Hi Ben, Lou, Dave
Thanks for the kind comments and support <blush />
I do wonder though... about T1, did any of you try to follow the manual steps and think that they need to be changed or improved somehow? The manual steps were designed to make winding T1 quite reliable. Doing everything in one long winding means you automatically get the "sense" (anticlockwise vs clockwise) correct for all windings. And my idea with loops that are cut one by one, should mean that it is a lot more manageable to fit the wires in the right holes. You only have to do 2 wires at a time, not 8. But I am very interested to hear if you think that the method can be improved - or maybe if your alternative methods are something that you feel worked best for you, but the manual steps should be left alone. Maybe winding and installing T1 is a very personal thing :-)
73 Hans G0UPL
On Sun, Nov 5, 2017 at 6:15 PM, w7aqk <w7aqk@...> wrote:
Ben and all,
?
It sounds like you and I are similarly afflicted!? My eyes are not
very good either, one having macular degeneration to the point that everything
is a blur with that eye.? Thus my vision tends to be 2 dimensional rather
than 3 dimensional.? It¡¯s weird!? I¡¯m even close to your 76 year
mark¡ªtwo more weeks!
?
I agree that T1 is a bit daunting, but mostly it is just cumbersome with
those 8 legs.? Your method makes some sense, but seemingly has some
complications as well.? Admittedly I fumbled around a bit installing T1,
but eventually I think I came around to a process that worked pretty well.?
It¡¯s a bit difficult to describe, but I¡¯ll take a stab at it.
?
First, you need to make sure that you have the 4 connections on each side
of the toroid nicely aligned as they come off the toroid.? I used WA4MZS¡¯s
drawing as a guide.? Each connection on the left has an opposite connection
on the right, i.e. 7 and 2, 3 and 8, etc., but these leads are only ¡°opposing¡±
in how they are inserted into the board from top to bottom.? They are not
the opposing ends of the same winding.? Then I make sure that each
successive pair is somewhat shorter than the pair just above it.? 3 and 8
are shorter than 7 and 2, etc.? I work from the ¡°top¡± inserting 7 and 2
first.? Then I go to 3 and 8, and since they are shorter, they aren¡¯t
crumpled too much due to the insertion of 7 and 2.? I ¡°coax¡± 3 and 8 into
their respective holes with needle nose pliers.? Then I go on to 5 and 4,
and finally 6 and 1.? Working from ¡°top to bottom¡± seemed easier than doing
the reverse.? Once all 8 leads are inserted in their respective holes you
can pull each lead from the bottom of the board to tighten everything up
nicely.? Before soldering anything, I checked for proper continuity on each
pair that actually opposes each other¡ª1 and 2, 3 and 4, etc.? With 8 leads
it isn¡¯t difficult to get a couple of leads crossed, but the procedure I
followed seemed to prevent that, or at least minimize the probability.?
?
I¡¯m not suggesting that my method is necessarily better, but once I settled
on this process, things seemed to go relatively smoothly.? I fumbled around
a bit before coming to this method.? Clipping each successive pair shorter
seemed to help a lot¡ªyou just don¡¯t want to have the last pair be too
short!? This also helps you properly identify each pair.? If all your
leads are approximately the same length, it¡¯s easy to get them confused.? I
think my lack of ¡°3D¡± vision made things a lot more difficult in my case, but
when I went to dealing with just 2 wires at a time, it seemed much easier.
?
I hope this makes some sense to somebody!!!
?
Cheers,
?
Dave W7AQK
?
?
?
?
From: Ben Bangerter, K0IKR via Groups.Io
Sent: Sunday, November 5, 2017 5:43 AM
Subject: [QRPLabs] QCX T1 installation: A better
way?
?
I
began assembly of my 20 M version of the QCX nine days ago, and all went well
thanks to the excellent manual provided by Hans.? Until I got to the most
difficult component - the transformer T1.? I had no difficulty winding T1,
but when it came to installing it on the populated board - fitting eight thin
wires into the proper eight holes in the pcb, essentially simultaneously - that
was a bit much for my 76 year old eyes and fingers!? So I removed the three
small windings from the toroid, and installed the toroid, with only the large
winding, on the board, soldering both leads.? I straightened the wires of
the three removed windings and soldered one end of each length in the three
outer holes for those windings.? Then one by one I wound those three small
windings on the toroid, starting over the top of the core, passing the wire
under the core (with the aid of a tweezers) to the outside, and repeating the
process until the three turns were completed.? Then I inserted the free end
of the wire through the inner hole for that winding.? Verifying that the
sense of each winding was correct, I tightened the wires and soldered the last
three connections.? This process went very smoothly, and I am pleased with
the result.? If you have difficulty with the installation procedure?
as described in the manual, you might want to try my method.
Of course,
when it came time to align the QCX, the peaking capacitor was fully meshed and I
had to add turns to the large winding!? But that went well, and the
alignment process proceeded smoothly.? R24 ended up fully counterclockwise,
but the image rejection is excellent, as is the sensitiviy.? The rf power
output was low, as many have experienced, about 1.0 - 1.2 W with a 12 V supply
(increasing as the key is held down for a few seconds).? My first contact
(from Connecticut) was with OZ0JX in Denmark, with my 1 W and dipole up 20
ft!? I subsequently raised the power output to 1.6 - 2.0 W by removing one
turn from each of the LPF inductors.? And I solved the turn-on issue with a
diode (1N5711) between pins 7 and 20 of the ATmega328P.?
Hans has
done an incredible job with this project, great hardware design, software
design, board layout, and the best construction? manual ever done.?
And all at such a low cost!? Plus he spends a lot of time in support of
those of us encountering problems and having suggestions or questions about this
remarkable little rig.? What a fine contribution to the QRP world and the
Ham Radio builder/maker community! Ben - K0IKR
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