Wellbrook Magnetic Aerial

[Radio Fixer]

Seems you are really happy with the Loop John. The video shows what it can do.

Soon will be fixing mine up properly

thanks Gary

[Eddystonepete]

Hi John, totally agree with your findings on the wellbrook, great results if a bit dear. I bought one of the Degen loops, similar to the Kaito, it worked but was a bit noisy. Before I got the wellbrook I used this design.

http://www.m0lmk.co.uk/2015/02/14/active...na-for-hf/

Was the best of many I bulit and tried pre Wellbrook. I tried tuned loops too, some gave great results but were inconvenient to tune or overloaded the front end. I,ve got the Wellbrook on a rotator in the loft but before that had 2 of the above active loops at 90deg. My Rxs are FRG7700 and Cross Country SDR4

Peter

[Geaney]

Any suggestions for a rotator for my aerial?   Right now it's fixed but of course if I can rotate it all the better.  

Also I was wondering about impedance matching for vintage radios.   Even though the performance is already excellent I assume most radios if this ilk are set up for a 'long wire' type aerial and an impedance of around 300 Ohms.   Ideally therefore I should have some form of 50 Ohm to 300 Ohm matching transformer in the feed to my vintage sets.   Having surfed around I haven't found anything suitable so would appreciate the views of the team on this.

Cheers,   John

[Radio Fixer]

Conrad Electronics used to do a rotator for less than £60 but discontinued it in 2014 which is a shame. Don't know of any others at this sort of price.

I asked the chap at Wellbrook about matching . For radios that have a balanced input (three of my domestic sets have this facility) he can supply a Balun which might improve the sig to noise performance even more.

On radios that don't have that, just long wire input, I don't think a transformer would make much difference. You could try adding a few hundred Ohms in the lead to the aerial socket but probably you will lose as much gain in this as you do from the mismatch as it is.

Gary

[Eddystonepete]

Hi John, The Wellbrook doesnt give very large peaks as you turn it but gives a quite sharp null. If you carefully chose your direction you may not need a rotator!. That said how about using a radio control servo for a rotator?  Remember that you only need 180 deg. rotation. Most RC servos are a bit fast for this job but a sail winch servo is slower and more powerful. They can be driven by a "servo tester", one chip giving a 1 to 2 millisecond pulse every 20 milliseconds. Heres one,

http://www.ebay.co.uk/itm/GWS-Digital-Se...1677285120

I never thought about matching but I wanted a splitter that would feed 2 rxs. This one, the DH-P worked fine

http://www.dxing.info/equipment/rolling_..._bryant.dx

I used a ferrite bead and fine wire. Maybe altering the turns would give matching too. as a splitter it worked very well, only losing about half an S point with no noticeable loss of intelligibility.

Peter