Any thoughts on the 'proper' selection of a low-pass filter for the output of an Si5351? Is it sane to think about a 60 meter low pass for the 4.7-5 MHz, or would most anything work to clean the signa

Billy - Ashar's receiver troubleshooting video gives an overview of the board and talks about where and why some of the parts might be missing. My recent pre-Raduino didn't need C103 either. Cheers, A

You're welcome! Sorry...this didn't appear to mention C103...I forget where he covered the purpose of that. Sorry also for missing an H in Ashhar's name. ---In BITX20@..., <billy.shepherd@

I noticed that my receiver got noisier when I disconnected the built-in VFO and added the Si5351. I get that a filter re-shapes the waveform, but I'm wondering about whether it's useful to clean the o

Thanks Joel - that's one of the pages open at least twice in this stack of Chrome tabs I'm trying to wrap my head around. ;) I don't have an o-scope yet so my 'noisier' comment was also a subjective a

I'm using LiFePO4 and it's a drop-in replacement for lead-acid (4x cells at 3.3V nominal; use lead-acid voltages - 10V minimum; 13.8V max.). LiCo/LiMn could be a bit more challenging as they carry mos

If one plans to run from LiFe2O4, there's no need to do anything different than when one runs lead acid. Minimum cell voltage is 2.1VDC, Ultimate max is about 4.1V, but for long life most folks don't

Frank, There are a number of different cells in the lithium family. Each has different voltage ranges and reactions to abuse. What most of the public call "Li-on" is the lithium cobalt oxide cell used

In the new schematic for the BITX40 shipping with the Raduino, there's a 0.1uF cap in each of the freq gen output lines between the Si5351 and the radio. Pete N6QW comments that the blocking caps are

It looks like the base is split between 9V from the 7809, but 4.5 isn't 3.3. Thanks - I'll wire a cap when I stuff this tangle of wires into a box. :) Andy

Congrats on the compile! You called it right when you identified that the sketch was written for the V1.1.2 library. Thankfully, it's pretty easy to update the code for V2. Here's the 'read me' info f

After a couple of searches and some reading from the archives, I got a thought. Normally that's a dangerous thing, but I'll toss it out for the real experts just in case. hi hi Would it be possible (o

Can't say - I have no idea what the "cap discharge through a transistor" approach is, and haven't yet found anything about it in searches.

Adding another relay apparently isn't a new idea, but one that apparently works. http://g4ufs-bitx20.blogspot.com/2014/06/ridding-click.html I'm still trying to find details of the mods Uli, DF5SF cre

Thanks Jerry - I guess I was looking too far back. Can anyone link to an example of how to implement such a mod? (Can anyone confirm that the transistor and associated bias bits needs to be installed

Jerry, The archeology might have paid off. I think this matches what Farhan mentioned and what others call the 'transistor across the cap' fix. I'll give it a shot. Picture in our archive from K5DNL:

Pete N6QW has a full "how to get the BITX on the air" series that includes links for the keyed connectors. Main page: http://www.n6qw.com/Bitx40.html Wiring is in Phase 4: http://www.n6qw.com/Phase4.h

I'm happily retired but still get too much email. That's why the only email I receive from groups is important owner/admin messages. When I'm ready to scan the new traffic, I visit the site with coffe

Farhan's in here somewhere saying that the board's designed for 13.8V nominal with a max of 15. https://groups.io/g/BITX20/message/18201?p=Created,,,20,1,0,0::Relevance,,voltage,20,2,0,4105151 You can

Thanks very much for this, John. For the record and/or posterity, I was unable to get a full 1A from HF Sigs' board #869. I turned both R136 and RV1 fully clockwise, then opened RV1 until the Fluke 87