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AA You may be correct there in your summing up - I believe the RNI Ampliphase, was the 100kw version, so it probably suffered even more from low power distortion. It must have been made for export from the USA, as 50kw was normally the max that could be used in the USA.
I believe the 50 on the Ross, was never run at more than 35kw -to extend tube life & to conserve fuel. Though is might have been a bit more when they first started.
I'll bring this thread to Alan Beech's attention, he might be able to enlighten us, further. Previous Message
Im not a TX engineer but my understanding is that RNI used an Ampliphase transmitter like several other offshore stations did and the RCA Ampliphase system has to be set up accurately and the antenna has to be matched well to the transmitter.RNI often sounded distorted on Medium wave because the antenna was not a good match to the transmitter giving a fair bit of reflected power (SWR). This presumably was due to the antenna originally being built for 1610 KHZ but the station changed frequency a number of times to lower channels - especially during the jamming.These lower channels were a fair bit lower than the natural resonant length of the tower on the Mebo 2 and presumably they did not modify the matching coils and capacitors enough to compensate fully.
The Ampliphase transmitters also tended to sound distorted if run at much lower power for some reason. The one on the Ross did as well when they turned it down to save diesel or in rough seas.
A TX engineer will likely be able to give more detail on these factors.
on 3/5/2023, 7:10:23, in reply to "