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Those batteries ought to last quite a while!

Hello everyone. I am very new to the forum. I have recently built the U3S kit and the 20m band filter. I tuned the filter with a signal generator and oscilloscope.? I can clearly see it attenuating

Good evening all, I just wanted to write a quick note and thank all those who have offered, both in-group and via personal email, to help me get my QCX40 back on the road. Someone has kindly offered

I folowed the instructions from Simon VK3ELH. except I use a Arduino Mega (ATmega 2560) wires are even the same colors. as in the instructions and the same pins??? gnd? 13 12 11 10 the sketchs I

What is the recommended GPS chassis mount connector that will fit in the QRP-Labs QCX enclosure?? thanks mike. n0mpm

That's what I did, but I used 5ea. 3.2V LiFePO4 cells to get 16V.? A LM386 board and a 3D printed box and Speaker grill and I'm done for now!

Thanks for the input, Hans.? I have some cheap Chinese LM386 audio amp boards that I got some time ago (maybe from Banggood), so I will use one of those and see how it works.? I'm making a

Before you pull the SI chip, have a very detailed look using a magnifier to see if there any solder “whiskers” along the pins of the chip. Check for continuity and shorts to each pad of the SI,

Hi Chris Fear not with the firmware. I shall leave you well alone on that. I There is room. The chip Flash is quite full, over 95% if I recall... but I wrote the code in a huge hurry and without

Hi Al It won't. You need an audio amp. Or you could do a nice push-pull pair of ordinary transistors and incorporate the final IC10 op-amp to remove the crossover distortion. That would be a nice mod.

For my QCX, I was about to build up a small speaker box using an LM386 amp and a 2.25" speaker (one that has a substantial magnet, rubber suspended speaker cone, and tweeter), but then I got to

My grandson and I are still stuck on step 1 "LCD contrast adjustment". We are following the current Trouble Shooting page under "Digital Section" and are getting the results as listed under"LCD all

RS are a nice motivational site I find. Usually you go there and after the instant pffff noise, tutting and shaking head for a bit it motivates you to find a cheaper distributor and part. My

Hi Chris, Karlis Yes! All agreed with Karlis! Chris: ?17 for a set of LM4562 from RS? Hi hi. I didn't say I got a good deal from RS specifically hi hi. Yes Karlis is correct, the first stage has 40dB

Even IC5 is AF, but it sees a very quaint signal, so noise voltage and noise figure is paramount there. IC5 gives about 40 dB of gain, after which the total receiver noise figure (or sensitivity)

Thanks for the info Hans - appreciated. That helps a lot with this idea. Karlis YL3JG thanks also! The LM4562 is a rather good across the board looking at the datasheet. Especially if you got a good

Hi Chris Nice job. Yes I was just about to say what Karlis said. I use LM4562 everywhere, even though only the first state (IC5) needs such a high performance low-noise op-amp. I do that because: 1)

I would say if you want to really save power, replace the hungry LM4562s where it makes sense, i.e. all of them except for the first stage, IC5. It's a nice low noise part, but each of those suckers

Hi, I was somewhat inspired by Kent W9WB's switching regulator mod and decided to have a bash at this myself. I looked around for regulators that had documented frequency. Turns out Recom's R-78E-0.5

Carl, If replacing the Si5351 is going to solve your problem, as you're only about 25 miles away, either ship it (with a new Si5351A) or bring it over and we'll replace the chip. Please contact me off