Built the Ultimate 3S, with GPS unit, for six bands (10, 15, 17, 20, 30 & 40 w/relay board & inserted in proper position), and case. (Bought at FDIM 2017.) With the Si5351A module plugged in, I adjusted the bias of the Q1 transistor by rotating the potentiometer R5 from anti-clockwise to clockwise. I set the U3S on CW and used the right button to provide power for SWR tuning. THE PROBLEM: My power meter did not register any power, HOWEVER and my K3 rig was monitoring the signal and showed a signal strength on the sdr scope (elecraft P3) & I heard the power go up, I then backed off anticlockwise for a slight drop in power… BUT still the power meter showed no power (at least indiscernable power). I know my power meter is properly working, since prior and after the above Q1 test, I calibrated my power meter and checked the meter reading against 0.1, 0.2, 0.3, 0.5, 1 & 5 watts from my K3. Also, I tried quite a few WSPR contacts on 20M & 17 M. No DX station heard my WSPR, HOWEVER my K3 was monitoring the signal and it did register the Ultimate 3S WSPR signal properly. As a control, I sent some WSPR signals of 200 mW from my K3 and they were well received in Europe by many stations.

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I replaced the BS170 transistor (Q1) with a new transistor and still the exact problem stated above. Not solved.

I don’t know if related or a separate problem, but when in CW mode, after a message is sent, it appears the transmitter remains on but at a much lower power. I heard this on my K3, while monitoring the signal. By pushing the U3S right button the transmitter turns off. Again, when in CW mode the full transmitter power does not move the power meter, but enough power is being put out to clearly monitor the signal with my K3. (If a separate problem, we deal with this later.)

Help!

Howard, 4x1zz

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开云体育

Hi Howard,

Re-read the manual, there are two alternative configurations of T1 that need different connections on the PCB. Make sure you chose the correct one.

The alternative method to setting the PA bias is a good check to make.

I guess the PA doesn't draw any current at anypoint.

If you change the meter to read volts and follow the voltage from the PA supply Voltage pin through to the Drain connection of the PA FET's it will go 'missing?

The good news is it's probably only a piece of wire.

regards Alan

Still very low RF output (not discernable on my QRP calibrated watt meter). I replaced the Bifilar torid?and wound the simple 25 turn single winding (and yes I made the proper jumper and used the hole next to C4). Still very low RF power! And yes, I was able to set the potentiometer for BS170 transisitor, since the power out was enough to see on my K3 in the same room.
Still need help.?
Just a note that should not matter.
For all the low pass filters, at each capacitor position, the PCB (Rev 2, the latest) provides space for two capacitors in parallel, required for the LF band kits. For capacitors having 5mm spaced wires, I inserted the capacitors wires into two holes as in the example in the instruction sheet... But I also inserted the smaller spaced capacitors in the same manner... this should zero difference.
Please, still need help.?

I'm measuring power from with an antenna. I know my watt meter is working because I calibrated it with 0.1 and 0.2 watts from my K3.
As for measuring the drain voltage on the BS-170, I should measure voltage from the gate (middle leg) to ground? And where exactly do I measure the RF from the syn board to ground?
Sorry about the question. (I can build antennas & mechanical devices and test them physically without fear, but electrical/electronics I would rather double check with people with knowledge.)??
Tnx

Hi Howard,
I had this problem, check that the BNC is not shorted, centre pin to shell should be OC. I had a very very small solder bridge on one of the lpf's, it was my highest frequency in slot 5, always in circuit.
Have you got the highest frequency lpf in slot 5 then going down in frequency to slot 0?
My U3s is wound with 25 turns on T1 and output drops as frequency increases.?
Instead of using tune, try running through a programmed series of cw transmissions from low to high.?
Hope you sort it,?
Andy

Howard

Have you tried running it without the relay board to get a simpler system, the relay board adds more possibilities to make mistakes.

73 Jan

I think that is wrong. The highest frequency lpf goes in slot 1.

Roger
G3YTN


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Sent from my Android device with K-9 Mail. Please excuse my brevity.

More thoughts.
Does it take more current when you transmit.
If you use the method of measuring the current when you adjust the bias does the current increase?
Set the bias for a slight increase just a few milliamps.

Jan

Yes, sorry my bad,
Highest frequency lpf in slot 1 nearest the rf output?
Andy

TNX for your time and suggestions... I will incorporate these checks on my U3s during the rainy weekend. Howard 4x1zz

I found that there is short between the RF out and ground when the Low pass relay board inserted. (I used the RF out and ground from the low pass relay board... also all the filters were in the proper order highest frequency to lowest from 1-5 with 0 being the lowest.)?
Sooo, I took off the low pass relay board and inserted the 20 Meter LP filter on the U3 board and went solo, connected the RF out and ground from the U3s board. I have now only a drop more power... the watt meter needle did move a tad... but still very very low RF.
??

What about power consumption does it increase when transmitting?
Does the power consumption change at all when adjusting the bias?
If you had a short between ant and ground (I take it you had the same short between ground and RF in) you would probably destroy the PA fet.

Jan

I was asked to check?the drain voltage (DC and RF) on the BS-170: I measured on receive 5.08 volts and on transmit I measured 5.17 volt. (Positive lead on the drain and negative lead on ground.)
At the Gate of BS170, on receive, I measured 1.84 volts and transmit 1.82 volts.
I hope this information is good, for your suggested next step to solving my very low RF power out.
Tnx for your time.

These were DC measurements on the bs170. I need to read about the RF probe, from the reference you sent me and then build or borrow one to make the measurements you are suggesting.?
Also, it was suggested that maybe I burned out the BS170, when the low pass relay board was in the circuit and caused a short between the RF out and ground? (now it out of the circuit)... but if I have these DC measurements now, it means that BS170 is still good. Yes?
Thanks again, for your time... we will solve the problem... (that's the spirit). I'll work on the problem during the week... in and around my volunteer work.
73 Howard 4x1zz

I do not see where anyone has mentioned the W0-W1 and W2-W3 jumpers. Do you have the correct configuration?
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> I finally got it all together...now I can't remember where I put it<

Wes

AE6ZM

Hereford, AZ

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Hi Howard,?
OK on the short between rf out and ground, that is the same problem that I had.
Try putting the lpf relay board back in and then use only 1 filter, put it in position 1 and see if the short disappears. It may be that one of the lpf's has a short, mine did and it was the filter that was always in series.
Be aware that as the frequency increases, power output decreases. Try the 40m lpf and see what power it gives.
Another way to check the lpf's is to pull them from the board and check continuity, the two outermost pins on one end, doesn't matter which end, should be O/C, if there is continuity there is a short on that particular filter.
Good luck?
Andy.

Oh, and the bs170 may be ok, mine was transmitting into a short and was ok, I've also transmitted with no antenna or dummy load fitted and it was ok.
Andy