A disk-what? Ah, a Discone!

Well,

Today has been a day of antenna fiddling. The first thing I did was put up a Discone antenna on the front of the house:

This is supposed to be a general coverage receive antenna from 25MHz to over 1.3GHz plus it is resonant for transmit on the Amateur 6M, 2M, 70cm and 23cm bands.

Here's what it looks like connected to the return loss bridge and Spectrum Analyser:

The markers at the bottom of the image above show the resonant points we are interested in and it does indeed seem to be a reasonable match to 50R at those frequencies (as is a 50R resistor, of course). How good an antenna it is remains to be seen. I am hoping this will hear more of LEO satellites than the collinear I have.

We have had some more really bad weather over the last few days and very much by luck I found a broken jubilee clip (Read hose clamp) in the garden yesterday. Looking up I could see it was off the 4M and 6M beam antenna I installed back here:

http://g0mgx.blogspot.co.uk/2013/05/thatll-never-work-will-it.html

So I have had the antennas down again today, it's surprising how big my "mini beam" is when it's on the ground:

You can see that I have to remove the outer parts of the one element to get it past the fence next to the raised border in the garden! But I have replaced the clip and also altered the resonant point of the 4M section to be exactly at the Meteor Scatter frequency of 70.110MHz.

After adjustment the "dip" is now ~70.12MHz with a return loss of > 32dB ; the SWR at 70.11 (my target) is 1.05:1 and across the band is no more than 1.7:1.

and at 50.23MHz the SWR is a respectable 1.2:1:

Looks pretty damn fine to me!

Cat's been next to useless:

Fun, egh?

Now that the smoke has settled

Well,

You may remember the mishap I had with my FT-847 back here:

http://g0mgx.blogspot.co.uk/2013/11/my-ft847s-got-no-nose.html

It's been repaired, and as predicted I had melted some of the components in the 4/6M low pass filter. I had also burned some of the PCB tracks - I got lucky really as the PA itself survived.

To further my adventures on 4M Meteor Scatter I think I need to find a better way of generating some high power RF without running the 847 at maximum bananas. Hence a new linear project has been born.

I've scribbled down my thoughts over the design, I want to include some software based control and alarms so I can watch out for:

• To much drive
• High SWR
• PSU problems
• Over temperature

It would also be good to include a software based power measurement and SWR reading on the output.

Here's the rough starter design:

I've stuck the appropriate numbers into Elsie and have the Low Pass Filter design also:

I've ordered a 300W 50-75 MHz RF module (no PSU, heatsink or cooling) so I'll start to think about the software for the linear controller over the next week or so - it will be Arduino based for sure.

There was a lovely UK morning captured on Antenna Cam here today:

Good, egh?

Meteor Scatter - You can't be serious?

Well,

Meteor Scatter has for a long time been established as one mode of radio communication (this is bouncing signals back down to Earth off Meteors) used by the elite. You used to need a large hill, about 10-12 Gigawatts of power and a huge antenna system for your chosen band.

Not any more.

The amazing modes in the WSJT family have made MS more accessible to Muppets like myself.

So, after modifying a few switches and cables in the Shack, I have my TS590 routed to my Linear Amplifier that I acquired back here:

http://g0mgx.blogspot.co.uk/2012/09/how-much-power.html

This now allows me to run full legal UK power on 6M to the 4 + 4 element antenna I got here:

http://g0mgx.blogspot.co.uk/2013/05/thatll-never-work-will-it.html

So, I then did some research and found this excellent talk in video format from the recent RSGB convention, this is GW8JLY talking about his MS experiences on 144MHz:

http://vimeo.com/77358505

I also have downloaded, printed and studied the WSJT user guide. Here are some screen shots of my MS experience from this morning:

So the bit I have circled in the image above is the signals from DL5WP, you can clearly see a burst of received signals. Here is the other window in WSJT7 showing the decoding of those signals:

There's also a chat room for MS nutters here:

http://www.on4kst.org/chat/index.php

Where you can arrange QSOs and discuss MS stuff.

This morning I've worked DL5WP in Germany and S59A in Slovenia.

Thanks Chaps!