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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 recently 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 station signing "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.
  • A sprog/mixing product on 1908kHz from two commercial MW AM broadcast stations in Christchurch, ZL
  • 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)
  • A carrier with 60Hz hum modulation sitting on 14000 kHz, transmitting from the North East of ZL
  • Commercial broadcasters from P5, BY, ET and elsewhere, broadcasting mostly on 80m and 40m regardless of the ITU regs
  • 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
  • Illegal CBers 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
  • The 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 UPS burnt out ...
  • The swish-swish washing 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 locations ...
  • All manner of wideband HF noise sources allegedly doing double service as WiFi routers, plasma TVs, PLT/mains networking and ten zillion cheap and nasty unsuppressed switchmode power supplies raising the noise floor for all of us in the same manner as light pollution threatens Earth-bound astronomy

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 intruder. Unfortunately, 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 modes on the HF bands are probably RTTY (45.5 baud, 170 Hz shift) and PSK31 , plus Olivia (either 16 tones within a 500 Hz bandwidth or 32 tones within a 1000 Hz bandwidth)  and JT65 (particularly on the WSPRnet frequencies). 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/WSPRnet 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.

I am the deputy Monitoring Service Coordinator for NZART’s Monitoring Service, supporting the main man John ZL1GWE.

I run a Google Group (email reflector) for Australasian and South Pacific hams to report and share information on ham band intruders affecting IARU Region 3. All Australasian hams who are concerned about non-ham intruders on the amateur bands are welcome to join the group, earwig for a while to find out how it works and then hopefully contribute details of intruders such as the times (plus durations if possible) and frequencies heard, MP3 recordings (most of us use Audacity with the Lame plugin to make MP3s), waterfall spectra, signal strengths and ideally directions, or perhaps just a note about other identified signals heard at the same time. It all helps. Information on intruders is collated from the reflector and other sources to contribute to the IARU Monitoring Service reports, and to persuade the authorities to act on clear infringements.

Current and former IARU Monitoring Service people belong to the group and frequently share their wisdom and knowledge with us, for example helping us identify stations or give us tips on how to DF (Direction Find). As an example, I wrongly assumed curious mis-timed CW signals in the SSB segment of 20m, and similar indecipherable code on 7015kHz one ZL evening, were intruders but most likely they were legitimate Wabun Morse sent by ancient JA hams using hand keys, evidently. Far from being intruders, these are historic ham masterpieces!  Each Wabun character is a Japanese kana, with the Wabun transmissions starting with the DO prosign. Fascinating stuff.

Listings of shortwave intruders (plus some legitimate users such as the NCDXC propagation beacons!) that have been professionally DF’d and identified are published once a quarter by the ITU. Read how modern software-defined radios are used to interpret complex signals received by antenna arrays for professional, if not amateur HF direction finding purposes. Use one of the web-enabled SDR to cross-check any QRM you find, for example this Dutch SDR.

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 websiteLidList logo 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 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 bDX CoC logo new 125 on blackloody 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. “ LISTEN TO 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.

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