[IRCA] The "Pipe Dream" Traveling MW Monster Loop Antenna

[D1028Gary@xxxxxxx]

Hi Mark,
 
Thanks for your generous comments on the collapsible large MW loop antenna  
system, which are greatly appreciated (especially from a DXer of your 
technical  stature).
 
Of course I agree with you that cardioid-pattern directional antennas like  
the Flag, Kaz, Ewe, etc. are optimal for DXing in the face of strong 
in-line QRM  from the back side, such as when chasing TA's from the NE, or chasing 
DU's from  the NW. In the winter of 1972-73, I was a young sailor DXing on 
a ship at the  Charlestown Navy Shipyard in south Boston, so I know how bad 
the QRM is from NYC  and other big cities.
 
The "Pipe Dream" collapsible MW loop system was primarily designed to give  
a huge DXing boost to travelers unable to erect large antennas (for various 
 reasons), but who still want excellent gain in a remote location. The  
figure-8 reception pattern, while dicey in some situations, still provides  
exciting DX possibilities during autumn TP DXing here in the NW (at Grayland),  
when Asian stations typically can be received easily in the null of local  
domestics. A large 6' MW box loop design also provides superb gain for  
users of modest receivers like Ultralight radios, making them very  competitive 
in sensitivity with more expensive models. The degree of  DXing gain and 
nulling ability provided by a 6' collapsible PVC loop  could allow even a $9 
Tecsun R9012 owner to have serious fun at Grayland,  around October. 
Considering that the total cost of a collapsible 6' PVC  loop system is around $40, 
it may provide great DX value for the $$.
 
Of course I have great interest in your car-based micro superloop system,  
Mark, and hope to experiment with it when more time is available. As with  
most tinkerers, I have discovered that there seems to be far too many  
interesting hobby projects for the limited free time available. Thanks  once again 
for your comments, and for your great antenna experimentation and  radio 
reviews in previous years, which gave inspiration to the current group of  
tinkering fanatics.
 
73, Gary
          
 
 
In a message dated 5/5/2009 11:43:38 A.M. Pacific Daylight Time,  
markwa1ion@xxxxxxx writes:

This is  quite an advancement in large, but still portable, loops.  I 
think  urban DXers will like the fact that it is passive so it doesn't 
produce  any distortion products on its own.

Some may be able to make good use  of this, but here on the East Coast, 
an antenna that gets stuff from the  direction opposite to desired DX is 
not often going to be the first  pick.

I have not used a tuned loop as part of DXpedition activity for  many 
years.  Antennas that are broadband and have a cardioid pattern  - Flag, 
Kaz, Pennant, SuperLoop, Ewe, etc. - dominate the DX scene here in  the 
New England states since many of us are trying for TA's while wanting  
to beat down all the backside interference from NY, NJ, PA, OH,  etc.

The set-up I prefer for car-based shore outings is shown at  
"http://home.comcast.net/~dx_lab/pictures/micro_superloop.htm";.  A  
broadband amplifier (DX Engineering RPA-1) is used between the output  
of this antenna and the receiver, but a tuned one could be used  
instead.  I'm usually doing broadband SDR-based spectrum capture on  the 
Granite Pier outings, so broadband gain is the typical  approach.

A regular (figure-of 8 pattern) loop can still be useful  around here 
when things open up to Latin America.  The DX is then at  a right angle 
to the "pests".  The loop could be something like what  you have or 
something broadband like the Wellbrook ALA-1530.

Any  broadband antenna can be made into a tuned antenna by running its 
output  through a regenerative preselector ahead of the receiver.  There 
are  several good articles on those in NRC Reprints (and likely online 
as  well).

Those wanting an old-school type tuned loop that's quick to set  up and 
gives good results can also look into Gerry Thomas' Quantum  designs.  
The C. Crane one does a pretty good job too.  I do use  these 
occasionally at home and on casual travel, though seldom on  "serious" 
beach DXpeditions.

Anyway, throughout the hobby recently,  there's been an encouraging wave 
of experimentation and homebrewing.   Thanks Gary for this offering.

Mark Connelly, WA1ION - Billerica,  MA

<<
Hello Guys,

In the experimentation here to  develop huge MW loop antennas using
lightweight, tough PVC frames, I had  often thought wistfully about how 
effective
these monster loops would  be on nearby ocean beaches-- if only I could 
fit
them  in my  compact car. It seemed like an impossible dream-- or was  it?

...

73, Gary  DeBock
>>
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