Coax Question?

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barefootindian
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Coax Question?

Post by barefootindian »

Hi all, would there be much of a difference between RG 213 or Westflex 103 for a run of 80 meters strictly for 27 MHz using an Anytone quad 5 into a RM kl 203p into an astroplane copy antenna?
What say ye?
Thanks all.
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ch25
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Re: Coax Question?

Post by ch25 »

viewtopic.php?t=14494

I doubt you'll see/hear the difference on 27MHz between those two.
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bigpimp347
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Re: Coax Question?

Post by bigpimp347 »

you'll be surprised the different at 80mtrs
but don't be tight with the plugs and try to keep anything in line out of line,
even over a couple of mile a simple switch box or SWR meter in line can lost signal.
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ch25
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Re: Coax Question?

Post by ch25 »

bigpimp347 wrote: 04 Jun 2021, 11:18even over a couple of mile a simple switch box or SWR meter in line can lost signal.
How much loss in dB is swr inline?
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bigpimp347
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Re: Coax Question?

Post by bigpimp347 »

ch25 wrote: 04 Jun 2021, 11:41
bigpimp347 wrote: 04 Jun 2021, 11:18even over a couple of mile a simple switch box or SWR meter in line can lost signal.
How much loss in dB is swr inline?
depends on the quality.
i've experimented with my mate locally and noted signal difference from bugger all to up to 2 and 3 's' points
then there's the impedance bump caused by stuff inline so the radio no longer see's a true 50ohm feeder so more loss can be seen there also.
in dB don't know never tried it on the analyser to check.
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Re: Coax Question?

Post by wa10 »

Im using a bit more than 80mtrs of 213 & westflex 103,
103 is almost half the loss of rg213 measured with a decent watt meter at the antenna, It won't change what you can hear on cb radio,

103 is semi air spaced & a pita to route, It won't withstand the abuse that 213 will take.
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barefootindian
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Re: Coax Question?

Post by barefootindian »

Thanks for the answers lads. I was thinking the rg213 might be the best type of coax to go for. The run is pretty straightforward with some slight curves to work around and the rg213 is most likely more flexible for the job. I had the same run using rg mini8 with separate barrel connectors at 25 meters for the first one, and 30 meters for the second one joining the final 25 meters going into the kl203.
I'm sure there was some loss in that setup but when the skip was running my signal made it into Sweden for a ten minute QSO @ a radio 5 signal 4 on a halfwave silver rod barefoot, and also into Italy on a couple of nights with a lemm a t 92 5/8 wave also with good qso's, so I was thinking if I had just 1 uncut run of coax that might help the situation a bit better.
Thanks for all the replies lads and they were very helpful as per usual.
barefootindian
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Re: Coax Question?

Post by barefootindian »

I don't always use the RM kl 203. I prefer to talk barefoot if possible cos that's where the fun is for me.
I talk to some locals fellas on upper side band who would be between 15 to 40 or so miles from my QTH and depending on which way the groundwave is running on any particular evening/night,they could get me from just a sound in the back of the box and no signal, to maybe a signal 3 and up. It really depends on conditions at the time. Sometimes the boost in power doesn't make a bit of a difference and another time it may be a little help.
One chap has talked to me a few times demonstrating his power from 1 watt to 1 kw @ a distance of 20 miles and while conditions were good on that night it was surprising to me to be able to hear him sound low and no signal @ 1 watt to much better signals as the power went up. He normally keeps it at around 25 watts or so.
There are other times when the noise is just mad and no one can get talking to anyone because of it.......aahhh radio fun..
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The Collector
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Re: Coax Question?

Post by The Collector »

The old rule of thumb was to have the shortest possible length of the thickest, shielded co-ax you could get, in a single run (no joints) and straight from aerial to radio if possible (no swr meters, low-pass filters, matchers etc in-line). Every joint and instrument in-line loses just a miniscule amount, but added up it could make the difference between being able to converse with someone or not.

This is only a small part of it though as the aerial type, mounting, position, groundplane effect, overall height, reception of radio (common Cybernet vs Uniden argument), power output and just pure luck with the skip conditions etc all play a more major part. But, as a supermarket chain says: "Every little helps".

Not that I know everything about SSB though as 99% of what I've learnt is based on FM stuff ;)
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Re: Coax Question?

Post by original45 »

Messaged knights last night for specs on their best quality milspec rg58 , received reply earlier "we don't have specifications for this coax". ?????.😂. Not exactly what I expected .
Finding the best coax not only to suit your need But the best for value too is a real pain .
Personally liked unispectra rg58 tinned copper 96% braid. But not available presently.

Need to replace several mag mount leads to improve swr and don't think the 223rg will be suitable as it's solid conductor.
My advice is if you find a good coax buy more and store it safely although I believe conditions deteriorate coax.
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ch25
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Re: Coax Question?

Post by ch25 »

Replacing coax is not the way to improve swr anyway.
Unless it is 75Ohm coax :)
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Re: Coax Question?

Post by original45 »

Can only go by findings other day, had a swr of 1.5 on channel 1 mid, channel 40 high .
40 mid and 1 high, close to centre were 1.4 ,added the extra patch and centre dropped to 1.1.,
Why Chris I don't Fully understand yet is linked to length I'm sure as tried 3 patch lead lengths all improved shortest more so.


Any thoughts
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ch25
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Re: Coax Question?

Post by ch25 »

If you really want to know what is SWR at the antenna you have 2 choices.
Get instrument which can subtract coax from measurement or use 180° length coax.
When SWR readout is changing when you change coax length it means, that antenna is far from tune.
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original45
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Re: Coax Question?

Post by original45 »

You know better than 1 Chris , I stumbled upon it by accident.
Will have another play with it when time allows. Such technical equipment would be wasted on me Chris .
Will look again and try tuning antenna again see what happens.
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Re: Coax Question?

Post by Werthers »

I wouldn't get hung up on coax types just experiment and use what suits you best. Just beware that some of the coax you get from certain sites isn't what its advertised as.
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