking arteries, you'll get a lot of unwanted signal. Additionally, CB operates on a frequency that is capable at certain times of long-distance skywave propagation or "skip." I can remember having a CB walkie-talkie as a kid and not being able to find a clear channel for all the South American operators.

    Be wary of "peaked" or "tuned" CB transceivers, as they have often been modified in a way that makes their operation illegal. Yes, illegal operation is widespread on CB now that operator licenses are no longer required - but we want to be above reproach, don't we?

    In an area with less interference, you can communicate over a fairly impressive range with a perfectly legal CB - especially if you have transceivers capable of single-sideband (SSB) operation. SSB into elevated horizontal antennas will work even better. And nobody has to take a test or pay a license fee to run one.

    fme

Page 2 of 51 FirstFirst 123412 ... LastLast

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •