Re: Less output power

Soundararajan Ra.

I am getting the following voltage
in in pre driver transister  q13 base 20 mv collector 1100mv
hot end of R136 100 R preset 500 mv set mid level
Driver Q14 base 250 mv collector 500 mv
transformert5 & t6 checked for short circuit of winging and cleared with tooth pick.
Till no improvement

On Mon, Nov 21, 2016 at 1:54 PM, Ashhar Farhan farhanbox@... [BITX20] <BITX20@...> wrote:

at the base of the predriver it is about 300mv, at the base of the driver it is about 1 volt and the PA gate is about 3-4 volts.

- f

On Mon, Nov 21, 2016 at 1:53 PM, 'Soundararajan Ra.' vu2rjw@... [BITX20] <BITX20@...> wrote:

Dear Farhan
please let me know the rf voltage level to be at the  base of pre amplfier q14 and gate of q15 with respect to ground if we measure by cro.
vu2rjw soundar

On Mon, Nov 21, 2016 at 1:26 PM, Ashhar Farhan farhanbox@... [BITX20] <BITX20@...> wrote:

the inductor can lead to self oscillations. you must find out the reason for low output.
- f

On 21-Nov-2016 1:22 pm, "'Soundararajan Ra.' vu2rjw@... [BITX20]" <BITX20@...> wrote:

Dear Farhan and sandeep
Thanks for your reply.
adding a inductor  in series 47 ohms is a good solution because it will resist some portion of preamp power going  to the ground ,Please let me know the value of inductor you are using.

On Sun, Nov 20, 2016 at 9:50 PM, Ashhar Farhan farhanbox@... [BITX20] <BITX20@...> wrote:

i would look at shorts in the driver or predriver transformers. try increasing the drive with the metal preset near the driver transistor

On 20-Nov-2016 9:44 pm, "Sandeep Lohia sandeeplohia12@... [BITX20]" <BITX20@...> wrote:

U will find a 50 ohm resistance on Gate of IRF510, replace it with 1K, this might double the out put power,    at the cost of instability sometimes...

I had used an inducter coil in series with 47 Ohm...

On Nov 20, 2016 8:46 PM, "vu2rjw@... [BITX20]" <BITX20@...> wrote:

Recent i got smd version of BITEX40 and came on the air.
After few conversation my output level was dropped.My antenna was well matched and it is minimum 1:1.1 to 1.2 for entire 40 meter band.
I checked for loose connection
I have replaced mic
Two times IRF510 replaced
when mic removed condition,  current was set for 100 ma
i am getting only  around 2 watt,in my diamond sx200 swr meter , with 12volt dc feed,output was connected to 50 ohm dummy load.,
please let me know what are the further points to be checked   with CRT oscilloscope to raise the power level.

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