Feding a doublet antenna

I’m thinking of building a Norcal doublet for portable use but want to use it with my 817 via my Z817 tuner. Am I right in thinking I can do this via a 4:1 balun?

In reply to G4ZHI:

For what it’s worth I use a homebrew doublet with an Icom IC703 (with it’s internal ATU) and a 4:1 balun. With the balun inline the doublet tunes up on 40m through to 6m. I can’t see that your proposed system is vastly different and should work very well.

In reply to G4ZHI:
Hi Bryn

I regularly use a double length (88ft) Norcal doublet for SOTA activations. Of course the impedance presented to the tuner on a given band will depend on the twin feeder length but FWIW I do use it with a 4:1 balun into my LDG autotuner for the 706 and it will tune anywhere. It even works nicely on Top band with the feeder strapped and fed against a counterpoise.

73 Marc G0AZS

In reply to G4ZHI:
I wouldn’t bother about a 4:1 balun. Try to feed directly from the Z817 to the balanced line. Please have a look at my pictures on top of GW/SW-020 and SW-011:
On the top of the first page you can see the L and C values my tuner reqired.

More pictures of my Norcal-Doublet are here:

What I couldn’t find in the Z817 manual is the tuning range of L and C.

Have fun with SOTA.

73 de Dominik, HB9CZF

In reply to G0AZS:

My 102-foot doublet fed with 300-ohm ribbon to an MFJ-949E gives me the occasional chasing contacts on Top Band without strapping the feeder or using a counterpoise, Marc, I’m sure that an 88-foot doublet would give contacts on Top Band with a manual tuner (which has a wider range than an autotuner) and no strapping or counterpoise.


Brian G8ADD

Thanks to all who replied to my posting. Looks like a weekend of antenna constructing!