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Signals Intelligence for Regular Folk – Part 1, by Tunnel Rabbit

This is another attempt to put a vital part of a security operation into an affordable box, that will provide ‘the mostest, for the leastest’, the quickest, and in the easiest way. In time, the basic tools will be the foundation of whatever improvements to an area of your security plan that fits you.  At present, the discussion is about radio related topics as it pertains to a security operation. The pros know that actionable intelligence should drive defenses.  We will likely not have the time to develop that lofty level of intelligence, yet there is one type of intelligence where the “low hanging fruit” is easily had.  We seek to discover this threat, so that action will be taken. This certain and basic information, a no-brainer, is about threats that should cause one to heighten their defenses, if not put eyes on the problem. So what are we talking about?  Bad guys using radios to coordinate movement, against you and yours.

At the end of the day is it not what you got, but what you can keep. The ability to keep what we got is the goal. As alluded to, ad naseum, *Security will be job one*. You can have a dedicated security team that is supported by everyone else, yet sadly most of us will be hurting for certain without enough hands that make work light.  Can we have dedicated security team?  Gotta S2 for you? Got no clue? How about your own SIGINT? No? Bummer!  How can we cram, at least one of these important functions into something bite size that a prepper can chew? Can we consolidate capabilities, downsize one critical task? Is it possible to put at least some of it into a manageable size box that can provide at least some of what is the most useful?  Can we adapted these tasks to regular folk’s background, without a steep learning curve?  All these pesky questions were needed to be asked. As it pertains to the recent topic d’jour, we can indeed take a bite of the security problem out, by starting with a single scanner. The threat will not disappoint, and neither will a scanner, if used properly.  Give Grandpa, or the big kid, a scanner for Christmas. You might be glad you did.  It is a critical part of your security and commo plan, that does the first intel job: Warning.

My suggested purchase: The Uniden SR30c Scanner with the Close Call Feature.  Take a look at the SR30c Scanner overview and frequency chart [1].

$99 is a reasonable price. You can buy one here [2].

This scanner would make a good Christmas gift. Thsiscomes at a time of the year it would be a good to have something to play with. However, it is a serious multipurpose tool for the prepper who can read instructions, who has a penchant for play, and desire to improve retreat security. It is potentially a big stick. This is very important part of your retreat defenses…listening, and it is easy to implement. And no one will hear to you practicing. A scanner can be mobile, or at a fixed location.

The best way to get it done is with a scanner with a Close Call type of feature, or variations the marketed name, that is essentially a frequency counter…but we can skip all that stuff, and make it simple, and use a regular scanner too.  Yet the Uniden in several models that have a Close Call feature has an advantage.  Even if one does not know what frequencies they should scan, if only they could follow in the instructions on a You Tube video, and set up the Close Call function, they’ve gotta winner in their hand.  The Close Call feature can only be set to monitor either UHF, or VHF, but not both at the same time.  I would chose UHF to see if it would pick up GMRS/FRS radio.  Then use your own GMRS/FRS radio to test it out.  Ideally, I would also have a second scanner that could be set to monitor VHF as well.

[JWR Adds: I concur!  I’d recommend getting a pair of Uniden SR30c Scanners. That way you can have one set to UHF close call, and the other set to VHF close call.  And that fits with the SurvivalBlog  “Two is one…” motto.]

As security will be a major chore, these improve situational awareness and develop intelligence with a relatively inexpensive tool that can stand guard 24/7. It sips power, less than 250mah (1/4 of 1 amp at voltage), and without the Close Call, the older analog scanner, probably that Radio Shack thingy that you may already have in a box somewhere, those scanners need less power, as low as 75mah (milli ampere hours). Any scanner can work, but with any of the modern generation Uniden scanners with the Close Call function, frequencies that are unknown, and not programmed-in, can be picked up if the signal strength is high enough.

Using an external antenna, such as the discone antenna on the roof, will greatly enhance this ability.  Using it with a directional antenna are like using big ears to hear at distant, or weak close in signal from a certain direction.  Start with an omni-directional antenna such as 1/4 wave, or a discone.  Another and second choice antenna for transmitting and receiving that can go mobile with a mag mount, or sit on top of the fridge, is the very broad banded Tram 1181 dual banded 1/4 wave antenna.  Get two discones, one to listen on, one to talk on, and a Tram 1181 for mobile rigs.  High gain is usually the game, but a multi tool will rule in the future electronic battlefield ahead.

