BESPOKE STUBBY

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Southernboy
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BESPOKE STUBBY

Post by Southernboy » Sat 27 Jul, 2013 07:57

I am considering making up a dozen or so stubby aerials as per the draft pic below. They will be 110mm long and will be fitted with an internal copper wire coiled around a ceramic shaft to provide a wire of 400mm length connected to the screw in stud. This is important for wavelength reception and the lack of such an insert is the main fault with stubby aerials having a poor reception.
They will be made from high grade aluminium, and polished to perfection for those who want a "silver" finish. Alternately, they can be anodised black. They will come complete with the correct threaded brass stud to screw into the OEM aerial signal booster fitted to the z3's.
I will consider requests for other colour anodising for those who are seriously anal and want a blue, yellow, red or green finish....
At this stage I am just testing the water, and can only estimate the cost at around £.25.00 including postage to UK /EU. There are cheaper options on eBay etc, but not fitted with the 400mm copper wire aerial insert to provide excellent reception in such a "short" fitting.

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Re: BESPOKE STUBBY

Post by SeriousRikk » Sat 27 Jul, 2013 12:38

Well since the arial is something I have just focussed on, as I need to buy a new base :shock:
I would definitely be interested in one of these!
Richard - Old Zeddy's new home...

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OXO
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Re: BESPOKE STUBBY

Post by OXO » Sat 27 Jul, 2013 15:35

Is the construction a wire inside an aluminium sleeve, and the sleeve not electrically connected?

If so, then I suggest you test one as the aluminium will severely attenuate the rf signal.

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Southernboy
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Re: BESPOKE STUBBY

Post by Southernboy » Sat 27 Jul, 2013 16:17

The wire is connected to the top of the aerial from the inside...the hole up the ceter extends to about 8mm short of the topmost point inside the sphere at the tip, and then at the bottom to the brass stud which screws into the OEM base...it is coiled around a central stick of ceramic tube 3m in diameter...The wire is .5mmD coated copper. The entire aerial is connected / grounded where it screws into the base, but isolated from the car body at that point. It later makes it's connection after passing through the OEM base and the aerial wire which then goes to the head unit where it has the jack connection at the back...the head unit is obviously grounded to the car. :wink:
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OXO
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Re: BESPOKE STUBBY

Post by OXO » Sat 27 Jul, 2013 16:48

So the aluminium outer is connected to the wire at the base, and the coil at the sphere end?

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Southernboy
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Re: BESPOKE STUBBY

Post by Southernboy » Sat 27 Jul, 2013 17:00

The wire is connected at the top and to the brass stud at the bottom..the stud connects to the base by screwing into it. On the inside of the base unit there is a wire connected to the threaded female which the aerial male fits to. Inside the base unit the wire then continues to the head unit via the aerial cable center pole... The aerial proper is insulated from the car body by the insulated OEM base, and the large rubber grommet which holds it around the neck as it passes from inside to out at the rear fender hole. The OEM aerial is essentially a monopole system. The addition of a coils compensates to some dgree the loss of length in the aerial that were commonly found on cars, which had a length of around 750mm and constituted what is known as a 1/4 wave aerial..ie it's length constitutes 1/4 of a received radio wave. This is generally considered a "good" aerial, but it's not very popular anymore...so the insertion of a coil inside the aerial acts as compensation for the loss of length by increasing the gain. It isn't a 100% compensation, but does go a long way to provide a strong signal without an excessively long antenna. Most mobile phones, wifi etc use monopole aerials...they are tiny units, but are comfortable at microwave freqencies. Most transmissions today are FM and microwave, so the issue of a really good aerial is moot, since those type of signals require almost uninterrupted line of sight to be really effective.
The only signals which are reasonable in hilly terrain are medium and long wave which use the ionosphere as a reflector to be bounced downwards again and again. So, without "repeater" stations, FM and microwave are practically useless over long distances or hilly terrain.
Last edited by Southernboy on Sat 27 Jul, 2013 17:35, edited 1 time in total.
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OXO
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Re: BESPOKE STUBBY

Post by OXO » Sat 27 Jul, 2013 17:30

Sorry to keep on, but is the stud connected to the aluminium part at the bottom?

