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Alexander, Good news! Just want to mention, the diode will drop 0.7V across it in this application. This is the reason the FET is used since it has a lower voltage drop across it. This is will

On second thought, opening QDX probably won't help. Today, I'm on 30m and pwr out is 5 watts with 12 vdc at 750 ma. Power supply steady - no trips nor dips- just short xmsns ! Sure is a mystery !

Hello Al and Evan, thank you both so much for your kind replies and detailed explanations, Q7 was the right guess! Wit Q7 as a search string I greped through the archive and found the other failures

Helmut Nice work to redeem that tuner, I bought one someone had partially assembled at a hanfest for a couple dollars, just to save another person from its limitations. Try opening your original

Hi Hans, Should anyone want to know this, I figured out a way to keep the QDX tx on during a *remote* terminal tx ptt test. On my Raspi 4 loaded a keyboard programme called 'Onboard', then configured

Peter, Could you leave the diode string in-line at all times and short it out with the Grove MOSFET swich, or do you need to be able to turn all the power off at times? 73, Willie N1JBJ

Hi Richard, I have added a 50 Ohm buffer?to my VFO-SigGen (Si5351A) using the two 74LVC2G17 in parallel.? Actually four drivers in parallel.? See the attachment. It works very well for me.? In the

Design any filter online here https://rf-tools.com/lc-filter/ - 73 de Andy -

Hi Alan and Sverre, your comments inspired me to try modifying my QDX for the higher bands. I figured how to use ELSIE and came up with an LPF that rejects third harmonics from 18-10m, AND includes

I have to shrink iPhone photos to get them to show. -- Colin Kaminski - K6JTH https://www.qsl.net/k6jth/

I designed some knobs and a new project case to fit the Manual Days ATU. The description and STL files are available at https://www.thingiverse.com/thing:5460017. If anyone here is interested I can

I appreciate all the help guys. I could never get the software to work for the QDX so I gave it to a coworker who's a digital guy. He's made a bunch of contacts. All's good. chris KD4PBJ

Tnx, Evan. Will look into ur suggestions tmw. 73, 'Willie', N4QA

Willie, This first step is to do a very close and?thorough inspection of the board for shorts or bridges between traces. What happens when you use the Terminal Transmitter Test program?? Does it

Charles.? There is no problem in changing supply voltage while the? QDX is on or indeed transmitting.? That is provided you can do this without any spikes that take the voltage above the

Hello Alexander, Sorry to hear that your QDX failed.? Based on what you have described, I believe that Q7 failed when or more of the BS170s failed.? I would be prepared to replace all 5 of the

Hey Willie ( Willie or Will is what my dad, W4MAI,sk 2006 used to call me ). My linear regulated supply is a 15 volt max, 2A max jobby that seems to be working nominally. Presently set for 12 vdc, 1

Power supply capacity? Try a different supply? 73, Willie N1JBJ

Alexander, Sorry that you ran into trouble with your QDX. I think the first place to look is whether or not Q7, the reverse polarity protection FET has shorted to ground. That would give you the low

Mine runs off a raspberry pi. Why not put it at the antenna then just use wifi of the pi to remote desktop into it from a tablet or laptop? David W5CWT