It is certainly worth the extra power consumed, the batteries used, and a 100 bucks to cover a muy importante part of the security plan. Scanners if used actively, are early warning devices, and an intelligence collection device.  Cost of purchase is low, it is cheap to feed in terms of batteries, and it is multi-purpose. It can listen to your Dakota Alert Sensors, your communications net, and pick up radio transmissions from unexpected signal sources, be them friend or foe, and on frequencies well known, or unknown. Good stuff!

A quick and easy approach that makes it easier for those without a frequency list is to plug in the 2 meter ham band repeaters in your area, MURS, and Business band on the VHF side, and GMRS and FRS, plus any 70cm repeaters in your area, and set it to scan the list and use the Close Call option to monitor the UHF side. Even if you do, or do not have a MURS Dakota Alert sensor [5] using MURS channels, or if using the Dakota Alert Sensors without external UHF antennas, then monitor the UHF side. Program with the computer to have a back up, and to make the process easier. There are other way to configure it (set it up), but this a good start for most folks. Any frequency flashed on the scanners display is a Close Call signal, and should be recorded by quickly writing it down, and added to the scanner list, then investigating the source.

Any signal that is nearby should be identified as either ‘friend or foe’, whether is a voice or just a mic click.  If the Close Call hears it, it is dangerously close, by rural standards.  Even if you hear a GMRS, FRS, or MURS from any scanner, then they are dangerously close. That is: within a 1/4 of mile if GMRS/FRS, and within 1 mile if MURS.  Any unidentified user is not a friend, they are foes until proven otherwise.  Put eyes on them, or stand guard. Using directional antenna, and a map and compass can start the process of determining who is on the other end. (For the low budget guys like myself, or as a field expedient means, string up some common RG59 TV cable, and strip out 19″ of the inner wire to act as a receiver antenna, and plug the bare wire on the other end directly into the thrift store scanner.  Duct tape works.  It doesn’t get cheaper than that. Rude and crude.)

I forgot to mention, most scanners including this Uniden series, does not cover the entire spectrum that the now ubiquitous Baofeng UV5r covers. It does not cover 512-520Mhz, or the 220Mhz Ham (amateur) band.  A tri-band Boafeng is slow, but may be used to sweep the 220 to 260mhz range.  And a Boafeng can scan a few frequencies well, or better, be use as a single frequency receiver to monitor the primary channel. Nor does this Uniden cover other military bands below 400 MHz, where the military uses intra-squad headsets on freqs between 399 to 400Mhz. Some older scanners and higher end scanners do.  Yet often is forgotten is the 220Mhz Ham band. I do not know of a scanner for that. One can cover some of those loose ends with a bank of many scanners sharing an antenna.  With a 20 dollar USB-RTL Dongle, and a laptop or Raspberry Pi, but these consume lots of power.  Unless you have a large alterenative powerr system at your retreat, then leave that set up only to switch on to scope out potential threats.

(To be concluded tomorrow, in Part 2.)

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Comments Disabled To "Signals Intelligence for Regular Folk – Part 1, by Tunnel Rabbit"

#1 Comment By RandomMike On November 5, 2019 @ 9:09 am

The latest Baofeng models scan much faster than the older ones.

#2 Comment By Tunnel Rabbit On November 5, 2019 @ 6:45 pm

Baofengs can be a bit deaf as compared to a scanner. This lack of sensitivity can be improved, or compensated in part, using an external antenna. The Baofengs I program for others will scan GMRS, FRS and Murs. I try to keep the list short as possible, so that it will scroll through the mentioned service regardless. This way any one can passively be listening at anytime.

The more eyes and ears paying attention, the better. To utilize limited resources well, spare Boafengs can be assigned a short scan list that includes the 2 meter and 70cm Amatuer bands, and another Baofeng can cover Emergency Services. In the right hands, Baofengs are versatile. Taking the approach of a ‘master of managing scarce resources’, I would rather have 3-4 spare Baofengs, than one scanner. However, it would be costly to put all of those Boafengs on a good antenna, but it can be done if it was absolutely necessary, and it is not.

