ICOM IC-202E [IC-202S]

IC202E is my 2nd 2m rig, I use it mainly for mobile operation with a 25W linear amplifier. The rig is small and have better reputation than it deserves, but as a second rig it is not so much used and it not much - if any - strongsignal problems in this area or places I've operated from. For mobile it is neccessary to use headphones when driving, otherwise it is impossible to hear what the opposite operator says.

Antenna removed to add some space

Battery holder removed...

IC202E rear view. 2x BNC-connectors, Blue: RX Ant, Red: TX Ant., 2x RCA phono jacks and standard KEY/PTT jack

IC202E S-meter modification. Remove R50 labelled "FULL".

RF dBm µV p.d. S-unit reading difference dB/S-unit
-120 0.22 S0 - -
-115 0.4 S1 5dB 2.5dB/S
-110 0.7 S3 5 2.5
-106 1.1 S5 4 2
-102 1.8 S7 5 2
-97 3.2 S9 5 2.5
-89 8 S9+10 8 80%
-80 23 S9+20 9 90%
-69dBm 80µV S9+30 11 110%
-57 316µV S9+40 12  
-37 3.160mV S9+60 20dB  

S-meter readings after modification

SSB/CW squelch for IC202 based on signal to the S-meter

Using IC202E in more complex environment.
The original circuit for PA and RX antenna switching is shown, the diode D25 connects the signal to RX for receiving, and a smaller DC-voltage is available on the antenna connector. This voltage may be used to switch external equipment, but it is somewhat impractical because it might give a missed signal to switch to transmit. Better is to have a positive signal on transmit, and if the signal is broken nothing happens - only the exciter (IC202) is switched to transmit, but no harm to the power amplifier, still the pre-amplifier need some backward protection.
I found it more practical to use a separate connector for receive - the original connection is also bad for noise figure, and a dc voltage through a resistor is fed to the TX connector. The original connector is used for transmit, and another BNC connector is used for receive. Dide D25 is left open in one side or removed, and the cable from RX now goes to RX-connector. A 4k7 resistor from +TX 12V goes to TX-connector.
I have lost the circuit diagrams for modifications.

IC202E PTT modification Ver. II (89-07-17). Using external PTT control for CW-operation.
Remove D17, R55, PTT connection to Mode-sw S3
Connect 1N4002 in series with R54, 22k from Q12 emitter to Q13 base, 10k from Q13 base to ground.
Note: Q12 in IC202E is Q11 in IC202S, Q13 in IC202E is Q12 in IC202S

Es stand in der CQ-DL, Band 2, Testberichte
A really very interesting book from DARC showing testreports by DL1BU for the following equipment:
Atlas 210/215, CRF320, Drake R-4C, Dressler D200, FT-221, FT-301, FT-901,
IC-202S, IC-211, IC245E, IC-280E, IC402, IC-701, KDK FM 2015R, KDK FM2016E,
LT470 (Braun), Multi 2700, REIS SE200XL-A, SB-104, SE301 (Braun), TS-520, TS-820,

Vergleichtest FR101, FT-220, FT221, HG70D, IC201, Multi2000, Multi2700

CQ-DL 3/79: 3-Watt-Kleintransceiver für SSB und CW von Icom IC-202S für 144MHz, IC-402 für 432MHz [DL1BU, Günter Schwarzbeck]