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securing toroids in K2, why not?

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R Thompson

securing toroids in K2, why not?

I just installed the first toroid, RFC14, in my K2 kit. After
winding it, I sprayed it with conformal coating, and just before
installing it I put a small dab of RTV3145 (non-corrosive) silicone seal
on the end next to the PC board and then soldered it in place.

So.... I turn the page in the manual and the very next thing in bold
is "Do not use adhesives or fixatives of any king to secure toroids to
the PC board.

Would this also apply to conformal coating? Should I remove RFC14
and take the RTV off it?

Thanks,

Ron VE8RT

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Johnny Siu

Re: securing toroids in K2, why not?

U don't need all those adhesive for all toroids. 73 Johnny

Sent from my iPhone 4

R Thompson <[hidden email]> 於 2011年7月3日上午9:02 寫道：

> I just installed the first toroid, RFC14, in my K2 kit. After
> winding it, I sprayed it with conformal coating, and just before
> installing it I put a small dab of RTV3145 (non-corrosive) silicone seal
> on the end next to the PC board and then soldered it in place.
>
> So.... I turn the page in the manual and the very next thing in bold
> is "Do not use adhesives or fixatives of any king to secure toroids to
> the PC board.
>
> Would this also apply to conformal coating? Should I remove RFC14
> and take the RTV off it?
>
> Thanks,
>
> Ron VE8RT
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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Don Wilhelm-4

Re: securing toroids in K2, why not?

In reply to this post by R Thompson

Ron,

I suggest that you indeed do that. Actually on RFC14 it will likely
make little difference because the exact inductance is not critical, but
once the RTV hardens, you will have a bear of a time getting it off
should it ever need replacement. Do not use any fixatives on any more
of the K2 toroids. Many compounds will alter the inductance, and it is
just not necessary. To emphasize that point, I often refer to the K2
that I built for an OTR truck driver. That K2 lived for years in the
cab of his 18 wheeler, and never suffered any toroid damage - the
toroids were adequately supported by their leads.

More specifics, T5 (and sometimes, but not often, the inductors in the
LPF) may need "tweaking" by adjusting the turns spacing. The use of any
fixatives will prevent that, and require you to purchase new cores and
rewind the toroids.

Build the K2 as specified in the manual, and you will have no problems -
if you add or subtract anything, it may not work correctly.

73,
Don W3FPR

On 7/2/2011 9:02 PM, R Thompson wrote:

R Thompson

Re: securing toroids in K2, why not?

Thanks Don,

I've received a few helpful responses already, which I
appreciate. I could do without the RTV, except I like it at RFC14
because its jammed into a tight space, and as you mentioned, its a RF
choke which wouldn't be critical.

For a very long time conformal coating has been used in my
field, avionics. Its great stuff to reduce board corrosion in damp
environments, even if its just from condensation. That is if its
applied carefully and the board and adjustable components and
contacts are well masked. If it won't mess things up, when its
finished I'd like to apply conformal to parts of the board,
especially the underside of the board.

Back to the RTV on RFC14, there is a very small dab of it on the
bottom of the core, just to keep it upright. Anymore than a small
dab would be a waste.

OK, future cores I'll leave alone unless the manual says
otherwise. And conformal coating parts of the board can wait until I
look into this further. I have spare cores and wire, and an
reasonably good LCR meter at work, I'll see what difference the
coating makes in the value of toroidal coil.

Ron

On 2-Jul-11, at 7:29 PM, Don Wilhelm wrote:

> Ron,
>
> I suggest that you indeed do that. Actually on RFC14 it will
> likely make little difference because the exact inductance is not
> critical, but once the RTV hardens, you will have a bear of a time
> getting it off should it ever need replacement. Do not use any
> fixatives on any more of the K2 toroids. Many compounds will alter
> the inductance, and it is just not necessary. To emphasize that
> point, I often refer to the K2 that I built for an OTR truck
> driver. That K2 lived for years in the cab of his 18 wheeler, and
> never suffered any toroid damage - the toroids were adequately
> supported by their leads.
>
> More specifics, T5 (and sometimes, but not often, the inductors in
> the LPF) may need "tweaking" by adjusting the turns spacing. The
> use of any fixatives will prevent that, and require you to purchase
> new cores and rewind the toroids.
>
> Build the K2 as specified in the manual, and you will have no
> problems - if you add or subtract anything, it may not work correctly.
>
> 73,
> Don W3FPR
>
> On 7/2/2011 9:02 PM, R Thompson wrote:
>> I just installed the first toroid, RFC14, in my K2 kit. After
>> winding it, I sprayed it with conformal coating, and just before
>> installing it I put a small dab of RTV3145 (non-corrosive)
>> silicone seal
>> on the end next to the PC board and then soldered it in place.
>>
>> So.... I turn the page in the manual and the very next thing
>> in bold
>> is "Do not use adhesives or fixatives of any king to secure
>> toroids to
>> the PC board.
>>
>> Would this also apply to conformal coating? Should I remove
>> RFC14
>> and take the RTV off it?
>>
>>

