Alan, A long time ago I received a couple of "A" grade Si570s after asking for a sample!! On one of them when using a thick wire to dead bug it I cracked the ceramic substrate around the corner

Thanks Alan, Missed that one.... Not used on TCXO but in another application I never was a fan of soldering direct to the pads of one of the 'cheap' Si570's in case they tore off under the stress of a

A method of mounting and connecting devices like these. https://groups.io/g/QRPLabs/message/27233 73 Alan G4ZFQ

Correct, Perhaps if you take the OXCO route as you have documented characteristics for the Si5351 kit at VHF, it would be a useful half way step to repeat the testing with the

merci beaucoup Gilles, many thanks Alan, i knew, ther was something written somewhere.... in the next weeks i'll try different clocks with my Arduino-based transmitters.... I'll report my

What we do not know is just how sensitive the WSPR decoder is to frequency accuracy. I use 26MHz TCXOs and have decoded my 2m transmissions with no problem. There was some discussion a few months ago

This is explain in assembly manual of Si5351A of QRPLabs. "The SiLabs Si5351A chip is a cousin of the famous and popular Si570 chip, but is much less expensive. Unlike the Si570 however, the Si5351A

Hi Hans, hi all, somwhere i read about, that the reference clock of the Silab synth in a U3S MUST be at 27 MHz. Of course this depends on the firmware of the U3S. But i think, i heard that there is

Hi, If i look on the diagram, R36 has one end grounded. So putting the pot on this side SHOULD produce zero output ! The pot is also a logarithmic version and sound level SHOULD follow a smooth

Hi all, This afternoon i wanted to bridge the reverse protection diode on my 40 m QCX, to save some power drop. After doing this and putting the board back into the enclosure, i measured the power and

Hi, I have looked for other posts with same problem but could not find exact issue. Problem: Gain control (volume) goes from medium to loud but does not turn volume completely down. I've check

Hi Henning, In that case, what you're seeing is very much like what I saw before I installed the TCXO which changed chirp and drift to discrete frequency jumps. Eventually, I lifted the TCXO a couple

Hi Jeff This would not be a good point. The signal there is the Keying signal. What you want, I believe, is a Tx/Rx switching signal. You want the return from TX to RX to occur after a certain delay,

Hi Kevin I'd suggest it will all work fine, just proceed regardless.... it is quite difficult to get a decent accurate oscilloscope display at 27MHz even with a high bandwidth 'scope and probes. 73

Hello Andy, I`m using parkmode 0. I have only one enabled mode screen so the parking frequency should be the 2m frequency itself? Yes, I tried transmitting every 4 Minutes but this didn`t changed the

Hi Curt, App note 4 states use a 25 turns inductor not bifilar wound at 200mw. Either set the u3s with a power meter or use the current method of biasing, that should put you somewhere close. Do

Hello Halden, sorry, my fault, I scambled the definitions. I used the word "txco" without thinking. I`m talking about the original Si5351 synthesizer using the kit-supplied 27 MHz crystal. I have no

Hello Henning, Looking at your first screenshot and the second it looks as though you are running from one wspr transmission straight into the next. Have you tried leaving a gap between transmissions?

Thanks for your reply Curt. Anyone have any idea about setting the power output of on the U3S either before or after connecting the U3S to the amplifier? Curt M

Hi Henning, In your first post, you wrote that you were using a txco. I thought you meant TCXO, so my comments were based on that. But your recent post refers to a 27 MHz crystal oscillating at