NOAA All Hazards Radio has been around since 1960. I have a Midland Weather Radio receiver in my house because we live in a rural area. We certainly do have weather events; Severe Thunderstorms being the most common. We have also had Tornados, Floods, Hurricanes, Winter Storms and Blizzards. It is useful to have, especially when the cell phone and/or public network go down.
That system operates on the same frequencies and manner as the NOAA All Hazards Radio system.
It appears that the Canadian government is discontinuing service as of March 16, 2026 and replacing it with an app. That seems short sighted to me; I don’t know how many users of Weather Radio Canada there are, but I’d bet there are quite a few. It also assumes that everyone in Canada has a smart phone. Given the economy and the expense of a new iPhone (or Android), I think this is far from the case.
Nautel NG1000 NOAA transmitter
I did get thinking about what would happen here if the NOAA system went away. Could the Emergency Alert System still get reliable local alerts out over the air? I know that most of the radio and TV stations in this area still monitor the NOAA frequencies as a third source for local activations. Over the years, EAS activation for things like Tornado Warnings has saved quite a few lives, especially out in the mid west.
I am seeing more and more people getting into (or back into) vinyl recordings. This is somewhat heartening. My personal feeling is that good analog recordings offer a great way to enjoy music, particularly older music. The other nice thing; when I am holding a physical disk, it is mine. I bought it, I own it. No one can track it or delete it from my device.
Grooves in a vinyl disk seen through an electron microsope, courtesy of Eric Muzipov @microscopyspecialist
Vinyl is actually Polyvinyl Chloride or PVC. Columbia records switched from Shellac record disks to PVC around 1947. According the the RIAA, vinyl sales peaked in the US around 1973. It is possible to find new vinyl in a few places like Target, Walmart and Barnes & Noble. There is a large market for used vinyl recordings in local record stores like Dark Side Records.
Technics SL-1200 Mk II turntable
Many years ago, I retrieved this Technics SL-1200 Mk II turntable from the trash heap. This particular turntable had been through the flood after Hurricane Irene (2011). It spent more than 48 hours completely submerged in some pretty dank water. Following that, it went into the barn for many years without being looked at.
At some point in the last few years, I decided that I wanted a turn table for my Hi-Fi system. I retrieved the Technics unit from the barn and began the rehab. Fortunately, both the service manual and user manual are easy to find on line.
I disassembled the entire unit and inspected all of the parts. As it turned out, it was fresh water and the damage did not look too bad. There is some pitting on the under side of the platter and some general corrosion on the strobe dots. It took a while and a good deal of patience and elbow grease to clean everything off. The electronics in this turn table are only for control of the direct drive motor. Audio passes through to the outboard pre-amp. There is one 450 uF 50 VDC capacitor in the power supply which looked good, so I left it alone.
I put it all back together, but realized quickly that it needed to be set up correctly. There are many videos on Youtube that show how to align this particular model turntable. A complete alignment is important because the stylus must meet the grove at the correct depth and angle in order for the playback to be accurate.
The mechanical setup consists of five main things;
The turn table must be completely level front to back and especially center post to stylus (the track of the tone arm)
The height of the tone arm (stylus angle in the groove)
The vertical tracking weight (proper frequency response, stylus and record wear)
The anti-skating (proper pressure on both sides of the record groove, correct amplitude)
Alignment of the cartridge in the cartridge head (stylus angle in the groove, proper left/right phasing, stereo separation and image)
These items are very easy to deal with on the SL-1200. It has feet that can be adjusted to level the unit. The leveling of the tone arm track is especially important to get right.
The height of the tone arm is set with the base arm ring. Some turntables do not have this adjustment, particularly consumer grade units. The tone arm should be level when the stylus is on the record.
The tracking weight is set by the tone arm balance weight. First, the tone arm is balanced so that it floats (in other words zero weight). The tracking weight depends on the cartridge and stylus being used. In this case, the cartridge is an Audio Technica AT-OC9XEN Moving Coil cartridge with an elliptical stylus. The tracking weight for that cartridge is 1.8 to 2.2 grams. I set mine to 2.0 grams.
