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Hi again all

I made inquiries through my supply chain. I can get a few hundred of these
30pF CYMI trimmer capacitors and make them available in the QRP Labs shop
price $2.50 for 10. This is not a USA source.
They would ship from Japan like the rest of QRP Labs stuff. Would this
help?

73 Hans G0UPL


On Wed, Nov 29, 2017 at 9:06 AM, QRP Labs <hans.summers@...> wrote:

Hi all

Sorry for the slow answer, I only read the daily-digest version of the
group.

To be sure, you are right, I get these CYMI for a great price! One big
reason why QRP Labs kits are such low cost is because I work hard on
finding the best pricing for all the components. It all adds up. When I
make the BPF kits I make 3,000 at a time...
which means 6,000 trimmer caps... it does help with bringing the price down
:-)

I can make some inquiries and see if I can get a smaller quantity. How
many do you need? The lettering on the top of the capacitor shell reads
"CYMI" and under that, "FS".

I found these capacitors to be decent quality and very reliable, though
of course you can always melt something by over-heating during soldering,
but generally I have never had that problem.

During the development of the BPF kit I first tried this style of
capacitor:

GKG60015/SG9035-ND/262545
In my opinion they were horrible...
1) they melted very easily during soldering
2) they were not easy to adjust with a standard screwdriver - I guess
some special tool is preferred
3) You cannot see what is going on inside that small blob of plastic - so
making adjustments is horrible

The latter point is important. With the CYMI capacitors used in the BPF
kit you can physically see the angular displacement of the fixed and
movable sets of plates. The reason this is important is because often in
the circuit you have other components all with tolerances, particularly
inductors - which have quite some variation depending on how you wind them
etc. When everything is installed, and you peak the BPF or try to adjust
the VFO limits or whatever - if the capacitor plates are fully open, or
fully closed, you know something is wrong. Likely it is necessary to add or
remove a turn of wire on a toroid inductor somewhere. I give this advice on
all my kits. With the CYMI capacitors you can SEE what capacitance it is
set to (approximately). If it is at either the two extremes, you know
things are not optimally adjusted, and have to take other remedial actions,
on the inductors.

Those tiny 6mm encased plastic trimmers are cheaper. But they didn't
match my idea of what quality I wanted for the BPF kits. That is why I
chose the more expensive CYMI ones.

73 Hans G0UPL

Hi all

Sorry for the slow answer, I only read the daily-digest version of the
group.

To be sure, you are right, I get these CYMI for a great price! One big
reason why QRP Labs kits are such low cost is because I work hard on
finding the best pricing for all the components. It all adds up. When I
make the BPF kits I make 3,000 at a time...
which means 6,000 trimmer caps... it does help with bringing the price down
:-)

I can make some inquiries and see if I can get a smaller quantity. How
many do you need? The lettering on the top of the capacitor shell reads
"CYMI" and under that, "FS".

I found these capacitors to be decent quality and very reliable, though of
course you can always melt something by over-heating during soldering, but
generally I have never had that problem.

During the development of the BPF kit I first tried this style of
capacitor:

goodman/GKG60015/SG9035-ND/262545
In my opinion they were horrible...
1) they melted very easily during soldering
2) they were not easy to adjust with a standard screwdriver - I guess some
special tool is preferred
3) You cannot see what is going on inside that small blob of plastic - so
making adjustments is horrible

The latter point is important. With the CYMI capacitors used in the BPF
kit you can physically see the angular displacement of the fixed and
movable sets of plates. The reason this is important is because often in
the circuit you have other components all with tolerances, particularly
inductors - which have quite some variation depending on how you wind them
etc. When everything is installed, and you peak the BPF or try to adjust
the VFO limits or whatever - if the capacitor plates are fully open, or
fully closed, you know something is wrong. Likely it is necessary to add or
remove a turn of wire on a toroid inductor somewhere. I give this advice on
all my kits. With the CYMI capacitors you can SEE what capacitance it is
set to (approximately). If it is at either the two extremes, you know
things are not optimally adjusted, and have to take other remedial actions,
on the inductors.

Those tiny 6mm encased plastic trimmers are cheaper. But they didn't match
my idea of what quality I wanted for the BPF kits. That is why I chose the
more expensive CYMI ones.

73 Hans G0UPL