Recommend me an Antenna design for the loft.

Hi all, hope you're well.
As I'm not allowed to put up an external antenna, I'm having to make do with what I can use in the loft.
I currently have a Double Bazooka (inverted) and tuned to resonance on 27.555Mhz.
It works fine but I'm wanting to experiment with something that will be a little better.
As I enjoy learning and experimenting, I'd like to build myself something different.
I have plenty of wire but don't really know what to do with it.
I was wondering if anyone on here has built a wire antenna for the loft and are pleased with it's performance?
Or simply tell me what worked for you.
If so, could you please let me know and /or recommend a design. Links appreciated.
Or perhaps you could recommend a book or a website on the subject.
Cheers
Dale
26-CT-3550

Right so given you mention 27.555 I'm assuming you're more interested in DX.

Personally I'd bin the double bazooka and just use a normal wire dipole anyway as there's no advantages to the double bazooka over a dipole. When I made one years ago I felt it was a bit more deaf than a wire dipole.

So if it were me I would build a Moxon rectangle and use a cheap TV rotator. I used one on a 10m band entry during a contest about 10 years ago when the last solar cycle was just starting to wake up 3 years before its peak and at 16ft worked over 100 countries in 16hrs in a single weekend with 100W including longpath to China. It would be 12ft wide by 4ft deep and have a turning radius of 6.5ft. So if you can find a clear 13ft square space in the loft it's a go-er. If you're not overly concerned about rotating it you could point it east as it has a fairly wide beam width but you'd lose the ability to work the Americas in an afternoon and evening. You could build one for use indoors with PVC tubing. If you've got about 12ft square space then you could fit in a hexbeam.

Either way to beat a humble dipole for DX you're looking at a beam.

For local contacts depending on the vertical height you have available a simple 1/4 wave groundplane antenna would do the job.

Thanks for the recommendations Crusader, you certainly know your stuff (you replied to my Microphone question) I'll look into your recommendations, and yes it's for DXing,
I'm finding the Triple more fun and less formal than the ham bands at the moment as my first foray onto 2 meters (I've only been licensed for 3 months) left me a little tongue tied, adjitated and maybe even Mic shy, so freebanding is more relaxed for me. But hopefully that will change in the future.

You live in a beautiful part of Yorkshire, I did my driver training around your QTH whilst based at Leconfield back in the 80's. You probably know or have heard of Dave M0ogy? He does some great vids on YouTube about his CB /Rigs collection, he's not far from you.
Anyway, I'll have to look into those Antennas, you've got me thinking now. The beam sounds interesting too - is that the same as a Yagi? What's the difference? The loft would take one, their just so expensive, but yes as you say point it East and away I go.
Thanks for the advice, you're a very helpful member who certainly knows his stuff. Respect.
I have so much to learn. Totally different ball game to what I did in the 80's.
Cheers
Dale
26-CT-3550

I've heard of Dave. Funny you should mention Leconfield. I'm ex-REME, a little after you by the sounds of it, and was a vehicle mechanic/auto electrician in Hangar 2 workshops would be around 1992-93.

Yes a beam is the same as a yagi, just another way of referring to it. As I said, the Moxon don't buy one home brew one. All you need to do is to get some PVC tubing, a couple of joiner pieces and two T pieces from B&Q. Make them into a H with each long leg being 3.71m long and the bar between them 1.44m. That'll support the wire. Depending on how ghetto you want to be get a dipole centre too, one of these puppies. If you're not fussy about how it looks you can just solder the driven elements directly to the coax centre and braid.



So this is what we're going to be building.



THESE MEASUREMENTS ARE ALL FOR BARE WIRE. If using insulated wire reduce the lengths by around 5%.

A=3.705m
B=0.563m
C=0.09m
D=0.782m
E=1.436m

So the reflector you need to cut a length of wire 5.269m plus say another 10cm to allow for tuning.
The driven elements you need two lengths 2.42m. You'll also want a couple of lengths of string say 15cm long to use for "C".

Make up your "H" with the PVC.
Attach the dipole centre to the middle of one of the long legs.
Attach one of the 2.42m driven elements to each side and secure to that leg.
At the far end of each of those driven elements loop a small amount of the cable back on itself and secure loosly with a cable tie just tight enough so it grips but you can still slide the cable through if you tug it.
Attach the reflector element to the other long leg. Again loop a short bit of the cable back on itself, about an inch or so and again secure with a cable tie.
Use the string through the loops on the ends of each side of the driven elements and its corresponding end of the reflector element and tie it so it's tight enough that when you lift the antenna the unsupported wire doesn't droop. The space between the folded back ends should be about 9cm.

Congratulations you've just built a Moxon beam.

To attach the coax you'll need it to come out at right angles to the driven element for a couple of feet so just tape it to the 4ft bar that connects the two long legs.

If it needs tuning (don't bother if it's below 1.6:1)  then just undo a little of the loop on the driven element if the SWR is higher on Ch1 than 40, fold back a little more if Ch40 is higher than Ch1. Once done then tighten up the cable ties and re-tension the string.

The direction the antenna will be listening and transmitting is in line with the 4ft bar in the direction of the dipole centre so broadside to the driven element.

As an aside...

If you find the H design might be a bit flimsy then just make a complete rectangle from PVC piping and 90 degree bends. I'd still put the bar in the middle for supporting the coax.

Actually now I've typed all this up I'm all motivated. Might go to B&Q/Screwfix, get some bits and build myself one for the 6m band given the activity. I've already got one in the shed for 10/11m.

Great. I'll give it a go. Thanks.

Sleeping on it I think it'd probably be better doing the PVC rectangle than the H. If you try it and like it you could make a more permanent one up out of copper piping, using a bit of hosepipe where the string goes. That'd be far more wider bandwidth so if you ever got your ham ticket you could use it as a 10 and 11m antenna.

Cheers Crusader, I'm going to look around for everything I'm going to need. Doing more research on the Moxon, I notice it has some good performance reviews, which gets me excited and I'm looking forward to having a go.
Thanks
Dale
M7DEW
26-CT-3550