The exclusive amateur
shortwave bands are anything
but exclusive. Non-ham
intruders are a constant
threat, creating QRM and
making DXing and especially
weak signal working a misery.
Here are just a few of the
ham band intruders spotted
and in some cases identified
by hams in the South Pacific:
- Russian Morse characters sent with a poor quality TX on 14240kHz (for some reason Russia has a military allocation in the 20m amateur band).
- Encrypted speech in the 10m beacon sub-band with a RTTY-like synchronizing signal.
Hand-sent 24wpm CW on
14014 kHz from a non-ham
"SNZL". He was
initially sending VVVs,
then called “DQ2L
DE SNZL ZJT ZQQ ZVU ...
DQ2L DQ2L DQ2L DE SNZL
SNZL ZJT ZQQ ZVU [during
which he made a mistake
and sent 8 dots] ... DQ2L
DQ2L DQ2L DE SNZL SNZL
ZJT ZQQ ZVU QYT6K" I
presume this was a
military station misusing
the 20m ham band.
sprog/mixing product on
1908kHz from two
commercial MW AM
broadcast stations in
- A pirate using the call ZL9BI on 30m CW and calling himself “Tom”,
believed to be in the
vicinity of ZL but not
due South of us where
Auckland and Campbell
Islands are ...
A dubious CW op called “Fred” variously using the calls FR6GTO, FR6GTO/P [10Mb MP3!]and FR/F6GTO but seemingly located in Europe, not Reunion.
- Fishing buoys transmitting on 10m from somewhere on an Easterly bearing from ZL, plus many more around the globe on 160m.
A VK/ZL propagation radar system accidentally QRMing 30 and 20m (more below).
carrier with 60Hz hum
modulation sitting on
14000 kHz, transmitting
from the North East of ZL.
from P5, BY, ET and
mostly on 80m and 40m
regardless of the ITU
Pirate fishermen from 4S7 and villagers in YB using ham equipment (presumably) to chat to each other using SSB on various ham segments on 5kHz channel spacings.
transmitting nasty AM and FM signals on the high HF bands, at times wiping out the ham beacons and causing QRM to legitimate ham QSOs.
dreadful buzzsaw Over The Horizon Radars (OTHR) from BY (~43 pulses per second), 5B4 (~50 pps) and/or F and elsewhere (including the phantom pharter at ~80 pps and the chopper at 26pps) that wipe out great chunks of prime shortwave ham spectrum at peak DXing times, reminiscent of the bone-crunching dakka-dakka Woodpecker formerly broadcast from a massive antenna array near Chernobyl until finally their PSU rather spectacularly burnt out ...
machine noises made by wave radar (called CODAR),
often accompanying OTHR.
- RTTY and other data-mode ham band intruders, including a curious 10 kHz-wide fog horn,
various encrypted/indecypherable data signals and, um, a Dalek.
- Gurgling water 17m harmonic/spurious mixing product of a Cuban broadcast station on some lower band.
Dotters, channel markers, fishing buoys, licensed ham beacons or unlicensed pirate beacons typically sending curious callsigns or strings of single letters such as N N N N,
T T T T or E E E E or V V
V V from various
manner of wideband HF
noise sources allegedly
doing double service as
WiFi routers, plasma TVs,
PLT/mains networking and
a hundred zillion cheap
and nasty unsuppressed
switchmode power supplies
raising the noise floor
for all of us in the same
manner as light pollution
A technical configuration issue with the TIGER experimental propagation monitoring radar system demonstrates the value of Intruder Watch. Hams noticed and started complaining about what sounded like data mode transmissions particularly in the 30m band and sometimes on 20m too. Through the Google group (more below), we started working as a team to investigate the source. The direction was hard to pin down but seemed to be roughly South or West of ZL, an unusual direction for any short path signals! Eventually, the intruder was traced through the TIGER website which conveniently reports the frequencies being scanned, and sure enough the radar was spending a fair bit of time in the 30m band. The 30m band is not an exclusive ham band so we have more limited options than with, say, 20m but investigating the TIGER system further led to the discovery that their license forbids interference to other services, in other words they are not a primary user of 30m either. Contact with the TIGER team led to the equipment being checked and the problem being traced to a configuration option that was supposed to prevent transmission in the 20 and 30m bands but had somehow been lost. The system was taken off-air for most of a day and reconfigured to skip the ham bands (plus guard bands on either side) and peaceful DXing resumed on 20 & 30m - a good result all round! Thanks to the Intruder Watchers and TIGER team for responding so positively.
