[TowerTalk] Loading Coils

[Jeff Blaine]

The key point of this original mention seems, to me, to be lost. Which 
is that if a guy needs a prefab coil for his application, here is a 
source.  Given this kind of stuff is getting hard to find, that seems a 
good post by the original lister.  The suitability of that coil to a 
given application is a **completely** separate topic.

Debating the guy's decision to nickle plate the coil is part of the 
application end, not the offer end.  You may as well add in the wire 
gauge and spacing as well to the debate as these are of similar 
importance.  Ni is more resistive than Ag, but if the currents involved 
are low then the drop in Q may not be an issue. Again, it depends on the 
application.

Guys with skills to roll their own are unlikely to buy a prefab coil.  
My guess is that buyer of this guy's coils are likely going to be in a 
less selective procurement mindset as a result.  So maybe this is just 
the ticket.

I'm not saying that the coils are good or bad as a category, rather that 
it's great to see someone making something hams can use.  And that's 
becoming more and more rare these days unfortunately, as are the number 
of folks actually making something by their own hand.

73/jeff/ac0c
alpha-charlie-zero-charlie
www.ac0c.com

On 8/2/2025 3:37 PM, john at kk9a.com wrote:
> I believe the old B&H coils were made from tinned copper.  Isn't that
> coating even less conductive than nickel plated?
>
> As far as aluminum coils go, they may not be good for amplifiers but several
> big name antenna companies use them on 40m Yagi elements for loading and
> they appear to work well.
>
> John KK9A
>
>
> Jim VE7RF wrote:
>
>
> ##  nickel plated,  He's joking right ?  Years ago, I replaced the silver
> plated copper tubing coil in a hb amp with an IDENTICAL  aluminum tubing
> tank coil.  Talk about HOT.
>
> Nickel ?    You may as well douse it with lighter fluid, and toss in the
> zippo.
> Measure the Q of the nickel plated coil vs the copper coil, or silver
> plated copper coil......and you will be in for a rude awakening.
>
> Nickel is worse than phosphor bronze.  I just ran a typ 160m  coil through
> K6STI's ' coil'  software....and using copper the Q was 1222.   With
> phosphor bronze, it dropped to 464.....and nickel plated is even worse !  (
> aluminum was a  Q of 857  using 3003-0 alloy).
>
> No doubt he wanted nickel so it was weather resistant.
>
> I wind my own copper tubing coils....then silver plate em.
>
> Jim  VE7RF
>
>
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