Unsolderable wire?

[Bob E.]

I am trying to solder some RG-6 shield to a pcb. The braid won't tin. It's
almost like it's dissipating the heat faster than I can apply it. With both a
temp-controlled iron (set as high as 700F) and a mondo 100W stick I finally
tried. The solder will barely melt when touched to the braid opposite the
iron.

I've applied some Kester rosin paste flux as well using my trusty Kester
60/40 lead-based rosin core solder. No joy. I'm not holding the braid against
the PCB now, I'm just trying to tin the braid and then deal with melting the
2 solders (on the PCB and the braid) together later.

My first attempt--before I realized that I was overheating it--I melted the
dielectric insulation.

The mesh is made from some silver-colored braid which I thought is tinned
copper but now I'm of the opinion that it's steel; it's certainly not
aluminum. There is also foil which is probably aluminum but I've trimmed that
back and it's not part of this frustrating process right now.

What's the trick to getting this braid to take solder? I've never seen this
before.

Thanks.

[Spehro Pefhany]

If it's like this cr*p they sell at Home Despot, it's copper clad
steel core with an _aluminum_ braid shield:-

http://www.cerrowire.com/files/file/49223_CERRO_CoaxialCable_6U_QUADLR.pdf

That would explain the copper-like heat conduction that you're
observing.

I suppose you could try an aluminum flux, but can't you just unravel
and gather enough of the shield to crimp into a ring terminal or
something?



Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
sp...@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

[Michael A. Terrell]

It's not made to be soldered. It's CATV cable that's made for crimp
on 'F' fittings.

--
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.

[Phil Allison]

"Bob E."

>
> The mesh is made from some silver-colored braid which I thought is tinned
> copper but now I'm of the opinion that it's steel; it's certainly not
> aluminum.

** A magnet will pick up steel wire - but no Aluminium.

> What's the trick to getting this braid to take solder?

** Unplated steel or Aluminium wires are not solderable by ordinary means.




.... Phil

[Tom Biasi]

Twist the braid into a wire and butt splice on a copper wire. Heat
shrink over it.

[Bob E.]

Yes it's that crap.

> I suppose you could try an aluminum flux, but can't you just unravel
> and gather enough of the shield to crimp into a ring terminal or
> something?

Yeah, that's my next move. I just couldn't believe that something couldn't be
soldered. I guess REALLY agressive flux is required, as you say.

When it comes to broadcast TV I try to solder every connection possible.
Every crimp is one more dB lost.

Thanks.

Crimps in hand...

[Spehro Pefhany]

I guess there's always better stuff like this:-

http://nordencommunication.com/download?file=1460-RG_6u.pdf

[Michael A. Terrell]

You must do lousy crimping, if you lose a dB.

[cjt]

I would have thought every soldered joint is one more reflection.

[Bob E.]

>> When it comes to broadcast TV I try to solder every connection possible.
>> Every crimp is one more dB lost.

I'm no RF expert, just my impression--possibly mistaken.

Thanks.

[Michael A. Terrell]

The loss should be under .1 dB for a good F connector, ant they are
used into the GHz range.

[John Fields]

On Sat, 18 Jan 2014 20:22:18 -0800, Bob E. <bes...@invalid.tv>
wrote:

---
Use crimp ferrules.

http://www.te.com/catalog/feat/en/c/10028

11.5 at:

http://snebulos.mit.edu/projects/reference/NASA-Generic/NASA-STD-8739-4.pdf

JF

[Jasen Betts]

On 2014-01-19, Bob E <bes...@invalid.tv> wrote:
> I am trying to solder some RG-6 shield to a pcb.

> The mesh is made from some silver-colored braid which I thought is tinned
> copper but now I'm of the opinion that it's steel; it's certainly not
> aluminum. There is also foil which is probably aluminum but I've trimmed that
> back and it's not part of this frustrating process right now.

yeah stainless steel braid, aluminium shield and a copper-plated steel
core. most of the RG6 I've used is like that.

a solderable F connector socket is probably the best way to terminate it.

> What's the trick to getting this braid to take solder?

Give up! If you can't give up spot weld it to some tinned copper.

--
For a good time: install ntp

--- news://freenews.netfront.net/ - complaints: ne...@netfront.net ---

[Syd Rumpo]

If it's for personal use, tightly wrap a dozen turns of tinned copper
wire (or silver plated) around the braid, twist the end together and
solder to these.

Cheers
--
Syd

[William Sommerwerck]

"Spehro Pefhany" wrote in message
news:v8lmd9tfpopj1kuv7...@4ax.com...

> If it's like this cr*p they sell at Home Despot, it's copper-
> clad steel core with an _aluminum_ braid shield.

Aluminum is a poor choice for a crimped connection. Remember the problems with
household aluminum wiring -- even when it was screwed down?

[Maynard A. Philbrook Jr.]

In article <0001HW.CF0092FA...@news.eternal-september.org>,
bes...@invalid.tv says...

Electroplated wire, most likely nickel.

Jamie

[Tim Williams]

Well, what does it feel like?

Steel wire feels very stiff. Grab a leaded component out of the box and
ponder the leads; they're probably tin plated steel (check with a magnet).
Most resistors, capacitors and diodes are. Some smaller ceramic caps have
thicker, softer copper leads; find some if you can.

Aluminum wire is very soft, floppy stuff. It is much softer than copper,
than copper is of steel. If that's what it is... oh well.

As for soldering practice... the old saw about "apply solder to the
opposite side of the joint" is complete BS. Forget about it. Don't try
soldering as you were told, make the solder happy and good joints will
follow. First goal, get the part hot: hold the iron on the part, and
apply solder right beside the iron, or to it, so the iron heats and wets
what it's touching. On a braid, solder will spread and soon the joint
will accept solder from all sides.

Tim

--
Seven Transistor Labs
Electrical Engineering Consultation
Website: http://seventransistorlabs.com

"Bob E." <bes...@invalid.tv> wrote in message
news:0001HW.CF0092FA...@news.eternal-september.org...

[dave]

A solder pot is preferred. Otherwise burn all the non-metallic weirdness
away with your trusty Zippo.

