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Messages - R4002

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Did some quick 11m band scanning this morning on the way to work (receiver is a Superstar 3900, older style version with Hustler IC-100 mag-mount antenna).  Noticed the usual in-band activity as well as what appeared to be semi-local two-way comms on 25.835 MHz AM (channel 19 on band A, or channel 19 down three bands on the de facto standard 6-band export frequency or channel plan).


Hearing some trucker communications / truck to truck chatter on 25835 AM this morning.  Talking about moving loads up to a meeting point or distribution point.  Two OMs with roger beeps.  No echo noted, but strong AM modulation and rapid fading up and down (indicating that they're moving). 

De facto standard 6 band export 11 meter (10 meter) radio channel plan.  Band D is the CB band (or the mid band 26.965 MHz to 27.405 MHz), Band C is the low band (26.515 MHz to 26.955 MHz), band E is the high band (27.415 MHz to 27.855 MHz).  Band B is the low-low band (26.065 MHz to 26.505 MHz) and Band A is the super-low band (25.615 MHz to 26.055 MHz).  So if the CB band is band D, channel 19 is 27.185 MHz, down one band is 26.735 MHz (band C), down two bands is 26.285 MHz (band B), down three bands is 25.835 MHz (band A).    This is the standard 6-band / 240 channel export radio channel plan.  Up one band would be 27.635 MHz (band E) and up to bands would be 28.085 MHz (band F).  One "band" is 0.450 MHz / 450 kHz.  Truckers love to flip the band switch up or down to find a clear frequency, instead of touching the channel knob, its easier to leave the channel setting where it is, and simply flip the band switch.  Because of this, the common trucker channels on the various A-B-C-D-E-F bands are popular places for AM activity during band openings.  Channel 19 is the obvious starting point, but channels 14, 15, 16, 17, 18, 20, 21, 22, 23, etc. are also popular.  I've noted trucker comms on 26.775 MHz (channel 22 down one band), 27.535 MHz (channel 11 up one band), 27.605 MHz (channel 15 up one band), but 27.615 MHz, 27.625 MHz and 27.635 MHz are all very popular (channels 17, 18 and 19 up one band).

Maybe this is the beginning of another band opening (yesterday I heard what sounded like several different business or trucking company comms on various 26 MHz frequencies in Band B (26.065 MHz to 26.505 MHz) and on the high channels (Band E), including 26.325 MHz, 26.365 MHz, 26.375 MHz, 26.405 MHz, as well as 27.585 MHz, 27.655 MHz, 27.755 MHz and 27.775 MHz, all AM mode. 

Noticing a large number of swooshes on the lower freeband frequencies - roughly 26.500 MHz to 26.900 MHz, with some in-band as well.  All 40 CB channels are busy at 1613 UTC.

Checking out the KiwiSDRs starting at 1600 UTC:

COMMSIGMA KiwiSDR on the CT/MA border:

Basically every single one of the legal 40 channels are busy, with 27.025 MHz, 27.085 MHz, 27.265 MHz, 27.285 MHz and several others booming in with AM activity.  I'm hearing a heterodyne on channel 23 (27.255 MHz) consisting of two OMs speaking Spanish to each other, and several FSK datalink or telemetry bursts on top of them.  OMs speaking English coming in at 1609 UTC, with QRM from channel 26 (27.265 MHz). 

Noting activity on the following out of band frequencies:

26-27 MHz - lots of the ISM swoops and wooshes showing up on the waterfall
26.345 MHz - OMs speaking English "what about his daughter?" "and Paul"
26.525 MHz - English language, southern accents, heavy fading
26.565 MHz - mix of Spanish and English, messy
26.815 MHz - weak AM carrier fading in and out
26.855 MHz - two OMs talking, sound like truckers, then crazy QRM from ISM - woooosshhh

Excellent, another 11 meter / CB band opening.

Any activity on the other AM DX channels?  Namely CB channels 11 (27.085 MHz), 26 (27.265 MHz) and 28 (27.285 MHz) and the out of band AM DX frequencies clustered around 26.7 to 26.9 MHz (26.915 MHz, 26.905 MHz, 26.885 MHz, 26.835 MHz, 26.735 MHz, 26.725 MHz, 26.715 MHz, 26.705 MHz and the other channels +10 kHz and -10 kHz from those)?

