Product Review Column from QST Magazine October 1997 Yaesu FT-920 MF/HF/6 Meter Transceiver Tune in the World for Less Than $300: Drake SW1 and Radio Shack DX-394 Copyright © 1997 by the American Radio Relay League Inc. All rights reserved.
Product Review Edited by Rick Lindquist, N1RL• Senior Assistant Technical Editor Yaesu FT-920 MF/HF/6 Meter Transceiver Reviewed by Bill Kennamer, K5FUV DXCC Manager The Amateur Radio transceiver has changed substantially since its advent in the 1950s. Each generation has provided new features that have gone from option to standard. Some of these, though revolutionary for their time, have become commonplace. The latest generation of transceivers feature expanded band coverage.
Table 1 Yaesu FT-920, serial number 7F020059 Manufacturer’s Claimed Specifications Frequency coverage: Receive, 100 kHz-30 MHz; 48-56 MHz. transmit, 1.8-2; 3.5-4; 7-7.3; 10.1-10.15; 14-14.35; 18.068-18.168; 21-21.45; 24.89 -24.99; 28-29.7; 50-54 MHz. Modes of operation: USB, LSB, CW, AM, FM, FSK, AFSK Power requirement: Receive, 2.0 A (no audio); transmit, 22 A (max), 13.5 V (±10%). Size (height, width, depth): 5.4×16.4×12.6 inches; weight, 25.3 pounds.
0 0 Reference Level: 0 dB PEP Reference Level: 0 dB PEP –10 –10 –20 –20 –30 –30 –40 –40 –50 –50 –60 –60 –70 –70 –80 –10 Y –8 FT 920 HF T –6 –4 –2 0 2 4 Frequency Offset (kHz) 6 8 –80 –10 10 i Y Figure 1—Worst-case spectral display of the FT-920 transmitter during two-tone intermodulation distortion (IMD) testing on HF. The worst-case third-order product is approximately 25 dB below PEP output, and the worst-case fifth-order product is approximately 31 dB down.
via the menu. The DW button activates the Dual Watch function. Dual watch sets the radio up to periodically check the VFO B frequency for activity while you’re tuned to VFO A. In theory, this sounds great. In practice, using dual watch requires enabling the squelch. This means that you hear nothing on either frequency unless there’s a signal. When the radio hears a signal on the VFO B frequency, it breaks the squelch and goes to that frequency.
tours did their job in tailoring transmit audio. Consensus was that audio level appeared to drop off on all four settings; you had to compensate with higher gain level or by using a bit more compression. The high-emphasis selection successfully produced “contest” type audio to cut through QRM; the changes wrought by the other settings were more subtle. But several stations said they thought the audio sounded “best” in the default position, with the digital equalization turned off.
Somewhat disconcerting were the results of the transmit intermodulation distortion (IMD) tests (see Figures 1 and 2). Almost as disturbing as the prominence of third and fifthorder products was the prominence of higherorder (ie, seventh, ninth, eleventh) products. Yaesu specified a third-order IMD figure of –31 dBc (see Table 1), a specification it met on 15, 17, 20, 40, 80 and 160 meters, where IMD performance was much better but not spectacular.
Table 2 Drake SW1, serial number 6H12910064 Manufacturer’s Specifications Measured in ARRL Lab Frequency coverage: 100 kHz-30 MHz. As specified Modes of operation: AM. As specified. Power requirements: 120 V ac; 12 V dc at 400 mA. As specified. Size (HWD): 4.4×10.9×7.6 in; weight, 4.7 lb. Sensitivity (bandwidth not specified): AM, test signal modulated 30% with 2.0 µV or less (typical). a 1-kHz tone. 10 dB (S+N)/N: 100 kHz, 10.5 µV; otherwise, as specified. Blocking dynamic range: Not specified.
Table 3 Radio Shack DX-394, serial number, C004541 Manufacturer’s Specifications Measured in ARRL Lab Frequency coverage: 0.15-30 MHz. As specified. Modes of operation: LSB, USB, AM, CW. As specified. Power requirements: 120 V ac, 13 W; 13.8 V dc, 300 mA. Size (height, width, depth): 3.8×9.2×9 inches; weight, 4.6 lb. SSB sensitivity, bandwidth not specified, As specified. 10 dB (S+N)/N, 1.7-30 MHz, 0.3 µV. CW sensitivity, bandwidth not specified, As specified. 10 dB (S+N)/N, 1.7-30 MHz, 0.1 µV.
