om3 收到了 我发的cw+af的板子 进行测试后进行了如下更改 求翻译
hi james,
i tested and adjusted new cwaf board. there was necessary to do some changes, especially in cwosc part. tune osc doesn´t work with my 150mh inductors (very low q)....i will change them with better one (will order somewhere).
so please do next changes:
1. af part - is working very good, only one change : r88 from 22k to 18k to have the same level with cw filter (maximum is on 580hz, fo rme it is ok) compare to ssb filter.
2. tune part - doesn´t work, i must change l1,l2.
3. cw osc: - change q8 with irlml5203 or similar fet, it is no more hot (30min.keying test), no more changes in keying circuit
- replace r20 (100r) with diode 1n4148 (cathode down to d2), otherwise during tuning abt. 10v is present on +12cw (going thru q8 up from drain to source).
- remove c2 (10n) to prevent q1 oscillation !!!..
- cy capacitor is 33 pf, i have c31 3-10pf to reach exactly 9 mhz (your xtal is different compare to george´s, so more changes is necessary to do
- check q3 current, should be cca 8ma,
- change c5 from 10pf to 47pf
- change r18 from 15k to 8k2 to have q2 cca 4ma current
- change r15 from 6k8 to 18k to have q1 current cca 6ma
- use r40 and r41 resistors 470r
- use 12r for r39 (2db attenuator 50ohm)
- l1/l2 use primary 18,5uh plus 10pf capacitor. i have local toroid with 22 turns of primary, 6 turns of secondary; add parallel capacitor cca 120 pf ( plus minus) to secondary part from bottom side of pcb to reach sinusoidal waveform at the output. output level on 50 ohm load impedance should be -2 to 0 dbm.
