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9:1 for U-Turn End Fed

December 31, 2014Club MainBy Admin

9:1 for U-Turn End Fed (about 40m of wire) 4-5 meters high

(Revised on Jan. 3. 2015)

The antenna works 160, 80 and 40 meters. It is fed by coax via 9:1 Unun utilizing opposite winding format, which takes hard to get ferrite core. (FT-240-75 Mix works best). Two separated earth rods are needed. The background noise is being pushed almost to S1 on 80m. TX loss due to this beverage RX like winding arrangement is absolutely negligible.

Coax connected to the ground eliminates all but the differential currents. Antenna wire is connected directly to earth rod through the secondary of the transformer, static build-up cannot occur. Local electrical noise from near homes and power distribution lines is eliminated. Antenna wire is trimmed to achieve 1:1 on working FQ on 80.

Coupling effects of stray capacitance observed on bifilar windings does not exist. No interference is self understandable because of half wave wire length for 80m.

What to expect:

TX: DX – No
RX: DX – Yes,

to the point, antenna is quiet due to beverage like transformer. If in Europe, you will hear NY etc. DX callers okay.

Local rag-chew:

Perfect! Antenna acts much like NVIS, DX-RX depends on your elevation.

Medium distance:

If you live on the isles, Northern Ireland and Belgium will speak highly about your signal.

Grounding (earth) conductivity

A bit outrageous observation from some users:

If you live in an older house, with good chance of several water pipe leaks, which means the house and the garden are virtually floating over the years (very common situation nowadays, since any type of maintenance is price prohibitive and utility companies are avoiding it) you can expect substantial results.

Linear loaded wire vertical:

The same feeding arrangement proved to be perfect for linear loaded wire vertical, built from 450 ohm ladder line feeder with inserted center wire, used as the radiator. Transformer ratio is subject to your analyzer results.

Should you care about some traces of DX performance, yet living in antenna restricted areas, you may want to try linear loaded wire vertical. Linear loading helps to reduce the length almost to 1/3 – leaving your 1/4 vertical for 80 meters just 7-8 meters long.

It sure brings the performance down too, but beats any portable. And – you don’t need the radials at all.

9:1balunend fedu-turn antennaunun
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