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Thank you to those who responded to my question. Bill Richardson’s informing me of the contrast control on the back of the VFO module did the trick. It was originally set to maximum. Now that the

Rlacement of MOSfets alone can't not solve the case. ?However there is reasonable improvement,. Interestingly, there is a dip in gain at 21.2MHz and recovered at 28 MHz. Twe need to analyse this

So this goes on for more than 28 hours then? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ Owner - Operator Big Signal Ranch – K9ZC Staunton,

BITX QSO Afternoon/Evening, Sunday, February 18, 3PM & 7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere. Join us as we make contacts from BITX40 to BITX40 on 7.277 MHz in 40

The same would be true for the RD16Hxxx devices, incidentally. john AD5YE

Indeed, there is the PA+ supply voltage on the IRF510 drains during receive. But zero drain current because the IRF510 gate voltage is zero and nowhere else for the PA+ supply to go.? Not so much as

Jerry But that does not remove DC from the finals.? I did not notice that the bias was dumped during receive.? That is my error.?? Arv_-_ Sent from my Verizon, Samsung Galaxy smartphone

I believe it has already been done for you. The LM78L05 regulator that supplies 5v to the IRF510 gate bias pots is in turn powered form the TX 12v rail. That TX rail is shut down during receive by the

I think Jerry has a much simpler idea -- just find a way to disconnect the gate bias during receive. This would put the gates at 0v, and effectively shut off the IRF510 drains. Probably a good

Like this: Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois Owner – Operator Villa Grand

In the case of the uBitx and Bitx40 we use the IRF510 FET's to turn off the PA power by shutting down the gate bias voltage source during receive. Drain current should be zero.

Post it here or on FB if you accept Paypal.? I bought a uBitx off a fellow ham that was in the same boat.? 73, Michael KM4OLT

Hello For power conservation it is possible to use a power FET to turn OFF voltage to the RF PA section during receive mode. Turn the switch device on with +TX power and off when this goes to

The FET's are more linear with a high quiescent current. Though the WA2EBY gets away with 10ma quiescent drain currents into the IRF510's which is a considerably less linear device than the

Thanks for your help Chris and your feed back, -- Regards John 2E0Eii

Thanks Marco for your reply a big help

Un solder the smc resistor and fit a higher wattage resistor to the top of the PC it will do the job chris g0wfh

Hi John, It is a double sided board. I would just remove the resistor and put in a 1/2 watt in its place. Also, check the transistor (Q14) to make sure it didnt sacrifice itself also. Good

Hi Guys can you give me some help i have popped R141 ,whilst working a station near Inverness who gave me 5/8/9 , Then Smoke !! luckily R141 let go , I would like to replace with a bigger value

Nick, Did you ever post the sketch for the TPA2016 AGC? Aug AG5AT