On 7/7/23 2:08 PM, Andrea I2UEA wrote:
Did it, but unfortunately it didn't work: same condition at 300MHz.
Is really the SI5351 generator overheating? The problem appears even when the device is just switched on.
Additional question: I live close to the centre of Milan and I receive very strong signals, especially from FM broadcast stations, receiving levels around + 6dBm (yes: 0,44 V !!!) or so. Can they affect the masurements?
Yes, very much so
There are two effects to be aware of:
1) if the signal is close to the test frequency, it makes it through the receiver. Broadcast FM is pretty wideband - the VNA's receiver is about 1 kHz wide, so if you're sweeping across that band, you'll likely get interference
2) saturation of the receiver. I can't remember what the max input before saturation is, but considering that the VNA puts out around 0 dBm, and with a short, all that comes back to the receiver, 6dBm probably won't saturate the mixer.