The more we know, the less we need. Knowledge and skills are more important than stuff. Eventually the stuff will run out, or be lost. Yesterday I fixed up 8 chainsaws for various persons. Perhaps I should have a shop. What would happen to these persons if the local shop closed up? They save hundreds by coming to me, and unconventional mechanic. I am unconventional in other ways as well. Baofengs are often snickered at, but their potential is unrecognized. And there are other resources that are ignored. Using cable TV coax for receiving antennas is cheap and easy. It is also possible to use this for transmitting antennas, but that is not easy to tune, but I do it often. For receivers, the impedance speed bump penalty for going from 72 ohm to a 50 ohm system is insignificant, especially if it apart of an antenna system that is mounted high. With ubiquitous and almost free cable TV coax, one can afford to run cable and antenna up as high as one can get it into a tree, or on a pole made from a tree. Put a Baofeng on one of those ‘poor man’ antennas, and it will be an adequate receiver.

#3 Comment By Hugh Farnham On November 5, 2019 @ 11:46 am

Great article. A Radio Shack 668 on Signal Stalker (Close Call) with a good discone amplifier and $15 RF amplifier can pick up a GMRS transmission 1 1/2 miles away – enough time to react.

Depending on the frequency, the RF noise floor in a very rural environment can be 8 db or lower than in a sububan location. That means your detection distance more than doubles.


#4 Comment By Tunnel Rabbit On November 5, 2019 @ 4:43 pm

That amplifier is very interesting. I was about to place a an order for some other essential things, and might throw that in. We should do all we can to hear these very weak hand held radios.

A high gain omni-directional antenna such as a slim jim can also hear well, and can pick up weak signals from many miles away. The ole axiom, ‘height is might’, applies to receiving signals as well. Get any resonant antenna up high, and the odds of receiving weak signals increases. Point a yagi, or other high gain directional antenna toward the main avenue of approach, not only picks up very weak signals, but confirms the direction from which is came. To reduce the number of scanners needed, and to increase the odds of intercepting a signal, I might use both an omni–directional antenna hoisted high between two trees, and a directional antenna tuned for GMRS/FRS to feed a single receiver/scanner. To help determine the direction, either antenna could be isolated, or unhooked from the receiver.

I have picked up 1/4 watt FRS transmissions, 5 x 5, from surprisingly far distances, however assume that these frequencies would normally only be received at very close-in ranges that might be potentially dangerous in violent times. The further out we detected these the better.

#5 Comment By Patriot Johnny On November 5, 2019 @ 1:09 pm

Remember too listening to public services such as police and sheriff’s departments, some have been using encryption where you can not monitor calls. However, my city police here in the upper Midwest uses Open Sky encryption but here is the kicker, the tactical units use their old analog frequency during special operations because they do not trust the Open Sky system (due to past problems) including their vice squad during special assignments. (A source in the department told me and I have heard transmissions myself.)

Just because these public services are using trunking, digital and encryption methods if the system goes down, they may have to go to analog operations. So the scanner that is mention in this article will be useful.

Also a note: monitoring the National Guard, other military branches and government agencies will be impossible to monitor due to encryption, frequency hopping, etc.

When monitoring for intelligence, always have a pen or pencil and paper handy to take notes or have a analog/digital recorder to record transmissions in case you miss anything.

Good article so far! Waiting for Part-two.

#6 Comment By Tunnel Rabbit On November 5, 2019 @ 5:01 pm

There are tons of YouTube videos. A scanner is an important tool worth the time and effort.

#7 Comment By Hugh Farnham On November 6, 2019 @ 12:20 am

Even a Close Call signal that is just digitized static is an indication… Trisquare used to make a frequency hopping radio, the EXRS. Could even do texts.

Yes, this radio really frequency hops, as seen on my spectrum analyzer.

#8 Comment By Tunnel Rabbit On November 5, 2019 @ 5:23 pm

Out here in the ‘boonies’, local government could not afford to make the jump and still rely on analog. However, they may not always used the published, and the frequency they are licensed and assigned.

