A bit more top band

Well,

Following the antenna I originally made here and then replaced here, I've been fiddling with the earthing arrangement for the system.

I've added some counterpoise wires which I have stapled to the fence and various other bits and bobs in the garden.

I've then made an artificial earth/counterpoise tuner thingamabob, much like this thing back here, and mounted it at the base of the antenna between the earth rods and the radials:

And then adjusted the capacitor for maximum smoke on top band when TXing.

There's quite a lot of current flowing, what improvement it makes I dont know.

Here's a map of FT8 and CW QSOs I've made on top band since the changes to the antenna:

Chopsey Cat (AKA Git Bastard Cat from Hell) is asleep in the conservatory:

whereas Maggie and Florrie Cat are tucked up in one of the dogs beds:

Local conditions.

Top Band (Again)

Well,

A while ago we had some work done in our garden, this resulted in the removal of a 'purglar'; now, this was all fine except it was supporting my top band antenna I made back here.

I've got round to making a replacement for the antenna today, nothing original - it's an end fed sloping, inductively loaded wire.

There's 54 feet of wire, 20 turns on a bit of tumble dryer vent pipe, then 5 feet to the feed point plus an earth rod (well two actually) on the sreen of the coax. Here's the inductor:

and this is the earth arrangement:

Now, I am planning to add several long counterpoise wires, but I haven't done so yet. I connected the antenna to my analyser thingamabob:

or if you prefer return loss:

I've been listening on the WSPR frequency tonight:

It will be a very inefficient antenna and also it has a very narrow bandwidth (like all inductively loaded antennas), but it's clearly hearing signals.

Here's a map after an overnight run:

I also took down the main 4M and 6M antenna today for maintenance, I've put somthing I had at the back of the shed in it's place temporarily, I've also put the 13cm antenna I had lying on my bench in the air:

Here's our two doing what Spaniels do on a beautiful frosty morning earlier today:

Good, egh?

Over the Pond (Again)

Well,

I left my TS-590 running WSPR last night on Top Band, here are the results as a map:

So the crazy antenna that I made back here:

http://g0mgx.blogspot.co.uk/2012/08/top-band-what-happens-there-then.html

Is still working fine.

I'm wondering if I could convert the antenna for the even lower bands by changing the inductor - the answer is, of course, that I can. However, the efficiency of the antenna will be further reduced as the frequency decreases. I think I need to understand the maths behind the efficiency calculations before I do anything too hasty.

Here's the new Ham Cat helping out yesterday. I have a full week off work so have some plans for some insanity in the shack... watch this space.

Interesting, egh?

Over the pond on Top Band

Well,

You may recall my ramblings about Top Band back here:

http://g0mgx.blogspot.co.uk/2012/08/well-this-top-band-twig-does-it-work.html

So on-and-off I've been leaving WSRP running on either Top Bank or 30M over night, just to see how far signals are getting, and have been wondering if this may ever happen:

Well, looks like it has!

Fun, egh?

Your are, you're completely Loopy!!

Well,

Following some interesting reading on Top Band RX antennas, here:

http://www.qsl.net/kc2tx/

I decided I might like to have a go at making one of those.... the main reason being that my experiments with my sloper from here:

http://g0mgx.blogspot.co.uk/2012/08/top-band-what-happens-there-then.html

especially when using it on WSPR, I seem to find that I am being heard by far more stations than are hearing me.... so perhaps a different antenna for receive may help...

So here is this ridiculous concoction:

and as you can see, perhaps not quite as rigid as it needs to be....

but anyhow, it was strapped to a wooden support and connected to the wireless.... result.... local MW broadcast stations significantly weaker on this loop then the sloper, but more interestingly the noise was higher on this antenna than the other.... a total disaster!

So I decided to solder another earth cable onto the existing slopers earthy side and plant some more copper in the garden:

We will have to wait and see if this improves the RX performance...

Here is an interesting image of me in concentration mode:

Cat's weren't much help as normal:

Here the Geddy cat is asleep on my laptop keyboard - not very handy!

Good though, egh?

Well, This Top Band Twig, Does it Work?

So, Top Band... This piece of wire strung across the garden will never work will it? There's even an inductor in there that's basically connected to air at one end....

Well, I left the TS-590 WSPRing on Top Band last night:

So it certainly seems to be working rather well!

I'm delighted!
 

Top Band, what happens there then?

Well,

Following some inspiration from my ever patient chum Vince, G0ORC, we built a "sloper" at his QTH for top band. The basic design was inspired from this site here:

http://www.mds975.co.uk/Content/amateur_radio_antennas_02.html

This is the site of Mike, M0MTJ. He has done some fine work on sloper antennas. I sent Mike some email to ask about the inductance being used in his Top Band antenna and he pointed me here:

http://www.k7mem.com/Electronic_Notebook/antennas/shortant.html

Now this is an amazing site including the java based calculators. So assuming that my "sloper" is half a loaded dipole I have done some calculations (this is after the first experiment at the QTH of G0ORC).... and I have come up with this design based on the space available in my back garden.

So, the inductor was wound on a piece of drain pipe which has an outside diameter of 63mm. Using the extremely handy Ring Core Calculator:

http://www.dl5swb.de/html/mini_ring_core_calculator.htm

And using the part for "Air Cores" I calculated that using my drain pipe I would need about 30 turns to create a 42uH inductor. So using some hard drawn copper wire I had here I made the coil.

I got hold of some "flex weave" antenna wire and cut an appropriate length. The coil looks like this in reality:

And this is the ground arrangement; I've driven two earth spikes into the ground which I have soldered an old piece of pipe between. To this I have soldered the outer of the coax feeder and also the end of a wire which I have trailed round the garden at ground level:

The antenna looks like this, although its rather hard to see - its the wire on the left hand side of the picture:

You can see above that the pole is looking rather bent, the co-linear that's on the top could come down as I don't use that for anything now, so I really should try and put up a thicker pole with some less bendy joints! It will do for now I'm sure.

But much to my total disbelief, when I stuck the antenna analyser on the end of this new sloping antenna; this is what I saw:

So it seems by some complete fluke I have managed to create a top band antenna. If it actually hears any signals will be a different matter, but only time will tell.

I also took the beam down again this weekend and have added a plastic owl to the top; his name is Oliver... I'm hoping his presence will reduce the amount of bird droppings on my back sitting area! I also hope it won't deter birds from the garden completely. You can see him on the top of the pole here:

We shall have to see.

Fun though, egh?