Hello, my son is in the process of constructing a U3S beacon. He has completed the board, low pass filter for 30m and fastened it together. When powered on by 4 AA batteries the kit turns on and he adjusted the menus to generate a CW test msg. From what can be seen no RF is coming out. A 3 ft wire was attached to the RF pin for testing purposes. We can provide detailed closeup photos of the unit. Not sure where to troubleshoot. Menus being correct tells me the microprocessor is inserted in place and doing its job. Low pass filter seems to be OK, where do we look next? Any suggestions are welcome.

Thank you,
Ivan Cholakov NO2CW

Thank you all for the great insight. We did the following today:
1. Detached and reattached the toroid that was pointed out as incorrectly placed. Added jumper as instructed.
2. Checked a few additional connections and one did not register well on the multimeter (we used enameled wire for the jumper) so we resoldered it.
Result:
1. The U3S is now transmitting. The amateur radio station next to it can receive the CW test signal.
2. PA Bias - this seems to be a little bit of a problem. In the absence of any test equipment we turn the potentiometer until the transistor starts to get hot. Idle consumption is 85mA and max consumption before transistor gets hot is 180 mA. This seems slightly low.
3.Using our home dipole ->? A station 30 miles away that we can control remotely does not receive the CW beacon. WSPR mode does not get detected or reported. This is using 100 ft of coax so as soon as the 5 days of rain here stops we will also test with a directly fed antenna.
Overall we are transmitting a signal but the indication is the signal is very weak. This could be due to the 100 ft of coax or due to more problems with the board where very minimal power gets transmitted.
Any suggestions are welcome. Thank you again.

I'm concerned you cooked the transistor please read the bias settings, how to in the instructions.?

You can measure current so you have the tools. Drop the pot counter clockwise then slowly run it clockwise until you see deflection/increase on your current meter then leave it there or back it off a hair.?

This is proper zero bias setting.?

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Do you have 5v solid power supply yet or are you still using dry cell battery? You need a better power source to continue.

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I run my unit at 100ft of coax and am heard around the world on all bands on a 20/40 dipole ?no tuner At 1w or less. Never seen the transistor warmer then room temp. On the U3?

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Do you have 5v at the transistor? Measured with multimeter?

What's your RMS or AC measured power on the RF at transmit into a dummy load??

Do you have a relay board attached??

Is your LPF properly oriented?

Did you check continuity on LPF?

Finally the power output is low you can cheat by running it with a local RX system and just touch parts of the board notice any change in signal on the rx?

Do you have any access to a oscilloscope??

Kelly K7MHI

Sent from a mobile device.?

On Jun 7, 2017, at 6:39 PM, Ivan Cholakov <ivantcholakov@...> wrote:

Thank you all for the great insight. We did the following today:
1. Detached and reattached the toroid that was pointed out as incorrectly placed. Added jumper as instructed.
2. Checked a few additional connections and one did not register well on the multimeter (we used enameled wire for the jumper) so we resoldered it.
Result:
1. The U3S is now transmitting. The amateur radio station next to it can receive the CW test signal.
2. PA Bias - this seems to be a little bit of a problem. In the absence of any test equipment we turn the potentiometer until the transistor starts to get hot. Idle consumption is 85mA and max consumption before transistor gets hot is 180 mA. This seems slightly low.
3.Using our home dipole ->? A station 30 miles away that we can control remotely does not receive the CW beacon. WSPR mode does not get detected or reported. This is using 100 ft of coax so as soon as the 5 days of rain here stops we will also test with a directly fed antenna.
Overall we are transmitting a signal but the indication is the signal is very weak. This could be due to the 100 ft of coax or due to more problems with the board where very minimal power gets transmitted.
Any suggestions are welcome. Thank you again.

Hello Ivan.?

On your remote receiving station, have you got an accurate PC time. Within one second accuracy.? There are a few PC time calibration programs on the web to keep your pic time super accurate.?

If not, you won't see any reports.?

My main U3S doesn't TX with much more power then you describe and I get out. Europe, USA mainly. Signal into about 30m of coax into a simple wire dipole.?

Also, the soldering on the LPF seems a little iffy. Especially C1, C2 and the winding on the left of the picture doesn't quite seem like it's taken properly.?

Are you using lead free solder.?? By the joints looking like they do I suspect you are.?

It doesn't sweat as well as leaded solder.?

Keep at it and you'll get there. It's just a learning curve you're in right now and it'll all come clear in the end.?

Kindest, James.?

On 8 Jun 2017, at 07:05, Kelly Keeton via Groups.Io <kellykeeton@...> wrote:

I'm concerned you cooked the transistor please read the bias settings, how to in the instructions.?

You can measure current so you have the tools. Drop the pot counter clockwise then slowly run it clockwise until you see deflection/increase on your current meter then leave it there or back it off a hair.?

This is proper zero bias setting.?

////

Do you have 5v solid power supply yet or are you still using dry cell battery? You need a better power source to continue.

////

I run my unit at 100ft of coax and am heard around the world on all bands on a 20/40 dipole ?no tuner At 1w or less. Never seen the transistor warmer then room temp. On the U3?

////

Do you have 5v at the transistor? Measured with multimeter?

What's your RMS or AC measured power on the RF at transmit into a dummy load??

Do you have a relay board attached??

Is your LPF properly oriented?

Did you check continuity on LPF?

Finally the power output is low you can cheat by running it with a local RX system and just touch parts of the board notice any change in signal on the rx?

Do you have any access to a oscilloscope??

Kelly K7MHI

Sent from a mobile device.?

On Jun 7, 2017, at 6:39 PM, Ivan Cholakov <ivantcholakov@...> wrote:

Thank you all for the great insight. We did the following today:
1. Detached and reattached the toroid that was pointed out as incorrectly placed. Added jumper as instructed.
2. Checked a few additional connections and one did not register well on the multimeter (we used enameled wire for the jumper) so we resoldered it.
Result:
1. The U3S is now transmitting. The amateur radio station next to it can receive the CW test signal.
2. PA Bias - this seems to be a little bit of a problem. In the absence of any test equipment we turn the potentiometer until the transistor starts to get hot. Idle consumption is 85mA and max consumption before transistor gets hot is 180 mA. This seems slightly low.
3.Using our home dipole ->? A station 30 miles away that we can control remotely does not receive the CW beacon. WSPR mode does not get detected or reported. This is using 100 ft of coax so as soon as the 5 days of rain here stops we will also test with a directly fed antenna.
Overall we are transmitting a signal but the indication is the signal is very weak. This could be due to the 100 ft of coax or due to more problems with the board where very minimal power gets transmitted.
Any suggestions are welcome. Thank you again.

Thank you all again for the comments. We resoldered the low pass filter toroids. They seemed very problematic as the wire would not allow to be tinned even after we tried some sand paper. I think we got it right at the end. Our WSPR signal was detected from stations 1000+ miles way. I am sure the unit is capable of a lot more but this was a good result.?
PA bias seems correct now but the entire adjustment procedure is still not 100% clear.