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9:1, EFRW Questions
https://hamradiodeals.co.uk/forums/viewtopic.php?f=43&t=140426		 Page 1 of 1
Author:  MI0PYN [ Thu Jan 09, 2025 12:34 pm ]
Post subject:  9:1, EFRW Questions
I'm sorry if these questions are stupid, but there seem to be so many conflicting bits of information around, I'd solicit yet another one :-)

I live in a semi detached house, with a 4 band HyEndFed EFHW with 49:1 mounted on my chimney. It's fed from my shack using some decent M&P coax. I am assuming that the coax acts as the counterpoise/ground to some extent as there is no separate connection for a CP at the antenna end, but I've not had any real RFI issues (that I'm aware of) other than a capacitive touch lamp which misbehaves when the radio is on TX.

I am considering whether to replace this with an EFRW, primarily to get some other bands which I don't have access to currently. If I were to use a 9:1 and a wire 45ish metres long, I believe I should be able to get a match (with a tuner) on most bands, certainly all that I'm interested in from 80m up. The wire would make at least 2 nearly 90 degree angles, but there would be 15m or so between each of the corners.

My questions are these:
    Would this be likely to provide any real difference to simply getting a longer EFHW and running it in a similar path? Currently I have a 20m long EFHW which just runs in a straight line.
    If I did go with the RW, would the coax still act as the CP if I simply didn't connect anything to the ground lug on the 9:1?
    If so, would a CMC down at ground level before the coax enters the shack be more prudent than with the EFHW?

Thanks in advance for your collective wisdom.
73,
Stefan MI0PYN
Author:  Mm0rmr [ Thu Jan 09, 2025 4:59 pm ]
Post subject:  Re: 9:1, EFRW Questions
You dont need a counterpoise with a 49-1 as there is very little current at the feedpoint and a high voltage and your coax will suffice. If i were you i would stick with the 49-1 and put a longer wire on that around 40m in length to start and shorten it and tune it on 3.550 for optimum swr as that will out perform any antenna with a 9-1. Antennas with a 9-1 are ok if your struggling for space etc and they receive ok but on tx any resonant antenna will work far better.
Author:  mm0hgn [ Sun Jan 12, 2025 11:02 pm ]
Post subject:  Re: 9:1, EFRW Questions
Hi i use a 9.1 unun with 53 ft of wire my ts 2000 auto tuner tunes from 80m to 10m no problem
Author:  Sangoma [ Mon Jan 13, 2025 7:52 am ]
Post subject:  Re: 9:1, EFRW Questions
an IL with the FP just above GL is very effective, and yes use the coax as an adjustable CP, thought sometimes a VSCP at the FP helps.
Author:  gm0gtu [ Thu Jan 23, 2025 12:33 pm ]
Post subject:  Re: 9:1, EFRW Questions
I have an end-fed wire here in Tenerife, 32.6M long, 9:1 UNUN, running horizontally with the last 5M vertical.
I have attached a single counterpoise at the UNUN, and I also have around a 9" string of ferrite beads on the coax. 10ft away from the feed point. I've had no problems with RF feedback.
Just be aware that there are good & bad lengths of "random wire" I have a table of good lengths that I can send to you if you wish.
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