10/11 meters / Re: 11 meters is active 1645 UTC 9 June 2019
« on: June 10, 2019, 1415 UTC »
I know lol

I meant there is a lot of activity within the 26.965 MHz to 27.405 MHz CB band, as well as activity on the 26.705 MHz, 26.715 MHz and 26.725 MHz frequencies listed.  I'm in the USA as well :D

After making that post I noted activity on other low channel frequencies as well:

26.105 MHz AM - English language, popular trucker channel
26.125 MHz AM - English language
26.405 MHz AM - English language, US stations, sporadic signals
26.475 MHz AM - English language, weak
26.500 MHz USB - Spanish language, Caribbean working frequency (previously logged)
26.555 MHz LSB - Spanish language, Latin American and Caribbean working frequency
26.585 MHz AM - Spanish language, Mexican trucker/11 meter AM channel (busy)
26.595 MHz AM - Spanish language, Mexican trucker/11 meter AM channel
26.635 MHz AM - English language, southern US accents
26.735 MHz AM - English language, probably truckers - this channel 19 "down one band"
26.805 MHz AM - English language, southern US accents
26.885 MHz AM - English language, AM DX channel (secondary to 26.915 MHz and nearby frequencies)
26.905 MHz AM - English language, mention of Florida
26.915 MHz AM - some very strong signals heard here, 26.915 AM is one of the more popular AM low band channels
26.945 MHz AM - English language, sounds like two locals talking to each other

10/11 meters / 11 meters is active 1645 UTC 9 June 2019
« on: June 09, 2019, 1652 UTC »
Lots of activity in-band, also hearing Spanish voices coming in very strong on 26.705 MHz, 26.715 MHz and 26.725 MHz.  Likely Puerto Rico, Miami, etc.  26715 AM and 26725 booming in at 1652 UTC.

22 Meter Band HiFER Beacons / Re: Antennas for covert install.
« on: June 07, 2019, 1943 UTC »
For mountaintop installation, I would lean more towards dipoles (as Josh mentioned, they will help you get as much RF as possible out, which is critical for low power beacons). 

When you mention mountaintop locations, are we talking above the tree line rocky terrain or lots of trees?  Trees do a great job of absorbing RF under certain conditions but can also be great natural dipole / wire antenna support structures. 

22 Meter Band HiFER Beacons / Re: Antennas for covert install.
« on: June 07, 2019, 1326 UTC »
Yes, a "dual-band" beacon for 22 meters and 11 meters would be awesome.   I'm looking at the frequency list for currently active 22m beacons and most of the beacons seem to be in the 13554 kHz to 13558 kHz range with a few others higher in frequency (I know most ISM QRM centers at 13560 kHz), then 13562 kHz or so up to 13566 kHz/13567 kHz.  22 meters 13553 kHz - 13567 kHz (x2 is 27106 kHz - 27134 kHz) or roughly CB channels 12 (27.105 MHz), 13 (27.115 MHz), 14 (27.125 MHz) and 15 (27.135 MHz).

Looking at the second harmonic of those frequencies and their relation to the 11 meter/CB band plan:

13553.0 kHz x2 = 27106 kHz / 27.106 MHz - 1 kHz above CB channel 12
13554.0 kHz x2 = 27108 kHz / 27.108 MHz - 3 kHz above CB channel 12
13555.0 kHz x2 = 27110 kHz / 27.110 MHz - right between CB channels 12 and 13, and probably a better spot for an 11m beacon
13557.0 kHz x2 = 27114 kHz / 27.114 MHz - 1 kHz below CB channel 13
13560.0 kHz x2 = 27120 kHz / 27.120 MHz - right between CB channels 13 and 14, but suffers from 13.56 MHz ISM QRM)
13562.0 kHz x2 = 27124 kHz / 27.124 MHz - 1 kHz below CB channel 14
13562.5 kHz x2 = 27125 kHz / 27.125 MHz - right on frequency for CB channel 14
13563.5 kHz x2 = 27127 kHz / 27.127 MHz - 2 kHz above CB channel 14
13565.0 kHz x2 = 27130 kHz / 27.130 MHz - right between CB channels 14 and 15, another good spot for a beacon
13565.5 kHz x2 = 27131 kHz / 27.131 MHz - also another good spot for a beacon
13566.0 kHz x2 = 27132 kHz / 27.132 MHz - 3 kHz below CB channel 16, probably another good frequency
13567.0 kHz x2 = 27134 kHz / 27.134 MHz - 1 kHz below CB channel 16, maybe not the best choice

So the best bets for dual-band 22m/11m beacons are looking like

13555 kHz (second harmonic: 27110 kHz) and nearby freqs 13553 kHz - 13557 kHz (second harmonics 27106 kHz - 27114 kHz)

