In message , Andy
writes



"Ian Jackson" wrote in message
...
Andy, is your endfed wire the one in your other thread of the 8th June (ie
the 80 Meter End Fed, fed with coax at the far end)? If so, presumably the
tuner is at the shack end. Or are you feeding it from the shack end.


In message , Andy
writes

--


Hi Ian,

Yes its the same. The tuner is at the shack end (house) and I'm feeding the
antenna with 50 Ohm RG-58 C/U coax at the far end of the garden. If I can
get it working well I will replace it with some RG-213 that I have here. I
put it back up yesterday and started experimenting again.

The End Fed at the moment has 15 feet of 300 Ohm slotted ribbon feeder. This
is all I had left spare. One side is connected to the wire antenna and the
other side left, not connected. The coax is connected to the 300 Ohm at the
bottom and the braid side is now connected to the unconnected side of the
300 Ohm and also to the earth ground rod.
On 80 the receive is up 2-4 S points compared with the 40m coax Centre Fed
Dipole. I have not had chance to get any actual reports on 80 yet. Maybe
this weekend.

73 Andy

OK, Andy. Noted.

I don't know if you will really improve things by using the 15 foot of
300 ohm feeder. It's a sort of a zepp, but with one side of the twin
feeder earthed. I would try disconnecting the earthed ('unconnected')
side from earth / coax braid. You can either leave it floating, or
connect it to the coax inner. It will then be approximately a
quarterwave on 20m, fed in parallel with the long wire.

Don't read too much into the excellent SWR you're getting with the
tuner. That's what the TX sees, but the tuner can't affect the SWR on
the aerial feeder. If the coax SWR is sky high (and it can be if the
impedance at aerial feed point is high), the coax losses will be much
more that you would get compared with when it is matched correctly. You
only get away with it by using the lowest-loss you can find, and keeping
the coax as short as possible.

I'm not surprised that 80m on the endfed is a bit better than the 40m
dipole. But what's 40m like on the endfed? That's when the feed
impedance (and coax SWR) will be very high, and where the RG-213 might
perform better noticeably better than the RG-58.

As I think I said before, although I am an advocate of simply using coax
(regardless), after all these years I am considering in investing in
something like a SG230 remote tuner for the far end of the coax.
--
Ian