Frequency stability ANAN100D
Posted: Tue Jun 12, 2018 2:09 pm
To add to my ANAN-100D 'issues' I have noticed something else.
Last night I was listening to the output of a single tone from the transverter TX output socket on a receiver and noticed that every now and then the audio pitch would wander a few tens of Hz then recover with 1 second. I do not know what is causing it. Because this was a single tone generated in the FPGA and that VAC was not active we can forget anything to do with audio.
I actually first noticed it on receive a few months when listening to a strong beacon, I was experimenting with the audio peak filter and assumed that it was caused by some PLL in the audio. The events are quite fleeting in nature and if the frequency goes back to the exact same place it was then I am not so sure that it matters much on the air. I will have to do more to confirm this.
Please do not talk about RF feedback or supply decoupling, these are not likely as the HF PA was disabled and I had around 0dBm coming from the transverter socket.
So has anyone else observed this? I was using a GPSDO locked receiver for monitoring. I will try to quantify the problem and then see if locking to 10 MHz makes the problem go away.
I am not having much luck with my second hand ANAN-100D.
Regards
Conrad PA5Y
Last night I was listening to the output of a single tone from the transverter TX output socket on a receiver and noticed that every now and then the audio pitch would wander a few tens of Hz then recover with 1 second. I do not know what is causing it. Because this was a single tone generated in the FPGA and that VAC was not active we can forget anything to do with audio.
I actually first noticed it on receive a few months when listening to a strong beacon, I was experimenting with the audio peak filter and assumed that it was caused by some PLL in the audio. The events are quite fleeting in nature and if the frequency goes back to the exact same place it was then I am not so sure that it matters much on the air. I will have to do more to confirm this.
Please do not talk about RF feedback or supply decoupling, these are not likely as the HF PA was disabled and I had around 0dBm coming from the transverter socket.
So has anyone else observed this? I was using a GPSDO locked receiver for monitoring. I will try to quantify the problem and then see if locking to 10 MHz makes the problem go away.
I am not having much luck with my second hand ANAN-100D.
Regards
Conrad PA5Y