[Baron]

Michael A. Terrell scribbled thus:

>
> "Bob E." wrote:
>>
>> Yes it's that crap.
>>
>> > I suppose you could try an aluminum flux, but can't you just
>> > unravel and gather enough of the shield to crimp into a ring
>> > terminal or something?
>>
>> Yeah, that's my next move. I just couldn't believe that something
>> couldn't be soldered. I guess REALLY agressive flux is required, as
>> you say.
>>
>> When it comes to broadcast TV I try to solder every connection
>> possible. Every crimp is one more dB lost.
>
>
> You must do lousy crimping, if you lose a dB.
>

I agree ! A good crimp is at least as good as the best solder joint.

--
Best Regards:
Baron.

[Phil Hobbs]

On 1/19/2014 2:30 AM, Michael A. Terrell wrote:
>
> "Bob E." wrote:
>>
>>>> When it comes to broadcast TV I try to solder every connection possible.
>>>> Every crimp is one more dB lost.
>>
>> I'm no RF expert, just my impression--possibly mistaken.
>
>
> The loss should be under .1 dB for a good F connector,

^^^^^^^^^^^^^^^^
Jumbo shrimp alert. ;)

Cheers

Phil Hobbs


--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

[Jeff Liebermann]

On Sat, 18 Jan 2014 20:50:34 -0800, Bob E. <bes...@invalid.tv> wrote:

>When it comes to broadcast TV I try to solder every connection possible.
>Every crimp is one more dB lost.

100% of the RF connectors I use for mountain top radio sites that I
deal with are crimped, not soldered. Well, maybe a few soldered
abominations such as PL-259 connectors.

The losses per connector are quite low. For example, here's a string
of random adapters:
<http://www.learnbydestroying.com/jeffl/antennas/connector-loss/slides/Adapter%20Colluge.html>
<http://www.learnbydestroying.com/jeffl/antennas/connector-loss/>
That's about 15 assorted adapters (30 connections) showing 2dB loss at
2.4 GHz or:
2dB / 30 = 0.07 dB loss per connection.
Unless you're working with high power levels, the connector loss is
not a problem.

Unless you're working with microwave frequencies, mismatch loss is
also not much of a problem. For example, if you insert a section of
75 ohm coaxial cable into your system, a TDR would certainly show an
impedance bump far larger than what might be produced by a solder
blob. However, the losses are fairly trivial. Much depends on the
frequency of operation. If you're doing microwave, then precision is
required. If you're doing lower frequencies, you can be fairly sloppy
and things will still work quite well.

Cut-n-pasted from my previous rant on the topic from
rec.radio.amateur.antenna.

Let's pretend that I mix in a 75 ohm coax connector into a
50 ohm system. Depending on the location of this "impedance bump",
the VSWR is no more than 1.5:1 which is generally considered marginal.
That's 0.18dB of mismatch loss.
<http://www.microwaves101.com/encyclopedia/calvswr.cfm>
If you're doing satellite or microwave DX work, then 0.18dB might be
important. However, for most other applications, it's a trivial
amount.

You might be amused to know that most of my rooftop antennas are fed
with 75 ohm coax and that my favored antenna designs are also 75 ohm.
There are various reasons, but the main one is that coax cable losses
are less at 75 ohms, than at 50 ohms. 50 ohms can handle more power,
but 75 ohms has less loss.
<http://www.belden.com/blog/broadcastav/50-Ohms-The-Forgotten-Impedance.cfm>
The only problems I have with 75 ohms is finding the proper connectors
and dealing with the pads needed to make my 50 ohm test equipment look
like 75 ohms. (Actually the real reason is that the 75 ohm stuff is
mostly CATV surplus, which tends to be really cheap).

More:
<http://www.qsl.net/n9zia/wireless/75_ohm_hardline.html>

--
Jeff Liebermann je...@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

[Bob E.]

> 100% of the RF connectors I use for mountain top radio sites that I
> deal with are crimped, not soldered.

This is where the original short length of RG6 was soldered to the pcb
antenna. It's an inexpensive broadcast TV antenna for home.

Rather than make a male crimp plus a barrel to join the 2 mailes, just solder
the long run directly to the pcb. Or so I thought...

I crimped 1/2" of center solid conductor to the braid and soldered the solid
to the pcb. It seems to work but I have no way to measure any loss. I plan to
replace this when I find some REAL copper RG6.

Thanks.

[Phil Allison]

"Maynard A. Philbrook Jerkoff."

> Electroplated wire, most likely nickel.

** But nickel plated stuff solders beautifully.

Jack plugs and sockets, DC plugs etc.


.... Phil

[Jeff Liebermann]

On Sun, 19 Jan 2014 16:01:53 -0800, Bob E. <bes...@invalid.tv> wrote:

>> 100% of the RF connectors I use for mountain top radio sites that I
>> deal with are crimped, not soldered.

>This is where the original short length of RG6 was soldered to the pcb
>antenna. It's an inexpensive broadcast TV antenna for home.

Thank you for disclosing what you're trying to accomplish. Context is
always important.

You're going to have corrosion problems. Note that all the
aforementioned crimped connectors have the crimped area sealed inside
the connector. In addition, they are usually wrapped in some form of
waterproofing (i.e. PTFE tape and electrical tape) to keep out the
water. Even if you solder the connections, the capillary action is
going to force the water up the braid and under the jacket. Depending
on the outer jacket slop, corrosion will rot up to several inches of
braid. You can try to seal the braid and solder connections with RTV
silicon rubber that doesn't contain acetic acid but I haven't had much
luck with that.

Using bare wires from the end of a coax cable is about as bad an
impedance bump as you can possibly create. However, it won't matter
for a TV antenna, that has wide bandwidth, but relatively little gain.
PCB TV antennas tend to be rather small, and therefore have even less
gain. Impedance discontinuities will not have a huge effect on
overall performance. Therefore, you can probably just attach some
spade lugs onto the ends of the RG-6/u coax, and use ordinary brass
screws and nuts to make the connection.

>Rather than make a male crimp plus a barrel to join the 2 mailes, just solder
>the long run directly to the pcb. Or so I thought...
>
>I crimped 1/2" of center solid conductor to the braid and soldered the solid
>to the pcb. It seems to work but I have no way to measure any loss. I plan to
>replace this when I find some REAL copper RG6.