Sweep between 150.000 to 156.000 Mhz, and set the scanner to stop and hold on any frequencies it receives. Sweep means the scanner will scan all frequencies with a determine range of frequencies. Periodically check the scanner, and record the frequency to develop a ‘frequency list’. Then record, then block out, or remove that frequency, and continue to sweep for a day or two. After a list is generated, program those into the scanner, and listen and record relevant information about the traffic in a note book. Record date and time. Update this list at least once a year. Hunting season is a good time of the year catch those who are otherwise silent. This is where most of the traffic is found. Often public services, or EMS can be found using Business Itinerants frequencies or other frequencies, either on a temporary basis, or even on a permanent basis. I know that local law enforcement uses frequencies as they will. It is so quiet out here, no one cares.

Both limit sweeps, and expand sweeps. Do the same for the Amateur radio bands as well. Amateur band can often provide lots of information. I would use those frequencies infrequently, as often, there is at least one Ham out there sweeping 2 meter. These can be the guys with the massive towers that hear everything, even a lower powered hand held. 2 meter is the worst place to be if you’d rather not be heard.

#9 Comment By Vagus On November 5, 2019 @ 2:43 pm

Side note, if you struggle to understand these articles, study guides for the Technician HAM radio exam can be had for free from multiple sources. Even if you do not intend to sit for the exam, just reading one will clarify 80% of the technical items (quarter-wave antenna, 60 cm band, directional antenna, etc.)

#10 Comment By Duane F Donovan On November 5, 2019 @ 3:25 pm

I listen to National Guard, other military branches and government agencies every day.

#11 Comment By James Wesley Rawles On November 5, 2019 @ 3:32 pm

Is that administrative traffic, or tactical traffic? Nearly all U.S. military communications (Active, Reserve,and National Guard) are now pseudonoise spread spectrum or frequency hopping with encryption.

#12 Comment By Tunnel Rabbit On November 5, 2019 @ 5:40 pm

Even out here in no where, I’ve picked up a transmission that sounded military and was on frequency assigned to military. It was between 141 and 142, probably from Hwy 93. It was brief.

#13 Comment By Butch On November 5, 2019 @ 3:56 pm

I bought a Uniden scanner with close call capabilities probably 10 years ago. . We live near lower British Columbia and the scanner picked up what seemed like hundreds of EMS related calls a night. I’d lock them out, only to have more (or the same ones) night after night. I couldn’t figure out how to get permanently lock them out, so it’s in a box. I’ll take another stab at it. Suggestions appreciated.

#14 Comment By Tunnel Rabbit On November 14, 2019 @ 4:23 am

Hi Butch,

I missed the email notification and your post. This will hopefully answer your question. The Close Call part of your scanner is separate from the scanning part. The frequencies it ‘hears’ cannot be locked out. I would start by developing a frequency list to be scanned, by sweeping all frequencies where the Canadian Emergency Services are assigned. I would also sweep up to the top of the VHF that it can hear, up to 174.000 Mhz. You can sometimes hear Canadian truckers, and ranchers near the top. Or simply use this link to find frequencies in your area. Use this site to look up Amateur Band Repeaters as well. And see if you can hear the Cranbrook 2 meter repeater because it has a ‘net’, an on air meet up on Sunday evenings, about 6pm. Many clubs on other repeaters do this as well. It could be a great source of information in bad times. From memory, try 146.940 Mhz. It is also an IRLP node, and traffic from around the USA and Canada, even Texas can be heard occasionally on that repeater. You can also install any or all of the Amateur Band repeaters in the U.S. that are within 150 miles of your location. You might be surprised.


Because the Close Call generally picks up or ‘hears’ the stronger signals, the weaker traffic will not be heard, if a list is generated by only using the Close Call part of the scanner. Get what you can from the Close Call, and put that on the list. You will know in the future that these signals are close by. Then turn off the Close Call function, and it will not be able to interfere.

#15 Comment By Willard A Edison On November 14, 2019 @ 8:21 pm

Tunnel Rabbit, thanks for that reply. I have printed it off and will get started. VERY MUCH APPRECIATED ! /Butch

#16 Comment By JBH On November 5, 2019 @ 4:38 pm

What is Close Call function?

