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Posts : 49 Times Thanked : 0 Join date : 2022-05-10 QTH or Location : belfast Equipment Used : none yet Age : 57
Subject: END FED QUESTIONS .. Sun Apr 07, 2024 2:15 pm
hi guys it's been a while from i was on here and i'm back with a few questions . i want to make an end fed antenna and have been doing a lot of homework but i can't get to the bottom of what i need .
i have about 14 meters of room for a sloped wire on top of a block of flats 120 feet up . i have been on 11 meters with an antron 99 for a while now but i think i'm gonna do my foundation and i have access to a yaesu ft 450d wide banded.
i know with a certain length of wire i can only get so many bands, so what are the most popular bands ? i would want to still use 11 meters .
so i know i need an unun and 9-1 and 49-1 seem to be the most popular . the unun would be on a small metal pole about 6 or 7 feet in length and the wire sloping away from it . there would be about 35 to 40 feet of coax running up to the unun and a further 8 feet in the flat .
from what i have read the unun would not need to be grounded because the coax would act as the ground and i would maybe need a 1-1 balun to help with the rf noise .
so what unun do i need and do i need to make the wire a certain length ? will the internal tuner be enough to sort the signal and if i do need a 1-1 balun where does it go ie close to the radio or up at the unun ?
i'm starting from scratch here guys so please be kind if i'm asking silly questions .. thank you ..
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VanRougeT4 Senior contributor
Call Sign : G1DBS - F4WEY Posts : 161 Times Thanked : 12 Join date : 2024-02-17 QTH or Location : Montreuil sur Mer Equipment Used : XIEGU G90 + XIEGU XPA125B amp.
Subject: Re: END FED QUESTIONS .. Sun Apr 07, 2024 5:45 pm
@Bass 666
I've recently been looking into end fed antennas, and am at the moment constructing one for temporary use. There's a very useful site that I will link to below.
As I understand it, you can create a 'random' wire multiband end fed that uses a 9:1 unun. The wire isn't actually random though. What you must do is avoid half wave lengths for each of the bands you want to use, that makes the impedance at the fed end about 450 ohms. A 9:1 unun will bring that down to a usable 70 ish ohms on all the bands you want to use. That's within the range of any antenna tuner/matcher.
You can avoid electrically earthing the coax by having a counterpoise.
For 40 20 & 10 I'm going to start with an end fed length of 41 feet. If that doesn't work too well I'll shorten to 35.5 feet.
Posts : 49 Times Thanked : 0 Join date : 2022-05-10 QTH or Location : belfast Equipment Used : none yet Age : 57
Subject: Re: END FED QUESTIONS .. Sun Apr 07, 2024 6:25 pm
VanRougeT4 wrote:
@Bass 666
I've recently been looking into end fed antennas, and am at the moment constructing one for temporary use. There's a very useful site that I will link to below.
As I understand it, you can create a 'random' wire multiband end fed that uses a 9:1 unun. The wire isn't actually random though. What you must do is avoid half wave lengths for each of the bands you want to use, that makes the impedance at the fed end about 450 ohms. A 9:1 unun will bring that down to a usable 70 ish ohms on all the bands you want to use. That's within the range of any antenna tuner/matcher.
You can avoid electrically earthing the coax by having a counterpoise.
For 40 20 & 10 I'm going to start with an end fed length of 41 feet. If that doesn't work too well I'll shorten to 35.5 feet.
thanks for the reply .. yeah i have been watching loads of youtube vids on 41 foot wires and they are all fairly good .. the counterpoise problem for me as i have read is ok because the coax i use to get to the unun is so long it will act as the earth .. a 1-1 balun is needed for rfi but it seems there are conflicting stories about where it is placed .. some say at the back of the radio and others say just before the unun ? more homework needed ..
VanRougeT4 Senior contributor
Call Sign : G1DBS - F4WEY Posts : 161 Times Thanked : 12 Join date : 2024-02-17 QTH or Location : Montreuil sur Mer Equipment Used : XIEGU G90 + XIEGU XPA125B amp.
Subject: Re: END FED QUESTIONS .. Sun Apr 07, 2024 6:42 pm
BASS 666 wrote:
Quote :
the counterpoise problem for me as i have read is ok because the coax i use to get to the unun is so long it will act as the earth .. a 1-1 balun is needed for rfi but it seems there are conflicting stories about where it is placed .. some say at the back of the radio and others say just before the unun ? more homework needed ..
I would lay out a 17 foot counterpoise and wind 6 turns of 6 inch diameter in the coax close to the radio. If that doesn't work for you, put a 1:1 balun somewhere in the line. Easy to experiment position; either at the antenna end of the coax or near the rig. But you may find, if all is constructed carefully and with a counterpoise, that you don't need the 1:1 balun.
Deb
BASS 666 New Member
Posts : 49 Times Thanked : 0 Join date : 2022-05-10 QTH or Location : belfast Equipment Used : none yet Age : 57
Subject: Re: END FED QUESTIONS .. Sun Apr 07, 2024 6:47 pm
VanRougeT4 wrote:
BASS 666 wrote:
Quote :
the counterpoise problem for me as i have read is ok because the coax i use to get to the unun is so long it will act as the earth .. a 1-1 balun is needed for rfi but it seems there are conflicting stories about where it is placed .. some say at the back of the radio and others say just before the unun ? more homework needed ..
I would lay out a 17 foot counterpoise and wind 6 turns of 6 inch diameter in the coax close to the radio. If that doesn't work for you, put a 1:1 balun somewhere in the line. Easy to experiment position; either at the antenna end of the coax or near the rig. But you may find, if all is constructed carefully and with a counterpoise, that you don't need the 1:1 balun.