If you have a PCB, why not use a PCB mounted F connector?
<http://www.ebay.com/itm/111244951312>
<http://www.ebay.com/itm/261373960762>

I tried to find such a coax cable from my distant past. It had a
copper clad steel center conductor, aluminum foil shield, and a very
loose braid of flash galvanized steel wire braid over the shield. The
braid was only for strength and not for shielding. The zinc plating
was for galvanic compatibility with the aluminum shield. Such a cable
was not intended to be soldered, only crimped. I saw it at STV
(subscription TV) in Smog Angeles in the 1960's. However, I couldn't
find it which suggests that it's either uncommon, not in current
production, or my memory is faulty.

It would be helpful if you could provide any markings on your cable so
that it can be identified.

[Bob E.]

> Thank you for disclosing what you're trying to accomplish. Context is
> always important.
>
> You're going to have corrosion problems.

Continuing disclosure: it's indoors, wall-mounted.

> If you have a PCB, why not use a PCB mounted F connector?
> <http://www.ebay.com/itm/111244951312>
> <http://www.ebay.com/itm/261373960762>

It was my call (based on almost no RF expertise) that any solder connection
was much better than the best crimp and that crimps are used strictly for
convenience. I'm beginning to doubt these presumptions...

> It would be helpful if you could provide any markings on your cable so
> that it can be identified.

<http://www.cables.com/Products/92003.aspx>

Thanks.

PS, a police helicopter just flew over the neighborhood at a few hundred
feet. The digital channel I was watching blanked out completely. This at
about 50 miles from the broadcast site, as the crow files (Sutro Tower).

[Jeff Liebermann]

On Sun, 19 Jan 2014 20:35:10 -0800, Bob E. <bes...@invalid.tv> wrote:

>> Thank you for disclosing what you're trying to accomplish. Context is
>> always important.
>>
>> You're going to have corrosion problems.
>
>Continuing disclosure: it's indoors, wall-mounted.

Ok. You won't need to deal with anti-corrosion precautions.

>> If you have a PCB, why not use a PCB mounted F connector?
>> <http://www.ebay.com/itm/111244951312>
>> <http://www.ebay.com/itm/261373960762>
>
>It was my call (based on almost no RF expertise) that any solder connection
>was much better than the best crimp and that crimps are used strictly for
>convenience. I'm beginning to doubt these presumptions...

I consider crimping better than soldering mostly because soldering
requires some skill, but crimping can be learned by almost anyone.
With ratcheting crimpers, it is possible to guarantee that the degree
of compression is both sufficient and uniform. Crimp and compression
connectors also will survive the SCTE IPS-TP-401 40 lb pull test,
while soldered connectors often fail this test. In general, crimp and
compression connectors are much better at keeping water out. I've
seen much better reliability after switching to crimp type connectors.
They're also cheaper. I can't think of a single advantage to soldered
RF connectors.

>> It would be helpful if you could provide any markings on your cable so
>> that it can be identified.
>
><http://www.cables.com/Products/92003.aspx>

Bingo. Aluminum braid over aluminum foil shield. You can't solder to
the aluminum. Find a different cable with a copper braid (or use a
connector as I previously suggested).

>PS, a police helicopter just flew over the neighborhood at a few hundred
>feet. The digital channel I was watching blanked out completely. This at
>about 50 miles from the broadcast site, as the crow files (Sutro Tower).

Can I guess(tm)? I don't think the helicopter is large enough to
complete block out the signal unless the TV station signal strength
from Mt Sutro to your PCB antenna is rather weak. That's about what I
would expect at 50 miles with a small PCB TV indoor antenna. Digital
is ummm... digital and tends to deliver either a very good picture, or
nothing. At 50 miles, I would have recommended a bigger, better and
possibly amplified (to compensate for the coax cable losses) antenna.
You might want to check your location with:
<http://www.tvfool.com>
to see if the indoor PCB antenna is adequate, and if a bigger antenna
will be of any benefit. Otherwise, the police helicopter might have
been transmitting video on some frequency to the ground which
overloaded your TV receiver front end.

[Phil Allison]

"Bob E."

>
> PS, a police helicopter just flew over the neighborhood at a few hundred
> feet. The digital channel I was watching blanked out completely. This at
> about 50 miles from the broadcast site, as the crow files (Sutro Tower).

** Low flying aircraft tend to do that ...

Just like a nearby metal structure causing "ghost" images, they produce
strong reflections of the transmitted signal so your antenna gets two
similar strength signals, one of them delayed by a few microseconds.

This is often enough to seriously corrupt the wanted signal so large amounts
of data are lost.

End result, the pic freezes or pixellates crazily.

Bad luck if you live near a major airport and rely on an off air signal.


... Phil

[Bob E.]

> I've
> seen much better reliability after switching to crimp type connectors.
> They're also cheaper. I can't think of a single advantage to soldered
> RF connectors.

Of course I agree re. connectors. In my situation the original (short) coax
was soldered to the pcb. I thought that duplicating this connection when
replacing with a longer run of coax was better (re. loss) than introducing
connectors. Soldering F (or other) connectors vs. crimps, I agree: a
nightmare.

Thanks.

[Bob E.]

> Bad luck if you live near a major airport and rely on an off air signal.
> ... Phil

Just the PD "serving and protecting".

Thanks.

[Michael A. Terrell]

Phil Hobbs wrote:
>
> On 1/19/2014 2:30 AM, Michael A. Terrell wrote:
> >
> > "Bob E." wrote:
> >>
> >>>> When it comes to broadcast TV I try to solder every connection possible.
> >>>> Every crimp is one more dB lost.
> >>
> >> I'm no RF expert, just my impression--possibly mistaken.
> >
> >
> > The loss should be under .1 dB for a good F connector,
> ^^^^^^^^^^^^^^^^
> Jumbo shrimp alert. ;)

There are good ones, but you won't buy them at retail stores.

[Michael A. Terrell]

The loss is horrible in copper braided coax at TV frequencies. The
cost is excessive, as well. 'Headend cable' used to be silver plated
copper braided coax, but that was abandoned for foil & drain when
headends passed 216 MHz. That silver plated coax was over a dollar a
foot, in the '70s.

[Tim Williams]

"Phil Allison" <phi...@tpg.com.au> wrote in message
news:bk38f3...@mid.individual.net...

>> Electroplated wire, most likely nickel.
>
> ** But nickel plated stuff solders beautifully.
>
> Jack plugs and sockets, DC plugs etc.

