View Full Version : Trawler Interference
Wed 2nd Jun 2010, 12:28
Being situated just under 2 miles from the sea front in St Leonards, Hastings and fairly high up, with a Triband antenna in the attic, I can often hear what appears to be shipping, perhaps French or Belgium trawlers jamming simplex channels such as S13 145.325 at the moment.
What is the legal position on this? Is it inevitable and bound to happen due to high TX power they are using ? Is it safe for me to broadcast on the same frequency, then identify myself, and warn them they are being heard on an Amateur frequency, always assuming they can understand English?
Wed 2nd Jun 2010, 19:24
You may well be hearing a harmonic of their transmissions What receiver do you use? FM on ships is restricted to 10 watts (well it was when I sailed a yacht!) and is from 156Mhz to 157Mhz so pretty near our. Also they don't work on the same frequency, it is split with one tx on one and rx on another, so you shouldn't be able to hear the whole conversation on say S20.
However it is well know that our frequencies are abused by many trawlers. I found a net of Northern Irish trawlers on the 5Mhz band frequency which is a French Navy frequency. I thought that a bit dicey, knowing what the French are capable of. :-) and just below 3.5Mhz is thick with illegal transmissions from all over Europe, especially Italy.
For peace of minf you can get a Band Pass Filter which will greatly reduce any harmonics coming into your RX and also leaving your TX. Very worthwhile. It covers 144 - 146
Thu 3rd Jun 2010, 06:20
Thanks. I was only having a QSO with a local guy on SU16 yesterday evening, who also lives near sea further along the coast from me. He says the Trawlers are notorius for interfering here. But the signal I hear on S13 is possibly Carne ( If I spelt it right ) some 80 miles away across the channel. But I suppose just as when I hear some locals having a QSO and never giving call signs I suppose I best not interfer.
I recently bought an Antenna switch intended for an old 2 M Trio 7500 and the FT 60R handheld, for the Triband. But my pal is trying to install a CTCSS board on the Trio as the old tone burst not only failed to access the local 2 M repeater, and anyway now both the Hastings 2 M and 70 CM Repeaters only recognise CTCSS. Meanwile I trust it is not doing any harm by using the Switch with my old Commtel scanner and the FT-60R so I can scan all the 2 M and 79 CM channels along with others until I hear some activity.
When my pl brings the Trio back I will probably keep it and the scanner connected to the Triband, and only use the handheld as portable. But I do not want too invloved in using a Band Pass Fileter especailly if it invloves tinkering withe the inside of a TX. Besides with all the littel used Simplex channels available it is no real prbelm having one or too being jammed.
Thu 3rd Jun 2010, 11:12
Don't worry about fitting the Band Pass Filter. It is external and fits inbetween the rig and the antenna. Its just a little box with 2 SO sockets on it. Not even powered.
Thu 3rd Jun 2010, 12:21
Thanks I will have a look on eBay.
Tue 7th Jun 2011, 01:51
Ham Radio here in US, 2 mtr 60 watts FM mobile is selling for $120. I afraid many bought those radio to use as business radio, here 144.000 to 144.500 MHz there is a lot of illegal operations.
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