Anti-skating is generally set for the same value as the tracking weight. However, this is sometimes too coarse. A test record with a blank band on it can help get this exact. It does not make a huge difference, but it is nice to confirm this anyway.
The alignment of the cartridge in the head shell is important, especially with an elliptical stylus. This is done using a Cartridge Alignment Protractor which can be downloaded for free from the vinylengine.com website
Schiit Audio, Mani phono pre-amp
I purchased this piece of Schiit a few years ago to use with my vacuum tube amplifier. I have since switched to a Kenwood VR309 for my main listening setup. While the phone preamp in my Kenwood stereo is pretty good, I think this preamp sounds better, especially with the moving coil stylus.
Circa 1960 Beethoven Symphony No. 7 in A Major. Murray Hill Records, One Park Ave, New York, NY
So, how does it sound? Pretty darn good. I dusted off some of my high school record collection and enjoyed explaining to my SO why a particular song was good. I also found a whole stash of like new Classical vinyl at the local Habitat for Humanity Restore, which was more to her liking. I love those places, you never know what you will find.
History is one of my interests. Working in Radio over the years, there is plenty of interesting history that surrounds the first electronic mass media. My parents grew up in the depression/WWII era. For them, radio was a vital information source. Listening to FDR’s fireside chats about the economy and the progress toward recovery was a friendly voice reassuring them that times were indeed difficult but they would get better. Then the shock of the Pearl Harbor attack on December 7th rippled through the airwaves on a Sunday afternoon. These are the life long memories of my mother, who is now 92.
Preserving some of this history for following generations, who take the free flow of information for granted, is a worthwhile cause. Thus, I want to visit, then write about the many Radio Museums around the country. Each is a little bit different with its collection and interpretation of radio history.
Over the Christmas/New Years holidays, my SO and I went on a road trip around Western North Carolina and Virginia. We visited the Asheville Radio Museum along the way.
One thing that I found interesting is the People’s Radio. This was from Nazi era Germany (1933-45).
Folks Radio
This radio only had medium wave and was designed only to receive radio stations from Nazi radio stations. In order to possess a radio, a permit from the government was needed.
Nazi German Broadcast permit
Having a radio receiver without a permit would lead to an arrest and possibly being sentenced to death. In addition to that, getting caught listening to a non-Nazi radio station would result in arrest, imprisonment and later in the war, possibly death. It was no trivial matter.
Atwater Kent console with Philco table top receiver
Older radios were often treated as a piece of furniture. My parents both said that evenings were often spent sitting in the living room listening to the radio. Radio dramas were performed live and included programs like Amos ‘n’ Andy, Mercury Theater of the Air, Jack Benny, Ed Sullivan, The Lone Ranger, The Fleischmann’s Yeast Hour, Calling all Cars, The Answer Man, Dick Tracy, Death Valley Days, The National Barn Dance, to name a few.
Early tabletop radios were powered by batteries1935 Zenith Stratosphere 1000Z console radio Zenith Promotional Materials
The top of the line console radio was the Zenith Stratosphere 1000Z. The porcelain cat was a notable feature for these radios.
The Asheville Radio Museum holds Amateur radio license W4AFM. They have a decent display of vintage Amateur radio gear.
Old Amateur radio circa 1915Collins 30-S-1 HF Linear AmplifierAN T-74/CRT-3 life boat transmitter
This is a WWII era life boat radio which transmitted on 500 KHz and 8,280 KHz. It was powered by a hand crank and could send an automatic SOS or a CW message could be sent manually by the key button. The round door on the front contained a wire antenna. After 1947, the HF Lifeboat frequency was changed to 8,364 KHz, which remained in use until about 1992.
There are several other displays on early telephones, the proximity fuses developed during WWII and so on.
The Asheville radio museum is located in room 315, Elm Building, A-B Technical Community College, 16 Furnihurst Drive, Asheville, NC.
Special thanks to Stuart Smolkin for coming in on his day off to give us a tour.
