[time-nuts] Firmware and antenna for Stanford Research FS700 Loran C frequency standard

[Ole Stender Nielsen]

I use a home-made untuned loop antenna with 4 windings of 2.5 mm2 
insulated wire on a 80 x 80 cm wooden frame, and with a grounded base 
pre-amplifier mounted on the antenna frame. A schematic is enclosed for 
you to copy.
The pre-amplifier is powered through the cable, and loads the FS700 
input as required.
I live about 290 km from the island of Sylt, and get nice noise margin 
figures from the FS700, normally about 40 dB, often up to 46 dB.

For larger distances to the transmitter site, you may need to insert 
additional amplification between the grounded base pre-amplifier and the 
FS700, and that requires that you provide power to the pre-amplifier 
through a bias Tee, and that you load the FS700 input to keep it happy. 
A while after I installed the antenna in the attic, I added additional 
amplification, not due to a low signal level, but because I wanted to 
use the loop antenna for other longwave services too, and that required 
that I had to split out the signal.

Best regards
Ole

Den 15-07-2015 kl. 18:02 skrev Dr. David Kirkby - Kirkby Microwave Ltd :
> Does anyone know of the latest firmware for the Stanford Research 
> FS700 Loran-C frequency standard? I know someone who has one with 
> firmware 1.20, but I don't know if there's any later firmware. I 
> recall asking Stanford Research about firmware for the SR620 but got 
> no response, so I don't know if I will have any better luck with the 
> FS700.
>
> What's the best sort of antenna for these? I know Stanford sell one, 
> and by the cost of new professional equipment, the $250 is not 
> abnormally high, but I'd rather look at building something if I 
> purchase one of these standards. I did think of using a half-wave 
> dipole, but my garden is just a wee bit  too small.:-)
>
> Dave
>
>
>
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