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Southernboy
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Re: BESPOKE STUBBY

Post by Southernboy » Sat 27 Jul, 2013 17:40

The copper wire is connected to the stud at the bottom, but is otherwise insulated. The stud forms a connection to the center core wire of the aerial cable after it passes through the OEM base which is another gain booster in effect.the aluminium antenna is insulated from the car permanently as is the OEM antenna. The OEM antenna is exactly the same principle without an interior coil. The OEM antenna actually has an exterior coil wound around a flexible fiberglass rod and insulated for protection from the elements. If you look at your OEM antenna, you will clearly see the outer coil.
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OXO
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Re: BESPOKE STUBBY

Post by OXO » Sat 27 Jul, 2013 18:23

Yes I know about the Oem one.

The point I am trying to get to with your design is that if the internal coil is completely surrounded by an aluminium tube, it won't work well, because the aluminium is screening it. It will be no better than a plain wire of the length of the tube. For a helical antenna (which is what you describe) to work, there must be no metal between the coil and the air.

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Southernboy
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Re: BESPOKE STUBBY

Post by Southernboy » Sat 27 Jul, 2013 20:30

That's not correct. The coil on the OEM aerial is also sealed within a covering...the coil I will be inserting is connected to the aluminium via the stud which screws into it (the antenna) and the aerial base, the aluminium antenna operates in conjuntion with the coil, it isn't a separate entity.
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OXO
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Re: BESPOKE STUBBY

Post by OXO » Sun 28 Jul, 2013 06:58

It's important what the covering is made from. Metal is a lot different than paint or resin.

That's all. I don't want to have an argument. Good luck.

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Southernboy
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Re: BESPOKE STUBBY

Post by Southernboy » Sun 28 Jul, 2013 08:11

It's a discussion...you're asking questions which concern you, and they're valid enquiries. I hope I've answered them, and that you have a clear picture of what I am proposing...sometimes it's a tad difficult trying to explain something very simple.
If you prefer, I can email you a sectional sketch, that way you could have a visual reference, and be able to offer some concrete advice etc...any technically valid contribution / direction will be welcome. :wink:
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Re: BESPOKE STUBBY

Post by eyerisk » Wed 31 Jul, 2013 12:57

How much........I would be up for one ?

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Southernboy
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Re: BESPOKE STUBBY

Post by Southernboy » Wed 31 Jul, 2013 13:15

Hi mate...I'm still gathering the costs etc..I have also re-designed it so that it will enhance it's "reception" abilities somewhat...as soon as I ahve it prepared, and a decent "prototype" to show how it will work / perform...I will post a few pics etc and a cost. Should be ready with that by next week sometime... :wink:
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Re: BESPOKE STUBBY

Post by snoops » Wed 31 Jul, 2013 13:30

I'm not in to all that techie stuff - I'll leave it to you guys to hammer out a good design.

If it looks good and I get a good reception on the radio and the price is reasonable them I'm interested - but I'd like it in pink :D :D only joking - I would like a black finish please - not into Chrome.
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Re: BESPOKE STUBBY

Post by aceman » Wed 31 Jul, 2013 13:31

Wondered when you were going to offer these up, I remember our conversation about them many moons ago. :D
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Southernboy
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Re: BESPOKE STUBBY

