Modification
and TEST RESULTS
of BLC8G22LS-450 pallet for QO-100
my goal for this work:
I got
some pallets from mobile base stations originally made
for the 2.1-2.2GHz
range and tried to modify it for the use on QO-100
(DATV).
This is not easy because
the pallet uses an internally matched power transistor
BLC8G22LS-450AV which is very narrowband and it is an
ASYMMETRICAL DOHERTY DESIGN. The amplifier gives
more than 150W
output on the original frequency or after modification
for 2320MHz.
But for the use on 2.4GHz it is difficult ... there is
an big loss of performance.
After some analysis of the circuit and some testet
modifications
it was possible to tune the
amplifier to a gain peak on 2405 MHz.
The maximum output reaches about 75W in
DVB-S2 mode and with good signal quality.
NOTE: there was
no need to change the bias circuit, so the
temperature compensated bias is in
original state and working well!
AND NOT ONLY THE
SIMPLE MOD GIVEN BY BATC (G7NTG)
IS NEEDED YOU HAVE TO MODIFY SOME MORE
THAT IT WORKS!
i got the following results
modification of the driver input
(MW7IC2240)
VSWR in range 1.7-2.7GHz after modification (c) by
dg0opk V1.0
measured GAIN, OUTPUT, CURRENT
and EFFICIENCY
of the complete module after modification (c)
by dg0opk V1.0
QRG: 2408MHz
DC 28V
input
(dBm)
|
output
(dBm)
|
output
(W)
|
gain
(dB)
|
current
(A)
|
efficiency
(%)
|
-19
|
19.4
|
0.087
|
38.4
|
1.5
|
|
-9
|
29.9
|
0.977
|
38.9
|
1.8
|
|
-4
|
24.8
|
3.02
|
38.3
|
2.3
|
|
1
|
40.0
|
10.0
|
39.0
|
3.3
|
10.8
|
4
|
43.0
|
20.0
|
39.0
|
4.4
|
16.2
|
6
|
45.0
|
31.6
|
39.0
|
5.5
|
20.5
|
7
|
45.7
|
37.1
|
38.7
|
6.0
|
22.1
|
8
|
46.4
|
43.6
|
38.4
|
6.7
|
23.2
|
9
|
47.0
|
50.1
|
38.0
|
7.5
|
23.8
|
10
|
47.7
|
58.8
|
37.7
|
8.4
|
25.0
|
11
|
48.0
|
63.1
|
37.0
|
9.2
|
24.4
|
13
|
48.7
|
74.1
|
35.7
|
11.0
|
24.1
|
I
tested the amplifier module now over some weeks also
running longtime
transmissions in DVB-S2 via OQ-100 with up to 75W
output.
(green marked in the table the
best range for use on DATV DVB-S2 mode)
ALL IS WORKING VERY STABLE and with GOOD SIGNAL
QUALITY
update 2.april 2022
made some tweaks on one
an other pallet and got some more
gain and output
measured
GAIN, OUTPUT, CURRENT and EFFICIENCY
of the complete module after
modification (c) by dg0opk V1.2
QRG: 2408MHz DC 28V
input
(dBm)
|
output
(dBm)
|
output
(W)
|
gain
(dB)
|
current
(A)
|
efficiency
(%)
|
-20
|
20.8
|
0.12
|
40.8
|
1.5
|
|
-10
|
30.6
|
1.2
|
40.6
|
1.7
|
|
0
|
41.3
|
13.5
|
41.3
|
3.8
|
12.7
|
3
|
44.7
|
29.5
|
41.7
|
5.5
|
19.5
|
5
|
46.4
|
43.6
|
41.4
|
7.0
|
22.2
|
6
|
46.9
|
49.0
|
40.9
|
7.4
|
23.6
|
7
|
47.2
|
52.5
|
40.2
|
8.0
|
23.4
|
8
|
48.0
|
63.0
|
40.0
|
9.3
|
24.1
|
9
|
48.3
|
67.6
|
39.3
|
10.0
|
24.1
|
10
|
48.7
|
74.1
|
38.7
|
11.0
|
24.0
|
11
|
49.2
|
83.1
|
38.2
|
12.3
|
24.1
|
12
|
49.8
|
95.5
|
37.8
|
13.8
|
24.7
|
13
|
50.0
|
100.0
|
37.0
|
14.6
|
24.4
|
14
|
50.4
|
109.6
|
36.4
|
16.0
|
24.4
|
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