Coax Enquiry???

[barefootindian]

By the way, would there be much of a difference to my output signal on ssb if I joined rg58 with tri lan 240 both of which are rated at 50 ohm using a pl259 barrel coupler??? I take your point about having the signal as clean as possible and using the low pass filter last before I hook up to the antenna.

 

[The Mad Scientist]

By the way, would there be much of a difference to my output signal on ssb if I joined rg58 with tri lan 240 both of which are rated at 50 ohm using a pl259 barrel coupler??? I take your point about having the signal as clean as possible and using the low pass filter last before I hook up to the antenna.

you would be better off using the same coax type if you choose to do it that way. otherwise if you use two different coax types you could end up with a impedance hump. adding the barrel connector will just add insertion loss into your feedline. it would be better to just measure the total coax length you have now and choose what you would like to use and cut one continous length.

 

[Beetle]

The insertion loss and slight impedance bump might be verifiable with lab-grade instruments, but the guy on the other end of the contact won't know it, and your transmitter won't either, if the coax and connectors are in good condition. 50 ohms made by Belden and 50 ohms made by Times-Microwave or anyone else are all (wait for it....) 50 ohms.

 

[The Mad Scientist]

both are correct. i was refering to coax types of different volicity factors. in any case, it is a better practice to have it one length. is it not?

 

[Beetle]

both are correct. i was refering to coax types of different volicity factors. in any case, it is a better practice to have it one length. is it not?

If possible (and practical), yes. But I'd bet the OP won't notice any significant difference, IF both pieces of coax are in good shape and the connectors properly installed. I've used worse feedline mishmashes than this and worked the world on 15M with 10 watts CW.

 

[barefootindian]

Hi all and thanks again to Bandit35 and to yourself Beetle. I asked the question as I wasn't sure if doing that ( mixing coax grades) though also knowing not to mix different Ohm types ie 75 and 50, if the loss value would be all that noticeable~ however it seems that it may not be.I still have no LMR 240 but I'm making enquiries with various cable suppliers to try to purchase a 100 meter drum at a suitable price. It'll be good when I finally get on air. Thanks again folks.

 

[The Mad Scientist]

your welcome. please let us know how you make out with it.

 

[psycho]

Hi All, Has anyone used a type of coax called LMR240. I was going to get a roll of Mini RG 8 and was wondering if it was generally a solid enough performer for cb transmissions. So I went on the web and clicked on a forum from eHam net, and the subject was a question which was 'Which is better RG213 'v' RG8 Mini'? and I read down the screen and one contributer mentioned a coax called LMR240. I then went on a search for same and found that it is a 50omh coax with an attenuation of 1.3 or 1.7 or so. It's claimed to have a lower loss dB wise than RG8 mini. Does anyone know about or used this type of coax in their set-up. How has it performed for them???

Someone on Eham asked asked which is better 213 or mini 8?????????? That is pretty ignorant question for a ham operator to ask.
LMR 240 is double shielded handles 1500 watts and is the size of mini 8.....perfect for mobile applications.

 

[The Mad Scientist]

it sure is.

but it hleps to remember that it is a foam dielectric and extra care needs to be used when installing it, as it is much easier to ruin when pinched in a door or trunk...etc. as compared to a ploy dielectric coax.

 

[barefootindian]

Bandit35 I'll let you know how things go when I finally get on air. It's gonna be a few weks though. I'm hoping it all works out. Thanks again.........

 

[The Mad Scientist]

no problem, good luck and happy fathers day.

 

[Groundhog KSS-2012]

I found a page here called, "Why 50 ohms?"
I know 50 ohm cable is what most of us use but, trying to understand calculations and figures on this page just blowed my mind!
Some of you might understand a lot of this and/or, may have already read it. Thought it might interest some of you.

Microwaves101 | Why Fifty Ohms?

Microwaves101 | Why Fifty Ohms?

www.microwaves101.com