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-   -   My long awaited outdoor AM aerial (https://www.vintage-radio.net/forum/showthread.php?t=145216)

stevehertz 29th Mar 2018 2:02 pm

My long awaited outdoor AM aerial
 
4 Attachment(s)
A long wire outdoor aerial for AM reception is something that I have been meaning to do for decades. Finally fed up with trying to pick up AM stations amidst the sound of crashing waves and rockets taking off (AKA digital hash interference), I did it. My kindly neighbour allowed me (well, my local rigger) to fit a lashing kit to his chimney, and I did the rest myself. From the lashing kit, using egg insulators I hung black PVC covered wire across to my recently made redundant, under the eaves insulators that until last year held my mains supply cables. From there the downlead went down to ground floor level and in to the house through a hole drilled in the top corner of a plastic window frame. I used a length of clear plastic tubing to shroud the wire as it turns a corner and passes through the hole. The bit of yellow tape at that point is soon to be replaced with amalgamating tape.

I fired up a hifi tuner using just its ferrite rod AM antenna, and as usual the noise was atrocious, unlistenable. Then, connecting the aerial wire it was as if I had switched to FM! On R5Live, no sign whatsoever of digital interference and the bandwidth so much better too. Job done at last, well pleased!

camtechman 29th Mar 2018 2:27 pm

Re: My long awaited outdoor AM aerial
 
Brilliant and great to have good neighbours too !

Nymrod121 29th Mar 2018 3:20 pm

Re: My long awaited outdoor AM aerial
 
Nice one :)
I put a 60' long wire up a couple of weeks ago with the aim of firing up my old Sony ICF2001 to see if I could pick up anything on H.F. e.g. WWV. I think I'll need to build an Antenna Tuning Unit to try and get rid of some of the air-borne wideband noise ...

Guy

Herald1360 29th Mar 2018 3:36 pm

Re: My long awaited outdoor AM aerial
 
If those are cable ties up by the old supply insulators, don't expect them to last very long!

I'd put the egg into the loop in the aerial itself, then tie it back to the old insulator with some suitable polyprop rope or even a bit of galvanised coathanger.

Station X 29th Mar 2018 4:04 pm

Re: My long awaited outdoor AM aerial
 
Quote:

Originally Posted by Herald1360 (Post 1030674)
If those are cable ties up by the old supply insulators, don't expect them to last very long!

Especially not white ones and black ones don't last long either. I've found that orange polypropylene string seems to last forever.

G6Tanuki 29th Mar 2018 4:29 pm

Re: My long awaited outdoor AM aerial
 
True: solar ultraviolet light doesn't play well with most cable-ties.

Be aware that some "orange polypropylene string" is designed for electric fencing and has a thin steel 'tracer' wire woven into it!

When attaching antennas to Eggs I usually thread the wire through the egg-hole, double it back on itself, and give it 10 or so twists tight up against the egg. Never had one fail yet.

Station X 29th Mar 2018 5:25 pm

Re: My long awaited outdoor AM aerial
 
Quote:

Originally Posted by G6Tanuki (Post 1030693)
When attaching antennas to Eggs I usually thread the wire through the egg-hole, double it back on itself, and give it 10 or so twists tight up against the egg. Never had one fail yet.

That's fine for stiff wire, but I use ex-military Kevlar cored stuff. What I do is tie a clove hitch round the egg.

emeritus 29th Mar 2018 11:22 pm

Re: My long awaited outdoor AM aerial
 
The high quality cords and rope you can get from yacht chandlers, being designed for use at sea, are very resistant to the weather. I bought some when I built a swing for my children almost 25 years ago. It was more expensive than the stuff I could have got from a builders' merchants, but it has showed no sign of deterioration, despite being out all year in all weathers.

Herald1360 29th Mar 2018 11:56 pm

Re: My long awaited outdoor AM aerial
 
Quote:

Originally Posted by G6Tanuki (Post 1030693)
Be aware that some "orange polypropylene string" is designed for electric fencing and has a thin steel 'tracer' wire woven into it!

In this application with the egg as insulator, that wouldn't matter any more than an old coathanger. ;D

Andrew2 30th Mar 2018 9:25 am

Re: My long awaited outdoor AM aerial
 
Success! That must be a relief, but what happens when your neighbour gets a new gizmo that puts out acres of wideband hash? This happened to me shortly after I'd been allowed to attach the far end of a random wire (very much like yours) to a small engineering premises nearby. All was beautifully quiet for about 6 months, then one lunchtime all hell let loose.
Their new CNC milling machine turned out to be the culprit. There was nothing to be done about it, so down came the wire and up went a Wellbrook loop! Good luck.

stevehertz 30th Mar 2018 12:25 pm

Re: My long awaited outdoor AM aerial
 
Oh, sorry to hear about your problems with your AM aerial and your concerns about mine. Let me reassure you, in my case my neighbour won't be installing a milling machine, or anything else that might create a problem for that matter. He's a retired close friend who follows a simple lifestyle and I'm well aware of his circumstances. :thumbsup:

stevehertz 30th Mar 2018 3:11 pm

Re: My long awaited outdoor AM aerial
 
1 Attachment(s)
I've just added a large stand off insulator to the point where the downlead enters the building to stop it chafing on the pebbledashed brickwork. Final siliconing of entrance hole, around the base of the insulator, and applying amalgamating tape in place of the yellow insulating tape to follow shorty.

