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:
http://www.swiss-artg.ch/hb9czf/sota/gw_sw020/gw_sw020.htm
http://www.swiss-artg.ch/hb9czf/sota/gw_sw011/gw_sw011.htm
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:
http://www.swiss-artg.ch/hb9czf/sota/sota.html
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.
73
Brian G8ADD
Thanks to all who replied to my posting. Looks like a weekend of antenna constructing!