This is not a new idea, many people have discussed it in the past. The National Radio Systems Committee (NRSC) has a guidance paper, NRSC-G102 which gives a detailed explanation of why synchronized AM carriers are beneficial. There was even a move by some to have it included in the AM revitalization plan of a few years back. The NAB opposed this idea, saying it would be too expensive. That is unfortunate because out of all of the revitalization initiatives, GPS locked carriers had the best potential for an actual technical improvement. While it may be expensive for some very old tube type transmitters, for more modern solid state transmitters, GPS referenced carriers can be implemented as little as $200.00 US.
The FCC rule (73.1545(a)) for AM Carrier frequency specifies:
AM stations. The departure of the carrier frequency for monophonic transmissions or center frequency for stereophonic transmissions may not exceed ±20 Hz from the assigned frequency.
40 Hz is quite a bit of movement on a 20 KHz AM (18 KHz in ITU region II and III) channel. The reason for trying this is simple; there are many co-channel and first adjacent channel AM stations which at night, interfere with each other.
Typical AM spectral mask
Above is a typical spectrum analysis of an AM station on 940 KHz. This was a 10 minute peak hold for an NRSC-2 spectrum mask measurement. The carrier is approximately 20 dB greater than the audio, which means that most of the interference between co-channel AM stations is created by the carriers beating against each other. By locking carriers to the same reference, that carrier interference will be greatly reduced. NRSC-G102 goes into great detail on the listenability of interfering stations with synchronous AM carriers (Page A-3).
Stations drifting off frequency also cause greater adjacent channel interference.
Almost all transmitters made in the last 30 years have an option to use an external frequency generator or 10 MHz reference. The required drive levels vary. The easiest way to implement this is by using a GPS locked programmable frequency source such as the Leo Bodnar LBE-1420. It can be programmed to any frequency from 1 Hz to 1.1 GHz, has a frequency stability of 0.000001 PPM (10-12), and an output level of 3.3 V peak-to-peak. This drive level is not enough for some transmitters. For those situations an additional amplifier such as a Mini Circuits ZHL-3A+ is needed.
Here are a few AM transmitters that except an external RF source including a GPS disciplined oscillator.
Nautel J-1000
An external RF source can be plugged into the EXT RF IN connector (J-6) on the Remote Interface board. The source must be on the carrier frequency ± 5 Hz and have a peak-to-peak voltage of between 5 – 15 V (sine wave or square wave), 50 ohm impedance.
Nautel J-1000 external RF input
An external 10 MHz signal can be connected to the RF synthesizer board 10 MHz REF INPUT (J2). The external 10 MHz frequency reference must be precisely 10.00 MHz and have a peak-to-peak voltage of between 2.2 – 8.0 V (sine wave or square wave).
Jumpers on the Remote Interface Board and RF synthesizer board need to be configured appropriately for each source. Consult the manual pages 3-9 and 3-11.
Nautel ND series
An external RF source can be connected to ABA1J1 on the external interface board. The RF drive must be on the carrier frequency ±5Hz with level of between 5 – 12 V peak-to-peak (sine wave or square wave) and have a 50-ohm impedance.
Nautel ND-1 remote interface board
Do not remove the crystal from the RF Drive board as the PDM frequency for the modulator is derived from it.
To select the RF drive source for the transmitter the links on the RF Drive board need to be changed. Consult the manual pages 3-3 and 3-14.
Nautel XL series
An external 10 MHz signal can be connected to the RF synthesizer board 10 MHz REF INPUT (J2). The external 10 MHz frequency reference must be precisely 10.00 MHz and have a peak-to-peak voltage of between 2.2 – 8.0 V (sine wave or square wave).
Nautel XL-12 10 MHz reference input
An external RF frequency source can be connected to the Exciter Interface board, J7. The external drive signal must be between 5 – 12 volts peak-to-peak (sine wave or square wave). Consult manual pages A1 and B4.
Nautel XL-12 external RF input
Nautel XR series
An external RF source can be connected to the remote interface board’s digital EXT RF IN (J6). This replaces the internal carrier frequency oscillator for one or both exciters (A/B). The external RF source must be the carrier frequency, within ± 5 Hz, have peak-to-peak voltage between 5 – 12 V (sine wave or square wave). Consult the manual pages 7-1.
