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Re: VLF: VO1NA

To: [email protected]
Subject: Re: VLF: VO1NA
From: [email protected]
Date: Wed, 15 Feb 2017 18:22:10 -0330 (NST)
In-reply-to: <[email protected]>
References: <[email protected]> <[email protected]> <[email protected]> <[email protected]>
Reply-to: [email protected]
Sender: [email protected]
Hi Stefan,

I'm not sure how much voltage the coil will take.
So far, there is no smell of ozone or burnt insulation.
Coils wound with 6 strands would arc and short with more
than 20 ma.  So far the 12 strand coils are fine with 20 ma.

The 0.08mm wire is very long and very inexpensive and available,
unlike 0.4 mm.  It isn't really litz as it's only twisted together and
not cabled of bundles of 3. Perhaps its AC losses are lower than a single conductor of equivalent cross section. The DC resistance is about twice that of 0.4 mm. I think the skin depth at 8 kHz is 0.7 mm
so 0.4 mm is an ideal diam if a 2 km length is available!

73 and congrats again on your inspiring VLF/ULF transmissions.

Joe

On Wed, 15 Feb 2017, DK7FC wrote:

Hi Joe,

How much current or voltage will the coils hold?
Why did you choose RF litz wire for a VLF TX coil?
Good luck!

73, Stefan

Am 15.02.2017 20:45, schrieb [email protected]:
Hi VLF,

Thank-you for the interesting reading and congrats on your latest
milestones.

There have been some very modest steps taken on this side of the
pond.  New coils were wound with 12 strands of 0.08mm insulated
copper: 2 pies 170 and 110 mH, combined 487 mH, 234 ohms DC.
The 100m wire at H=15m was just tuned and I'm happy to be QRV again
on VLF a month after the licence was renewed.

73
Joe VO1NA





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