Monday, March 26, 2012

More Ground Radials for the Vertical and Inrad Filters for the FT1000MP V

Added a few more ground radials to the vertical, I figured any spare wire I have I just add, including the disused moxon that is lying in the back garden, I just laid it out flat and connected up a ground radial! Listening out last night before going to bed I heard my first VK on 30 meters so something must working because I’ve never heard a VK on the inverted V.
10 and 12 meters opened up for a short period over the weekend and I had some fun contacting Japan using the cobweb, only a couple of stations but at least I was getting out.
As the vertical is now working well, the spare 30 meter inverted vee has been sitting around doing nothing except for comparing against the new vertical, so I did a quickie experiment by trimming it down to the 12 meter band to see how it compared against the cobweb. Interestingly the background noise was much louder, but no real noticeable difference.
I’ve recently felt that the cobweb is somewhat lacking in performance and may need a tweak here and there, especially on 20 meters where the swr is slightly up (2:1), it doesn’t provide a problem because the tuner on the radio corrects it, but I’m still going to take the cobweb down in the near future just to give it a clean and a check-up as it has been battered by the winds over the winter period.
With more experience I’ve noticed I am definitely lacking with regard to filters when it comes to CW. For SSB I have an NSDSP 1062 amplified module which is a great DSP kit that fits in my Yaesu SP2000 speaker. I bought it sometime ago after hearing my Brother in Law using it with his FT1000, you fit yourself and it certainly does work, I would highly recommend it especially for crowded SSB/noisy bands, unfortunately though as stated by the manufacturer, it's no good for CW.
So what about CW filters for the FT1000MP V? Well you can purchase the Inrad filters or the Yaesu filters if you can get hold of them, both sets of course are expensive, £200 for the Inrads! After doing a thorough search I have ordered the Inrad filters, YF-110CN and the YF -114CN which from what I have gathered should give me the necessary filtering that I require. Evidently they take about 3 weeks to arrive so I’ll let you have updates when I get them especially on the fitting process which should prove interesting.

Tuesday, March 13, 2012

Further work on the 30 Meter Vertical

Over the weekend I did some more work on the 30 meter vertical. Being slightly na├»ve with regard to verticals as I have had little experience in building them I thought that it would be fairly quick and easy, which to be honest it can be, but reading up on the web suddenly opens up a whole new can of worms with regard to ground radials and SWR.

Initially I thought my SWR reading of 1:4:1 was out and I was certain I could get a better result, but with a little bit of investigation via the web 1:4:1 is pretty well spot on for a vertical. However ground radials are a separate issue, in that for optimum performance according to many experts you need at least 120! And there was I with my paltry 12 pieces of telephone cable consisting of 4 wires per cable, a grand total of 48 wires.

So armed with this new knowledge I rechecked the SWR and also the resistance; 1:4:1 with a resistance of 40 ohms, actually not bad but in a perfect world R should really read 36 ohms. So I added some more ground radials to see if it would have any further effect. I had been given some old overhead telephone cabling which consisted of 7 wires per cable and since I had a spare 8 connections left in my choc connector, I did a bit of fidling and wired up two more cables giving me a further 14 radials.

With the connection box opened I could add a load more radials

The actual length of the extra radials is much longer than the 30 meter quarter wave (23ft), but since I had the room to fit them I thought what the hell and buried them a few inches below the ground. So I now have varying lengths of radials, 48 at 23ft and 14 at approximately 40ft.

Initial tests show little difference, but I suppose that’s not surprising, interestingly though the SWR remained at 1:4:1 but the resistance at the base of the antenna was now 38 ohms which was certainly better, however connecting the MFJ at the shack showed the resistance back at 40 ohms, obviously the 30 metres of coax from antenna to radio had come in to play, ( I do have a 1:1 balun), but no real surprises. I guess this is where your surrounds and ground come in to play. 

