What's the best Coax for our use?

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MiXiN
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What's the best Coax for our use?

Post by MiXiN » Thu Jul 22, 2021 3:05 pm

I've heard LMR400 is good, but if kinked, it's easily broken.

Can anyone give some pointers to as to what the next best option would be?

I'll only need a 10 metre run, and it would be best if it can be bent around corners with reasonable ease.

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Re: What's the best Coax for our use?

Post by Bton-FM » Thu Jul 22, 2021 3:22 pm

What about RG213? Get yourself a crimp tool and some N-type connectors as well to fit on the ends.

PL259 connectors are ... how shall we say it ... WANK!

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Re: What's the best Coax for our use?

Post by thewisepranker » Thu Jul 22, 2021 5:05 pm

All coax is knackered if kinked, not just LMR400. Good luck kinking it though. The centre conductor is solid, not stranded - it's hardly flexible.

It all depends on how much you're willing to pay for your coax, higher performance costs more. LMR400 is nice but pricey. RG213 is acceptable but quite lossy. WF103 is better but a bit more expensive.

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Re: What's the best Coax for our use?

Post by Albert H » Fri Jul 23, 2021 2:37 am

Also, it depends how far you need to go with your coax and what you're trying to pass through it. A short "patch" lead could be made out of lowly RG58. Link receive aerials can be connected with RG59 or ordinary "low loss" TV coax. I have even used "Belling Lee" TV connectors for link receive aerials and even for link transmitters (my stuff all worked in the UHF TV bands and matched 75Ω so I could use cheap and readily available TV Yagi aerials)
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Re: What's the best Coax for our use?

Post by MiXiN » Fri Jul 23, 2021 8:47 am

Thanks for the replies.

My Antenna (Sirio GPA 66-108) unfortunately uses a SO239 socket, so I guess I might as well go for RG213 as it's already presumably going to be a lossy socket.

Why Sirio don't use a BNC, N type or similar socket is beyond me.

I'm not too keen on how thick RG213 is as I use this on HF, but I can live with it.

I've used an homebrew 1/4 wave GP antenna before made out of thick enameled copper wire and found it really easy to tune, so I went for a more robust version.
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Re: What's the best Coax for our use?

Post by mikroman » Fri Jul 23, 2021 12:42 pm

10 meters of rg213 is quite acceptable on VHFII (0.7dB loss is negligible in practice). The PL259 does a good job in the same frequency range if it is well mounted. The disadvantage is that in itself there is no good protection against moisture. But with this type of antenna this should not be a problem either. However be careful this antenna is not DC grounded so there is a greater risk of atmospheric discharges making a mess on the equipment.

In the absence of a better one, rg58 can also be used, the loss is somewhere around 1.2dB at 10 meters. Noticeable but still acceptable loss. I just wouldn’t push more than 100W into it.

Regarding the receiving antennas and cables, Albert is absolutely right. I had the opportunity to mount an eight field antenna for 380MHz reception. During the assembly, I improvised and used an RG6 about 8 meters long. When replaced with 1/2 heliax the voltage on the frontend increased imperceptibly.

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Re: What's the best Coax for our use?

Post by Bton-FM » Fri Jul 23, 2021 6:16 pm

mikroman wrote: Fri Jul 23, 2021 12:42 pm The PL259 does a good job in the same frequency range if it is well mounted. The disadvantage is that in itself there is no good protection against moisture.
This is what I was getting at - they aren't waterproof at all! Also, they are a nightmare to fit when compared to an N connector. If you don't have a massive soldering Iron to solder the braid/centre pin with, the dielectric of the coax will melt and will no longer be 50 Ohms any more.

There is definitely a significant mismatch caused by the SO239/PL259, but it's not enough to worry about as a pirate at 100MHz.

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Re: What's the best Coax for our use?

Post by mikroman » Fri Jul 23, 2021 7:04 pm

Yep!
there is another possibility - the purchase of a PL-N adapter. After assembly, do heat shrink tubing (Raychem have great products) and if everything is done well, you have no problem with this anymore.

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Re: What's the best Coax for our use?

Post by mpx » Fri Jul 23, 2021 8:42 pm

Use RG213 MIL spec with solid PE dielectric and it shouldn't melt if you have a half decent soldering iron, an Antex 30W will do it.

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Re: What's the best Coax for our use?

Post by MiXiN » Sat Jul 24, 2021 3:12 am

mpx wrote: Fri Jul 23, 2021 8:42 pm Use RG213 MIL spec with solid PE dielectric and it shouldn't melt if you have a half decent soldering iron, an Antex 30W will do it.
I bought myself 10M of Mil Spec' RG213 today, and I'm quite well versed with soldering PL259 plugs on as I've done it many times in the past.

