Ashhar, Absolutely correct the IMD is typically developed at an extremely low level most likely at the very first part of the Transmitter driver preamp. This is very common knowledge in the Broadcast Transmitters, Seldom is the IMD product part of the PA Stage.
Regarding FT8, I just got back on HF after almost three decades, I bought an sBItx v3 and I've been operating FT8 with it, mostly on 20m. My antenna is only a G5RV Jr. strung up in my attic, and my sBitx shows 10-13w out on 20m (I get the full 25w on 40). So for me, regardless of the fact that it's my computer communicating with another computer, I've worked 24 countries in less than 3 weeks, I'm in upstate NY, and two of the countries I've worked are Japan and Australia. So for me, given my setup, FT8 still is a challenge for me, the challenge being adding new countries. I plan on stringing an EFHW up in my attic to see how that performs vs. the G5RV Jr.
Thanks for posting these conversational videos. They were interesting, fun and imparted a lot of knowledge. Thanks all for taking the time to make them, especially as your time with Farhan must be limited. 👍 73 G0ACE
Enjoyed the discussions. Yes, IMD is cumulative.. so one has to look at every stage.. About 6 dB difference in IP3 figures between each stage should keep IMD down to a manageable level. The envelope restoration techniques for SSB seem to go back to the 50s.
Farhan has such a wealth of knowledge and innovation, he is a real gift to the community.
Ashhar, Absolutely correct the IMD is typically developed at an extremely low level most likely at the very first part of the Transmitter driver preamp. This is very common knowledge in the Broadcast Transmitters, Seldom is the IMD product part of the PA Stage.
Regarding FT8, I just got back on HF after almost three decades, I bought an sBItx v3 and I've been operating FT8 with it, mostly on 20m. My antenna is only a G5RV Jr. strung up in my attic, and my sBitx shows 10-13w out on 20m (I get the full 25w on 40). So for me, regardless of the fact that it's my computer communicating with another computer, I've worked 24 countries in less than 3 weeks, I'm in upstate NY, and two of the countries I've worked are Japan and Australia. So for me, given my setup, FT8 still is a challenge for me, the challenge being adding new countries. I plan on stringing an EFHW up in my attic to see how that performs vs. the G5RV Jr.
Thanks for posting these conversational videos. They were interesting, fun and imparted a lot of knowledge. Thanks all for taking the time to make them, especially as your time with Farhan must be limited. 👍 73 G0ACE
Enjoyed the discussions. Yes, IMD is cumulative.. so one has to look at every stage.. About 6 dB difference in IP3 figures between each stage should keep IMD down to a manageable level. The envelope restoration techniques for SSB seem to go back to the 50s.
I know how to finalize my finals now..finally, thank you!!
looking forward to grab the first zBitx! thank you Ashhar!
What about QPSK64 as a modulation format?
Hi, serious question, what will happen to your lab after your time?