#17 Comment By Tunnel Rabbit On November 5, 2019 @ 5:35 pm

‘Close Call’ will receive any strong signal, or signal that is close by, that is transmitted on any frequency in either UHF or VHF, as the user presets. The user does not need to know the frequency, it simply pops up. It is not scanning, but opens up on any signal, but the signal has to be strong enough, or ‘close’ by. You gotta be ready to look at the scanner when it ‘hears’ traffic as the frequency is only displayed for a moment. Write it down, adding it to your scan list. If someone shows up near by and is using a radio, it might be possible to hear their traffic. I put it on a good external antenna to increase it’s other wise, limited range.

#18 Comment By JBH On November 5, 2019 @ 9:32 pm

Thank you

#19 Comment By Jake On November 5, 2019 @ 5:30 pm

I highly recommend augmenting scanner coverage with SDR (software defined radio). I am able to substantially increase my perimeter coverage with SDR and it is possible to run the software on micro computers such as Beaglebone or Raspberry PI at very low cost.

#20 Comment By Tunnel Rabbit On November 5, 2019 @ 8:48 pm

RE: SDR RTL Dongles:

If I could be a dedicated SIGINT guy, these are invaluable tools. I will have that on standby. Unfortunately I must wear many hats. If there is qualified personnel available to tend a radio room, then this option can be switch on at a moments notice should the threat/situation justify it’s use. The Raspberry consumes the least amount of power, but full size screen allows the user to visually see weak signals better. Power consumption is going to an issue once off grid.

Unfortunately to use this 20 dollar, and invaluable tool, the operator must have their eyes on the screen to see a signal, and then to quickly click on the frequency in order to monitor is audibly. However, it is a powerful tool that should be at the ready. It can see very weak signals. I busted a local ham testing a new to him 6 meter repeater on his bench using a signal generator with only a dumby load as an antenna. He was surprised at my phone call. It was just a tiny blip on the screen, but in part of the spectrum that was worth investigating, cause it should not have been there….

#21 Comment By Jake On November 5, 2019 @ 10:30 pm

Good points Tunnel Rabbit. There are logging tools so that one need not sit and watch the screen. It also obviates the need to run a power-hungry monitor at all times.

#22 Comment By GW On November 5, 2019 @ 6:49 pm

I have jusr recently started learning about using radios to communicate, and I have a question- what would be the advantage of the Uniden SR30C vs the Uniden BC125AT? Is the close call feature why it is recommended? I ask because the BC125AT looks like it can scan more frequencies, but I don’t see that it has the close call feature.
I am looking forward to learning more about scanners and ham radio, even though I’m starting off with very little knowledge.

#23 Comment By Tunnel Rabbit On November 5, 2019 @ 8:20 pm

I would take a scanner with a Close Call feature that scans only 100 channels, over a scanner that scans 500 channels, yet has no Close Call. We are attempting to improve situational awareness, more than collecting and developing intelligence. 100 channels is plenty as it will cover the most often used frequencies that might pose a threat. Scan MURS, GMRS, FRS, all the Ham band repeaters and national calling frequencies and Emergency Services. The Close Call will cover everything else when the signal is from a stronger source that would also be near by. Also pick up a scanner for CB, 27 Mhz, and you’ll be a in good shape, and read to move to the next level, time and money permitting.

#24 Comment By Anonymous On November 5, 2019 @ 8:49 pm

Thanks for the clarification. That makes perfect sense. One more question- as far as rechargeable AA batteries for the SR30C, do you have any recommendations?

#25 Comment By Tunnel Rabbit On November 5, 2019 @ 9:37 pm

One down side of these scanners is that they are power hungry, and will go through batteries every day. This is not only inconvenient, but a risk if the scanner power supply not reliable. Relying on one’s memory to remember to change the batteries is not the best idea, if there is a better way to supply this important security tool with power. Because of it importance, if set up for off grid power source, the most reliable and electrically efficient means to power it with 9 vdc from a universal power adapter that uses 12 vdc, and set to 9 vdc. Confirm the polarity of the plug selected before inserting it in the scanner. The second best way is with a 115 vac transformer if the electricity is supplied by an inverter, or grid power. I would also have installed Eneloop rechargeable batteries to power the scanner should it’s primary source be interrupted.