In addition to my low wattage Antex 15W iron, I've got an 80W Antex Soldering Iron, and this is perfect for this job.

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Re: What's the best Coax for our use?

Post by thewisepranker » Sat Jul 24, 2021 1:21 pm

mpx wrote: Fri Jul 23, 2021 8:42 pm Use RG213 MIL spec with solid PE dielectric and it shouldn't melt if you have a half decent soldering iron, an Antex 30W will do it.
You're supposed to solder the braid in the two windows, to the main body of the connector. There's no way you're going to get a wet joint there with a 30W iron. It's sometimes a struggle with a 200W Weller because of the crappy plating.

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Re: What's the best Coax for our use?

Post by mpx » Sat Jul 24, 2021 2:06 pm

I usually manage to solder the two windows on the cheaper PL plugs with a medium Antex iron, the ER30. The small XS25 won't do it, but my 100W wide tip is a bit overkill. I avoid the cheap plugs with the white plastic centre which melt and go for the brown 'bakerlite' type. Getting a good solder joint to the outer edge of the two windows can be tricky but with decent solder it works okay. Too much heat and the outer sheath starts to break down so there is a happy point of just enough heat to do the job.

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Re: What's the best Coax for our use?

Post by MiXiN » Sun Jul 25, 2021 1:18 am

thewisepranker wrote: Sat Jul 24, 2021 1:21 pm
mpx wrote: Fri Jul 23, 2021 8:42 pm Use RG213 MIL spec with solid PE dielectric and it shouldn't melt if you have a half decent soldering iron, an Antex 30W will do it.
You're supposed to solder the braid in the two windows, to the main body of the connector. There's no way you're going to get a wet joint there with a 30W iron. It's sometimes a struggle with a 200W Weller because of the crappy plating.
Every day is a school day.

I never knew that the braid needed soldering through the 2 holes, and have always just screwed the coax in with the braid brushed back, then just soldered the centre conductor to the pin.

I've never had any issues in the years I've done this, and all patch leads I've ever bought have been done like this.

Is this just a VHF thing or are there different methods of doing it?

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Re: What's the best Coax for our use?

Post by rigmo » Sun Jul 25, 2021 9:37 am

thewisepranker wrote: Thu Jul 22, 2021 5:05 pm All coax is knackered if kinked, not just LMR400. Good luck kinking it though. The centre conductor is solid, not stranded - it's hardly flexible.

It all depends on how much you're willing to pay for your coax, higher performance costs more. LMR400 is nice but pricey. RG213 is acceptable but quite lossy. WF103 is better but a bit more expensive.
WF103 £1.85 only

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Re: What's the best Coax for our use?

Post by rigmo » Sun Jul 25, 2021 9:46 am

MiXiN wrote: Sun Jul 25, 2021 1:18 am

Every day is a school day.

I never knew that the braid needed soldering through the 2 holes, and have always just screwed the coax in with the braid brushed back, then just soldered the centre conductor to the pin.

I've never had any issues in the years I've done this, and all patch leads I've ever bought have been done like this.

Is this just a VHF thing or are there different methods of doing it?


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Re: What's the best Coax for our use?

Post by mpx » Sun Jul 25, 2021 11:10 am

Westflex is good stuff, the only thing is though if it gets water in it your rig turns into a welder and you're fecked. Same if it gets kinked.

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Re: What's the best Coax for our use?

Post by MiXiN » Sun Jul 25, 2021 11:43 am

rigmo wrote: Sun Jul 25, 2021 9:46 am
MiXiN wrote: Sun Jul 25, 2021 1:18 am

Every day is a school day.

I never knew that the braid needed soldering through the 2 holes, and have always just screwed the coax in with the braid brushed back, then just soldered the centre conductor to the pin.

I've never had any issues in the years I've done this, and all patch leads I've ever bought have been done like this.

Is this just a VHF thing or are there different methods of doing it?

I always did it this way like many others I know, including Martin Lynch's store -

I'll try the other way now.

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Re: What's the best Coax for our use?

Post by MiXiN » Sun Jul 25, 2021 11:53 am

mpx wrote: Sun Jul 25, 2021 11:10 am Westflex is good stuff, the only thing is though if it gets water in it your rig turns into a welder and you're fecked. Same if it gets kinked.
I was seriously considering buying this Messi & Paoloni Ultraflex 7 but I got a good deal on some Belden RG213 - https://www.hamradio.co.uk/accessories- ... d-5633.php

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Re: What's the best Coax for our use?

Post by mpx » Sun Jul 25, 2021 12:07 pm

Moonraker sell f-zero coax, 1.5dB better over 100m at £1.60 a metre
https://moonrakeronline.com/f-zero-coax ... -per-metre vs 213 (6dB/100m) at £1.30 a metre. For shorter runs the difference is negligible

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