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Those are all good reasons the LTM8078 won't be the best choice for this particular application, I really just picked it by going on the Analog Devices web site and filtering for a dual-output

Wayne, As Tony AD0VC pointed out, the commutating diode across L14 is definitely a good idea regardless of which FET you use. The TN0106 produces a much higher spike voltage than the BS170 because

This is interesting, Tony. I'm gonna have to study the schematic to determine the direction of the diode. I think I read of this solution in another post. For now...I live in the far SE corner of GA,

My apologies to the group. I called out the wrong transistor - I meant to spec the TN0106 as a good replacement for the BS170. Thanks Tony for refreshing my memory, it’s been months since John Z and

Hi! I received my QMX today, assembled it, and flashed latest firmware (1_00_009). I didn't test it on air yet (only with a dummy load). I have several issues with it. Two are serious, other are

I ran a TN0106 in my high band QDX for several months and had no issues. I had better output on 10 meters than with the BS170 but nothing dramatically better. I also ran the VN0606 in my low band unit

Lead shape and/or packaging. Mike WM4B Sent: Tuesday, August 29, 2023 7:04 PM To: [email protected] Subject: Re: [QRPLabs] BS170 Fail Thank you. Does anyone know if there is a real

Thank you. Does anyone know if there is a real difference between the variants of the BS170? I just ordered BS170P mosfets. There were other variants, but I went with this one since it was actually

The TN0606 seems to have a much higher input capacitance than the BS170 and this may translate into slower switching and increased dissipation especially on higher frequencies . Hard to say if they

I have a QRPometer from NM0S. (It was originally a 4SQRP kit, and is now offered by its designer.) It is both a power meter and an SWR meter, and when used as an SWR meter has an absorptive

Hi, my QMX is running well at +12V. Had to repair the Q103/Q104 short issue first by moving a bit the bigger one. Fortunately I measured the short before using it. I went the assembly my way: -

A resistive bridge, NOT the transformer kind, has 6dB of insertion loss which absorbs much of the reflected power, so the VSWR the transmitter "sees" is ~1.5:1 or less, regardless of what the load is

Hi Chris, when my QMX was very unsensitive (-53 dBm) I found my mistake, I have cross wired the two?of three trifilar pairs?(B-C and C-B instead of B-B and C-C). When I repaired that I was

Jerry, you can’t send characters one at a time to the mini, that why you are seeing the ‘ reply. you have to put the whole command together and send it as a block. 73 Ken g4apb

I tried USB to RS232 on my QCX Mini and it didn't work for me. USB to TTL worked like a charm. Jim - W4BQP since 1953

What we observe is that the LIN_REG_EN line goes from floating high to being pulled to the 3.3V MCU high state which as far as the V_IN line is concerned is low.? Hans has done this in his setup

Besides having higher voltages, a USB to RS232 signal will be inverted compared with a RS232 TTL signal.

The US equivalent to the Kanga pocket trans match is EMTECH's ZM-2. 4SQRP has a similar tuner to QRP Guys and Pacific Antenna has some too. -- 73, Dan? NM3A

That's true, but it wasn't really the question, as I recall it. The question was about what made the lower voltage segment on the LIN_REG_EN line. Since I don't know the microprocessor, I can't

Yes, but typically modern processors have a variety of control methods that can be configured, one of which is an 'open collector' style where it only pulls the line low and leaves it to float high.