Description of the modifications

 

Disassembling
- Remove Parts 1, 2, 3 by preserving the Part1/Part2 cable.
- Side above, preserve only Part 1 on the radiator, dismount all the remainder.
- Cut the frame at the red line to preserve only the length of radiator.

Mechanical engineering
- The captive nuts and screws and bolts in 2.5 and 3 mm will be re-used for the assembly.
- Cut out a plate which will receive Conv. CCC/CC, the board of control and various connectors. It will be fixed at the back of the radiator (some old drillings are usable).
- Cut out the plates of the sides and that of the back which receive the ventilators.
- Carry out the assembly while using what already exists and while supplementing by every corners worked for the passage of the cables.
- Envisage the fixing of catches N and others on angles with the front one.
- A sheet stainless case galvanized was built with a baffle allowing ventilation in spite of an exposure to the bad weather. Not to forget a fine mesh on the air intake.

Modification of part RF (Part 4)
Within sight of the pictures:
- Remove Capas chips.
- Add copper on the lines.
- Decrease, with the cutter, the coupling to use now like probes of control HF.

SMA Connector Input
- Disunite Part4 of the radiator and to give every. screws to maintain board plated with box, where the connector must be installed.
- Protect to the maximum
- Drill and tap with alcohol (not oil!) without deteriorating the circuit.


Adjustments
Caution: the coupler 3db of exit supports only 120 W HF uninterrupted, carrying pure!
- To adjust the quiescent current to 1 A on each MRF21125.
- If you have a sweep oscillator, to modify lines to improve the band-wide.
- Not to make a tunes for more than 100 Wout, if not right time to see a max.
- To test the max. one with pulsate (CW auto on speed max.)

Results
- 220 Wout for 18A on the final. Above the converter 48v/28v limit, which is a safety.
- Gain of the unit: 21db.
- Temperature on T1 (hottest): stabilized with 60°C after CW 12' (CQ) 220 Wout or 100 Wout carrying continuous.

 

Output Coupler GSC245-HYB2100 MRF 21125
Impedance 50 ohm Nominal
Frequency Range 2000-2200MHz
Average Coupling Insertion Loss 3.3dB max (Typ. 3.2 dB)
Amplitude Level Balance 0+/-0.3 dB (S31-S21)
Phase Balance 90+/-4 Degree
V.S.W.R 1.2 max
Isolation 20dB min
Input Power 120W Avg/CW
Operating Temperature -40 up to 125 Deg.C
Storage Temperature -40 up to 85 Deg.C
(-20 up to 35 Deg.C for tape and reel materials)
Technical Data.pdf

 

F2TU - Philippe