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-
- TM-221A freq coverage mod
- =========================
-
- This modification will allow you to change the transmit and receive
- characteristics of your TM-221A quite significantly from its current status.
- Some of the modes you will have access to will be useless as they require
- other modifications to be carried out in other parts of the radio. These
- would usually have been done by the manufacturer at assembly depending on
- where the radio was to be marketed in the world. eg. Europe / England /
- Australia / America / Japan etc etc.
- In no way do I condone transmitting outside the approved Amateur Bands as
- laid down by the DOTC. What you do with the radio is your business, I am
- merely showing you ways to increase the versatility of your radio.
-
- Resistors RX Range TX Range AO FS SH RE SC CT TO MS MT
- 22 23 24 25
- 0 0 0 0 138-174 138-174 N B Y M Y AL Y -- -- *1
- 0 0 0 1 138-174 138-174 N B Y M Y AL Y -- -- *2
- 0 0 1 0 144-146 144-146 N B Y M Y AL Y -- -- *3
- 0 0 1 1 138-174 138-174 N B Y M Y AL TX -- -- *4
- 0 1 0 0 144-146 144-146 N B Y M Y AL TX -- -- *5
- 0 1 0 1 154-174 154-174 N A Y Y Y Y Y -- Y *6
- 0 1 1 0 138-148 138-148 N A Y Y Y Y Y -- Y *7
- 0 1 1 1 138-174 138-174 N A Y Y Y Y Y -- Y *8
- 1 0 0 0 138-174 142-152 Y A Y Y Y Y Y -- Y *9
- 1 0 0 1 138-174 144-148 Y A Y Y Y Y Y -- Y *10
- 1 0 1 0 138-174 138-174 Y A Y Y Y Y Y -- Y *11
- 1 0 1 1 142-152 144-148 Y A Y Y Y Y Y -- Y *12
- 1 1 0 0 144-148 144-148 Y A Y Y Y Y Y -- Y *13
- 1 1 0 1 118-174 138-174 N A CA AL Y Y Y CF Y *14
- 1 1 1 0 118-174 144-146 N A CA AL Y Y Y CF Y *15
- 1 1 1 1 144-146 144-146 N A CA AL Y Y Y CF Y *16
- -----------------------------------------------------------------------
- 0 = Not Present 1 = Present N = No Y = Yes M = Momentary
- AL = Alert TX = Transmit CA = Call CF = Call Frequency
- A = 5/10/15/20/25 Khz Steps B = 5/10/12.5/15/20/25 Khz Steps
- AO = Auto Offset FS = Frequency Steps SH = Shift RE = Reverse
- SC = Scan CT = CTCSS TO = Tone MS = M.IN Shift MT = M.IN Tone
-
- CF sets the Call Frequency which is then the Frequency that is loaded into
- the VFO each time the Call function is used.
-
- TX transmits a set tone of 1750 Hz. The tone cannot be changed.
-
- *1 thru *5 receive nothing and transmit very little due to other changes
- required in the rig.
-
- *6 thru *16 receive and transmit in the Amateur Band as well as out of it,
- although retuning of the RF stages would be required if transmission out
- of the Amateur Band were to take place at more than the odd transmission!
-
- ****** NOTE ******
- Transmission outside the Amateur Band by Licenced Amateurs is strictly
- illegal unless prior permission is obtained from the DOTC.
-
- Resistors R22,23,24 & 25 can be found on the rear of the main display board.
- If you wish to gain access to these and properly identify them the service
- manual would be of great advantage.
-
- VK3TDR @ VK3RPA
-
-