I have some mil spec, high-temp wire that's nickel plated. Beautiful
stuff, strands wound in layers. It takes an unusually high temperature
and a long time before the solder wets and soaks into it. It does tin,
but I wouldn't say it solders "beautifully", not with ordinary fluxes.

[Phil Allison]

"Tim Williams - Wanker & TROLL"

>
>> ** But nickel plated stuff solders beautifully.
>>
>> Jack plugs and sockets, DC plugs etc.
>
> I have some mil spec, high-temp wire that's nickel plated.

** Yaaaawnnnnnnnnnnnnnn....

You have a monstrous, AUTISTIC brain too.............

> It takes an unusually high temperature and a long time before the solder
> wets and soaks into it. It does tin, but I wouldn't say it solders
> "beautifully", not with ordinary fluxes.

** Watch:

https://www.youtube.com/watch?v=73R7eXxjo34

Pure nickel, plated onto brass.

Solders like a dream.

Fuck knows what fucking shit you have.

Asshole .



... Phil

[Kennedy]

On 20/01/2014 7:38 PM, Phil Allison wrote:
> "Tim Williams - Wanker & TROLL"
>
>

Was I the only one to see this predictable response coming & get a
giggle out of it?

[Phil Allison]

"Kennedy = Kunt "


FOAD - you stinking autistic MORON

[Kennedy]

On 20/01/2014 6:18 PM, Tim Williams wrote:
> "Phil Allison" <phi...@tpg.com.au> wrote in message
> news:bk38f3...@mid.individual.net...
>>> Electroplated wire, most likely nickel.
>>
>> ** But nickel plated stuff solders beautifully.
>>
>> Jack plugs and sockets, DC plugs etc.
>
> I have some mil spec, high-temp wire that's nickel plated. Beautiful
> stuff, strands wound in layers. It takes an unusually high temperature
> and a long time before the solder wets and soaks into it. It does tin,
> but I wouldn't say it solders "beautifully", not with ordinary fluxes.
>
> Tim
>

Interesting table:

http://www.efunda.com/materials/solders/solderability.cfm

[Kennedy]

On 20/01/2014 7:45 PM, Phil Allison wrote:
>
> "Kennedy = Kunt"
>
>
> FOAD - you stinking autistic MORON
>

Settle down Phil, one day you're going to blow a gasket! :)

[Phil Allison]

"Kennedy = Kunt"


FOAD - you stinking, pig ignorant, autistic MORON

[Phil Allison]

"Kennedy"

> Interesting table:
>
> http://www.efunda.com/materials/solders/solderability.cfm


** Shame it is quite wrong.

As anyone with REAL experience of soldering knows.

What is your experience ?

Other than child molesting, that is.

[DecadentLinuxUserNumeroUno]

On Mon, 20 Jan 2014 19:43:02 +0800, Kennedy <ken...@fakemail.com> Gave
us:

T. W. == W & T


Naaaaahhh!!!

He has smarts.

[DecadentLinuxUserNumeroUno]

On Mon, 20 Jan 2014 22:45:27 +1100, "Phil Allison" <phi...@tpg.com.au>
Gave us:

>
>"Kennedy = Kunt "
>
>
>FOAD - you stinking autistic MORON

You must be Japanese...

Phil Allison == Assholeson Phil

Hardly had to change a thing.

[JW]

On Mon, 20 Jan 2014 22:50:08 +1100 "Phil Allison" <phi...@tpg.com.au>
wrote in Message id: <bk4grc...@mid.individual.net>:

>
> "Kennedy = Kunt"
>
>
> FOAD - you stinking, pig ignorant, autistic MORON

Do you kiss your mother's quim with that mouth?

[dave]

On 01/19/2014 10:48 PM, Michael A. Terrell wrote:
>
> Phil Hobbs wrote:
>>
>> On 1/19/2014 2:30 AM, Michael A. Terrell wrote:
>>>
>>> "Bob E." wrote:
>>>>
>>>>>> When it comes to broadcast TV I try to solder every connection possible.
>>>>>> Every crimp is one more dB lost.
>>>>
>>>> I'm no RF expert, just my impression--possibly mistaken.
>>>
>>>
>>> The loss should be under .1 dB for a good F connector,
>> ^^^^^^^^^^^^^^^^
>> Jumbo shrimp alert. ;)
>
>
> There are good ones, but you won't buy them at retail stores.
>
>

Use Snap-N-Seal type F-connectors. They are moisture proof and
positively crimp correctly.

[dave]

On 01/19/2014 10:53 PM, Michael A. Terrell wrote:
>
> "Bob E." wrote:
>>
>>> 100% of the RF connectors I use for mountain top radio sites that I
>>> deal with are crimped, not soldered.
>>
>> This is where the original short length of RG6 was soldered to the pcb
>> antenna. It's an inexpensive broadcast TV antenna for home.
>>
>> Rather than make a male crimp plus a barrel to join the 2 mailes, just solder
>> the long run directly to the pcb. Or so I thought...
>>
>> I crimped 1/2" of center solid conductor to the braid and soldered the solid
>> to the pcb. It seems to work but I have no way to measure any loss. I plan to
>> replace this when I find some REAL copper RG6.
>
>
> The loss is horrible in copper braided coax at TV frequencies. The
> cost is excessive, as well. 'Headend cable' used to be silver plated
> copper braided coax, but that was abandoned for foil & drain when
> headends passed 216 MHz. That silver plated coax was over a dollar a
> foot, in the '70s.
>

The easiest way to spot good headend cable was to try to bend it. It
drapes, like mic cable; not stiff.

My ham radio antennas are all 50 Ohm designs, but I do cheat on the
receive loops and repurpose old Echostar cable around the house.

[dave]

On 01/20/2014 02:18 AM, Tim Williams wrote:
> "Phil Allison" <phi...@tpg.com.au> wrote in message
> news:bk38f3...@mid.individual.net...
>>> Electroplated wire, most likely nickel.
>>
>> ** But nickel plated stuff solders beautifully.
>>
>> Jack plugs and sockets, DC plugs etc.
>
> I have some mil spec, high-temp wire that's nickel plated. Beautiful
> stuff, strands wound in layers. It takes an unusually high temperature
> and a long time before the solder wets and soaks into it. It does tin,
> but I wouldn't say it solders "beautifully", not with ordinary fluxes.
>
> Tim
>

I have a Hakko station with 50 Watts max power. I also have a Weller
150W gun. And an old Radio-Shack Ungar 45 W for the occasional
emergency. There are situations where The Weller gun comes in handy,
when the other 2 don't get hot enough. Failing all 3, we have the trusty
Bernz-O-Matic.

