500 kHz Experiments

From July 1908, 500 Kilocycle frequency commenced operation as the recognised international CW marine calling and distress frequency. In the UK and Ireland this service ceased in 1997 due to advances in telecommunications technology.

However, in the past few years, special permits were issued in Britain to radio amateurs for experimental purposes using frequencies in the range 501 to 504 kilocycles.

Ray, GI3PDN is the holder of one such license and a few weeks ago he contacted Tony (EI5EM) to see if a crossband QSO could be arranged with EI0MAR at the Martello Tower in Howth.

A sked was arranged with EI0MAR operating on 3550
kilocycles and Ray operating on 501.5 kilocycles.
A successful two-way QSO was completed with 559 reports
both ways.

Ray was using a home-brew transmitter running less that
one Watt into a 300 foot long inverted Vee antenna. No such antenna was available at Howth where a 40-meter
dipole tuned for 80 metres was used for transmit and
receive.

The rig used at EI0MAR was a Yaesu FT-747 running about 70 Watts. A second successful crossband QSO then took place with Finbar GI4PDE (also EI0CF) in Derry but the report on 501.5 kilocycles was not as good at 339. Tony, in arranging these QSOs approached it more in hope than in expectation and was pleasantly surprised and very satisfied with this successful wireless telegraphy experiment. A big thanks to Ray and Finbar for two very memorable QSOs.

EI0MAR is located in the Vintage Radio Museum in Howth
and is QRV most Sundays. Further information is available on the web or by email from “ei0mar at eircom dot net”.

A booklet about the museum and its history along with the history of wireless is available for free download at ei5em.110mb.com/museum.html.

Source: IRTS