EFHW 80M Loading coil

[Buick Mackane]

Anybody ever tried adding an 80m loading coil to a 40m EFHW ? If so what was your bandwidth on 80m & VSWR ?

[Alan Pilot]

SWR is no problem you just get a very narrow band width can't remember what but narrow.

[Buick Mackane]

Ok alan thanks for replying

[Buick Mackane]

There's a guy selling these coils on ebay for £25, I'll knock one up for a fraction of that price (£5 for magnet wire) i'll report back with my findings

[securityguy]

Just need about a 110uH coil and about 2m of rat tail after it, I get 80m on mine using this. The bandwidth is narrow but the band edges do come in using the built in radio ATU.

[Buick Mackane]

Just need about a 110uH coil and about 2m of rat tail after it, I get 80m on mine using this. The bandwidth is narrow but the band edges do come in using the built in radio ATU.

What bandwidth do you get without the ATU ?

[Whisky1]

I got about 500khz usable spread before I needed a tuner, 49/1 with around 60ft of wire then 110 with a tail of around 6 feet.
I was ok with it for the size and whilst it wasn't a dx buster I did work s/america and india on 100 watts at around 40ft L config no radials.

[Buick Mackane]

I got about 500khz usable spread before I needed a tuner, 49/1 with around 60ft of wire then 110 with a tail of around 6 feet.
I was ok with it for the size and whilst it wasn't a dx buster I did work s/america and india on 100 watts at around 40ft L config no radials.

Nothing wrong with 500 khz bandwidth, That's more than the entire 80m band, Suppose it depends on a few factors like height above ground etc

[securityguy]

Just need about a 110uH coil and about 2m of rat tail after it, I get 80m on mine using this. The bandwidth is narrow but the band edges do come in using the built in radio ATU.

What bandwidth do you get without the ATU ?

Mine is tuned perfectly on 3674khz and goes to 2:1 at 3743khz and 3632khz so almost 100khz is 2:1 or better.

[Buick Mackane]

Just need about a 110uH coil and about 2m of rat tail after it, I get 80m on mine using this. The bandwidth is narrow but the band edges do come in using the built in radio ATU.

What bandwidth do you get without the ATU ?

Mine is tuned perfectly on 3674khz and goes to 2:1 at 3743khz and 3632khz so almost 100khz is 2:1 or better.

I'd be happy with that

[securityguy]

What bandwidth do you get without the ATU ?

Mine is tuned perfectly on 3674khz and goes to 2:1 at 3743khz and 3632khz so almost 100khz is 2:1 or better.

I'd be happy with that

Let us know how you get on. If you're making your own coil, this is the best calculator imo because it allows you to put your target henries value in and spits out the required dimensions based on what you have https://www.translatorscafe.com/unit-co ... inductance

[Buick Mackane]

Mine is tuned perfectly on 3674khz and goes to 2:1 at 3743khz and 3632khz so almost 100khz is 2:1 or better.

I'd be happy with that

Let us know how you get on. If you're making your own coil, this is the best calculator imo because it allows you to put your target henries value in and spits out the required dimensions based on what you have https://www.translatorscafe.com/unit-co ... inductance

Cheers for that, Reckon i'll need around 80 turns of 0.63mm wire on a 42mm OD Former, I'll post the results when i get it set up

[Buick Mackane]

Did adding the 80m trap effect the SWR on the other bands ?

[securityguy]

Did adding the 80m trap effect the SWR on the other bands ?

It's not supposed to, but in reality it did a bit, but nothing significant.

[Buick Mackane]

Did adding the 80m trap effect the SWR on the other bands ?

It's not supposed to, but in reality it did a bit, but nothing significant.