Re: Resources mentioned regarding portable antennas


Fred Dittrich
 

Bryan

Your presentation gave us a rich source of devices for go packs. Thanks for sharing.

73

Fred AE0FD



At 10:46 PM 3/10/2020, you wrote:
I mentioned a couple of resources at the meeting tonight.

Here are links to them.

“Random Wire Lengths�

https://udel.edu/~mm/ham/randomWire/

http://www.hamuniverse.com/randomwireantennalengths.html

Good lengths in ft: 29  35.5  41  58  71  84  107  119  148  203  347  407  423

Trapped End Fed Half Wave Antennas

http://peanutpower.co.uk/efhw

There are quite a few resources on the internet about trifilar winding a 9:1 transformer.

For the 9:1 and 49:1 transformers you can also wind a primary and secondary on the same core independently.

In the example below L1 (primary) has 3 turns and L2 at 9 turns.  Ratio is 1:3, square that 3 and it is a 9:1 transformer.  Could also easily wind a primary with 2 turns and secondary with 14 turns for EFHW (49:1).
 
Wired up ~17’ radiator and 6’ counterpoise.  Kx3 had no trouble tuning it anywhere.  Typically I use a 58’ radiator with 9:1 or the trapped EFHW.

The article about portable masts can be found here: http://www.4sqrp.com/4sqrpNewsLetter/201908.pdf

72/73 de Bryan, k0emt

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