13560 kHz (second harmonic: 27120 kHz) and nearby freqs 13558 kHz - 13562 kHz (second harmonics 27116 kHz - 27124 kHz), although your 22 meter beacon wouldn't do so well with all the ISM QRM on 13.56 MHz

13565 kHz (second harmonic: 27130 kHz) and nearby freqs 13563 kHz - 13567 kHz (second harmonics 27126 kHz - 27134 kHz)

Your best bet on 11m (as far as a dual-use beacon goes anyway) is to stay as close to the halfway point between the CB channels, so 27.110 MHz, 27.120 MHz and 27.130 MHz.  CB channel 14 on 27.125 MHz is doable and 1-2 kHz either way from the 27110/27120/27130 center frequencies probably wouldn't hurt too much either.  Plus, 27125 is just easy to remember (22 meter frequency 13562.5 kHz). 

I know there was a Part 15 beacon in operation on 27.120 MHz (maybe it was 27.125 MHz?) at one point or another. 

I strongly support your plan to do multiple beacons.  You could do 2 MHz, 4 MHz, 8 MHz, 13 MHz/22 meters and 27 MHz/11 meters. 

If you decide to do a dedicated beacon for 11 meters then I would recommend using one of the four R/C frequencies (26.995 MHz, 27.045 MHz, 27.095 MHz, 27.145 MHz or 27.195 MHz) or going slightly above or below the CB band to get a clearer frequency.  Of those frequencies, 26.995 MHz, 27.145 MHz and 27.195 MHz are probably your best bets.  Since those frequencies are used for data transmission, a low powered beacon transmitter would fit right in.  Staying within the CB band (even if you use a dual-band 22m/11m beacon transmitter) will probably reduce your chances of being noticed.

Under FCC rules, you can transmit data/telemetry on 26.995 MHz, 27.045 MHz, 27.095 MHz, 27.145 MHz, 27.195 MHz or 27.255 MHz.  26.995/27.045/27.095/27.145/27.195 are data-only channels and have a 4 watt maximum power limit under Part 95 of the FCC rules for the Radio Control Radio Service.  27.255 MHz is also CB channel 23, but...under FCC Part 95, the maximum power goes up to 25 watts for professional-level remote control, paging, datalink and telemetry systems operating on that frequency.  There are several known systems using 27.255 MHz and paging and FSK datalink / telemetry signals have been heard on 27.255 during band openings, making those telemetry and other systems de facto 11m beacons.

Or, if you want to stay out of the QRM from within the CB band, use 27.500 MHz, there are other beacons operating on that frequency as well.

A lot of 4x4 (=16) guys and gals use cb to talk whilst trail riding. Had a Francis Wheeler Dealer .25wl antennae on the Samurai, people told me it looked like an rc car.

Ahh, yes, the 102" (or 108") stainless steel whip, 1/4 wave for CB.  Pretty hard to beat as a mobile antenna, especially with the massive spring at the bottom.  :D

Yes, you can still buy CB radios and yes people still use CB radios.  Here are some of the newer CB radios on the market:

Ranger (RCI) Superstar SS-158FB4.  The SS 158FB4 is the latest incarnation of the famous Superstar 3900 series radios, this all-mode AM/FM/SSB beast includes a built-in amplifier and is rated at 100w carrier/400w PEP AM/SSB and covers has 12 bands to choose from covering 24.265 MHz to 29.655 MHz.  An easy mod can change that to 24.715 MHz to 30.105 MHz, giving the operator full coverage of the 12 meter ham band, the 10 meter ham band, the CB band and all frequencies in between:


Uniden Bearcat CMX560 - hide the radio itself under your seat and control everything from the handset/microphone.  Designed for very small vehicles and off-road/Jeep applications.  40 channel FCC approved 4 watt AM carrier power.


Uniden Bearcat CMX660 - tiny 40 channel 4 watt AM CB radio designed to fit in modern, small vehicles and for off-road purposes (read: install this in your Jeep, bro).  This radio is quite small, 4 inches wide, 1 inch tall and 4 inches deep.


Stryker SR-25MC (available under a dozen other brand names and model numbers, I believe it is a rebranded Anytone) - coming in at a tiny 4.9 inches wide, 1.4 inches tall and 4 inches deep! this clearly-designed-for-the-Russian-taxi-drivers 11 meter export CB radio covers the usual 240 channels - 25.615 MHz to 28.305 MHz AM/FM modes. 


Ranger (RCI - the company that builds Galaxy, Ranger, Superstar, Connex, Mirage, etc. radios), Uniden, Cobra and the various Chinese companies wouldn't be putting the money into designing and building new radios if the market wasn't there. 