The old “dipole versus vertical” is an interesting topic to read up on and of course there are pros and cons to both, with the general outcome being that the vertical is better for DX. But it all depends on your own situation; whether you are surrounded by buildings or trees or have the right ground etc. I think as an experiment I will re hoist the old inverted V and do a weeks comparison testing just to see how my particular surrounds effect each antenna. Certainly I’ve never had an issue when using the inverted V and the vertical is more of a fun build, but since I have gone to the trouble of burying all those blasted radials I’m not packing it away just yet!

Monday, March 5, 2012

The 30 Meter Vertical Goes Up

Well I gave it some thought and decided over the weekend to progress with removing the moxon and try putting up a 30 meter vertical. I used the same principle for building an earlier 30 meter vertical but this time covered the wire antenna with PVC tubing and some fibreglass pole I had stored away. Unfortunately both PVC and fibreglass are white but I will darken them at a later date, but in the meantime at least it stands out a lot less than the scaffold pole I had for the moxon and certainly wont rub against any washing!


The picture above is literally just after completion and testing, the reason for the bend is that yesterday was a pretty windy day, I'm amazed I got it up at all!
SWR is very good 1:1 right across 30 meters and performance wise is probably better than the inverted V that I have hanging off the cobweb.
Below is a picture of the buried radials and the box containing all the connections (see earlier posts for how its all connected up). Although there only appears 12 wires showing it is in fact telephone wire so inside each cover are four thin wires making a total 48 radials which for the moment seems to do the job nicely, but I have room for a further eight cover connections should I require.


The other good news is that with a tuner the vertical behaves extremely well on other bands especially 10 meters and surprisingly enough 40 meters. Although some of the radials I did cut for 40 in case I wanted to lengthen the antenna at any time. So all in all a good weekends work.


Above is the moxon complete with poles placed to one side, I've advertised it in the local club website as it would be a shame to let it just sit there doing nothing.
Finally the picture below is of the silver birch tree that I've got my W3DZZ hanging off although its pretty difficult to see which is quite good news to me because that means no complaints! The telephone lines and the electric cable seems to stand out a lot more than the W3DZZ, but if you look closely you can see one trap bottom left just above the hill and the other trap to the middle right in front of the silver birch just below the telephone lines. Incidentally I get no issues from the electrical cable hanging below the telephone lines.


Thursday, March 1, 2012

Complaints From Up High

I know I’ve been sailing close to the edge with regards to antennas; having the Cobweb, the 30m inverted V, the Moxon and my W3DZZ was pushing it, especially the more recent addition of the Moxon, which combined with a small rotator is on a twenty five foot pole that I have attached to a swing arm, so that I can raise and lower at will, this way it's hidden from the nearby road.

Living in an area of oustanding beauty is not the ideal situation for a Radio Amateur, basically you have to be careful what you put up. Neighbours are not a problem in my case, but I am situated close to a pretty cotswold village and even I can see that masts all over the place sometimes do not fit in with their surrounds.

The only place I could fit the Moxon mast was parallel to our washing line which has been fine for the past few weeks, but my XYL out in the garden the other day served me with a cautionary warning that the garden was beginning to look like an eye sore and there was no way come the spring the washing was going to swing next to that dirty old antenna when in the resting position!

As no doubt many an amateur will realise you can only goes so far in designing and erecting antennas, there is a fine line between keeping your land/garden tidy or a mess, and you’ll soon know when you’ve crossed the line! My XYL is pretty good when it comes to the antennas, not everybody likes to see a forty foot mast with a Cobweb antenna attached to their house or a load of wire stretching from tree to tree and although she has no interest whatsoever in my radio hobby she puts up with my antics.

So the Moxon is going to have to be removed, but in all fairness I really cannot complain, it was an experimental project purely for 10 meters and it worked reasonably well, but 10 meters is at present fairly quiet and besides I have the Cobweb and W3DZZ to play with and providing I remove the Moxon I reckon I will be able to replace it with a vertical, so long as it doesn’t interfere with any washing!

I still fancy constructing a vertical specifically for 30 meter band; which will mean I can also remove the inverted V, better to have a single pole than the two extra wires hanging off the Cobweb mast.
For the moment the weather has not yet changed to be so warm as to hang out the washing, so at least I have a number of weeks to plan what I’m going to do.