Power adapter from 12 vdc to 9 vdc for the scanner:

If not provided with the scanner, this Power Adapter that converts 115vac to 9 vdc will do:


Best deal on rechargable AA batteries I know of:

#26 Comment By GW On November 6, 2019 @ 4:08 pm

Thanks for the recommendations, they are appreciated!

#27 Comment By John McDonald On November 5, 2019 @ 7:20 pm

You may also want to consider adding CB and marine radio bands to your list for post-SHTF scanning. There are thousands of CB radios still in use, and if you live anywhere near a large body of water there are usually lots of marine band radios around. Base units for both usually run on 12V, and handheld units for both bands are available and pretty common, so you may see those in use post-SHTF. Note that Baofeng radios don’t cover the CB band (26-27MHz), but they do cover the marine band.

#28 Comment By Tunnel Rabbit On November 5, 2019 @ 8:29 pm

An inexpensive broad band scanner that cover 25mhz to 950 mhz, and is found on Ebay. It is the ICOM IC-2SRA or the 70 cm version. Replacement batteries are a available or it can be operated on 7.2 volts. These offer only 60 channels in memory on the scanner side, yet that is enough if this scanner is used in conjunction with another scanner, or a second IC-2SRA. Older scanners are inexpensive ways to cover parts of the spectrum that are now restricted, or not included inexpensive and modern scanners. The old Radio Shack scanners are actually quite good, easier to use, and use less power. In this way we can also scan CB, 6 and 10 meter, military in UHF and even 220 Mhz. Unless there are repeaters in the area, there would be very little traffic on these, except CB.

We are looking for early warning from local threats, therefore coverage need only be for common analogue radios. If getting into actual SIGINT, the requirement might be greater, and include digital as well.

#29 Comment By Tunnel Rabbit On November 5, 2019 @ 10:03 pm

Here is another low cost, $22.00 option for scanning CB:

#30 Comment By Anon On November 6, 2019 @ 12:19 am

I don’t disagree with the value of this. But unless it’s your hobby it will steal time from you (if it’s your hobby it is already stealing time). I am 76 YO and so far I have never needed a scanner or radio to alert me that someone is near and may be unfriendly. What are the odds that I will need it ever or that anyone will? Is it worth my time and money? I certainly have hobbies and spend time and money on them so if it is your hobby then enjoy. But to prepare for god knows what that may never happen and if it did and was all that bad would probably kill you in the first minutes (as in a nuclear war) seems a waste of time and money. Survival skills, food, and certain equipment makes sense but I’m not sure scanners and radios do. I admit I’m not into this kind of thing. I have a cell phone but it’s always off and I don’t even carry it with me when I go someplace. In fact I don’t even know where it is right now, haven’t turned it on in a month or so. But as for food! I eat four times a day, which I guess is why I prioritize that and not radios.

#31 Comment By Jake On November 6, 2019 @ 1:24 am

Anon, if there are bands of roving thugs after a SHTF scenario it is always good to have early warning. To each his own but I have found radio monitoring to be a decent force multiplier.

#32 Comment By Tunnel Rabbit On November 6, 2019 @ 3:13 am


It is good to put it all into perspective, and from time to time reevaluate one’s priorities. Common sense is not so common, nor is a well balanced approach. We can indeed become too focused on a topic that we enjoy, that is our hobby interest, or profession, and to a fault, by ignoring other important parts of our security plan. I could have a more elaborate communications plan, but others would not, or could not participate. Yet the knowledge is there for the future.

It is best to keep it simple enough so all can use it. If no one in my group could use a radio, then radio is no good. If they can handle one channel, or may be a two channel radio, then that is all that can be used. Most will not learn anymore than they have to unless motivated. If there are not enough persons to monitor radio and scanners, then we do not. We should not forget that there other methods of communication, and methods to detect threats that will not be using radios. Even though I enjoy the topic and could delve further into it, I try to remain well balanced and learn as much as possible about other important topics as well. My weakest point currently is medicine. Even though we a professional or two to cover that, I’ve found that my participation there has already improved that part of the plan, and I may be able to help more in the future as well, should my knowledge there continue to grow. If that specialist becomes sick or is lost, then some of the knowledge will still remain. Cross training is very important. Any one can learn to shoot a gun, but do they know tactics? Not likely. Medicine, tactics, and other topics are also important. I am a master of none, or only a few.