The SR-25MC (and others) are examples of several dozen Chinese AM/FM export rigs that have flooded the market over the past few years.  Here's a list of the current models produced by Chinese radio manufacturer Anytone: 



I also worked in the industry before and after HD was introduced. The problem with AM is that FM replaced it as a primary medium for younger (in the 70's-80's-90's) listeners, because it was clearer, and had stereo. Then in the 00's and 10's you had the RFI problem plaguing AM, which didn't help.

Your average listener is not going to tune to a noise-wracked band even if it has "compelling" programming.

As for big radio companies, they are keeping AM on the air in many places, by putting talk on them, brokering programming, etc. If the big conglomerates hadn't proliferated after dereg, a lot of AM's would be off the air already. WABC, KABC are prime examples. Their audiences aged out, and they are only on the air because they are owned by conglomerates that presently are running whatever on them until they decide to sell them.

But who is going to buy a 50KW station with no listeners and tons of overhead? There are stations for sale on the market right now with no takers. Outside of very small markets, the era of the mom and pop radio station owner are gone.

All digital will work if only because of car radios. HD AM is in about one third of the new cars with radios. HD AM may fill certain niches that aren't available on FM because of an overloaded FM band -- religious and ethnic programming probably.

People can afford HD radios more than in the 00's when HD was introduced. Sangean sells them for less than $100. If a consumer can afford over $100 for a smartphone or video game console, they can certainly afford an HD radio.

One problem with new radios is that OTA radio itself is heading more and more online. The days of OTA radio, FM as well as AM, HD or not, are numbered. Maybe we have 30 years left.

At least in the (medium-sized urban) market I live in, AM is a mixed bag of talk radio, news, religious programming (although there's a lot of that on the FM band as well), several sports radio stations and ethnic programming.  Some of the ethnic stations are slowly migrating to FM via translators (or just moving to the dual-band model) while others are staying with AM.  Sports radio is basically only on AM.  However, you do make a good point, BoomboxDX....a lot of radio content is now being streamed via Internet and cellular networks instead.  I'm in my early 30s and as I mentioned before, the only reason my peers even really are familiar with AM broadcasting is because of sports radio (local and skywave) being on AM.  The only reason my friends know about skywave sports availability is I was there to give them lessons in "AM radio's best kept secret" - the ability to listen to distant stations at night, including a given sport's team's 50,000 watt flagship station.

Eventually they'll sell off the 500 MHz band and that will go to 6G or whatever generation of mobile networks we're on at that point.  Over the air radio (and television) will eventually go away, if things keep going in the current direction. 

CB is alive and well, although a lot more so in some places vs. others.  Even just having mobile CB gear and a few handheld FRS radios puts one several steps ahead if/when the North Koreans explode a high-altitude nuke over the middle of the country and knock out the power grid with the resultant EMP. 

In rural areas, its still quite popular and more often than not, installed in pickup trucks, etc.  I have seen many an Antron-99 (and similar vertical CB base station antennas) installed on many a farmhouse. 

There is a slow migration from CB (read: export radios with extra channels and amplifiers) and/or the VHF marine band to licensed VHF business band frequencies as far as the hunting clubs in my area go but there's still a lot of them who still use CB as a fall-back.

It's what a certain state government emergency management communications official I knew once called "redneck interoperability".  Yes, you certainly can still buy them and they are producing/developing new radios all the time.  The state police actually have a Cobra CB as part of their communications equipment installed in their mobile command posts, and the state DOT motorist assistance trucks have CBs installed for listening to channel 19 (and talking to truckers, when required). 

With a proper antenna and use of SSB, CB, even at modest power levels, provides excellent range.   The sheer number of radios out there also cements the usefulness in an emergency situation.  This could also be said about FRS/GMRS...there are just a lot of radios in the hands of a lot of people. 

Local CB around me exists in both AM and SSB forms, with the SSB operators operating both within and above the CB frequencies, depending on if the band is open (when the skip comes rolling in, they change frequencies).  I have heard local AM CB chatter on the "lowers" too, but that seemed to be hunting club related comms and not a regular net. 

Also truckers.  And kids with Jeeps.  And preppers.  Even snobbish ham operators...  CB isn't going anywhere. 


You're right, R4002.
There are many ISMs on 40 MHz.