Post by Southernboy » Wed 31 Jul, 2013 13:53

....the more one reads on these things, the more one needs to read on these things...and eventually one realises that the problem between aesthetics and performance is an ongoing issue...I recently saw an article on Mercedes Benz cars where they had incorporated a "Ground Plane" (GP) of some 400mm diameter into the boot lid...Briefly, the GP needs to be as near as dammit to the length of the aerial rod to give "excellent" results...This is not practical in most instances, and definitely not aesthetic most of the time...it's a compromise at best between aerial length, ground plane and pre-amplification...and then finally one can arrive at an aesthetic conclusion which hopefully is acceptable to the end user...
My re-design is somewhat "novel" in that it will have two settings...1. in town...and 2. out of town. and it is designed to be an all in one unit....tricky to say the least. But at the end it should provide as good a reception as the OEM aerial otherwise it will not be good enough...and at the same time provide a really "cool" stubby acceptibility aesthetic.
In town isn't an issue...mostly...it's when you get out of town and the reception begins to deteriorate due to distance and interference by geography...that's when a longer aerial becomes more desirable from a reception point of view..
Used to be the "telescopic" aerials which were useful in that way, now they are definitely "un-cool"...So...I think I've managed to resolve the issue to a degree...not perfect, but very innovative...watch this space...and it is easily made in pink too....just another anodising option... :wink:
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OXO
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Re: BESPOKE STUBBY

Post by OXO » Wed 31 Jul, 2013 13:53

Southernboy wrote:Hi mate...I'm still gathering the costs etc..I have also re-designed it so that it will enhance it's "reception" abilities somewhat...as soon as I ahve it prepared, and a decent "prototype" to show how it will work / perform...I will post a few pics etc and a cost. Should be ready with that by next week sometime... :wink:
NP. I pm'd you my email at the weekednd.

Chris

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Southernboy
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Re: BESPOKE STUBBY

Post by Southernboy » Wed 31 Jul, 2013 13:58

Hi Chris...I got that...I'll be on your case asap I have some bits etc from my engineers...You'll be the first to see the "proposed" item so that you can offer some more tech input etc.. :wink:
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Re: BESPOKE STUBBY

Post by BladeRunner919 » Wed 31 Jul, 2013 15:24

Southernboy wrote:In town isn't an issue...mostly...it's when you get out of town and the reception begins to deteriorate due to distance and interference by geography...that's when a longer aerial becomes more desirable from a reception point of view..
I wonder if that's more of a problem in SA than it is here in the UK anyway? We don't have the distance between towns that you may do (generally).

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Re: BESPOKE STUBBY

Post by gookah » Wed 31 Jul, 2013 17:29

I too have a stubby aerial,
since fitting it, and, as the radio is no longer useable, I no longer have that annoying crackle, hum and interference of Chris Moyles or any other self-opinionated DJ inbetween the tunes I am listening too, ..

Suits me down to the ground. :D
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Southernboy
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Re: BESPOKE STUBBY

Post by Southernboy » Wed 31 Jul, 2013 18:10

That's the problem with the "average" stubby...the reception of radio signals....and that is what I'm trying to minimise.
The problem is the length of a stubby...it's a fraction the length of a radio wave and consequently it's ability to reproduce the signal is weak....obviously going longer is what we're trying to avoid.
Here in SA it makes no difference how long the aerial is...there are huge areas out of town where the only option is to have an iPod or such...or have a good singing voice... :D I would like to have a stubby with a 50 mile signal reception - at least - which is about what I get from the OEM antenna..I have a pretty cool design worked out, which I am hoping will achieve close to that sort of range...it would obviously be perfet for the UK where one is never very far from anywhere else except perhaps in some areas of Scotland.
Anyhow...we'll see what transpires...I'm currently shopping the planet for ready made balls that will fit on the top...found some interesting suppliers in the USA...and cheap as chips too....$.45.00 for 90 balls...trouble is I really don't want that many...but I've sent them a message and I'll see what comes back...the cost of having balls made here is greater than "instant" balls from the USA...it'll all come together next week or two...
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Re: BESPOKE STUBBY

Post by Orinoco » Wed 31 Jul, 2013 20:15

Hi
I'll take one if they work as my stubby is poor for radio reception.

Let me know if and when they are available.

Cheers
Orinoco

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