MrBungle 30th Mar 2018 5:07 pm

Re: My long awaited outdoor AM aerial
 
Looks good. Nice to hear about nice neighbours. I'm still negotiating with mine over sticking a simple inverted V up on the end fence, which is mine.

Currently using "half a roll of grey 7/0.2 tied around a large rock and chucked over a tree". Works and no one has noticed it yet as you can't see it at all more than about 10m away. If anyone is inclined to try this, wear a hard hat. The romantic picture of throwing it over a branch and it staying there doesn't happen until the 5th attempt or so, the first four declining into a game of lawn darts with rocks.

Hash is terrible. Is it better out in the sticks? I'm right in the middle of London and it's awful.

stevehertz 30th Mar 2018 5:18 pm

Re: My long awaited outdoor AM aerial
 
Quote:

Originally Posted by MrBungle (Post 1030955)
Looks good.
Hash is terrible. Is it better out in the sticks? I'm right in the middle of London and it's awful.

Personally I don't think that you can say either way for definite. I live in the countryside but I have the normal amount of devices - including common or garden digital teles - that shove out digital hash by the bucket load. I mean, just about everything you buy these days has a wall wart SMPS to supply it. So, SMPS and digital noise everywhere. I suppose I stand a better chance of getting away from it in the countryside - like my outdoor aerial here - but otherwise if you've got normal digital stuff in the house like computers, teles etc etc, then no matter where you live you're going to get hash inside the house. An outdoor aerial in London? You tell me?

MrBungle 30th Mar 2018 5:47 pm

Re: My long awaited outdoor AM aerial
 
I can get a tiny improvement here if I turn everything off, which incidentally isn't popular with the other members of the family. However I can still pick up things from neighbours. If I didn't have any, that might not be an issue :)

Outdoor isn't much better than indoor really here. I am under Heathrow approach so that may not be helpful either.

Guest 30th Mar 2018 6:37 pm

Re: My long awaited outdoor AM aerial
 
Don't forget the drip loop in the wire going through the window, silicone is good better not test it too much (given the price of new windows).

stevehertz 30th Mar 2018 7:09 pm

Re: My long awaited outdoor AM aerial
 
The clear tubing that shrouds the downlead is there to protect it as it passes through the insulator and the hole in the window frame. But because of the 'stiffness' of the tubing and combined with the tension and movement of the downlead my design doesn't use or need a drip loop. Like I said above, I will finish off with a fillet of silicon in and around the tiny gap around the sleeving as it passes through the window. No water will get in. I've thought it all through!

stitch1 30th Mar 2018 8:34 pm

Re: My long awaited outdoor AM aerial
 
Looks good, nice to have a decent and ‘authentic’ aerial.

My house is full of modern stuff and I don’t know why but I don’t have much of an issue with hash, QRM or whatever even on internal AEs.

For better signal strength I simply have long wire strung around the loft.

John

Hartley118 30th Mar 2018 9:31 pm

Re: My long awaited outdoor AM aerial
 
Quote:

Originally Posted by Andrew2 (Post 1030833)
Success! That must be a relief, but what happens when your neighbour gets a new gizmo that puts out acres of wideband hash? This happened to me shortly after I'd been allowed to attach the far end of a random wire (very much like yours) to a small engineering premises nearby. All was beautifully quiet for about 6 months, then one lunchtime all hell let loose.
Their new CNC milling machine turned out to be the culprit. There was nothing to be done about it, so down came the wire and up went a Wellbrook loop! Good luck.

I agree that, whilst a well-positioned long wire can give a good signal, a loop aerial can be an even more effective solution to local interference. I had always believed that with electromagnetic waves, the electric field went hand-in-hand with the magnetic field. However, this only applies to the far field, many wavelengths away from the source. Our AM interference problems tend to arise from locally generated interference, where textbook EM radiation is not yet established in the near field. Here a loop antenna, responding only to the magnetic field, can be a revelation in signal clarity. My Wellbrook loop is testimony to this assertion, cleaning up MF and HF signals to a remarkable degree. Worth trying and generally easier to install than a long wire.

Martin

Andrew2 31st Mar 2018 12:25 am

Re: My long awaited outdoor AM aerial
 
Quite. After struggling with mounting noise levels for years, I bit the bullet and bought a 1530 and certainly didn't regret it. Noise dropped by several s-points, even with the loop indoors. When I mounted it at gutter height at the rear of the house, I couldn't believe the improvement. Back then (around 2002 IIRC), the Wellbrook cost about £120, now they are far more expensive and I think I would be tempted to build the (in)famous 'Wellgood' copy. In fact I have built a number of active loops using plastic hula-hoops and conduit junction boxes with the two-transistor PA1M circuit and they work well, although the HF response is a bit droopy compared with the Wellbrook. As there is a l-o-n-g thread about loops already, I'll shut up!


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