Broadcast Electronics AM2.5 – AM10A, AM5E
The transmitter has an external RF input on the top of the unit (EXTERNAL RF INPUT). The input is designed for an external stereo generator or reference oscillator with a signal level from 5 to 15 volts peak-to-peak. To use this input, program jumper P7 on the exciter circuit board in position 1-2. Consult the manual page 2-19.
Broadcast Electronics AM500 – AM1A
The transmitter has an external RF input on the ECU rear-panel (EXTERNAL STEREO RF INPUT (J1). The input is designed for an external stereo generator or reference oscillator with a signal level from 5 to 15 volts peak-to-peak. To use this input, program jumper P7 on the exciter circuit board in position 1-2. Consult the manual page 2-20.
BE AM1A external RF input
Harris Gates AM series
An external RF source can be plugged into J-1 on the Oscillator board. The source must be on the carrier frequency ± 20 Hz and have a peak-to-peak voltage of 5 volts. Frequency source selector P-6 must be set to external. Consult the manual, Oscillator Board Schematic.
Harris DX series
An external frequency generator can be connected to J2 on board A3. Jumper P5 should be set to either 20K ohms or 50 ohms depending on the source impedance. Jumper P6 can be set to either external source or automatic source selection. The drive level needs to be 4 to 4.5 volts peak-to-peak square wave for high impedance inputs or 0 to +25 dBm for 50 ohm impedance sources. Consult the manual, page A-2.
Newer DX series oscillator boards which have automatic source selection will fail over to the internal oscillator if anything happens to the externally generated RF signal.
Harris DAX
An externally generated carrier frequency or 10 MHz reference signal can be connected to connector J11 for the external carrier or J10 for the 10 MHz reference on the External I/O board. External carrier or 10 MHz reference must then be enabled via the VT100 screen. The external carrier frequency or 10 MHz reference must be above 2.0 volts peak-to-peak. Consult the manual page 3-15.
Harris 3DX
An externally generated carrier frequency can be connected to J12 (RF CARRIER) jack on the external IO board. The drive levels need to be 4 to 5 volts peak-to-peak, square or sine wave. On the carrier frequency +/- 5 Hz. The input is impedance is selectable for either 50 ohms or 10 K ohms.
An externally generated 10 MHz reference frequency can be connected to J10 (10 MHz REFERENCE). 10 MHz reference level needs to be 1 to 5 volts RMS, square or sine wave. The input impedance is selectable for either 50 ohms or 10 K ohms.
Programming for these options is done on the exciter setup page. Consult manual page 2-43.
Harris SX series
SX series transmitter have either an oscillator board or a frequency synthesizer board. Both will accept an external frequency source. The oscillator board is A16J1 and it needs a 5 volt peak-to-peak carrier frequency signal. Frequency source selector P-6 must be set to external.
The frequency synthesizer board external frequency input is also J1, however, it requires a 10 volt peak-to-peak signal. Frequency source selector P-6 must be set to external.
Conversion table for various RF power levels into a 50 ohm impedance
Volts, Peak-Peak
Volts, RMS
dBm
mW
2.2
0.77
10.8
12
3.3
1.23
14.35
27
5
1.76
17.9
62
10
3.5
23.9
250
12
4.24
25.5
360
15
5.3
27.5
562
20
7.07
30
1000
A 10 MHz reference input is preferred over direct carrier frequency generation simply for the ease of implementation. With direct carrier frequency generation, the frequency output of the GPSDO needs to be double checked. One misplaced digit and severe damage to the transmitter can result.
AM Tube type transmitters, plus early solid state transmitters such as the Harris MW1A may have instructions for implementing AM stereo. Since the AM stereo exciters generated the carrier frequency, those instructions would be a good guide on how to connect an external frequency generation source. However extensive modifications may be needed to the oscillator section depending on the transmitter.
Honestly, this is cheap enough that I think all new AM transmitters should come with this from the factory.
