Hi Everyone,
I always use a coax with a string of toroids either a 1 foot attachment or the 50 foot with the toroids already in the 50 foot piece. ?I've done this initially when I received reports that my audio had a crackle or as they say "RF in the shack" sound. ?This is caused by RF on the outside braid of the coax feeding back to the radio. ?This is especially prevalent in end fed antennas typically deployed in POTA situations. ?It's especially prevalent when running 100 watts such as an FT891. ?Evidentially the audio chip is delicate for this back EMF so while I was deploying the toroids to improve my audio I'm also protecting my radio because the audio chip in my radio its still OK. ?I've place links below to the ABR industries two coaxes options that I use. ?This back RF is especially present if you do FT8 because of the constant RF transmission.
Below is Ham Radio Outlet who sells ABR industries cables. ?The LMR 240 lightweight coax options are great for POTA activations. ?They sell LMR 400 options too on their websites. ?BTW the Ferrite bead should be mounted at the radio end NOT on the antenna end to be most effective at blocking the RF coming down the coax.
The 1 foot jumper with the ferrite beads with an end mounted male and female PL259's
The 50 foot coax with the ferrite beads
The 100 foot coax the the ferrite breads
Hope you guys find this information useful. ?I highly recommend using them to improve your audio and protect your radios. ?And every radio not just the TX-500!
As Always,
Best 73,
David
K9AT
David Holmgren K9AT "Ruffers"