I am saying that some ALC is not going to be an issue. Nowhere in this am I advocating running your audio really high, thinking that the ALC will take care of it. You can use ALC or not, as you choose when you run WSJT modes, or Olivia (MFSK). In that case, the use of ALC will NOT distort the transmitted signal-amplitude waveform.
Jt65 specifications manual#
On the other hand, the WSJT manual says that its output is a constant-amplitude signal, meaning that good linearity is not necessary. PSK31 does contain amplitude shifts, as an example, therefore you don’t want any ALC action that could result in distortion of the amplitude changes in the waveform. In such a case, the use of ALC will NOT distort the signal waveform. Whether the use of ALC matters or not depends on the transmitted digital mode.įor example, FSK (Frequency-Shift Keying i.e., RTTY) is a constant-amplitude mode (frequency shift only). As a result, no unwanted sidebands are generated, and no special amplifier (including a transmitter’s final stage) linearity requirements are necessary. Multi-frequency shift keyed (MFSK) modes with low symbol rate– such as the Olivia digital modes–use a single carrier of constant amplitude, which is stepped (between 4, 8, 16 or 32 tone frequencies respectively) in a constant phase manner. The notion that one must NEVER use ALC when transmitting digital modes is not accurate. Note also that the radio was transmitting USB-D1, which means the first data/soundcard input to the radio.Īlso, some people complain about my use of ALC, because, in their view, ALC (automatic level control) is a no-no for data modes. Compression was set for standard USB operation. I had the radio set for 20-Meter USB operation on the Sub VFO. However, the truth is that compression was not being used (as is proof by carefully taking note of the zero meter movement of the Compression activity). Some have noted that it appears that I’ve left on the Compression of the transmitted audio. Your radio’s manual should tell you the specifications regarding the duty cycle it can handle! If you run more power than your radio can handle with the given duty cycle of the mode in use, you will blow your radio’s finals or in some other way damage the radio! Beware! I’ve warned you! Nor is SSB, a mode that operates with a duty cycle much lower than 100%. Olivia, for instance, is a 100-percent duty cycle mode.
NEVER run your radio’s power out at a level that exceeds what it can handle in reference to the duty cycle of the mode you are using. I bought an extended four-year warranty.ĬAUTION: Check the documentation of your transceiver/transmitter. My insurance covered all of the blown items, and that provided me this chance to obtain a repack version of the Icom IC-7610. Thankfully, all of that was covered by my homeowner’s insurance policy, less the steep deductible.
Jt65 specifications Pc#
The surge came in through the power mains, and fried my uninterruptable power supply, the interfaces between my PC and radio, and fried the radio. The antenna was NOT connected, but I did not unplug the power supply chain and my computer from the wall. The radio ran cool, no significant heating.Ī few months ago, a lightning strike took out my ham radio station.
Jt65 specifications full#
The radio is rated as being able to handle 100% duty cycle at full power. K8CJM is located in Dayton, Ohio, and I am located in Lincoln, Nebraska. The transmissions are of a two-way Olivia digital-mode radio conversation between station K8CJM and station NW7US on 12 November 2019 (UTC date). This video is a quick capture of my running the Olivia Digital Mode on HF, on the 30-Meter band. I turned on the IP+ and the distortion of the adjacent signal disappeared, and once again, I heard the weak signal IN THE CLEAR! WOW! In short: I was listening to an s-0 (i.e., no strength-meter movement) weak signal of a DX station, when right adjacent to the frequency came an s-7 signal, wiping out my ability to copy that weak signal. It also improves the Third-order Intercept Point (IP3) while minimizing the reduction of the receiver sensitivity. This function optimizes the Analog/Digital Converter(ADC) against distortion when you receive a strong input signal. One of the most useful (and, to me, amazing) features of this Icom IC-7610, is the IP+ function, which, when turned on, improves the Intermodulation Distortion (IMD) quality by optimizing the direct sampling system performance.