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Trouble with EFHW kit #efhw

 

Just build the KM4ACK EFHW today and threw it up in a tree, about 35 feet, sloping to ground. Put an SWR meter on it and found the lowest SWR I can get is 2.3 and that is at 6.8. I tried shortening the antenna by about two feet, wrapping the excess around the antenna. Almost no change in the SWR, still about 2.3 and that is at 6.9, Before I tear out the transformer and rewind it, could anyone suggest troubleshooting tips? Continuity checked out.
Thanks,
Phil, K3UT
Wally Tuck
 

My 80m EFHW is 134' with 49:1 unun and I get about 1:2 SWR. Mine followed a different plan and I use a nanovna to measure its SWR. I have good SWR on all ham bands except 160 and 6 meters.


On Sun, Feb 13, 2022 at 15:12, PHILIP GRAITCER via groups.io
<pgraitc@...> wrote:
Just build the KM4ACK EFHW today and threw it up in a tree, about 35 feet, sloping to ground. Put an SWR meter on it and found the lowest SWR I can get is 2.3 and that is at 6.8. I tried shortening the antenna by about two feet, wrapping the excess around the antenna. Almost no change in the SWR, still about 2.3 and that is at 6.9, Before I tear out the transformer and rewind it, could anyone suggest troubleshooting tips? Continuity checked out.
Thanks,
Phil, K3UT

 

Just build the KM4ACK EFHW today and threw it up in a tree, about 35 feet, sloping to ground. Put an SWR meter on it and found the lowest SWR I can get is 2.3 and that is at 6.8. I tried shortening the antenna by about two feet, wrapping the excess around the antenna. Almost no change in the SWR, still about 2.3 and that is at 6.9, Before I tear out the transformer and rewind it, could anyone suggest troubleshooting tips? Continuity checked out.
Thanks,
Phil, K3UT
Can you post a pic of your toroid please? If the dip is at 6.8/6.9, the wire is still too long. Extra length is shipped with each kit to allow for minor mistakes.

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73, de KM4ACK
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I think I have found the error in my winding. I will attempt a correction - if I can remove the hot glue ;-). For my information, about how long is the wire that comes with the kit? Thanks again for a very nice kit.
Phil, K3UT
 

I would think that you did make an error in winding. Mine was better then 1.5:1 on 40,20,15,10 AND 12 meters. 12 was a pleasant surprise. It¡¯s a great kit and works perfectly with the SOTABEAMS Traveler mast in an inverted V.?
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Don
W6CZ
DM07bk
 

I think I have found the error in my winding. I will attempt a correction - if I can remove the hot glue ;-). For my information, about how long is the wire that comes with the kit? Thanks again for a very nice kit.
Phil, K3UT
The kit ships with ~68' of wire.

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73, de KM4ACK
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I rebuilt the transformer and now have a 1.86 SWR at 7.020. It is 2.1 at 14.030. Should I continue to mess with it? I have it up about 35 feet and slopes to 6 feet.?
 

Hello,

The thing to do when tuning an antenna is to take several SWR measurements across the band. Then look at the one with the lowest SWR and see what frequency it is at. With just one SWR measurement there is no way of knowing if the wire is too long or too short.

If memory serves, that kit comes with wire that is a bit long, but don't take my word for it, check the 40 meter band at every 100 kHz.?

So for example, if the lowest SWR is near 7.000 mHz then the wire is too long. If the lowest SWR is at 7.300 mHz, then its too short.

Hope this helps.
?
-- Mike WB8ERJ

Geeze! What is he up to now?
 

You should have enough wire now to shorten or lengthen to dial in SWR....mine is barely 1.2:1 across 40m.?

This efhw is a fantastic piece of kit.


73 de,
KN4UNO
???


On Mon, Feb 28, 2022, 17:15 PHILIP GRAITCER via <pgraitc=[email protected]> wrote:
I rebuilt the transformer and now have a 1.86 SWR at 7.020. It is 2.1 at 14.030. Should I continue to mess with it? I have it up about 35 feet and slopes to 6 feet.?

 

Mike is correct. Each kit ships with ~68 feet of wire allowing the operator to tune it for their favorite portion of the band.
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73, de KM4ACK
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