HFU HF Underground

Technical Topics => Equipment => Topic started by: Josh on February 23, 2020, 0142 UTC

Title: NEMP Rated surge arrestor
Post by: Josh on February 23, 2020, 0142 UTC

IS-50NX-C1
SKU: IS-50NX-C1
$19.95
https://fairradio.com/product/is-50nx-c1/

I feel this is an excellent price for the amount of protection.
Keep in mind they ground the antenna side center conductor with an inductance while a cap isolates the rig side center conductor and a gas discharge pill protects the works.

Title: Re: NEMP Rated surge arrestor
Post by: NJQA on February 23, 2020, 1246 UTC

The frequency limits they show are real too.  I saw an installation where the installers used similar surge supressors for the HF antennas.  The antennas were dead as a door nail.  Replacing the supressors with ones rated for HF made everything good again.

Title: Re: NEMP Rated surge arrestor
Post by: Josh on February 23, 2020, 2111 UTC

I've one rated for hf, works down to wwvb even. It must comprise a highpass of sorts as I can't see how it could pass vhf and up, but not hf.

Title: Re: NEMP Rated surge arrestor
Post by: NJQA on February 24, 2020, 0301 UTC

The isolation capacitor in series with the center conductor is large enough for VHF and higher, but not for HF.

Title: Re: NEMP Rated surge arrestor
Post by: Josh on February 24, 2020, 1937 UTC

Kinda what was expecting, I also think the gas discharge pill doubles as the cap.