The back bone of our security system is actually low tech, and requires no batteries. We actually do not need radio, or other high tech devices to secure our AO, but for those who can see the advantages, radio can improve the chances of surviving. And if the threat is great enough, using radio may actually work against us, and therefore should only be used on rare occasions, and in a very secure way that few can. If that becomes the case, our security plan will suffer little as it can revert to the basics, and emit zero RF. Being low tech has it’s advantages. Unfortunately few still know how to operate that way, therefore making radio a more important topic.

#33 Comment By LogDog On November 6, 2019 @ 12:57 am

Thanks for another great article TR! I look forward to the next.

Does anybody know of a way to automatically log the transmission frequencies that a scanner
hits on? I figure there’s got to be a way with RTL-SDR, but I haven’t found one yet.

#34 Comment By LoupGarou On November 6, 2019 @ 1:27 am

Just a suggestion: Get the BC125AT as a starter scanner for a few reasons, first it covers more of the VHF and UHF spectrum, it does have Close Call (and also temporarily saves the found frequencies in special memory positions), and you can tether it to your PC and Android devices to not only program it, but to also remotely run it and add a few REALLY useful tricks. For starters, look here:
(And they do make a “Pro” (paid for) version that does even more. The free version will program the scanner, but it will also automate the search function to search any frequencies between two frequencies and not only remember their frequencies on the Android device, but show you graphically where all of the “found” ones were (like a slow moving waterfall display).

And if you want to have a bit more capability on the SIGINT side (a lot more), I would suggest looking into the HackRF, with the Portapack added to it, and the latest Havoc Firmware. It is all the SIGINT capability that any group would need on the go.

One last thing, SIGINT is not COMINT, and while you may run across many signals and listen to them, do not get discouraged by the encrypted ones. While you may not be able to listen to what they are saying (COMINT), you can figure out a LOT about their communications even if encrypted (true SIGINT). This is especially true if you know if the signal is SIMPLEX versus Repeater Output versus Repeater INPUT. If you get your local frequency lists from RadioReference, notice that there is a “Show Inputs” box above a lot of the lists. This lists the INPUT frequencies of the repeaters that you would normally listen to the outputs of. The outputs can be heard for tens or miles. The inputs will only be heard fairly close to your location (less than 10 miles or 5 miles if your antenna is below 10 feet off the ground). This means that you can scan for the outputs in one memory bank to listen to the county wide chatter, and scan the inputs on another memory bank to see if you have anything in your neighborhood happening (a great first warning system).

You can also use the FCC ULS license search to find frequencies that are not normally known:


#35 Comment By Tunnel Rabbit On November 6, 2019 @ 4:24 am

Interesting and useful tools for the scanner! Lots of great suggestions there. I’ll comment a bit on some of that.

There is always more to learn and do, and winter time is a good time to close the gaps in our knowledge, be it in radio, or medicine, or what ever the driving interest might be. Like learning to use iron sights before using a scope, get to know the basics and manual way first. And although I am the most knowledgeable about radio in my group, my primary job will likely not be radio. Therefore what ever is adopted has be usable for those less inclined to learn about radio. Set it up to be simple.

And what says one cannot use the inputs without the tone, will others be listening to the inputs? Few. Or better yet, go narrow band, no tone, and 12.5 Kh off the input frequency? Most will sweep 2 meter efficiently and by 25 khz steps, skipping over frequencies that are off whole numbers and off by 12.5 khz, right in between, if your radio can go narrow band. Most can these days. Amateur radio operators typically use wide band and accepted practices, but if it is not against the rules, why not? Do the unusual, and get off the beaten path. If necessary equipment is limited to 2 meter, why not use horizontally polarized and directional antennas as well? If we know how we might be monitored, or conversely, how we might monitor others, we can operate in a way that reduces that chance of interception of our signals.

Same approach can be used in other areas of the spectrum some day, such as the Marine band. Agree. Where there is no licensed user, in times of chaos or emergency, these could be quiet spots to be. Research those while there is still access and time. Here is an alternative source that compliments the first provided.


#36 Comment By John McDonald On November 11, 2019 @ 6:36 pm

Just as a note for those interested, Amazon has the [15] on sale for $90 right now.