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| The camping washing line spool used for the antenna wire. |
Ten Megahertz (30m) turned out to be a useful band for us, allowing CW contact after CW contact, despite poor conditions after a geomagnetic storm and a K index of five.
The antenna we used was a portable 40-10m multi-band end-fed half wave (EFHW) with a 49:1 Unun using an FT240-43 toroid.
It used a wire 9m vertically metres up a fishing pole and then about 5.8m out.
The novel thing was that I only built it the day before and it uses a Coghlan camping washing line spool with the string taken off and about 21m of wire wound onto it.
What kind of choke should be used? A few loops of coax, some ferrite beads, something else? Thanks.
ReplyDeleteSee G3TXQ's site at http://www.karinya.net/g3txq/chokes/. It depends on the frequency you are operating on. Too for for >4 KOhms would require 10 turns of RG58 on a 4.25 inch former or 12 turns on an FT240-61 Toroid at 14MHz.
ReplyDeleteNice blog, thanks for sharing such a nice blog.
ReplyDeleteSteve loved talk to HARS.Sometimes you recommend 200-2 toroids and sometimes 243-43, what is difference please M0OLG
ReplyDeleteT200-2 toroids (red) are made of iron power and good for making tuned circuits, such as used in the monoband EFHW. FT240-43 toroids are made of ferrite and are better suited to wideband transformers, such as the multiband EFW. Hope that helps.
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