Ron VE8RT [hidden email]
Yellowknife, NT, Canada
62 26.765N 114 22.503W Grid Square DP22tk
"Who are these that fly as a cloud, and as doves to their window?"
Is 60:8

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Don Wilhelm-4

Re: securing toroids in K2, why not?

Ron,

Forget the LCR meter with the K2 kit - other than to evaluate the
effects of various "fixatives" for toroids.
Wind the toroids with the number of turns specified and all will be OK.

As far as conformal coating, again, it makes repair or rework a "pain" -
but if you insist ...
What I can say is that I have worked on many K2s (over 600 to date), and
some have been subjected to extreme environmental conditions (salt
spray, high humidity, etc.), and on all of those, even though the
exterior of the K2 shows signs of corrosion from that environment, all
those I have seen look "pristine" on the surfaces of the boards. Based
on that, I would discourage using any conformal coating, it is just not
necessary unless you intend to dip your boards in salt water.

I have no idea what problems may occur if you would use a conformal
coating, other than that the coating must be "worked through" if any
repairs or upgrades are needed in the future.

When measuring with an LCR meter, be certain it is working at the
frequency that the toroid will actually be used. Many LCR meters work
at a low fixed frequency, and the results obtained from those meters can
be misleading when the toroid is used at the frequency that it was
designed for.

73,
Don W3FPR

On 7/2/2011 9:48 PM, Ron VE8RT wrote:

> Thanks Don,
>
> I've received a few helpful responses already, which I
> appreciate. I could do without the RTV, except I like it at RFC14
> because its jammed into a tight space, and as you mentioned, its a RF
> choke which wouldn't be critical.
>
> For a very long time conformal coating has been used in my
> field, avionics. Its great stuff to reduce board corrosion in damp
> environments, even if its just from condensation. That is if its
> applied carefully and the board and adjustable components and
> contacts are well masked. If it won't mess things up, when its
> finished I'd like to apply conformal to parts of the board,
> especially the underside of the board.
>
> Back to the RTV on RFC14, there is a very small dab of it on the
> bottom of the core, just to keep it upright. Anymore than a small
> dab would be a waste.
>
> OK, future cores I'll leave alone unless the manual says
> otherwise. And conformal coating parts of the board can wait until I
> look into this further. I have spare cores and wire, and an
> reasonably good LCR meter at work, I'll see what difference the
> coating makes in the value of toroidal coil.
>

R Thompson

Re: securing toroids in K2, why not?

Thanks Don,

good point on the LCR meter, it measures values at 1KHz. The
remaining coils are being installed as per the manual.

I service avionics for living, the better gear has conformal coated
boards. The coating is very thin, applied as an aerosol, and hasn't
been a problem for repairs, a soldering iron will melt through it no
problem. Older coatings, which were applied very thick, were a
headache. Its hard not to want to use it, I've had my gear end up in
puddle at Field Day after a gust of wind blew over the tent, tables, and
all.

First things first, I'll finish it as per the manual.

The help here has been wonderful, and fast! Thanks everyone, and
enjoy your long weekend!

Ron VE8RT

On Sat, 2011-07-02 at 22:14 -0400, Don Wilhelm wrote:

> Ron,
>
> Forget the LCR meter with the K2 kit - other than to evaluate the
> effects of various "fixatives" for toroids.
> Wind the toroids with the number of turns specified and all will be OK.
>
> As far as conformal coating, again, it makes repair or rework a "pain" -
> but if you insist ...
> What I can say is that I have worked on many K2s (over 600 to date), and
> some have been subjected to extreme environmental conditions (salt
> spray, high humidity, etc.), and on all of those, even though the
> exterior of the K2 shows signs of corrosion from that environment, all
> those I have seen look "pristine" on the surfaces of the boards. Based
> on that, I would discourage using any conformal coating, it is just not
> necessary unless you intend to dip your boards in salt water.
>
> I have no idea what problems may occur if you would use a conformal
> coating, other than that the coating must be "worked through" if any
> repairs or upgrades are needed in the future.
>
> When measuring with an LCR meter, be certain it is working at the
> frequency that the toroid will actually be used. Many LCR meters work
> at a low fixed frequency, and the results obtained from those meters can
> be misleading when the toroid is used at the frequency that it was
> designed for.
>
> 73,
> Don W3FPR
>
> On 7/2/2011 9:48 PM, Ron VE8RT wrote:
> > Thanks Don,
> >
> > I've received a few helpful responses already, which I
> > appreciate. I could do without the RTV, except I like it at RFC14
> > because its jammed into a tight space, and as you mentioned, its a RF
> > choke which wouldn't be critical.
> >
> > For a very long time conformal coating has been used in my
> > field, avionics. Its great stuff to reduce board corrosion in damp
> > environments, even if its just from condensation. That is if its
> > applied carefully and the board and adjustable components and
> > contacts are well masked. If it won't mess things up, when its
> > finished I'd like to apply conformal to parts of the board,
> > especially the underside of the board.
> >
> > Back to the RTV on RFC14, there is a very small dab of it on the
> > bottom of the core, just to keep it upright. Anymore than a small
> > dab would be a waste.
> >
> > OK, future cores I'll leave alone unless the manual says
> > otherwise. And conformal coating parts of the board can wait until I
> > look into this further. I have spare cores and wire, and an
> > reasonably good LCR meter at work, I'll see what difference the
> > coating makes in the value of toroidal coil.
> >

Jim Campbell

Re: securing toroids in K2, why not?

In reply to this post by Don Wilhelm-4

Reminds me of a story that I heard years ago while on an assignment in
England.

Seems that the Rolls Royce company didn't have an automatic transmission
in their cars. Since automatic transmissions were the up-and-coming
thing they decided that they needed one to offer in the Roolls Royce.
Rather than design one from scratch they surveyed the field and decided
that the best of breed was one made by General Motors. They entered into
an agreement with GM to use theirs.

They took a GM automatic transmission into their shop and tore it down
completely. They wanted any transmission that was going into a Rolls
Royce to be top quality, inside and out. Everything passed muster
except for one part. It had a rough surface. That just wouldn't do so
they machined the surface to a Rolls Royce standard. The trouble was
that when the transmission was assembled it wouldn't work. They
contacted GM and found out that the surface in question had to be rough
or the transmission wouldn't work.

Best to trust the judgment of the design engineers.

72,

Jim - W4BQP
K2 #2268

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R Thompson

Re: securing toroids in K2, why not?

Hi Jim,

I've worked on aircraft for over 30 years and know what engineers can
do :-) There are many airworthiness directives issued after the
engineers have finished their work. I'd better not get something
started, as I really do appreciate the work of the engineers. More
field experience would help some of them.

Ron VE8RT

On Sat, 2011-07-02 at 22:47 -0400, Jim Campbell wrote:

> Reminds me of a story that I heard years ago while on an assignment in
> England.
>
> Seems that the Rolls Royce company didn't have an automatic transmission
> in their cars. Since automatic transmissions were the up-and-coming
> thing they decided that they needed one to offer in the Roolls Royce.
> Rather than design one from scratch they surveyed the field and decided
> that the best of breed was one made by General Motors. They entered into
> an agreement with GM to use theirs.
>
> They took a GM automatic transmission into their shop and tore it down
> completely. They wanted any transmission that was going into a Rolls
> Royce to be top quality, inside and out. Everything passed muster
> except for one part. It had a rough surface. That just wouldn't do so
> they machined the surface to a Rolls Royce standard. The trouble was
> that when the transmission was assembled it wouldn't work. They
> contacted GM and found out that the surface in question had to be rough
> or the transmission wouldn't work.
>
> Best to trust the judgment of the design engineers.
>
> 72,
>
> Jim - W4BQP
> K2 #2268
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
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AC7AC

Re: securing toroids in K2, why not?

In reply to this post by R Thompson

CONTENTS DELETED

The author has deleted this message.

AC7AC

Re: securing toroids in K2, why not?

In reply to this post by Jim Campbell

CONTENTS DELETED

The author has deleted this message.

Rick Dettinger-3

Re: securing toroids in K2, why not?

In reply to this post by Jim Campbell

Hi Jim

Good story! I think that was a few years ago. Rolls-Royce acquired a
license to produce the HydraMatic in 1952! I remember 1952 well, as
that was the year we got our first TV, The last ones on the block to
do so.

