Received my THz bands NoV, and it seems we can operate on lots of very tight slots between 275GHz and 3THz.  The NoV isn’t clear what it means when it says we are not permitted to use 296 to 303 GHz, I guess that means we can use up to 295.999999999 GHz, but does that mean we can use 303.000000001 GHz up, or 304.000000000 GHz up?

Some of our allocations are on the edge of the absorption bands.  The table shows the bands we are permitted to use outside the restricted radio astronomy zones and those permitted within them.

Full details at http://rsgb.org/main/files/2016/10/161021_Guidance-for-275GHz_-Terahertz-Innovation.pdf

Now comes the fun of trying to blag some technology and devices from a lab somewhere.

With both of us beaming at IO81, John’s AS signal off the Heathrow stack was only a few dB less that the direct tropo.

I bought a nice 23cm bandpass filter from John G3ZTR at Aerial Parts of Colchester to fix a very nasty intermod problem with very loud local signals in the 1GHz range causing mixing products with DTV transmissions from Emley Moor, 51km away.

A homebrew version also worked, bit it wasn’t stiff and stable enough and really not suitable for masthead installation.

Response of the filter is good, I checked the passband using a GPIB/SCPI script in Perl using my SGLabs Prologix IEEE488 to USB controller.  Using the HP E4421B as the signal source, I put a 3dB pad either side of the filter as usual.  Output was measures using my HP436A using 8481A sensor. I set the generator level to give 0dBm with the filter replaced with a back to back SMA female adaptor.

Close-in results using this code snippet are in the first graph.

for($f=1100;$f<1510;$f+=2)
{
   chdir(“C:\\Program Files (x86)\\KE5FX\\GPIB”);
   system(“talk 7 \”SOUR:FREQ $f MHz\””);
   $r=`query 13 T`;
   chomp $r;
   $r=~/..D(.[0-9]{4}E.[0-9]{2})/;
   print “$f,$1\n”;
}

Measured insertion loss at 1296.200MHz is 0.08dB, certainly well within the quoted <0.3dB at 1296.  At 950MHz, measured loss is 38.9dB (quoted >35dB) and at 700MHz is it 41.6dB, again, better than the quoted figure. At the 648MHz subharmonic, it is -40.9dB.

Wider span to follow.