Many HF rigs use relays for bandpass filter switching, and other tasks. Unfortunately when changing bands, these relays cycle to the configuration needed for each band range. When using software to scan the bands, these relays are being cycled with each band change request from the software. Some HF rigs allow using a dual VFO mode that the Software can use to scan in such a way that the band relays are not cycled. Software uses a bandpass relay selection that allows receiver performance during scanning, but switches in the relays for band activity and transmitting. This approach saves relay wear and tear.
List of Radios for ALE: http://hflink.com/hardware/ PCALE will function with almost any amateur or commercial HF radio. For rapid channel scanning, PCALE (and MarsAle)uses the computer-to-radio CAT interface to control the transceiver frequency and mode. Some transceivers are better suited to ALE service than others, for various reasons. The following transceivers have internal circuitry that is optimum for fast Quiet Relay Scanning and Sounding with PCALE (and MarsAle): ICOM IC746, IC746PRO, IC7400, IC756PRO (Milspec 1030E-DSP), IC756PRO2, IC756PRO3, IC765, IC775, IC781, IC7800 (except mixer relays), PA relays handled by use of SPLIT VFO, all support up to 2 ch/sec scan rate, newer models at 9600 baud up to the 5 ch/sec and those that can do 19,200 baud at 10 ch/sec scan rate KENWOOD All Kenwood models after, but excluding the TS-440, PA relays handled by use of SPLIT VFO, all support up to 2 ch/sec scan rate, newer models at 9600 baud up to 5 ch/sec and those at 19,200 baud at 10 ch/sec scan rate YAESU FT-920, FT-990 with SPLIT VFO (FT-890 with special QS/S modification) all can do up to 2 ch/sec scan rate. HARRIS Harris RF-350 family: RF-350, RF-350K, RT-1446 URC, AN/URC-119, AN/URC-121(V) PA relays handled by BYPASS command, supports up to 2 ch/sec scan rate. ======================= 73 from Bill - WD8ARZ
