Magnum 257
Documentation Project

TX Alignment

1. Insert a mini jumper or diode on CON 1.
Set radio SSB channel 20 (E band).
Set RV9 (10K) to full clock wise.

2. Supply 1 KHz, 16mV TX MOD Input at USB mode and adjust T27, T28, T16, T29, T31 and T32 in order several times for maximum TX power.
Set mike gain minimum and then adjust RV6 (10K) for minimum carrier suppression in LSB/USB and in HI/LOW channels.
The difference of carrier suppression between at Mic-G min and Mic-G Max should be more than 35 dB or more.

3. Set variable power gain on front bezel to maximum and adjust L13, L14 and L16 so as RF power difference between A band channel 1 and J band channel 40 to be minimum and then adjust RV9 (10KB) so as RF power to be 23 Watts.
Make variable power minimum and adjust RV403 for 3 Watt RF output power and adjust RV405 for RF output power 1 Watt.
Set variable power gain maximum and adjust RV16 (5KB) for AM power 7 Watt and adjust RV14 (100KB) for FM power 23 Watts.
And then make V-pwr G minimum and check if RF power is not too much.
Also check if frequency tolerance in AM, FM and SSB is not too much.

4. Adjust RV8 (100Kohm) at AM no modulation so that S-RF meter points +30 or a little more. Adjust RV3 for 2KHz FM Dev at E band channel 20 and then check if it is 1.5-2.5KHz at A band and J band.
Adjust RV4 for 90% modulation at E band 20 channel and check if it is 85-100% in A and J band.

5. Adjust RV5 at TX, no mod at Ham band for 0.4 - 0.9 FM deviation which is for RPT adjustment.



Copyright © 1998,1999,2000, 2001

Disclaimer: Although the greatest care has been taken while compiling these documents,

we cannot guarantee that the instructions will work on every radio presented.