Given the popularity of
soundcard digital modes among
amateurs, it’s often
hard to figure out whether a
given jangly noise on air is
a legitimate ham digital
transmission using an obscure
or new mode, or a commercial
although some digital modes
software supports several
modes, decoding unknown
signal types is often
impossible without knowing
the precise ode i.e. the bandwidth, number of signal frequencies, speed of transmission etc.
Sometimes the band frequency
used is characteristic, but
mostly we rely on the
characteristic sounds of the
different modes to identify
them by ear. Soundbytes of intruders and QRM sources on the IARU Region 1 website help identify commercial data modes etc. Another site has audio
samples of many ham and
commercial data transmissions, and here’s another good one.
For what it’s worth, the most common digital mode on the HF bands is now FT8, followed by
(45.5 baud, 170 Hz shift) and
, plus Olivia
(either 16 tones within a
500 Hz bandwidth or 32 tones
within a 1000 Hz bandwidth)
. To hear what these
signals sound like, tune
through 14060 to 14110 kHz
whenever 20m is open. RTTY
signals will often be heard
around 14080-90, PSK31
clustered around 14070,
Olivia around 14076 or 14107,
and JT65/JT9/WSPR around
14095. There are also SSTV
signals on or near 14230. These are not the official ITU designations for types of emission, but if you’re interested, feel free to look them up in the official ITU Radio Regulations.
Unfortunately, irresponsible, incompetent and intolerant hams create a lot of QRM too. The EU zoo sometimes reaches nightmare proportions. Just listen to this outrageous behaviour heard on a DXpedition station’s TX frequency when someone quite rightly complained about their pileup wiping out a maritime net monitoring for news of a South Pacific tsunami. It’s a sad sign when somone can set up a website to name-and-shame the ham QRMers, pirates and lids, including sometimes
placeholders ready and waiting for the next big DXpedition, or
a LidList ...
DXpeditioners often jostle for position at the bottom ends of
the bands on CW, or on the usual RTTY and SSB spots further up, causing chaos if their pileups
intermingle. Partly this is down to the DXpeditioners who choose the listening frequencies they
announce and where they actually listen (not necessarily the same places!) but mostly it is caused
by over-excited and inconsiderate DXers who don’t listen on their TX frequencies. Frequency cops
who take out their frustration by berating them on the same TX frequencies just make the problem
worse. For more advice on how to reduce this self-made ham problem, look here.
Lastly there are the rude, ignorant and selfish hams who just keep right on calling, regardless of
any instructions to the contrary. This is quite a different situation to those who make the
occasional mistake, call out of turn or on the wrong frequency. Good operators may still make
mistakes but not very often, and they immediately correct themselves as soon as they realise. The
deliberate QRMers don’t stop, even when everyone else understands and obeys the instructions,
for example when I sent “<AS> <AS> <AS> PLS QRX” at 12 wpm but EA7BW still carried on
rudely and repeatedly calling me (giving my call and his, several times of course just to make quite
sure everyone knew he was causing the QRM), wiping out my QSO with a patient and polite JA on
15m. If a lid like EA7BW behaved like this in person, face-to-face, interrupting conversations by
shouting his name over and over, he’d get a bloody nose but, presumably feeling safe and secure
behind his transceiver in some far-off land, he evidently thinks it acceptable to
stamp all over other operators, doing his level best to spoil everyone’s fun.
The thing is, every time he sends his callsign, he identifies himself
unambiguously as the obnoxious cretin to everybody listening. “
ME! I’M AN IDIOTIC LOUD-MOUTHED THUG!
” he shouts to the whole
world, while quietly we record the evidence and inform the authorities <cue
evil laugh> Even more galling is when a lid then pesters me for a QSL card or
LoTW confirmation - no chance mate! Consider yourself blacklisted. Read the DX Code and grow up.