looking renewing my coax for my ocd will also be making a choke anyone recommend a good quality flexible coax only short run so losses not important.

Many Thanks In Advance

Andy....

What power level? And what diameter do you need to be able to bend it to?

Steve G3TXQ

100w at the moment maybe go to 400w later on and 2 1/2 inch pipe. im getting a lot of rf in the shack and the sdr radio doesnt like it.

Andy,

RG-58 is rated to about 350W continuous at 30MHz and would probably be OK for anything other than a 100% duty-cycle mode. RG-400 would be my choice if you needed a bit more "headroom".

But be aware that any air-cored choke will only be effective over a relatively narrow bandwidth; ferrite cored chokes are much more effective for wideband applications. More details here:
http://www.karinya.net/g3txq/chokes/

Look at how narrowband air-cored chokes are, and see how they can actually increase Common Mode current in some situations.

73,
Steve G3TXQ

Think the best for me might be beads on my coax i have lmr400 what do you think 6 or 10.

Many Thanks

Andy.

What frequency range are you trying to cover?

Steve G3TXQ

40m is the one i get most shack rf with.

You would need an absolute minimum of 10 beads, preferable a lot more.

Beads are not as effective as multiple turns on a ferrite toroid. 12 turns of RG-58 or RG-400 on an FT240-31 core would make a very effective choke for 40m.

73,
Steve G3TXQ

12 turns it is then.
Many Thanks for all you help & patience

That is on a core though and NOT airwound

billy

yes on the FT240-31 ?

Correct. Available here:
http://www.ebay.co.uk/itm/FT240-31-HUGE ... 43b1fe56fc

Steve G3TXQ

Cheers Steve going to get a couple, Any idea on where i can get RG400?

i picked up some 1588's today £2.00 each from haydon comms in Brierley hill

http://www.gigatronix.co.uk/default.php?_minc=show_part_template_1&__utma=173680181.2091883133.1343673054.1343673054.1343673054.1&__utmb=173680181.4.10.1343673054&__utmc=173680181&__utmz=173680181.1343673054.1.1.utmcsr=%28direct%29|utmccn=%28direct%29|utmcmd=%28none%29&_lang=&gpdb_product_id=7616&

Have never used them though.

You could also try eBay