TRANSMITTER SPECTRAL PURITY (IMD)
When we compare the IMD of a good amateur radio transmitter almost 50 years ago to that of today's most modern transceiver, we should all be ashamed of ourselves for not demanding better transmitters, just as we have demanded better receivers.
1968: Collins 32-S3
2014 FLEX RADIO 6500/6700
- What were cars like in 1968 compared to today?
- What were televisions like in 1968 compared to today?
- What were computers like in 1968 compared to today?
- What were our receivers like in 1968 compared to today?
- Today's transmitters? SHAME SHAME
It's not the radio manufacturers' fault . . .
We have never asked them to build us better transmitters.
It's time to stop calling 30 dBc "good"!
Yaesu FT-450 IMD
The slide on the right is an excerpt from Rob Sherwood's 2008/09 Contest University presentation, as presented in Dayton.
This slide compares the FT-450's IMD to that of the 50+ year old Collins 32S-3.
As you can see, the 3rd order was much worse but barely within legal specs.
Unfortunately the picture worsens as we look at the higher order products.
Keep in mind that it is not only the 3rd order products which disturbs neighbors, but ALL IMD products.
THIS IS A FILTHY TRANSMITTER!