Topband: Wellbrook receive loop performance

W2PM w2pm at aol.com
Wed Apr 11 12:24:06 PDT 2012


BCB work would be good for the Wellbrook and I suspect that is their target market. 

Sent from my iPad

On Apr 11, 2012, at 9:14, joe <galicic at comcast.net> wrote:

> I made some signal to noise measurements last night between my short BOG
> and LOOP. Local (100-300 miles away) cw signals. The Loop, which is
> still living in my basement, is within 3DB of the BOG.  I will move it
> outside soon and see what happens to SNR.  I still need to try it out on
> some weaker DX stations.
> 
> The LOOP has also proved to be promising on hearing multiple AM
> broadcast stations on the same frequency due to its good nulling
> capability.  I could never do this with the BOG or L.   
> 
> 
> On Tue, 2012-04-10 at 11:04 -0400, joe wrote:
>> I built it in one evening using two pieces of scrap 1x3 lumber for
>> spreaders. I pounded in four large wire staples to hold the wire to the
>> spreaders and threaded both loops through them. The five wire and one
>> wire pickup loop are not separated.  I used a variable cap of roughly
>> 150-200PF to resonate the 5 wire loop.  I fed the pickup loop directly
>> with RG-58 coax.  No matching transformer. The loop is roughly 32 inches
>> square.  I tune the cap for maximum noise for the desired frequency.
>> The loop is tunable from about 1600 - 1850 KHZ. 
>> 
>> I modeled my loop after the following designs for unshielded loops.
>> 
>> http://www.i1wqrlinkradio.com/antype/ch9/chiave1183.htm
>> 
>> http://members.verizon.net/~vze24qhw/loop.html
>> 
>> 
>> On Tue, 2012-04-10 at 08:49 -0400, joe wrote:
>>> I am experimenting with a small one meter square loop.  It is 5 turns of
>>> #14 wire with a one turn pickup loop.  Feeding the pickup loop directly
>>> with 50 ohm coax.  Using air variable cap to resonate the 5 turn loop.
>>> I have it setup in my basement on a tripod with small TV rotator and it
>>> works amazingly well.  I can null stations about 3-4 S units with it and
>>> it is about 4 S units (24 DB) quieter than my inverted L.  I also have a
>>> short 140 foot BOG and the loop performs nearly the same with the added
>>> ability null out noise sources.  I plan to move it outside and take some
>>> more measurements.  I'm pretty impressed so far.  -Joe KB3KJS
>>> 
>>> 
>>> 
>>> 
>>> On Mon, 2012-04-09 at 17:17 -0700, Jim WA9YSD wrote:
>>>> How well does this antenna perform in a City environment like mine on top of a 50 foot tower?
>>>> 
>>>> Stay on course, fight a good fight, and keep the faith. Jim K9TF/WA9YSD
>>>> _______________________________________________
>>>> UR RST IS ... ... ..9 QSB QSB - hw? BK
>>> 
>>> 
>>> _______________________________________________
>>> UR RST IS ... ... ..9 QSB QSB - hw? BK
>> 
>> 
>> _______________________________________________
>> UR RST IS ... ... ..9 QSB QSB - hw? BK
> 
> 
> _______________________________________________
> UR RST IS ... ... ..9 QSB QSB - hw? BK


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