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Greetings, I lost? the 1.2k resistor R-42 for the QCX+ in the key shaping circuit and want to use a 1.0k resistor as a replacement. Is this going to present a significant problem? A 200 ohm difference

That's quite a punch, Tony! Consider this: It gets worse when the load is at a low impedance. The drain currents go up sharply, and then so does the energy stored in the inductor, as the square of

I saw a video recently where a UPS driver put the package on the porch, took a photo of it, then picked up the package and went back to the truck. People like that should do jail time. Jack, W8TEE

Jack, I had a similar problem with a new USPS driver. I actually DID run over the package. Fortunately it was a very sturdy item with very good packaging and no damage was done to the contents. -- 73,

For good measure, here is the VN0606 drain picture. Tony ________________________________ Sent: Tuesday, August 8, 2023 6:36 AM To: [email protected] <[email protected]> Subject: Re: [QRPLabs] QDX

Those of you who have had good experiences with Fed Ex being responsive to your delivery instructions owe your local Fed Ex a big hug.? I have found my local Fed Ex to be impervious to requests. On

Yes, that makes sense. I am still learning my new scope. I had it set to measure "Top" instead of "Maximum". You can see from the graticule scale that it is about 70 volts. BS170 drain picture

* I also see a bunch of birdies - I check the frequencies when I get a chance. * On the audio sweep curves I see a notch at about 2.2K the varies from run to run and band to band - I have no idea of

Voltages good then. Every time I've had an Rx issue I've had bad voltages there. One required a new multiplexor (because of excess probing) and the other needed the trifilar toroid rewound. I did have

R401/R402 and C406 are designed to provide a 2.5v bias to the signals passing through the demodulator? switches (IC 403) and the? following amplifies that all need non-zero dc signals.? On my QMX

Tony, My guess is that when you were running the BS170s and seeing a flat-topped 60V you were observing avalanche breakdown of the BS170 drain. Drain-gate oxide breakdown can also happen at that

The voltage at the top of C406 (feeding T401)? is 2.5v, exactly as expected. I've checked voltage levels around pins 3, 4, 5 of IC402?and are all at 2.5v, also as expected. I can't see any rf

I ordered a Hantech 200MHz scope and FedEx delivered it by leaving it in front of our detached garage, which made it invisible from the house. Later that evening after a two hour torrential rain, I

The diode is a good idea I think. This is based not only on simulation but on measurements I have made with my scope. In my case, the loss of two or three sets of BS170 in my two QDX units led me to

We have a table on the front porch, and all our delivery folks have figured out that it's a Good Idea to put packages on the table. N6OTQ

I used that Fed Ex feature when I found myself in a similar situation with my QCX mini shipment. They just ignored it. When I returned home I found it sitting slightly soggy in the driveway having

Do NOT try to move a SMD device without heating all the pads. You will break something. Go to the local hobby/hardware store and get a heat embossing tool. Mine cost me 10USD from amazon. Or use a low

I put together a brief document with some of the more important QMX inspections and issues all in one place from info that others have posted. - Steve K1RF

What is the voltage at R401/R402 and the top of C406 (non ground side)? Have you done much probing on IC402 while powered? -mike/w1mt

Hi all. My newly constructed 12v QMX is running the latest 1_00_009 firmware and is generally working well, but has two possible receive issues: Receive Appears Slightly Deaf My QMX appears