Re: Ubitx v4 whining and swr check issue(?)

John (vk2eta)

The uBitx does transmit out of ham bands but the change of filters is set in relation to ham band edges.

Example for 40m, the 7-10Mhz  filter is switched ON when the frequency is set above 7,000,000Hz.
At or below that value the 3.5-5Mhz filter is ON. Therefore the available power at the antenna connection below 7,000,000Hz will be significantly reduced.

Although it is possible that an issue exist in the 7-10Mhz filter I suspect more likely an issue with the antenna.

Do you have or can you make a dummy load (example 20 x 1k ohms 1/4 watt resistors in parallel would give 50 ohms at 5 watts dissipation, usable with short burst of CW power to test the swr and confirm a very low swr on the 40m band)?

Regarding the whining, based on your "touch" test on the 25mhz crystal I strongly suspect a Nano oscillator issue. Changing the Nano fixed that issue in my rig.

73, John

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