Wednesday, November 23, 2011

Learning DX

Becoming more experienced in DXing, its funny how you find yourself getting better at picking out stations of interest. I’ve learnt to now put myself in to what I call “receive mode” which means I set up the FT 1000MP to how I specifically want it and together with a good set of earphones close myself off from any outside noise and almost go in to a receive trance.

One thing I’ve noticed is a distant station has a particular sound, a sort of distant echo, I thought at first it was my receiver playing up but after researching on the web I found out this is well known and is called “artic flutter” what a wonderful term!

Now through practise I concentrate on only a particular part of the band I am working on and without thinking just slowly trawl up and down mostly with the filters set at narrow. Unfortunately I only have the standard filters on the FT which I am hoping I will be able to rectify as soon as I can afford it. Never the less even with what I currently have and putting certain skills I’ve learnt in to practise has proved very useful in picking out a very faint signal and on a number of occasions I’ve managed to get in first before the rush starts.

Don’t get me wrong here, I’m not the greatest DXer going and I won’t deliberately set out to find a particular station, I haven’t got a large beam or tower but with the setup I have I am able to just amble slowly along the band to find a VK, J or ZL who is calling CQ. However with my newly made 10m Moxon which is currently pointing west, (I have no rotator at the moment), I can pick out a lot more faint stations than with the cobweb and this is proving fascinating and giving me a better insight in to why DXing is so popular.

Friday, November 18, 2011

Update on the Moxon Build

Well it’s finally completed with a mish mash of bits and pieces mostly nicked from the junk box. The only expense was the tubing and two plastic garden stakes for the spacers which I got from a local hardware shop for the princely sum of £24.00.
The SWR readings are spot on at 1:2:1 from 28.050 right up to 28.450 which will do nicely considering I’ll be mostly using it for CW.

Have now got to mount it on to my test mast which I will do over the weekend, I'll then have a play and report back!

A few pictures below; two from the beginning of the rebuild when assembling the old TV boom and making the reflector and one of the finished product in the advancing evening dusk (shows how keen I am)!

 Dismantled after the first attempt where I re-calculated the dimensions, the center block is an old bread board.

 The join for the reflector, a simple bit of carpentry an some jubilee clips

  The finish product in the evening dusk, not bad for a days work!

A final view from  from above!

Well this morning I did some more testing and all is working is it should so connected up to the FT1000 and fired it up, a definite improvement on 10 meters against the cobweb, especially with the Moxon pointed west where the US stations were booming in. The other good news is that with the ATU on the Yaesu I can add 12 meters and had a good CW qso's with a Russian station that gave me  a 579 and then a Japanese station who came back with a 589. The plan now is to find myself a light weight TV rotator and have some fun spinning it round! More updates to follow.

Wednesday, November 16, 2011

Building a 10M Moxon Antenna

Since the 10 meter band is now well and truly open I’d love to have a yagi for a bit of directional activity, but unfortunately I don’t think I will get the official stamp of approval so I’ve been pondering what else I could use similar to a yagi.

I did some searching on the web and came across the Moxon Antenna which looked to be just the job and fairly easy to build. I didn’t fancy the standard wire antenna with the cross support poles, I wanted something a little sturdier, and found this website which describes all the details for constructing a tubular Moxon including the Moxgen software for working out the dimensions. I inputted the information but setting the thickness was a bit tricky because I had different aliminium tube sizes throughout the rectangle (bought on the cheap from the local hardware store). Bending the tubing proved interesting but I managed to borrow a small pipe bender that proved very useful. Eventually I set it at an average of 12 mm on the Moxgen calculator thinking that if I overestimated I could always trim. (Better to have the length than it being too short).

So far the rectangle has been built and I have used an old TV antenna as the boom and pinched the plastic feeder complete with circuit board, but on testing I think I have over complicated the build so have removed the TV feeder (the circuit was shorting) and literally just attached the end of the coax using jubilee clips to each side of the antenna. First results show the SWR to be very high at 28.100 but an acceptable 1.3 at approx 26.500 so some trimming will be required.

Having done further checks on the thickness of the tubing I realised I had over compensated. The tubing is a mixture of 8, 10 and 12mm with the majority being at 10mm. so I have recalculated at 10mm and of course my original dimensions are slightly out, hence the high SWR. So last night I dismantled the rectangle and will now begin to re-trim to the correct lengths for 10mm, lets see if that makes difference, I’m told that the space between the reflector and driven elements are very important so I must make sure I get that absolutely correct; Any advice would be mucho appreciated……..more updates and pictures later!