THE HF EQUIPMENT OF
I 5 T G C
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THE STATION BUILT IN 1947
This equipment was built in 1947, utilizing components coming partly from old receivers
of the thirties and partly bought at the "surplus" market. Some transformers were wound
at home, utilizing old magnetic cores. The receiver was an italian surplus set,
Ducati AR18, modified for this purpose. The transmitter was equipped with two tubes type
1625 in parallel, class C, plate and screen modulated from a couple of the same tubes
in push-pull, class AB2. Output power was about 70 watts, even if there were not
suitable instruments for taking accurate measurements. The station worked
in "AM" and "CW", over the 7, 14 and 28 Mc bands, the only ones allowed in Italy
at that time.
THE STATION BUILT IN 1951
This equipment was built in 1951, utilizing components coming for the most part from
the previous version, that was entirely disassembled. The receiver was upgraded, becoming
a double conversion set, utilizing the AR18 as second conversion stage. The transmitter
was still equipped with two tubes type 1625 in push-pull, class C, also modulated from
a couple of the same tubes in push-pull, class AB2. Output power was still 70 watts and
the station worked in "AM" and "CW" over 7, 14, 21 and 28 Mc bands. The output stage of
the modulator was equipped with a clipping circuit for negative peaks, thus allowing
the modulation depth to reach about 100% without breaks of carrier.
THE STATION BUILT IN 1973
This equipment was built in 1973; it is an entirely new project, all solid state, except
the power amplifier that uses still three tubes 1625 in parallel. The station works in
"AM", "SSB" and "CW", over 3.5, 7, 14, 21 and 28 Mc bands. Output power varies from
140 to 50 watts, according to the band in use. The receiver is a full coverage,.007 to
30 Mhz, single conversion set. The transmitter consists of a low power (3 watts), solid
state exciter, plus the above-mentioned power amplifier.
THE PRESENT STATION
The station was upgraded in 1991, adding two new homemade sets. They are a
transceiver shown in the picture at left, and a linear amplifier, appearing at top on
the right side of the station in the picture below. The transceiver, all solid state,
is a double conversion set, the frequency is controlled by means of a synthesizer with
500 Kc steps and an analogic low drift VFO. Reception is allowed from 0 to 32 Mhz
continuously, output power is about 3 watts over all amateur bands from 1.8 to 28 Mc.
The linear amplifier is equipped with a couple of tubes type PL519 in parallel and covers
all amateur bands from 1.8 to 28 Mc; output power varies from 150 to 60 watts, according
to the band in use.
The picture at right, shows the entire equipment as it was in 1992. Now the disposition
is slightly different, but the sets are the same.
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Cesare Tagliabue I 5 TGC
Updated: September 2007