[dave]

On 01/20/2014 03:45 AM, Phil Allison wrote:
>
> "Kennedy = Kunt"
>
>
> FOAD - you stinking autistic MORON
>

There are 2 of us? And only one of you? Pretty brave man calling people
names from across cyberspace. You kiss your mama with that mouth?

[Syd Rumpo]

On 20/01/2014 10:18, Tim Williams wrote:
> "Phil Allison" <phi...@tpg.com.au> wrote in message
> news:bk38f3...@mid.individual.net...
>>> Electroplated wire, most likely nickel.
>>
>> ** But nickel plated stuff solders beautifully.
>>
>> Jack plugs and sockets, DC plugs etc.
>
> I have some mil spec, high-temp wire that's nickel plated. Beautiful
> stuff, strands wound in layers. It takes an unusually high temperature
> and a long time before the solder wets and soaks into it. It does tin,
> but I wouldn't say it solders "beautifully", not with ordinary fluxes.
>
> Tim

I have some Nickel plated copper wire - single core - which I bought
believing it to be tinned copper. It doesn't wet well with my ancient
'non corrosive flux' Multicore 60/40.

A touch of flux and it solders beautifully.

Cheers
--
Syd

[Phil Hobbs]

I don't have TV at home, and there's no way I'd use F connectors for
anything but entertainment.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

[Jeff Liebermann]

On Mon, 20 Jan 2014 11:10:46 -0500, Phil Hobbs
<pcdhSpamM...@electrooptical.net> wrote:

>On 01/20/2014 08:46 AM, dave wrote:
>> Use Snap-N-Seal type F-connectors. They are moisture proof and
>> positively crimp correctly.

>I don't have TV at home, and there's no way I'd use F connectors for
>anything but entertainment.
>Cheers
>Phil Hobbs

Ok, I'll bite. What's wrong with F-connectors? There are zillions
installed on indoor and outdoor CATV installations with no failures or
issues. Certainly there are connectors with better specifications,
but for the intended purpose and cost ($0.30/ea), F-connectors are
more than adequate. The only real problem I've found is the wide
variety of cables claiming to be RG-6/u. Making a connector that will
fit all these RG-6/u mutations is tricky, but T&B has done a decent
job with their "red" SNS1P6U Snap-N-Seal connectors:
<http://www.ebay.com/itm/221344116756>

So, what's wrong with F-connectors and what would you recommend the
CATV industry use instead?

[Michael A. Terrell]

Phil Hobbs wrote:
>
> I don't have TV at home, and there's no way I'd use F connectors for
> anything but entertainment.

That's your choice. I can't help that you are absolutely clueless
about the technology. There are millions of miles of Rg/6 with F
fittings used into the UHF range outdoors with a very low failure rate,
and lower leakage than some BNC connectors. If they were crap, they
wouldn't be allowed to use aircraft and commercial two way frequencies.
A couple bad connections in a cable system can shut down an airport, or
the local fire and PD.

[Michael A. Terrell]

dave wrote:
>
> The easiest way to spot good headend cable was to try to bend it. It
> drapes, like mic cable; not stiff.

The easiest way was to look at the imprint: 'Belden headend cable'.

[Michael A. Terrell]

Phil always advertises that he's a troll.

[Michael A. Terrell]

Why put it off? Who would mourn?

[Phil Hobbs]

On 01/20/2014 12:49 PM, Jeff Liebermann wrote:
> On Mon, 20 Jan 2014 11:10:46 -0500, Phil Hobbs
> <pcdhSpamM...@electrooptical.net> wrote:
>
>> On 01/20/2014 08:46 AM, dave wrote:
>>> Use Snap-N-Seal type F-connectors. They are moisture proof and
>>> positively crimp correctly.
>
>> I don't have TV at home, and there's no way I'd use F connectors for
>> anything but entertainment.
>> Cheers
>> Phil Hobbs
>
> Ok, I'll bite. What's wrong with F-connectors? There are zillions
> installed on indoor and outdoor CATV installations with no failures or
> issues. Certainly there are connectors with better specifications,
> but for the intended purpose and cost ($0.30/ea), F-connectors are
> more than adequate. The only real problem I've found is the wide
> variety of cables claiming to be RG-6/u. Making a connector that will
> fit all these RG-6/u mutations is tricky, but T&B has done a decent
> job with their "red" SNS1P6U Snap-N-Seal connectors:
> <http://www.ebay.com/itm/221344116756>
>
> So, what's wrong with F-connectors and what would you recommend the
> CATV industry use instead?
>

If the CATV industry likes them, well, I'm happy they're happy.
Instrument use is quite a different regime. F connectors use the centre
conductor of the coax as the contact, and are very susceptible to damage
with repeated mating cycles. The ones I've seen are also fairly far
from constant-impedance.

BNCs and SMAs for me.

[Tim Williams]

"DecadentLinuxUserNumeroUno" <DL...@DecadentLinuxUser.org> wrote in message
news:ap5qd95f2cprv181v...@4ax.com...

>>> "Tim Williams - Wanker & TROLL"
>>>
>>
>>Was I the only one to see this predictable response coming & get a
>>giggle out of it?
>
> T. W. == W & T
>
>
> Naaaaahhh!!!
>
> He has smarts.

Smarts? I'll have you know I've been called worse!

