I have finally achieved the near impossible and cleared the back log of
2800 emails from the BITX20 list.? All posts of enduring interest
between 15 December and today have been turned into news items on
.

For those who haven't been on the uBITx information site lately, I had a
break over the NZ summer - at first because of travel and summer
vacation time - then because of ill health.? I had a fall and cracked
open my forehead.? It has recovered well, just that slight "gang
warfare" look!? You will find posts in December, January and February
that were back-dated consistent with when topics were raised on the
list.? Enjoy!

With the release of the JackAl and then the v5 Board there has actually
been quite a bit of activity this year.

I made some judgement calls last year around the best mods for solving
the harmonics/spurs issues on the v3 and v4 boards.? I think these are
still valid and represent the easiest way of getting compliance (or near
compliance) for your uBITx (see the menu "fix" and then "spectral
purity").? I know that there are other mods and these are covered off in
the news items.? I suspect most folk want fixes that require minimum
effort - hence relay replacement and two replacement surface mount
chokes is what recommends.? Other solutions are a bit more
involved.

Hopefully all of you are still having as much fun as me at modifying
your uBITx.? I have a feeling that there are more mods just around the
corner.? Who knows where JackAl will take us, or what new features Ian
KD8CEC will throw at us?

73 Mike ZL1AXG

--
Mike Woods
mhwoods@...

On 12/03/19 1:36 AM, Curt via Groups.Io wrote:

Thanks for all the "hope you are better" comments.? My head wound has healed and the other health problems are receding, so all good at this point.

Curt- I think that we may never get clearer data, unless your larger group build can provide this information!

Gordon's approach with the daughter board (single end relay replacement) may well be easier to effect, but it sounds like it may also be at a slightly greater cost and complexity.? I do accept that removing multi-legged through-hole parts is not always an easy task, especially if you have never done it before.? It would be good if somebody had a video of doing this with techniques for breaking up the existing part, solder flux/wick work and removal of the individual pins.? This may make the task more straightforward for the regular constructor. I have the relays on the bench, but not yet installed. When I get around to doing the replacement I plan to try and make a short video of the repair work.

Many constructors seem really concerned about their rig's compliance.? I think this is probably an unnecessary concern given the power output of the uBITx.? Doing the mods cannot guarantee compliance, but doing both mods is likely to significantly reduce spurs and harmonics bringing it well within the unwanted emissions from a 100w rig.

73 Mike

Mike

I suggest that more, clearer data is needed before recommending a particular spurious fix.? The Axicom relays may work if a board does not require a huge improvement - I think this may be why some are not seeing compliance with this solution.? The alternative solution using 3 relays on a daughter board is actually easier for many builders since it has no need to remove relays from the board - but problem is that no one is sourcing it as a kit.? On the 45 MHz fix, I am not sure that replacing two coils is adequate in itself.? We honestly need more data.? Our own local club has a large group build - we can contribute data when we have it on v4.? I don't want the community having a false hope on any particular cure - and also want the community to understand that a sufficient fix is possible.?

Curt

--
Mike Woods
mhwoods@...