TE 0552G - Original Transistors

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Christoph, DF9CY

Mon Aug 04 2008, 10:44AM
Hi all,
can anyone tell us, which are the originally built in transistors in the TE Systems 0552G 50 MHz amplifier ?
Thanks in advance
Christoph
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Christoph, DF9CY
Tue Aug 05 2008, 09:24AM
Christoph, DF9CY
Registered Member #65
Joined: Thu Mar 20 2008, 04:27PM

Posts: 31
Got it

MRF492

tnx
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Ian, G5WQ
Wed Aug 06 2008, 09:07PM
Ian, G5WQ
Registered Member #81
Joined: Sun Mar 23 2008, 07:57PM

Posts: 29
hi christoph.
i know youve found the transistor details but thought id add to some of your discussions regarding the power from the TE amplifier .

i have tested 3 0552G amplifiers and to be honest they do not put out 375w as stated .

in reality you are more likely to see about 300w .

for my 0552G to produce 375w i need to drive it with 30w and to have the psu at 14.5v dc .

power measurement is taken with a bird 43 PEP meter and suitable slug .

at a nominal 25w drive with 13.8v dc psu i tend to see 300w output .

of course TE SYSTEMS state 375w PEP output which they may measure using more higher tech eqpt than i have .

with youre 11.9v and 240w output i think that may be about right anyway and perhaps all transistors are good .
.
if you increase the dc voltage supply you will see the power increase a fair amount if you add another 2volts input .

i also have an 0652g for 70mhz , this seems to be more efficient than is my 6m version .

i do not complain about the 6m amp because it will make 300w with 25w drive , which is plenty for what i need it for to use mobile or portable .

i think you will find that if other peoples 0552G amps are measured on more accurate meters, then they will find the amp produces a little less than 375w .

i did tune the capacitors on the input in my 0552g for maximum output and minimum input swr, as stated in the instructions from TE SYSTEMS .


73 ian
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Christoph, DF9CY
Thu Aug 07 2008, 12:52PM
Christoph, DF9CY
Registered Member #65
Joined: Thu Mar 20 2008, 04:27PM

Posts: 31
Thanks Ian,
Those 240w are OK then. Our power supply is at its limits with 11,85V. We see no drop in voltage at the amplifier terminals under full power. 300/240w are a bit under 1dB less and it compares to the datasheet indication for output power at various supply voltages. Gain now is 10dB that is OK. With this lower voltage it is a lot more robust against destruction. We measure with calibrated Rohde and Schwarz power meter and dummy load.
Measuring the bias voltages, we can not see any device not being good.

73 de Christoph

[ Edited Thu Aug 07 2008, 12:56PM ]
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