If you are running appreciable power compared to the size of the choke, then exposed to the elements aids cooling, particularly in RTTY and AM. See Jim Brown's amazing research on chokes. David G3UNA

I recognise that, however, are ferrites water absorbant at all? quick test, put one in a bowl of water and stick it in the freezer. : - ] David

Stephen I have no direct experience of cores breaking in cold wx, but I have heard it said that uncoated cores should be wrapped with tape or dipped to make it impervious to water and thus freezing. I

The CCW inverted U, particularly when the 2 ground connections are connected by a direct wire is more of a terminated loop like many others that have been around for many years, eg a Beverage or a fla

Did you notice any directional effects? Did you arrange the height/length as in the website? What was the swr like? David G3UNA

Sounds very interesting. For the ultimate in portability (or long term independent monitoring) a fully battery operated system would be an advantage, so, what is required of the pc? What is the minimu

It doesn't interest me, but there's a lot of competition in this area, so, is there something, other than price that gives you an edge? David G3UNA

I suppose you could look at it like that and I've thought several times about building one but my focus is on getting some directional quality. I have yet to model the inverted U and note Chris offers

Thanks, Roy. At one time or another I will have seen all of these but it's good to have them in one place and refresh my ideas of what's possible in back yard. I usually reject a lot of such articles

I bought the pair a while ago but still haven't installed it. Note you can join each earth spike with a thick wire across the intervening space. It would be good to compare notes of your arrangement,

EA5byp on 1823.6 clear as day with no snap, crackle and pop! Can't remember the last time I heard a quiet band David G3UNA

Listening in to TB and a station around 1942 is very clear with no typical local noises. How do I get it to tune down to cw portion? I've tried typing in and dragging but neither are working for me, p

I would be interested in hearing users' typical use of the multi-couplers. I think a couple of my members may be interested but are not sure about arrangements that are popular. David G3UNA

Would this be a T network attenuator to get 9 x 50ohm on the input of the balun? and an earth plane for the DUT and VNA? David G3UNA

Hi Chris Could you post a pic of your set up for this measurement, I'd like to test some chokes and I think jig layout is very important to avoid capacitive pick up.

Thanks, Chris they look very encouraging numbers. I'm not sure how to relate that to the numbers found for chokes from the likes of K9YC and G3TXQ. They look for resistive loss to the common mode sign

What isolation do you expect from the TIU 9:1 balun? David G3UNA

Hi Robin, I clicked on that link and it brought up some advertising David G3UNA

Chris I came across the following article for a rx terminated loop http://www.ok1rr.com/index.php/onair/8-qmgr This uses about 100ft (~33m) of wire which is similar to yours if you used a "ground" wir

After NARSA there is the Ripon rally on the 23rd and I'd be delighted to have you come along and show your wares. Then there's the Cambridge rally and so on. Looks like a busy year for you. David G3UN