73,
Rick Dettinger K7MW

>
> Reminds me of a story that I heard years ago while on an assignment in
> England.
>
> Seems that the Rolls Royce company didn't have an automatic
> transmission
> in their cars. Since automatic transmissions were the up-and-coming
> thing they decided that they needed one to offer in the Roolls Royce.
> Rather than design one from scratch they surveyed the field and
> decided
> that the best of breed was one made by General Motors. They entered
> into
> an agreement with GM to use theirs.
>
> They took a GM automatic transmission into their shop and tore it down
> completely. They wanted any transmission that was going into a Rolls
> Royce to be top quality, inside and out. Everything passed muster
> except for one part. It had a rough surface. That just wouldn't do
> so
> they machined the surface to a Rolls Royce standard. The trouble was
> that when the transmission was assembled it wouldn't work. They
> contacted GM and found out that the surface in question had to be
> rough
> or the transmission wouldn't work.
>
> Best to trust the judgment of the design engineers.
>
> 72,
>
> Jim - W4BQP
> K2 #2268
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
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> Please help support this email list: http://www.qsl.net/donate.html

Don Wilhelm-4

Re: securing toroids in K2, why not?

In reply to this post by R Thompson

Ron,

Not diminishing your field experience, but speaking only from my
experience with the K2 ...

Consider in the case of the K2, the engineer's decisions have been
scrubbed by first the Field Testers - ranging from experienced builders
(including other engineers) to those who are building a kit for the
first time - plus 12 years of positive customer experience.

That covers a LOT of field experience. I have been with the K2
experience for 12 years now (yes, I am an electrical engineer and
understand the design), and have found that the design decisions of the
K2 designers have been correct for the most part. Any minor problems
have been worked out between the designers and the testers and
customers. The K2 is a mature product, and all the bugs have been
worked out - I challenge you to find a new one (but if you do, it will
be definitely addressed). The K2 designer(s) have had a goodly share of
field experience themselves, plus a lot of prior successful transceiver
designs. Wayne Burdick designed the Wilderness Sierra and several other
successful transceivers before embarking on the K2 journey.
Transceivers that are still held in high esteem many years later.

I am quite familiar with the "pride of the designer" syndrome, having
spent 14 years of my professional career evaluating products prior to
announcement for a large corporation. My task was to assure that the
product met its specifications, and was achieved through extensive
testing under extreme conditions. Many products did not make the
grade, but others were modified as a result of the efforts of my test
team in order to provide the customer with a product that worked as
specified. In other words, I am well experienced in evaluating product
designs as well as creating test procedures to verify and support the
product. I can say that the K2 meets its specifications without
embellishment.

Again, there is no need to apply any fixatives to the K2 (or K1 or KX1)
toroids, If you prefer conformal coating, so be it, but understand that
it is at your own peril - some techniques could void your warranty. The
instructions to produce a working K2 are in the manual. Follow them,
and do not add or subtract anything, and you will be rewarded with a
very good transceiver - 12 years of experience by both testers and
customers is behind your efforts, and it is all documented in the manual.

73,
Don W3FPR

On 7/2/2011 11:12 PM, R Thompson wrote:

> Hi Jim,
>
> I've worked on aircraft for over 30 years and know what engineers can
> do :-) There are many airworthiness directives issued after the
> engineers have finished their work. I'd better not get something
> started, as I really do appreciate the work of the engineers. More
> field experience would help some of them.
>
> Ron VE8RT
>
> On Sat, 2011-07-02 at 22:47 -0400, Jim Campbell wrote:
>> Reminds me of a story that I heard years ago while on an assignment in
>> England.
>>
>> Seems that the Rolls Royce company didn't have an automatic transmission
>> in their cars. Since automatic transmissions were the up-and-coming
>> thing they decided that they needed one to offer in the Roolls Royce.
>> Rather than design one from scratch they surveyed the field and decided
>> that the best of breed was one made by General Motors. They entered into
>> an agreement with GM to use theirs.
>>
>> They took a GM automatic transmission into their shop and tore it down
>> completely. They wanted any transmission that was going into a Rolls
>> Royce to be top quality, inside and out. Everything passed muster
>> except for one part. It had a rough surface. That just wouldn't do so
>> they machined the surface to a Rolls Royce standard. The trouble was
>> that when the transmission was assembled it wouldn't work. They
>> contacted GM and found out that the surface in question had to be rough
>> or the transmission wouldn't work.
>>
>> Best to trust the judgment of the design engineers.
>>
>> 72,
>>
>> Jim - W4BQP
>> K2 #2268
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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> Post: mailto:[hidden email]
>
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