b91 SRA C400 and C502
SRA C502 (4m) on 10m
I didn't manage to convert it to 6m, but modified the receiver to
10m, and the
sensitivity was very good. Problem with those social democratic
constructions,
+12V as ground reference, with negative voltage regulators makes
service
complicated, but trade unions may celebrate - since you use very
much time
for service. It is however, possible to modify this - in a
civilized world, use the
receiver separated from the rest of equipment, with +12V supply
voltage, and
+9V regulator
SRA C502 receiver conversion
to 10m FM, overall circuit, note that operational
voltages refers to ground - not +12V as the socialist democrats
prefers, or was it for the English trade union?
Converting SRA C502 to 10m
Fig 98-1 29MHz HF trinn for C502 (Amatørradio April 1993 side
102)
Fig 98-2 Tilkoplinger på C502 (Amatørradio April 1993, side
103)
Fig 106-1: SRA C502 (4m) kort brukt til 10m FM sender (AR Mai
1993, side 136)
 |
 |
Fig 106-2: TX mixer SRA C502 for 10m, til høyre sees
tilkoplinger for spoler
(4m) kort brukt til 10m FM sender (AR Mai 1993, side 136)
Fig 107. 29MHz 0.1W 20dB gain forsterker med god selektivitet for
bruk sammen med SRA C502 TX modul
(Tekniske refleksjoner, AR Juni 1993 side 172)
Fig 108. 29MHz 10W 20(24)dB gain forsterker for bruk sammen med
SRA C502 TX modul
(Tekniske refleksjoner, AR Juni 1993 side 172)
SRA
C400 "UHF
rig"(FN205) .
it is some modifications in the power supply, and few in
the receiver.
The receiver is astonishing good and sensitive - in spite of what
it looks
like with those old Philips concentric trimmers
The advantage with this old rig is that it uses commonly
available components, or it is easy to find replacements.
se forøvrig
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