Building a 1:1 common mode coax feedline choke Ham Radio DIY Save money do it yourself

[@evil_lair_electronics]

This is the way! Makes a choke which is resistive over a broad frequency range, doesn't trash the coax with bends, and is not bulky. The alternative - winding coax through toroids, fails in all 3 of those categories.

[@survivalcomms]

Thank you ! Exactly so - feedline loss is real. Feedline twisted on a toroid is E-Waste. Thanks for watching !

[@SeedyKidd]

After the end feds - new series to demonstrate 😁 I'm currently using 2 Chokes made of rg58 turned on ft240s. I can feel you shuddering from here 😂 They measure up well as chokes though haven't checked loss. Enjoy your content.

[@pnyarrow]

Hi Brett. Great. Thanks for sharing. I just love that heat shrink tubing. Stay safe. ATB. Nigel

[@survivalcomms]

It is good stuff for lots of projects, Thanks for watching !

[@crx_ninja]

Gathered everything up and built it (the DYI choke) tonight, going to give it a go tomorrow evening. 73 N9SIR

[@survivalcomms]

Awesome ! It is a great project. Thanks for watching

[@TheSmokinApe]

Nice job 👍

[@GreekPreparedness]

I am the envy of all my friends for subscribing to SurvivalComms channel! LOLOLOL😄😄😄😄 got a question though. These 6 inches away from the connector are for no other reason that cable flex, aren't they?

[@survivalcomms]

They are green with envy :) Mostly it is flex and that you are trying to maximize or minimize the length of cable depending on if it is close to the feed point or close to the radio. Thanks for watching !

[@ammocraft]

Do you mind listing the part numbers for those torroids please? Also, would love to know what connectors you use for RG223…..all I can find is Amphenol, at eye watering prices, but like you, I have a heap of that cable! Lastly, what crimp pliers are they? Would also be good to see a second video on how you do the common mode choking measurements on the SA….or better yet, a Nano VNA as most people will have or could afford those. 👍

[@survivalcomms]

I bought a bunch of them from Palomar for another project. The part number is FB36-31 for the beads individually. They sell a kit PN # SLO-1/4-5 that is a five bead variant with the heat shrink. The connectors I used were Amphenol but I bought 50 of them at some point on ebay long ago. Common mode measurement wise I use a couple of leads with alligator clips on one end and RF connectors on the other ( these will work with any test equipment you calibrate for). Clip the grounds together and measure across the center conductor through the device under test. I did it with a nano VNA as well and the result were the same but filming a Nano VNA is a pain in the butt. Thanks for watching !

[@jimpiper5297]

Given the price for choke kits or assembled chokes, this is the way to go. I preferred to make separate chokes vs. assembled integral with the transmission line. But for one source I've seen 'out there', seems the individual chokes are assembled with a PL-259 plug connector on each end. DUMB IMHO as that design requires the use of an SO-239 barrel to connect the choke in line with one's transmission line. To me, the sensical approach is an SO-239 socket connector at one end and a PL-259 at the other. n6med

[@survivalcomms]

100% agree . Thanks for watching !

[@vicmiller7191]

Nicely Done Mister and thanks. take care and 73, Vic de KE8JWE

[@survivalcomms]

Thank you ! Thanks for watching !

[@Oregun]

Nice! Should the choke end of the feed line be placed at the antenna or at the radio for an EFHW?

[@survivalcomms]

I generally run a 25' counterpoise on a 40m EFHW with the choke at the feedpoint. Keep your eyes peeled - I am doing a deep dive on EFHW antennas right now. Thanks for watching !

[@Sky1]

can we use a bunch of the snap-on chokes instead?

[@survivalcomms]

You can try and see what happens. Thanks for watching !

[@Hydrostream1972]

Ferrite.. just a magnet 🧲

[@cgripp256]

Yes, Very specific ferrites/magnets are chosen based on frequency impedance and inductance.