It has been pointed out that the SEA245 has key clicks. The images below illustrate the issue
| The image to the right shows the spectrum and waterfall graphs from an Elecraft K3 located in Sparks NV (776 miles, 1249 km from here). The received signal level was S9 + 10 dB. Each horizonal division is 5 kHz. The waterfall shows transients going down about 3 kHz and up about 7 kHz. Since the transients are pretty short, they do not show up in the top spectral graph. | |
| The images at the right shows the rise time and fall time of the RF envelope of the SEA245. The images were captured from the RF sampler in the Daiwa 501H directional wattmeter. Trace 1 is forward power. Trace 2 is reflected power. The rise time is 59 us, while the fall time is 69 us. The ARRL Handbook for Radio Communications (2019) figure 11.9 recommends rise and fall times of 6 ms for 50 wpm on a non-fading circuit and 3.5 ms on a fading circuit. At 20 wpm, these increase to about 15 and 8 ms. The rise and fall times are about about 2% of the recommended times for 50 wpm on a fading circuit. | |
| This image shows the insides of the Daiwa 501H directional wattmeter. Note the directional coupler at the top of the photo. The red wire carries a DC sample of the forward power, while the white wire carries a DC sample of the reflected power. The scope images above were with a transmitter output power of 150 watts (resulting in a forward sample of 1.2 volts. |
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