03-08-2019, 06:13 PM
Nev
You are right : This is from the Tech Supplement for the 817ND :-
Power Amplifier Circuit
The transmit signal from the MAIN Unit arrives at connector J3001 on the PA Unit. The transmit signal (1.8 MHz to 430 MHz) delivered to the PA Unit is amplified by pre-driver Q3001 (2SC3357), driver Q3002 (2SK2596) and final amplifiers Q5401/ Q5402 (2SK2975: Lot 1 - 74, RD07MVS1: Lot 75 -).
Low-Pass Filter (LPF) Circuit
The transmission signal from the power amplifier circuit is passed through a low-pass filter which consist mainly of RL3001-RL3015, RL3017, and corresponding inductor and capacitor networks. The LPF is a 5th or 7th-order Chebyschev type filter, utilizing nine different sections for the various amateur bands at 1.8 ~ 430 MHz.
So it is just the ONE PA stage from 1.8 through 430 MHz. A little different from what I have seen in other models but I guess space really is at a premium in the 817 series radios.
In some ways it makes it easier for you - just one physical area to add an external heatsink for regardless of band used.
A small image of the PA block area is below...
You are right : This is from the Tech Supplement for the 817ND :-
Power Amplifier Circuit
The transmit signal from the MAIN Unit arrives at connector J3001 on the PA Unit. The transmit signal (1.8 MHz to 430 MHz) delivered to the PA Unit is amplified by pre-driver Q3001 (2SC3357), driver Q3002 (2SK2596) and final amplifiers Q5401/ Q5402 (2SK2975: Lot 1 - 74, RD07MVS1: Lot 75 -).
Low-Pass Filter (LPF) Circuit
The transmission signal from the power amplifier circuit is passed through a low-pass filter which consist mainly of RL3001-RL3015, RL3017, and corresponding inductor and capacitor networks. The LPF is a 5th or 7th-order Chebyschev type filter, utilizing nine different sections for the various amateur bands at 1.8 ~ 430 MHz.
So it is just the ONE PA stage from 1.8 through 430 MHz. A little different from what I have seen in other models but I guess space really is at a premium in the 817 series radios.
In some ways it makes it easier for you - just one physical area to add an external heatsink for regardless of band used.
A small image of the PA block area is below...
Doug VK4ADC @ QG62LG51
http://www.vk4adc.com
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If you have a comment or question, post it as it may trigger or answer the query in someone else's mind.
http://www.vk4adc.com
This Forum is only going to be as interesting as the posts it contains.
If you have a comment or question, post it as it may trigger or answer the query in someone else's mind.