[IRCA] Quamtum Loop vs. Space Magnet II

[Charles A Taylor <MWDXer@xxxxxxx>]

				9/24/08

Some Observations by Charles A Taylor, WD4INP
on the Quamtum Loop QX2 v2.0 built by Radio
Plus+ (as compared to my prized Space Magnet
II acquired from James T. Pogue K2HAR back in
1976).

The Quamtum Loop QX2 v2.0 I acquired three
days ago cost me a total of $265. An
amount well invested.

If you don't have one, then I suggest that 
you budget $25 per month to buy one.

The difference between the QX2 and the SM-2
is stark.

The Quamtum Loop QX2 v2.0 is most obviously
superior to the Space Magnet II.

The Space Magnet II has the obvious problem
of a high R-F noise level.

The Quamtum Loop QX2 v2.0 does not suffer
from this problem.

In my observation: The Quamtum Loop QX2 v2.0
is difficult to operate. 

The difficulty is worth the price. The
R-390A/URR or the Drake R8B is obviously
more difficult to operate than the Cadillac
of portable receivers: The Radio Shack TRF
12-656.

But either one is vastly superior to the 
Radio Shack TRF 12-656.

Every control on the Quamtum Loop QX2 v2.0
clearly has a use. In my observation, the
R-F gain control is, in fact, critical to
the noise floor of your receiver.

One drawback the Quamtum Loop QX2 v2.0 is
hand capacity sensitivity of the tuning
control! If you are willing venture inside
of your Quamtum Loop, I would suggest attach-
ing a pane of aluminum foil and grounding the
pane. I am not willing to make this modifi-
cation.

The inclusion of regeneration most certainly
improves the quality of the Quamtum Loop QX2
v2.0 utility.

I do not yet have any observations on the
current drain on a 9-V battery. However, the
12-V, D-C supply included with the Quamtum
Loop QX2 v2.0 merely adds one more oppor-
tunity for RFI sensitivity.

I have a terribly difficult RFI situation:
My wife's DirecTV modem spews forth a ter-
rible spectrum of hash from 500 kHz to VHF
and above. 

This RFI renders my prize EWE antenna nearly
worthless. My wife has agreed to revert to
a configuration that does not include a 
modem at the end of the contract period. If
I did not prize my marriage more than my
MW DXing hobby, then this would put a strain
on our relationship. But our marriage is
vastly more important than any of my hobbies!

Clearly a good loop antenna is critical to
my MW DXing hobby...one that I have enjoyed
for the past 53 years. 
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