Many thanks to SWLing Post contributor Dan Greenall, who shares the following guest post and asks, “Wonder who can add to this list?“:
A Look Back – DXing between 1610 and 1700 kHz
by Dan Greenall
1. The Caribbean Beacon, Anguilla West Indies 1610 kHz (1985 QSL)
2. NDB stations (non-directional beacons)
- transmitted call letters on CW, mostly from airports, heard in the 1970’s
- examples: MDE Medellin, Colombia 1690 kHz and RAB Rabinal, Guatemala 1613 kHz
3. U.S. Army Broadcasting Service KTRK 1670 Fort Meade, MD Feb 1996 articles and recordings
https://www.radioheritage.com/ktrk-k-truck-1670-khz/
4. FCC Part 15 Radio Stations
Example: WDKW 1630 “the Klaw” Dundalk High School near Baltimore, MD
Link to my recording made at a DX camp in Coe Hill, Ontario, Canada on April 20, 1997: https://archive.org/details/wdkw-the-klaw-1630
An internet search revealed the following;
Part 15 of the Federal Communications Commission (FCC) rules allows some low-powered radio devices to operate without a license on the AM and FM radio broadcast bands. These devices are subject to certain restrictions, including:
- Range: On FM frequencies, the effective service range is limited to about 200 feet (61 meters).
- Field strength: The field strength should not exceed 250 ?V/m (48db) at 3 meters.
- Detachable antennas: Part 15 rules prohibit detachable antennas on all Part 15 transmitters.
Some examples of Part 15 radio stations include:
- Microbroadcasting
Often used by hobbyists, drive-in theaters, or on college or high school campuses.
- Talking roadsigns, talking houses, or talking billboards
These transmitters air a repeating loop of information, such as traffic or highway construction. They typically operate on empty channels on the AM broadcast band.
- InfOspot
A custom product that can include special audio systems, USB / internet connectivity, cabinets, and antenna mounting styles.
- Free-radiate AM radio stations
Educational institutions can use a transmitter without a license if the signal coverage is limited to their property.
5. TIS (Travellers Information Stations)
1610 kHz with low power, usually around 10 watts, such as the one I hear near the Blue Water Bridge between Sarnia, Ontario and Port Huron, Michigan
6. Expanded AM broadcast band
Over a quarter century ago, these frequencies began to be used in the U.S. by BCB stations. I still have recordings of a half dozen of these from the early days.
WTDY 1670:
WNML 1670:
WMDM 1690:
KCNZ 1650:
KCJJ 1630:
KBGG 1700:
Also, here is a link to a column in Popular Communications magazine from February 1998.
Back in the 1970s there was pressure to fit in more medium frequency AM broadcasters. As a result
in 1978 the spacing of medium frequency (‘AM’) channel was reduced from 10 kHz to 9 kHz worldwide except for the Americas (ITU region 2).
In the Americas they kept the original 10 kHz bandwidth and allocated 10 kHz channels from 1600 – 1700 kHz.
The most obvious result on listeners was that in the Americas the carrier frequency is commonly the trade mark of the broadcaster and is easy to say. Elsewhere the carrier frequency has to be divisible by 9 so is not so easy to remember.
The main concern of commercial AM broadcasters was the competition with FM because it has a top audio frequency of 15 kHz where as AM was 10 kHz. They did not want a reduction to 9 kHz. However, since an AM signal is twice as wide as the frequency step it makes interference from other broadcasters a problem. As a result receiver manufacturers make the top audio frequency around 4 kHz to keep the interference out. This made the case for retaining 10 kHz step irrelevant. HD radio made this interference sound even worse, which is why many HD radio AM stations have stopped transmitting the digital signal.
All above very true.
I have the Sony XDR-S10HDiP which can pick up AM Stereo.
This old iPod jack table top radio has the same chip inside as the legendary Sony XDR-F1HD tuner and is very cheap on the used market – as little as $20.
I have a nephew who lives at the PA/MD state line and I intend to take this AM HD radio on my next visit to listen to all digital AM broadcasts from WWFD.
Another test I have for the ability of AM band radios is nearby transmitter channel filter separation.
My home is unfortunately 3 miles from a 5000 watt AM station on 630 kHz and 5 miles away from a 5000 watt station on 590 kHz. One hundred miles away in a city I used to live in is a station running 1000 watts on 600 kHz.
The situation is even tougher because the station on 590 kHz long ago briefly tried AM Q stereo and even today seems to be running an extra wide 12 kHz bandwidth.
The CCRadio original analog circuit model EP is a much better than average radio,
but it “goes crazy”
in this high RF field situation.
It greatly impressed me recently that the tiny $80 Qodosen DX-286 was just barely able to pick up copyable audio from the 600 kHz station when using an old Select-A-Tenna as an external antenna with the “null lobe” of its air core loop pointed in the direction toward the nearby 590 kHz station’s antenna.
What a blast from the forgotten band…….off to test the Icom 705 with a Pixel Pro loop on 1650 Khz
John Ve3IPS
Thank for this article which brought back similar radio memories.
To this day one of my tests for a “good AM band radio”
is to travel down to the Camp Nelson National Cemetery Civil War period burial area ( very little RFI) and see if the radio can pick up the 1620 kHz ten watt TIS station forty miles north where I-75 and I-65 are briefly combined. Then I tune to 540 kHz and see how 5000 watt WKFN comes in 190 miles away.
Any 1860s Civil War ghosts ease dropping on these tests do not seem to mind listening in either….