Tim (only an asshole on the internet)

[Jeff Liebermann]

On Mon, 20 Jan 2014 16:13:00 -0500, Phil Hobbs

<pcdhSpamM...@electrooptical.net> wrote:

>On 01/20/2014 12:49 PM, Jeff Liebermann wrote:
>> On Mon, 20 Jan 2014 11:10:46 -0500, Phil Hobbs
>> <pcdhSpamM...@electrooptical.net> wrote:
>>
>>> On 01/20/2014 08:46 AM, dave wrote:
>>>> Use Snap-N-Seal type F-connectors. They are moisture proof and
>>>> positively crimp correctly.
>>
>>> I don't have TV at home, and there's no way I'd use F connectors for
>>> anything but entertainment.
>>> Cheers
>>> Phil Hobbs
>>
>> Ok, I'll bite. What's wrong with F-connectors? There are zillions
>> installed on indoor and outdoor CATV installations with no failures or
>> issues. Certainly there are connectors with better specifications,
>> but for the intended purpose and cost ($0.30/ea), F-connectors are
>> more than adequate. The only real problem I've found is the wide
>> variety of cables claiming to be RG-6/u. Making a connector that will
>> fit all these RG-6/u mutations is tricky, but T&B has done a decent
>> job with their "red" SNS1P6U Snap-N-Seal connectors:
>> <http://www.ebay.com/itm/221344116756>
>>
>> So, what's wrong with F-connectors and what would you recommend the
>> CATV industry use instead?

>If the CATV industry likes them, well, I'm happy they're happy.

The CATV industry is never happy. If it were happy, innovation would
cease and the status quo would become permanent.

>Instrument use is quite a different regime. F connectors use the centre
>conductor of the coax as the contact, and are very susceptible to damage
>with repeated mating cycles. The ones I've seen are also fairly far
>from constant-impedance.

I believe that I mumbled something about "for the intended purpose". I
don't think anyone uses F-connectors for precision test equipment.
They're not really good enough. Looking at the pile, most of my CATV
specific test equipment uses BNC connectors. However, that's not
because the F-connector is in some way electrically inferior. It's
because the F-connector receptacles were not designed to survive
repeated insertion/removal cycles. The few that have built in
F-connectors allow for easy replacement, such as my Wavetek SAM-1000
which uses a panel mounted F barrel adapter.

The F-connector is certainly not constant impedance. On a TDR, the
bump is rather obvious. Yet, some cable and connector combinations
are rated and tested to 4.5GHz:
<http://www.tselectronic.com/shop/product/1694A-Belden-4.5GHz-RG6-U-Precision-Video-Cable-for-Analog-and-Digital-Applications/1026>
The recommended connectors are T&B SNS1P6 or FSNS6U compression
F-connectors.

I partly agree with you about center conductor problems. I assume
that you're referring to the copper plated steel center conductor,
found in most cheap RG-6/u cables, which is not intended for repeated
insertion/extraction cycles. Still, the rating is 500
insertion/extraction cycles minimum. The copper will eventually
scrape off. However, solid copper center conductor RG-6/u (such as
Belden 1694A) works quite nicely, without any damage. I couldn't find
a spec for insertion/extraction cycles for 1694A.

>BNCs and SMAs for me.

Crimp or compression plugs, in quantities of 100 on eBay:
F-connector $0.30/ea
SMA male $0.70/ea
BNC male $1.00/ea
For test equipment, the price difference is not enough to justify
using the cheapest. For CATV, which consumes connectors by the
millions, every penny counts.

Thanks.

>Cheers
>Phil Hobbs

[Jeff Liebermann]

On Mon, 20 Jan 2014 15:42:19 -0500, "Michael A. Terrell"
<mike.t...@earthlink.net> wrote:

> The easiest way was to look at the imprint: 'Belden headend cable'.

Which end is the head? (Sorry, I couldn't resist).

[Phil Hobbs]

Sure, horses for courses. I'm not telling them how to run their lives,
because I couldn't care less about their lives. ;) (Well, as
individuals, sure, but as for the industry, if CATV went away completely
tomorrow, it would suit me fine--provided only that they took their
tarts and talking heads with them.)

[Jeff Liebermann]

I assure you that the selection of RF connector will have no effect on
CATV content quality. I like the tarts, but can do without the
talking heads.

For what little it's worth, I didn't own a TV for about 15 years.
Except for being somewhat culturally deprived, I didn't miss TV in the
slightest. However, I then picked up a contract to review some
technical videos and needed a TV and VCR to play them. I soon found
myself watching broadcast TV, buying DVD's, putting together a media
center, subscribing to DirecTV, Netflix, etc. Today, I find that I
can't sleep without the TV running. I'm now watching a 1931 Boris
Karloff movie as I type. I'm addicted.

Hint: Don't judge connectors by the content they carry.

[Phil Hobbs]

On 1/20/2014 8:41 PM, Jeff Liebermann wrote:
> On Mon, 20 Jan 2014 18:55:56 -0500, Phil Hobbs
> <pcdhSpamM...@electrooptical.net> wrote:
>
>> Sure, horses for courses. I'm not telling them how to run their lives,
>> because I couldn't care less about their lives. ;) (Well, as
>> individuals, sure, but as for the industry, if CATV went away completely
>> tomorrow, it would suit me fine--provided only that they took their
>> tarts and talking heads with them.)
>> Cheers
>> Phil Hobbs
>
> I assure you that the selection of RF connector will have no effect on
> CATV content quality. I like the tarts, but can do without the
> talking heads.

Nah, sufficiently crappy connectors could improve the content a lot. ;)

[Michael A. Terrell]

Jeff Liebermann wrote:
>
> On Mon, 20 Jan 2014 15:42:19 -0500, "Michael A. Terrell"
> <mike.t...@earthlink.net> wrote:
>
> > The easiest way was to look at the imprint: 'Belden headend cable'.
>
> Which end is the head? (Sorry, I couldn't resist).

If you have to ask, you aren't qualified for the job. :)

The entire system of amplifiers is marked as Forward or Reverse so
just follow the reverse path to the head end. Unless it's Fiber enhanced
CATV.

[dave]

On 01/20/2014 12:42 PM, Michael A. Terrell wrote:
>
> dave wrote:
>>
>> The easiest way to spot good headend cable was to try to bend it. It
>> drapes, like mic cable; not stiff.
>
>
> The easiest way was to look at the imprint: 'Belden headend cable'.
>
>

It's easier to find in the dark if you feel for it. I knew a lot of CATV
people, including the Chief Head End Technician at Time Warner in
Houston; and we prized the supple stuff for personal use.

[Michael A. Terrell]

I had a full 1000' spool stolen from me.

[Steve]

Bob E. <bes...@invalid.tv> writes:

< I am trying to solder some RG-6 shield to a pcb. The braid won't tin. It's
< almost like it's dissipating the heat faster than I can apply it. With both a
< temp-controlled iron (set as high as 700F) and a mondo 100W stick I finally
< tried. The solder will barely melt when touched to the braid opposite the
< iron.

