Hardware review. Document T. How to select a HF transceiver? On what basis can we select a HF transceiver? What features made the difference between a mid-end and a high-end model? Is the price a good indicator?
Tadeusz Raczek, SP 7 HT Kielce, 31 marca ‘98
The well-selected components provide premium performance. Mechanical relays Mechanical relays using gold contacts have excellent deterioration resistance and superior conductivity. Large coils To reduce secondary distortion, large coils and capacitors are used in the high-amplitude filter switching circuits. The use of non-linear semiconductors is minimized. Power amplifiers The power amplifiers use a combination of push-pull final with two MRF transistors, having proven reliability in ultra professional communications.
In this concluding installment, we see how some of today's best amateur transceivers compare with one of today's latest commercial radios in terms of second- and third-order IMD, and how we can make our radios better. During a recent trip to Germany, I installed my favorite Hustler mobile antenna system a combination of the MO-I and RM on the aluminum railing of my 19th-floor hotel window in the Munich Sheraton. This translates into an elevation of feet above ground level, and among other things provides a spectacular view of Munich. With the Hustler antenna adjusted for resonance at 7. Despite the antenna's short length-about 2 meters-incoming signals immediately overloaded the TSS's receiver.
When operated with these 1st IF filters, narrow mode signals such as the CW and SSB modes are protected from adjacent and unwanted strong signal interference. When compared to a typical triple-conversion system, the double- conversion system dramatically reduces signal distortion and provides a high-fidelity RF signal to the DSP processor. Even in tough RF conditions, a weak signal can be clearly received by the IC