Line Isolator - Installing and Testing | Ham Radio
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- Опубликовано: 28 авг 2024
- It is generally accepted that a Line Isolator is necessary in most Ham Radio stations. Peter G3OJV, describes a simple method of both in stalling and testing one. It can also help to reduce noise.
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I really appreciate your tips on how to make the most out of available resources.
Hello and 73s from Arizona, USA. Always fantastic content and very well done. My go to elmer!
Thank you very much! Nice to hear from you. 73 Peter.
Hi Peter, I put up a 40m rotating dipole without rf choke or balun, and immediately I had rf in shack wipedout computer, installed a balun , helped a bit. But still rf, just watched your video about rf chokes. Great now I know I need one and ( WHY) . 👍, great informative videos. Been watching quite a few.
Thanks sean GI7ULG. 73.
You are very welcome
Great video, Peter! I'm a new ham with a very modest yard and equally modest budget, and I really appreciate your tips on how to make the most out of available resources. Many thanks, and 73! KK7IRZ
Very welcome!
g'day! I think it would have been nice to see what happens to those readings WITH an isolator in place.. OTOH I always enjoy your content for its information payload and value, thankyou! vk3ola
, isolator on end of coax& 31mix ferrites on scu-17 usb lead. Now my computer is rf free yyaaaa. Thanks 👍
Thanks for sharing this information. This demonstration is remarkable in its simplicity and very impactful in its depiction. Appreciated! 73 de KB3ZIM
Glad it was helpful!
Thanks Peter. Thanks for showing how simple it is to test and to fix the problem.
Glad to help
Glad to help.
Thanks again, Peter. A great and simple explanation.
Many thanks!
I was able to find some quite chunky ferrite beads with an internal diameter that was a tight fit on RG58 coax. I put 12 of them on a length of coax with gaps in between to keep it flexible and put some adhesive heatshrink over it. Add PL25(s and I use it as a patch lead from my antenna switch to the radio. It really does work incredibly well.
Yes a popular alternative.
Flickering LED lighting strips and device inserted/removed sounds from my PC told me I had a common mode current issue. I used the same ferrite as you with six turns and eliminated it. Thanks for a useful video.
Glad to hear you solved the problem
Thank You Peter! Very interesting subject! 👍👍👍
Glad you enjoyed it
5:31 that's just proof positive you are a very "well grounded individual"! 😁
Thank you, very informative!
You are welcome!
Very nice video Peter! 👍📻⚡Thanks! Tom - WA7FLY
Always used a handful ferrite clamp on's seem to help
tnks fer good info 73
I have the coaxial and also the usb cable to the trx threaded through the FT240-43 toroidal core. Each over one core. I have 8 turns of 0.8mm copper wire on the core and a led diode connected to its ends. This diode lights up when RF is generated. So I have immediate detection. RF can reach the coaxial via the antenna switch, etc. Try it and see what kind of RF you have and on which frequency.
Nice idea.
Thanks Peter, I never knew that
Thanks for watching.
Very helpful. Thank you. If there are significant common-mode currents of the sheathing and the choke prevents them from getting into the shack, are those currents sent back to the antenna to aid the transmitted signal, or are they just absorbed by the ferrite?
Some radiation and some absorbtion.
Great advice as usual...W6QR
Thanks for watching!
Thanks Peter. A quick question, does the choke affect the outbound RFas well?
No the outbound RF travels only on the inside of the coax.
Thank you I wasn't sure if it affected other parts of the coax. It is a pity that common mode energy can't be re-injected into the outbound signal. @@watersstanton
Fab video
Many thanks.
Nice test! Wich ferrite core did you suggest for a coax with 7mm of diameter? Thank you and 73 de IW0RZB
The first part of the code is diameter ie 240mm whilst the second part is the mix ie 43. So any diameter of 43 mix is fine.
@@watersstanton many thanks!
He mentioned mix 31 in the video - generally more effective for lower frequencies (like 60, 80, 160). Mix 43 is also a good multi-purpose … but a bit less effective at the lower frequencies. Basically, you’d just need more turns for the same choking impedance at lower frequencies.
Would it be OK to always have a line isolator connected and just leave it connected?
In a word, Yes.
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Another field test I read about is to first just barely insert the center conductor into your radio, and listen for noise level. Next, insert fully so that outer ring makes contact as well and if noise increases, you would probably benefit from a choke on it. For anyone curious, I found that somewhere on the Palomar Engineering website. I've not tried it yet, but plan to when I have time.
Not sure that is valid test - try the same test with and without the choke.
Why not put the line isolator closer to the balun?
No no no…. you will expose the res of the outer coax line to pickup as explained in the vifeo.
Would a 1:1 unun work?
The line isolator is only to correct transmission SWR and a choke near the antenna is to prevent the coax from radiating as part of the antenna is completely separate? @@watersstanton
@@m3snusteveyes
A 1:1 unun is just another word for line isolator.
Just like the W1JR balun... This is a line isolator in a housing with two SO239 plugs.
What Peter showed is just the same without any housing and plugs.
@@aarongriffin81the balun in the middle of a dipole is to avoid common mode caused from the antenna itself.
Both legs are subject to slightly different environmental conditions, this could create common mode current.
The line isolator right in front/ after the TRX gets rid of any other common mode current occuring because of a mismatched antenna or QRM from any probable source that's on the outside of the shielding.
It gets onto the shielding AFTER the balun in the middle.
This could be radiation from the antenna if it's too close and parallel to the cable, any electronics nearby etc.
It often happens with vertical middle fed dipoles, when the feedline is just dangling down, parallel to the lower element.
You need to guide it away perpendicular to the elements as far as possible and choke it right before the TRX.
I'm no native speaker so I hope you get what I tried to explain.
i certainly would not advise touching the PL259 while keying up. Please don't do this; fine if you are using an analyser but don't use your rig, not even at 5w Just saying, stay save
You are overstating the risk. The PL-259 outer is connected to the radio chassis, and there are many 5W HF handheld radios. So be careful but not to that extent!
@@watersstanton that maybe so, but a risk none the less and i would still suggest not to key up and place your hand anywhere near any patch cables or down the back of the rig. Invest in a analyser, would be perhaps a better suggestion.
add an isolator and try the test on 40 again!
Getting an RF burn is part of your initiation, if your system is producing results like peter is showing then where did your knowledge go to, I mean you did pass a test.