That just sounds like another excuse to the use the butane torch :)

[John G]

Steve wrote :

Steel, ment to be clamped not soldered?

--
John G Sydney.

[Ralph Mowery]

"Steve" <lo...@centurylink.net> wrote in message
news:87egc65...@centurylink.net...

Most of the rg-6 uses aluminum instead of copper or tinned copper. The
normal methods of soldering will not work on it.

[Tim Williams]

You're doing it wrong: never wait for dry metal to melt solder opposite the
iron. Tin under the iron, so there's thermal transfer. Then go around the
braid, spreading the tinned area around it. Mind the core will melt to goo
while you're doing this...

And as others have mentioned, if it's aluminum or stainless, you're screwed.

Tim

--
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Contract Design
Website: http://seventransistorlabs.com

"Steve" <lo...@centurylink.net> wrote in message
news:87egc65...@centurylink.net...

[John G]

Ralph Mowery expressed precisely :

I'll believe Aluminium or steel I must admit to only a little actual
experience.
Some Cable guy should give an actual answer.

--
John G Sydney.

[Michael A. Terrell]

The original RG6 used a copper center conductor, and a copper braid over
a stiff, solid insulator. It was barely useful for video. The RG6/U used
for CATV has a copper plated steel center conductor, foam inner
insulator and aluminum foil covered by aluminum drain wires. If it is to
be used overhead, it has a separate stainless steel 'messenger' wire
with a Siamese outer jacket over both the coax and the messenger
strand. I worked in CATV, and used to see 50,000 feet of it come in at
a time. The best way to be sure is see who made the cable in question,
and look up the OEM's specifications for that exact type of cable.

We used Belden, Commscope, and other American made brands back in the
mid '80s.

[DecadentLinuxUserNumeroUno]

He got most of it right.

As a former installer of a dual system (Cube) (Time/Warner)(Warner/
Amex)We had dual 'siamesed' cables and those used for "drops" had the
messenger strand.

However, ALL of it, indoor, outdoor, drop lines, and UG (underground)
ALL had a braided tin plated copper braid over the foil layers. The foam
core had a laminated immobile foil affixed to it, and then there was foil
and braid over that. I know because foil tears and braid does not, and
the fittings used in the industry get crimped on, and foil alone will not
endure those stresses over time, if not fail immediately.

But RG-6 can be bought in many different configurations. It is more
about the form factor and physical size and characteristic impedance.
RG-59 was the same impedance but slightly smaller but had a higher
capacitance per foot and could not be used on longer runs, whereas the RG-6
could perform over greater distances Mainly due to a thicker core to
shield spacing making for a lower parasitic capacitance per foot.

[Ralph Mowery]

"DecadentLinuxUserNumeroUno" <DL...@DecadentLinuxUser.org> wrote in message

news:nafb0t$t4q$1...@gioia.aioe.org...

> He got most of it right.
>
> As a former installer of a dual system (Cube) (Time/Warner)(Warner/
> Amex)We had dual 'siamesed' cables and those used for "drops" had the
> messenger strand.
>
> However, ALL of it, indoor, outdoor, drop lines, and UG (underground)
> ALL had a braided tin plated copper braid over the foil layers. The foam
> core had a laminated immobile foil affixed to it, and then there was foil
> and braid over that. I know because foil tears and braid does not, and
> the fittings used in the industry get crimped on, and foil alone will not
> endure those stresses over time, if not fail immediately.
>
> But RG-6 can be bought in many different configurations. It is more
> about the form factor and physical size and characteristic impedance.
> RG-59 was the same impedance but slightly smaller but had a higher
> capacitance per foot and could not be used on longer runs, whereas the
> RG-6
> could perform over greater distances Mainly due to a thicker core to
> shield spacing making for a lower parasitic capacitance per foot.

And you got most of that right. The RG number is mostly the physical size
of the cable. The reason rg-6 size is used is for lower losses at higher
frequencies. It is less expensive and able to be bent and handled in a
house easier than the rg-11 size.

The main loss in the cable up; to about 1000 MHz is the resistance loss of
the conductors. By making the center conductor larger there is less loss.
The foil is used to provide a very good shield to keep the RF inside the
cable, and the braid is mainly to provide a way to crimp it for a good
electrical connection.

[DecadentLinuxUserNumeroUno]

On Mon, 22 Feb 2016 11:42:12 -0500, Ralph Mowery wrote:

> "DecadentLinuxUserNumeroUno" <DL...@DecadentLinuxUser.org> wrote in
> message news:nafb0t$t4q$1...@gioia.aioe.org...
>> He got most of it right.
>>
>> As a former installer of a dual system (Cube) (Time/Warner)(Warner/
>> Amex)We had dual 'siamesed' cables and those used for "drops" had the
>> messenger strand.
>>
>> However, ALL of it, indoor, outdoor, drop lines, and UG (underground)
>> ALL had a braided tin plated copper braid over the foil layers. The
>> foam core had a laminated immobile foil affixed to it, and then there
>> was foil and braid over that. I know because foil tears and braid does
>> not, and the fittings used in the industry get crimped on, and foil
>> alone will not endure those stresses over time, if not fail
>> immediately.
>>
>> But RG-6 can be bought in many different configurations. It is more
>> about the form factor and physical size and characteristic impedance.
>> RG-59 was the same impedance but slightly smaller but had a higher
>> capacitance per foot and could not be used on longer runs, whereas the
>> RG-6 could perform over greater distances Mainly due to a thicker core
>> to shield spacing making for a lower parasitic capacitance per foot.
>
> And you got most of that right. The RG number is mostly the physical
> size of the cable. The reason rg-6 size is used is for lower losses at
> higher frequencies. It is less expensive and able to be bent and
> handled in a house easier than the rg-11 size.

Nobody ever used RG-11 in a house. It was always RG-59 and now with the
channel count and digital internet being added, most in-house installs are
RG-6 throughout, unless it is a cheap ass cable company.

It is not mere wire resistance either. The capacitance is also a factor
in why RG-6 is better than RG-59.

>
> The main loss in the cable up; to about 1000 MHz is the resistance loss
> of
> the conductors.

