70MHz (4m) RF Power Linear Amplifier, typical 8W in 50W out. Made in Dorset UK
The amplifier circuit and layout was created by me, Antony Nailer G4CFY of Spectrum Communications, in November 1991 and continued with the original PCB until mid 2020 when a new PCB was laid out. It was originally designed for use as a single stage amplifier for 2m or 4m or 6m with devices to give 25W output. A version using a BLW60 was also capable of 50W output in the 4m and 6m versions. The 25W versions are not. So popular but I still make a 2.5W in 25W output version TA25W6M as a companion to the FT690. It uses a BLW60 device with a forward bias of 50mA and is tuned for peak power output consistent with an input SWR better that 1.2:1. The 4m version gives 50W output for typically 8W input. The 50MHz (6m) version usually gives 50W output for 5 or 6W input. It comes with a 1 metre 42/0.2mm red/black twin power lead and runs from a 13.5V 10A supply and usually draws 6A continuous on DATA or FM, or peak in the case of SSB or CW. This is NOT a wideband amplifier but is tuned input and output followed by a low pass filter to reduce harmonic outputs to -60dB or better. It is RF sensed including the unique Spectrum communications monostable RF switching circuit giving fast attack and 500ms hang time to avoid relay chatter when on SSB. The item "70MHz (4m) RF Power Linear Amplifier, typical 8W in 50W out. Made in Dorset UK" is in sale since Sunday, August 16, 2020. This item is in the category "Mobile Phones & Communication\Radio Communication Equipment\Ham/Amateur Radio\Ham Radio Amplifiers". The seller is "spectrumcomms" and is located in Dorchester. This item can be shipped worldwide.