Post date: Dec 1, 2008 3:38:54 AM
FM broadcast stations form a plentiful and abundant beacon network for the tropo DX operator. Monitoring the FM broadcast band while in Namibia for stations on St. Helena and Ascension Islands, and on Brazil, will be a very important tool for the DXpedition. Two key components for this aspect will be a good antenna and a good receiver.
The antenna is already almost complete, and should be ready for testing by December 3. It is an 8-element LP design by Cebik. Elements are made from recycled 1/2" CATV hardline, and the test boom is an 8' long piece of pine. The elements will be transported to Namibia, and a new boom fabricated there. The small LP should give excellent F/B ratio and broadband response. While the gain is a bit lower than desired, the smaller antenna was chosen to reduce wind resistance with the high winds anticipated in Luderitz Bay.
The receiver needs to exhibit high sensitivity and selectivity. The Icom IC-7000 already planned for the expedition already covers the FM broadcast bands, and is therefore a candidate to do double duty as the 70cm primary radio and the FM broadcast receiver. However, a preferable approach would be to have a dedicated receiver for monitoring the FM broadcast band. The Sony XDR series of HD FM receivers have been getting good reviews. A Sony XDR-S10HDIP was purchased last week for evaluation. Initial testing with the supplied indoor FM dipole have shown astounding sensitivity and selectivity.