Uploaded August 2021 | Updated September 2026, 2 weeks ago
This is the build of my mains filter which I will use with my inverter generator when working portable on HF, VHF & UHF. You can use this filter in the shack at home too 👍🏻
The filter design is Ian White's GM3SEK and a link to his article on the design and build can be found below, as well as links to Ian's RSGB lectures.
As you will see in the video, after adjusting the position of the filter on the extension lead in relation to the generator, it is a success! I just need to do some more tweaking to achieve a better result on the 6m band, which may involve more cores at the socket end of the extension lead (there are types other than 31 & 43 to consider) and/or a different number of turns, including the main 31 snap-on core in the filter which I added two extra turns to the original design of seven (I may reduce this back to seven).
If you’ve tried a power-off test at home and know you’ve got mains RFI, then this may be the solution. Similarly, if you’re struggling with a noisy generator on the lower bands like me. A power-off test I did some time ago can be seen here: youtu.be/nNDfqjCgNV4
This would be a good project for a club and an asset for members to try out at home before they commit to buying the parts and constructing their own filter.
If your QRM is from outside your home, then why not try and hunt it down? See how to here: youtu.be/56IUtdBK-7U
This is one of many amateur/ham radio related videos on my channel. Please feel free to browse 👀, like 👍🏻 and subscribe 🔔 (it's free!), remembering to hit the bell so you’re notified of new videos as soon as they're published and you don't miss out.
Here's the link to Ian White's design: gm3sek.com/2019/10/11/clean-up-your-shack-2019
And Ian’s RSGB lectures on RFI/EMC issues can be found here: youtube.com/watch?app=desktop&v=LSL1h6MJbaI and an updated 2019 version for subscribed RSGB members here: thersgb.org/members/resources/login/?id=5844
I sourced my parts below from Mouser and CPC in the UK (double-check your order before purchasing). Outside of the UK the Schaffner commercial filter is likely to be a different model based on your country's mains voltage requirements:
• ABS Enclosure 170x170x75mm IO65 (CPC Order Code EN84544)
• PG11 Cable Gland Black x2 (CPC Order Code CBBR7352)
• Schaffner Power Line Filter 16A (Mouser Part Number 631-FN2030-16/06)
• Fair-Rite Type 31 Clamp On Core (Mouser Part Number 623-0431177081)
• Fair-Rite Type 43 Cable Core (Mouser Part Number 623-2643167851)
Plus:
• 2m of 2.5mm2 3 core mains cable
• Mains extension lead
• Cable ties / tape
0:00 Introduction
1:43 The Build
9:00 Testing & Results
11:10 Further Adjustments
11:40 Further Thoughts
Thanks.
Ian.
This is the build of my mains filter which I will use with my inverter generator when working portable on HF, VHF & UHF. You can use this filter in the shack at home too 👍🏻
The filter design is Ian White's GM3SEK and a link to his article on the design and build can be found below, as well as links to Ian's RSGB lectures.
As you will see in the video, after adjusting the position of the filter on the extension lead in relation to the generator, it is a success! I just need to do some more tweaking to achieve a better result on the 6m band, which may involve more cores at the socket end of the extension lead (there are types other than 31 & 43 to consider) and/or a different number of turns, including the main 31 snap-on core in the filter which I added two extra turns to the original design of seven (I may reduce this back to seven).
If you’ve tried a power-off test at home and know you’ve got mains RFI, then this may be the solution. Similarly, if you’re struggling with a noisy generator on the lower bands like me. A power-off test I did some time ago can be seen here: youtu.be/nNDfqjCgNV4
This would be a good project for a club and an asset for members to try out at home before they commit to buying the parts and constructing their own filter.
If your QRM is from outside your home, then why not try and hunt it down? See how to here: youtu.be/56IUtdBK-7U
This is one of many amateur/ham radio related videos on my channel. Please feel free to browse 👀, like 👍🏻 and subscribe 🔔 (it's free!), remembering to hit the bell so you’re notified of new videos as soon as they're published and you don't miss out.
Here's the link to Ian White's design: gm3sek.com/2019/10/11/clean-up-your-shack-2019
And Ian’s RSGB lectures on RFI/EMC issues can be found here: youtube.com/watch?app=desktop&v=LSL1h6MJbaI and an updated 2019 version for subscribed RSGB members here: thersgb.org/members/resources/login/?id=5844
I sourced my parts below from Mouser and CPC in the UK (double-check your order before purchasing). Outside of the UK the Schaffner commercial filter is likely to be a different model based on your country's mains voltage requirements:
• ABS Enclosure 170x170x75mm IO65 (CPC Order Code EN84544)
• PG11 Cable Gland Black x2 (CPC Order Code CBBR7352)
• Schaffner Power Line Filter 16A (Mouser Part Number 631-FN2030-16/06)
• Fair-Rite Type 31 Clamp On Core (Mouser Part Number 623-0431177081)
• Fair-Rite Type 43 Cable Core (Mouser Part Number 623-2643167851)
Plus:
• 2m of 2.5mm2 3 core mains cable
• Mains extension lead
• Cable ties / tape
0:00 Introduction
1:43 The Build
9:00 Testing & Results
11:10 Further Adjustments
11:40 Further Thoughts
Thanks.
Ian.
