[Premium-Rx] Mag Loop Antenna made for Kielradio

[David I. Emery]

	Does anyone know anything about a 1 meter magnetic loop HF
antenna made for Kielradio GMBH in Germany ?   A really rugged and fancy
commercial grade ("premium") HF antenna I believe.

	A couple of years back I bagged one at the MIT flea market from
the remains of a company that was trying to set up a similar HF Pactor
sailer mail station to the Kielradio system.  They had all kinds of HF
gear for sale (including Tentec RX-331s and ICOM 700/710 HF
transceivers).   I also grabbed a couple of RX-331s for a good price at
the same time and various other stuff.   Never saw the guy again at a
MIT flea, so I never was able to find out more about the loop.

	The HF loop antenna I have has a 5 pin power connector and a
type N coax connector -  both on a gray plastic box marked 5`8499.   The
multi-conductor cable to the power connector is cut, with no clue as to
what to connect where.   I did not acquire whatever connects to the
other end of the cable.

	Inside the box is a PCB with what looks like the obvious 
current to voltage converter amplifier marked "Kielradio GMBH 2003-04
rev 2.01 Mag Loop 4 - 28 mhz  24 VAC".

	And on the PCB is a terminal strip with two terminals marked "~"
(the standard sign for AC) and a third marked gnd.   And two others
marked "heater".   All have wires attached which presumably lead to the
5 pin plug on the outside of the box.

	Unfortunately though the PCB is not potted, the rest of the box
is filled with RTV rubber so it isn't possible to see what is in there.

	The PCB has 4 trim pots on it and two  trimmer capacitors and
what looks like IC voltage regulators and filter caps.   Behind it and
under the RTV rubber is what looks like a heat sink of some kind

	All of which leads to the obvious questions - does the thing
take 24 VAC (RMS presumably) 50/60 Hz to power the antenna current to
voltage converter ?   If so does this need to be center tap grounded  or
just floating 24 VAC ?   What current is needed ?

	And much less clear, what is the "heater" and what voltage or
current should be supplied for it ?   Is it needed or just there to
chase moisture out of the box or de-ice the loop ?

	And finally, does anyone have any notion of what in a HF loop
current to voltage converter would require 4 trimpots and a couple of
variable caps to adjust ?

	I suppose my questions are somewhat idiotic, in that I should
just apply 24 VAC 60 hz and see if she hears anything, but on the off
chance that someone on this group knows some details, specs, or lore I
thought I'd ask anyway...

-- 
   Dave Emery N1PRE,  die at dieconsulting.com  DIE Consulting, Weston, Mass 02493
"An empty zombie mind with a forlorn barely readable weatherbeaten
'For Rent' sign still vainly flapping outside on the weed encrusted pole - in 
celebration of what could have been, but wasn't and is not to be now either."