But, the big risk for the 40 MHz ISM transmitting equipment designers is the suppression of their 3rd harmonic, which falls right in the middle of the VHF aeronautical voice band!
ISM Band 40.680 MHz +/- 20 kHz = 40.66 MHz to 40.7 MHz band limits

40.660 MHz x 3 =121.980 MHz
40.680 MHz x 3 =122.040 MHz
40.700 MHz x 3 =122.100 MHz 

Very true.  Interference on the VHF airband is bad news.  Having said that, the 11 meter CB band produces harmonics on the VHF aeronautical band too (albeit at the 4th and 5th harmonics, not the 3rd harmonic for 40 MHz ISM).  CB channel 2, for example at 26.975 MHz, 4th harmonic is right on 107.900 MHz (at the very top end of the FM broadcast band, another bad place to cause QRM), 5th harmonic is on 134.875 MHz, in the voice (comm) portion of the airband. 

CB channel 6 (everyone's favorite unfiltered splatterbox amplifier producing all the harmonics/spurs channel) 27.025 MHz 4th harmonic is 108.100 MHz (in the nav portion of the airband) and 5th harmonic is on 135.125 MHz, also in the voice (comm) portion of the airband.  I'm sure ISM devices are filtered enough to not really have to worry about 4th/5th harmonics, but CB equipment is another story.  Some of the amplifiers used by guys on 27.025 MHz and other 11m frequencies have no harmonic filtering whatsoever and the possibility of throwing a several-watt signal on an aircraft frequency is very real. 

I suppose the potential interference on the 3rd harmonic as well as interference considerations for the 40.67 MHz SNOTEL system and military/government users in the United States (the military and some agencies of the US government - see here: https://wiki.radioreference.com/index.php/Tennessee_Valley_Authority#Transmission_and_Customer_Service_.28TCS.29 makes heavy use of the 40-42 MHz band) means 40.68 MHz ISM isn't as popular as 13.56 MHz ISM or 27.12 MHz ISM. 

Hmmm...diathermy equipment.  I remember reading somewhere about the origins of the CB service in the United States back in the 1950s and an issue with QRM from short wave diathermy machines on the original 23 channel CB allocation.

Also note:


The use of the 26 MHz, 27 MHz, 34 MHz, 35 MHz and 40 MHz bands (40 MHz R/C band in the UK goes from 40.665 MHz to 40.995 MHz in 10 kHz steps, despite the 40 MHz band being an EU-standardized FM military band). 

I wonder how many of these ISM users use the 40.680 MHz frequency vs. 13.56 MHz or 27.12 MHz.  I know these sporadic-E openings have included (sporadic) 6-meter/50 MHz band DX as well as 11-meter and 10-meter openings.  So perhaps 40 MHz (8 meters!) 40.66-40.70 MHz is another place to look for these ISM swooshers/swishers/heaters/fish hooks if/when the bands are open and 6 meters/VHF low band is active.

BTW, Exo and Chris, great waterfall images.  Always nice to see signals literally every 10 kHz from 26.7 MHz or so to 27.5 MHz or 27.6 MHz when the band is open enough for the ISM signals to be seen on the SDR waterfalls.

This is slightly off-topic but worthy of a mention as well:

Apparently the 40.66-40.70 MHz region is also used for R/C, datalink and remote control type purposes in Europe and elsewhere, much like the 26-27 MHz Part 95 R/C frequencies are used for datalink purposes in the USA (and everywhere else).  I know its a different part of the rules (ISM vs. Part 95) but the regulator agencies seem to have no problem with assigning these things to the same bands. 

Also, don't forget the US Government's SNOTEL snowfall/precipitation telemetry data link network on VHF low band 40.670 MHz.   https://wiki.radioreference.com/index.php/SNOTEL

I doubt they have issues with interference from ISM but when the band is open 40.67 MHz is quite lively. 

I hear a lot of Florida stations during band openings as well as nearby points in the deep south and the Caribbean.  Seems like the skip zone for 26-30 MHz favors that sort of distance, although I have worked closer stations on channel 38 LSB and nearby frequencies. 

Seems like the frequencies just above channel 40 are popular with SSB operators in that part of the country, with 27.425 LSB, 27.430 LSB, 27.445 LSB and 27.465 LSB often busy when the band is open to that part of the country.  There is (or was) a Spanish speaking taxi cab dispatcher (distinctive voice, Mexican accented Spanish YL dispatcher) on 27.445 MHz (AM mode) as well, sometimes she comes in strong enough to cause QRM issues for the stateside stations working LSB on the same frequency. 

IIRC, his first bust/knock was the result of him broadcasting within the ham bands [on 3845 kHz / 3.845 MHz I believe], which (naturally) gathered a lot of attention.  Now that's hes outside the ham bands he may stand a chance of going longer before somebody drops a dime. 


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