Intro to Coax Cable Feedlines for Ham Radio

In this video we explore the basics of coax feedlines for beginners. Starting with the anatomy of a cable, we break down each component and briefly touch on their composition and purpose. Please note: I know that I use some oversimplifications - this isn't meant to be a comprehensive analysis, rather a quick start for someone new to the hobby. In a future video I'll give my recommendations of feedlines for different use case scenarios. 73s - AC3DS.

[@stayin91degrees]

this is so well put together, thank you for this! great video

[@transmittinguntilrobotsrep1045]

Thank you for watching and commenting. We appreciate the feedback. We are glad it was helpful! If you have any suggestions on other videos, please don’t hesitate to post. 73.

[@g0fvt]

Very well presented and accurate. Note that power handling and loss of the cables are worse with significant SWR.

[@paulgarcia1566]

Great video. You were great at explaining the details and made coax easier to understand. Thank you!

[@vasilatosianis4208]

Thank you for the explanation !

[@Ripper13F1V]

Fantastic video. I'm just knocked out both Tech and General and started to build my shack. I ended up getting LMR400 direct burial stuff. I didn't understand it, but you did a wonderful job explaining it and dissecting it. THANKS!!

[@transmittinguntilrobotsrep1045]

Congratulations on passing both the Tech and General! LMR400 is a great cable and will serve you very well for many years to come. Thank you for the feedback and good luck in your radio adventures! 73 - AC3DS

[@tnyberg67]

Helpful. So my question now is do we want a Velocity factor closer to 100% or less? It seems 100% is perfect? And for a 2M Mobile set up on a desk with a 50 foot run to the jpole 2meter antenna. it looks like RG8 is a bit thick for that little run? what is the most common cable for that setup? 213? Suggestions on where to get cable.

[@MrRockydee07]

What is the DRX-1518 coaxial cable? I like it because the connector can be removed for cable easy cable routing ... thanks

[@jonsimmons5041]

How do i find out my send receive frequencies

[@R50_J0]

For any direct burial flexible coax application, or burial in conduit, I would only use the "flooded" type of cable. Without flooded cable, one jacket pinhole or nick from a sharp rock and the braid will wick moisture into and along the braid. This ruins the RF characteristics of the cable. My thinking is, if I'm going to lay a significant run of LMR-400, then I'm going to pay a little more to protect my cable investment. The flooded cable's braid is impregnated with a silicone gel that completely resists ingress of water even if the jacket is breached.

[@thork0tjt515]

Great video!

[@transmittinguntilrobotsrep1045]

Thanks! I'm glad it was helpful. Hope to catch you on the air sometime. 73

[@jamescopeland5358]

Good video

[@Kim_Darkman]

for years I've been wondering why they keep using rg58 and such for magnet mounts and most mounting parts what comes with a cable?! does it really cost that much more for bigger brands/manufacture to use better coax?! I like to have better coax even in hf bands coz I like to get every performance out I can get, in any given situation..

[@g0fvt]

If the SWR is low a few metres of RG58 don't represent a huge loss at lowish frequencies. . Lower loss cables tend to be a bit unwieldy.

[@roguepilot1]

Have the robots replaced you? Haven’t seen a video in some time

[@bigcap01]

Is there a specific type of coax that works better or is there a specific coax for HF, VHF and UHF based on the megahertz? All so does coax length matter to get low SWR?

[@guyvaughn1067]

Awesome information! I love how you go deeper than other Ham videos go.. Are you a Physics teacher/professor?

[@transmittinguntilrobotsrep1045]

Thanks for the feedback. I do work in education, but I’m not a Physics or science teacher or professor. I do help to lead STEAM/STEM projects though. Really, I just love to learn and share. Please let me know if there are any topics which you think would be beneficial for the community and I’ll gladly work on them if possible. 73 AC3DS

[@guyvaughn1067]

@@transmittinguntilrobotsrep1045 A deep dive into any Ham topic would be very useful.

[@revbikerbigd8664]

Great video! How about testing coax lengths and finding shorts in cables using a MFJ 259D ?

[@transmittinguntilrobotsrep1045]

I wish I had a MFJ 259D - those are great analyzers! I've tested Coax lengths with my NanoVNA and it worked well.

[@warrenpercell297]

Can you explain "repeated bends"?

[@transmittinguntilrobotsrep1045]

Good question, thanks for asking: Fixed Bends are when you form a loop coil such as a choke balun with the cable and then leave those loops more or less permanently in place. These loops can be generally be smaller in radius because they won't have the stress of flexing. (Example: Fixed installation at the house.) Repeated Bends are when, with some regularity, you are coiling up the cable for temporary storage and then will be uncoiling it. Because you are repeatedly bending the cable, you want less stress on the internal structure so as to prevent fracturing. A solid center conductor can easily break with repeated bending. (Example: Going out to do Parks on the Air and bringing a 50' feedline with you and needing to roll it and unroll it every time.)

[@warrenpercell297]

@@transmittinguntilrobotsrep1045 Thanks for the clarification. Great video for beginners and old hands alike.