Deb
yeah iv seen the guys doing it with and without the counterpoise .. like you say it's easy doing it both ways to see whats what ..
VanRougeT4 likes this post
BASS 666 New Member
Posts : 49 Times Thanked : 0 Join date : 2022-05-10 QTH or Location : belfast Equipment Used : none yet Age : 57
Subject: Re: END FED QUESTIONS .. Mon Apr 08, 2024 12:42 am
VanRougeT4 wrote:
BASS 666 wrote:
Quote :
the counterpoise problem for me as i have read is ok because the coax i use to get to the unun is so long it will act as the earth .. a 1-1 balun is needed for rfi but it seems there are conflicting stories about where it is placed .. some say at the back of the radio and others say just before the unun ? more homework needed ..
I would lay out a 17 foot counterpoise and wind 6 turns of 6 inch diameter in the coax close to the radio. If that doesn't work for you, put a 1:1 balun somewhere in the line. Easy to experiment position; either at the antenna end of the coax or near the rig. But you may find, if all is constructed carefully and with a counterpoise, that you don't need the 1:1 balun.
Deb
if i cut 41 foot of wire do i have to allow for looping it round the isolator ? do i cut 41 foot spot on and then loop it round the isolator ?
VanRougeT4 Senior contributor
Call Sign : G1DBS - F4WEY Posts : 161 Times Thanked : 12 Join date : 2024-02-17 QTH or Location : Montreuil sur Mer Equipment Used : XIEGU G90 + XIEGU XPA125B amp.
Subject: Re: END FED QUESTIONS .. Mon Apr 08, 2024 7:49 am
BASS 666 wrote:
if i cut 41 foot of wire do i have to allow for looping it round the isolator ? do i cut 41 foot spot on and then loop it round the isolator ?
I intend to cut mine a bit long, say 42 feet, then trim or fold back for best vswr.
Deb
PS. We'll be in Belfast in May (round Ireland campervan trip) visiting the Titanic experience. Maybe catch you on 11m.
BASS 666 New Member
Posts : 49 Times Thanked : 0 Join date : 2022-05-10 QTH or Location : belfast Equipment Used : none yet Age : 57
Subject: Re: END FED QUESTIONS .. Mon Apr 08, 2024 9:29 am
VanRougeT4 wrote:
BASS 666 wrote:
if i cut 41 foot of wire do i have to allow for looping it round the isolator ? do i cut 41 foot spot on and then loop it round the isolator ?
I intend to cut mine a bit long, say 42 feet, then trim or fold back for best vswr.
Deb
PS. We'll be in Belfast in May (round Ireland campervan trip) visiting the Titanic experience. Maybe catch you on 11m.
i can be at the titanic building in 10 mins from where i live it's a good place to see ... enjoy ...
VanRougeT4 likes this post
kilomike 10 + Year member
Call Sign : 26CT360 Posts : 101 Times Thanked : 1 Join date : 2019-06-28 QTH or Location : Hertfordshire Equipment Used : Icom/ Kenwood/ Yaesu Age : 57
Subject: Re: END FED QUESTIONS .. Mon Apr 08, 2024 10:27 am
I would use this if you can https://www.hyendcompany.nl/antenna/multiband_40201510_m Its cut for or make it your self, works really well
40/20/15/10
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Purple Witch New Member
Call Sign : 31-CT-026 Posts : 17 Times Thanked : 1 Join date : 2024-04-06 QTH or Location : Faro Equipment Used : Yaesu FT450D
Have you room for, or considered using an inverted V dipole? Maybe something like a half size G5RV. You have the height for it. It should be good for 40-10m and it's cheap to buy or even cheaper to make. I run one and I also slope it an 45degrees to get extra directional lift. i have it tuned in best from 10-20m but it'll match in up to 40m with not much effort.
BASS 666 New Member
Posts : 49 Times Thanked : 0 Join date : 2022-05-10 QTH or Location : belfast Equipment Used : none yet Age : 57
Have you room for, or considered using an inverted V dipole? Maybe something like a half size G5RV. You have the height for it. It should be good for 40-10m and it's cheap to buy or even cheaper to make. I run one and I also slope it an 45degrees to get extra directional lift. i have it tuned in best from 10-20m but it'll match in up to 40m with not much effort.
its a thought i had for future antennas so i will go with the sloped wire and see how it goes first .. thanks ..
VanRougeT4 Senior contributor
Call Sign : G1DBS - F4WEY Posts : 161 Times Thanked : 12 Join date : 2024-02-17 QTH or Location : Montreuil sur Mer Equipment Used : XIEGU G90 + XIEGU XPA125B amp.
Subject: Re: END FED QUESTIONS .. Wed Apr 17, 2024 1:00 am
BASS 666 wrote:
VanRougeT4 wrote:
BASS 666 wrote:
if i cut 41 foot of wire do i have to allow for looping it round the isolator ? do i cut 41 foot spot on and then loop it round the isolator ?
I intend to cut mine a bit long, say 42 feet, then trim or fold back for best vswr.
Deb
As a test to see how it works, I strung the end fed up this afternoon. 42ft in an inverted L only about 12ft high at the tree end and 8ft high at the house end, with 4ft down to a 9:1 balun. A 17ft counterpoise just draped along the front of the house. 5m of coax into my van, and I grounded my G90 to the van body.
Middle of bands vswr before tuning. 10m 1:1 20m 1.4. 40m 1:1. 80m 1.5.