Another reason why mere foil shielding does not ring true. This is why
the center conductor is not a copper plated steel core, but a copper CLAD
steel core.

> By making the center conductor larger there is less
> loss. The foil is used to provide a very good shield to keep the RF
> inside the cable, and the braid is mainly to provide a way to crimp it
> for a good electrical connection.

There are different braid fill levels available. It comes down to what
the cable company wants to spend on their build.

[Ralph Mowery]

"DecadentLinuxUserNumeroUno" <DL...@DecadentLinuxUser.org> wrote in message

news:nafi66$1au8$1...@gioia.aioe.org...

>
> It is not mere wire resistance either. The capacitance is also a factor
> in why RG-6 is better than RG-59.
>>

The capacitance has almost nothing if anything at all to do with the losses
at the cable frequencies.

If you look at the charts the capacitance is nearly the same and often the
rg-59 is less than the rg-6.. The main losses is the I squared R loss of
the conductors.

[rickman]

The stuff I use has both copper center conductor and braid. Most RG-6
uses a steel center conductor with a copper plating since the skin
effect limits current flow to the surface at high frequencies and the
steel provides more strength for pulling and aerial runs.

--

Rick

[rickman]

Looking at the chart of loss vs. frequency for Belden 1694A Coax I see
0.24 dB at 1 MHz, > 3 dB at 270 MHz and > 6 dB at 1000 MHz. I don't see
any factor for frequency in I^2R. I suppose this could be skin effect
increasing the conductor resistance.

How do you tell when the losses are mostly due to the dielectric?

--

Rick

[Ralph Mowery]

"rickman" <gnu...@gmail.com> wrote in message
news:nafms0$6dr$1...@dont-email.me...

>> Looking at the chart of loss vs. frequency for Belden 1694A Coax I see
> 0.24 dB at 1 MHz, > 3 dB at 270 MHz and > 6 dB at 1000 MHz. I don't see
> any factor for frequency in I^2R. I suppose this could be skin effect
> increasing the conductor resistance.
>
> How do you tell when the losses are mostly due to the dielectric?
>

It is the skin effect of the center conductor mostly up to around 1000 mhz.
Below that the dielectric has very little loss.

There are places that show how to calculat the various losses depending on
the material and frequencies, but the math gets involved.

There is a chart here that shows the relative effect.
https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwjowZuWkIzLAhVFNT4KHRUQBukQjRwIBw&url=http%3A%2F%2Fwww.rfcafe.com%2Freferences%2Farticles%2FJoe-Cahak%2Frf-connectors-cables-joe-cahak-6-2014.htm&psig=AFQjCNGIEOiXBCpLe3a7WLhDueMCfF231w&ust=1456256383257029

[Ralph Mowery]

"rickman" <gnu...@gmail.com> wrote in message
news:nafms0$6dr$1...@dont-email.me...

If you really want to get into it, here is a place that gives the info.
Lots of math to look through. Much easier just to look at the chart for a
good indication of where the losses are.

http://www.rfcafe.com/references/articles/Joe-Cahak/rf-connectors-cables-joe-cahak-6-2014.htm

[DecadentLinuxUserNumeroUno]

On Mon, 22 Feb 2016 14:12:31 -0500, rickman wrote:

> The stuff I use has both copper center conductor and braid. Most RG-6
> uses a steel center conductor with a copper plating since the skin
> effect limits current flow to the surface at high frequencies and the
> steel provides more strength for pulling and aerial runs.

Nope. Copper plating is too thin. It is referred to as "copper clad".

Same thing for ground rods, except the reason in that case is abrasion
durability.

Goddamned cross-posting retards.

[M Philbrook]

In article <Bf6dnb0NpNQX-lbL...@earthlink.com>,
rmower...@earthlink.net says...

Or I could go into the archives at work "Brand-Rex", and get the
original designs specs and charts. Yes, those were the days.

We just retired the very first irradiation cross linking line ever made
for production use of any product. The actual first cross linker
irradiation unit for non commerical use was for the airforce, in a
hanger.

Our unit now sits on the floor waiting for a home in some antique
shop, 170k Watt version. It was getting hard to find chips to keep it
operating. Many BB chips, round can op-amps. The osc for the magnetic
amp was a UNI transistor that drove a transistor Flip Flip to generate a
100Hz sweep for the amp. In that circuit was wave shaping components to
get a step peak on the out sides of the sweep before it changed
direction.

Neat stuff for back then, real engineers not uC coders!

Jamie

[Cydrome Leader]

Did all this stuff make an electron beam?

[Andrew Gabriel]

In article <sNGdnTReYdJz31fL...@westnet.com.au>,

Ordinary soldering can be used with iron - soldering iron bits are
often copper core for thermal capacity and conduction, with iron
plating which wets well with solder but doesn't oxidise/corrode
as quickly as a bare copper bit does.

As you go to steel and then stainless steal, it gets harder to do.
Stainless steal in particular is protected from corrosion by a very
tough layer of chromium oxide (I don't know if it's possible to
solder stainless steel at all).

Aluminium has a similar problem - a very tough layer of aluminum
oxide which needs a suitable flux to strip through. However, it also
needs a different solder alloy to wet it - it's a long time since I
did it but ISTR using a solder alloy containing silver.

A secondary problem with soldering dissimilar metals is that any
moisture risks causing galvantic action/corrosion of the join, and
in the case of aluminium, this happens even between the aluminium
and the solder used. Selecting a flux which can strip the aluminimum
oxide well whilst not leaving any residue which eventually corrodes
the join is a bit of a challenge.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

[DecadentLinuxUserNumeroUno]

On Sat, 27 Feb 2016 11:20:43 +0000, Andrew Gabriel wrote:

> As you go to steel and then stainless steal

Engineering schlip?

[MJC]

In article <nas0qb$nod$1...@dont-email.me>, and...@cucumber.demon.co.uk
says...

>
> A secondary problem with soldering dissimilar metals is that any
> moisture risks causing galvantic action/corrosion of the join, and
> in the case of aluminium, this happens even between the aluminium
> and the solder used. Selecting a flux which can strip the aluminimum
> oxide well whilst not leaving any residue which eventually corrodes
> the join is a bit of a challenge.

This reminded me that I once knew about "purple plague". There's an
article about it in Wikipedia.

Mike.