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Low Frequency Activity in Kent

     Low frequency amateur radio activity in the County of Kent is a bit 'thin on the ground' on the lower LF bands 137kHz and 472kHz. It would seem the only Kent stations doing any regular transmitting are G4APB (Crayford), G4AYT (Whitstable) and G3TYB (Sittingbourne) on 472kHz (or 630m), the main band of interest here. G4AYT has a 5W driver transmitter and low power PA for 137kHz. Nick, G8NAV (Tankerton), at the time of writing has been receiving on 137kHz with good results. Hugh, M0WYE (formerly G6TMK), Wye, Kent, has been active on 137kHz in the past and is still interested in the band and LF generally. Brian, G6PKS (Herne Bay) receives on LF regularly. Colin, G6PBS (Rochester), has receive capability on 137kHz and 500kHz. Tony, G0PZX (Faversham and Chatham), has been active in the past on 137kHz (and the old 500kHz band RX).

     As of 1st. January 2013 NoVs for 500kHz are no longer available and the new LF band of 472kHz - 479kHz is available to UK full licence holders. This new band, being somewhat wider, offers all sorts of possibilities and has generated a great deal of new interest in LF operating.

     G4AYT's initial experiments on 137kHz in 2009 used just 250mW (0.25W) of RF from an LM386 IC, the antenna being a co-ax fed 40m combination of vertical 1.25" pole and wire, tuned with a series inductor of 150 turns of 26swg enamelled copper wire sliding on a ferrite rod (with no attempt to match this to 50ohms). This arrangement was good enough for 100% copy at G8NAV (a distance of just 2.6km), but was not detectable by G6PKS (Herne Bay). During 2010 G4AYT increased power to 5W using a TDA2030 IC with better matching to the antenna using a variometer to resonate and toroid transformer to match. Signals were now well received by G6PKS (6.7km), G8NAV and by G3XVL in Ipswich, Suffolk (80.3km). Unconfirmed reception was reported by G3XIZ in Biggleswade (120.9km). More power is now available at G4AYT using a modified BK Electronics mosfet amplifier.

     G8NAV has constructed a slightly unconventional variometer, consisting of one coil sliding inside another (piston method), to resonate his long wire antenna. However, for reception purposes we have all obtained generally better results with a small active antenna following a design by PA0RDT, the so called 'mini whip', but as we prefer to call it, the 'pepperpot' - because amazingly the whole antenna fits inside a large white pepper or spice pot easily purchased locally! Details of this antenna can be found on the LF ANTENNAS page.

      At G4AYT transmitters 1W/8W/25W have been built for the new 472kHz band and are already on the air having CW QSOs. G8NAV has built a 1W TX and is a good signal locally. Kent station G3TYB in Sittingbourne is also known to be active on TX and others are receiving on the band. Hopefully more will emerge in due course. Brian, G6PKS, has decided to part with his TX equipment (137kHz and 472kHz) but still has RX capability.

      Topband (1.8MHz or 160m) is quite busy in Kent. There is most days a net on 1966kHz (0930 local time) AM/SSB. Also there is the very popular Essex based 'AMPS' net 1908kHz under the control of G4FCX (Sundays at 1500 local time) AM which attracts many Kent stations. Monthly nets from Essex which reach into Kent are the CARS net and one run by Robin, G4DVJ, as well as several others on the fringes of the local area. There are also some keen SSB/CW DX operators in the county. Unusually for any band these days, activity on topband seems to be increasing. G4AYT can often be found on the band. There is a weekly AM net on 1966kHz +/- QRM, the "Home Constructor's Net" run by Bob, G4IOG (Newington, Kent), on Tuesday evenings at 2000 local time, primarily for users of homebrew equipment - but all are welcome. Most evenings (around 1700 local time) there is an informal net on 1908kHz - usually AM - some stations on this net have been copied by G4IMO in Wisbech. The White Cliffs Net has recently started on 1845kHz most days, shortly after 1000, attracting stations in the Dover/Folkestone areas, but all are more than welcome to join in. During many of these nets 2m (144.550MHz) is also monitored. I also understand that there is an AM 'calling frequency' of 1977kHz on the band, monitored on the hour (accuracy of this information unknown).

      137kHz Transmissions To/From G4AYT

             G4AYT's TTT (250mW) RX by G8NAV                        G4AYT (5W) RX by G8NAV                                   G6PKS (20W) RX by G4AYT

                    G4AYT (5W) RX by G6PKS                            G4AYT (5W) RX by G3XVL Ipswich           Possible RX of G4AYT (5W) by G3XIZ Biggleswade

          G4AYT (5W) RX by M0FMT 15k NE Luton     G4AYT (5W) RX by G3XDV Welwyn Garden City           G4AYT (5W) RX by M0BMU Hatfield

     

         G4AYT (25W) RX by M0FMT 15k NE Luton      G4AYT (25W) weak at G4WGT Chorley Lancs   G4AYT (25W) RX by G3KEV Scarborough N Yorks

    

           G4AYT (25W) RX by G3WCB Nr Windsor             G4AYT (25W) RX by M0BMU Hatfield          G4AYT (25W) RX by PA3CPM SE of Amsterdam

 Distances to the above stations from G4AYT in km:  G8NAV = 2.6,  G6PKS = 6.7,  G3XVL = 80.3,  G3XIZ = 120.9,  M0FMT = 115.0,  G3XDV = 99.8,  M0BMU = 95.4,  G4WGT = 352.8,  G3KEV = 344.6,  G3WCB = 110.4,  PA3CPM = 291.1

      472kHz Transmissions To/From G4AYT

      Best DX to date using 'normal' CW and 25W RF is a full two way QSO with PE5T, well to the north-east of Amsterdam in JO33BI, a distance of 411km or 255 miles (and during the day). Daytime CW activity on the band is quite low, at such times grabbers can provide a useful check that all is well and are useful for antenna comparisons. Below are examples of the G4AYT 25W RF signal at three grabbers in England, thanks to G3ZJO, G3YXM and G4WGT.

                      RX at G3ZJO Northampton                                       RX at G3YXM Birmingham                                 RX at G4WGT Chorley Lancashire