Say something then!

Well,

A while since I have posted; primarily because I am spending far too much time in foreign parts for my employer, rather than playing for me!

Anyhow, been rummaging around in the shack today and finally got round to configuring my MS station for 6M and 4M.

I have the antenna I put up back here for both bands:

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

And today I have got the digital interface working to my satisfaction into the FT-847:

You will see that I have used a SignaLink USB thingamabob to connect the radio to the PC:

http://www.tigertronics.com/slusbmain.htm

Now, the FT-847 has caused me a load of trouble in the past when dealing with digital modes; primarily in an unsatisfactory delay going back from TX into RX again. I have always interfaced the radio like this:

So here the PTT is combined with an audio line which is then decoupled using the capacitor you see in the graphic above.

This time I have interfaced into the Mic socket and used the PTT and audio in feeds available there:

Now, further inspection of the FT-847 manual today, and I find this:

which looks infinitely more sensible again!

So, I may yet change things once more to enable an easy switch between digital and voice operation.

I'm still using the amplifier I bought from Linear Amp (the DX Shop):

I'm scared stupid I'm going to overdrive this amplifier; I would like to find a way to restrict the output of the 847 permanently to 25W - any suggestions? I may well ask the question on the appropriate owners forum.

Fun egh?

That'll Never Work - Will it?

Well,

The VHF antennas here have always been somewhat of a compromise. Recently I moved my 4M or 70MHz antenna from the side of the house and put it on top of the HF antenna on the main mast. I also took down and filed (in the hedge) a 6M or 50MHz antenna. I saw this a while ago and wondered... could this really work:

InnovAntennas 4 & 4 ele

So, you guessed it, I bought one.

Here's the antenna as it starts to go together:

As you can see, there are 4 elements for 6M and 4 elements for 4M on the same boom. The thing that I didn't (and still don't) understand is how the thing works electrically as the 4M elements are all parasitic (there's no wires connected to them from the RF supply). The antenna has a direct coax connection without any kind of connector:

There's plenty of self amalgamating tape under the white PVC tape you can see, the connections themselves were then coated with Copper grease. The antenna also needs a coax wound balun - this is preventing me from feeding the antenna directly with Westflex 103 - it's just too thick to wind tight enough. I've had to connect a length of RG213 to the antenna, use that for the balun then have a join to the 103 close to the boom.

I then brought the tower down and changed the antenna on the top for this one:

While the antenna was in this position I attached the analyser thingamabob; the 70MHz resonance looked really good, but the 50MHz resonant point was more like 55MHz.... hmm I thought, perhaps I should raise the antenna and see.... no change at all.

I scratched my head for a while and re-checked all the dimensions - they seemed correct to me, here's the diagram I was following:

Suddenly I realised that the element centres that are labeled as 1800mm on the diagram are only 1500mm on the antenna! A quick email to InnovAntennas confirmed that I had indeed got the wrong parts.

The antennas are back in the air:

But the 6M or 50MHz elements on the top antenna are currently exactly 300mm too short.

Useless, hugh?