Take a DAB portable into a big open space where there are no confusing factors like reflections, standing waves, etc. Find a weak multiplex. Experiment with the length of the telescopic aerial. You'll be surprised.
Bill
I was talking about mobile reception.
Bill
Could I add that any old piece of conductive material will work as an aerial. It's just that unless it's resonant and matches the feeder it won't work very well (it won't be very sensitive). But if the incoming signal is so strong that the highly inefficient 'aerial' can still deliver adequate signal to the receiver it will work just fine.
Bill
Absolutely. And not just pieces of wire.
Bill
A quarterwave on the roof will outperform a screen aerial massively. Bear in mind though that the use of the same channel for different muxes in different (sometimes overlapping) areas is a big factor in limiting DAB mobile reception.
Bill
I must be about 50 years ago that colleagues did tests with Volvo to show that the roof was the ideal place of a car aerial. Almost any other location on a car gave distinct directional lobes.
That is because you live in the south. DAB is all but unusable where I live even with a good antenna and balun tuned to the right band.
It didn't help when the Bedale transmitter mast burned down. It was still pretty useless before that and drops out on the A1/M62 too.
The only thing that DAB does better than FM is the inter programme gaps. Insufficient bitrate and the wrong codec badly implemented.
If there is plenty of signal around it hardly matters what the antenna looks like provided that there is enough of it (length of wire).
Quite a few makes fitted roof aerials as standard once - even in AM days. Rover and Rolls-Royce. Perhaps automatic car washes stopped that fashion. Until the sharks fin versions appeared.
BL, when it existed, reverted to wing aerials on one car and one of my colleaguesn wrote to them asking why "That's where the stylist said it had to go." was the reply.
Also roof racks
But science works best. The person experimenting here, was able to demonstrate directionality and polarization with his antenna.
The simulator predicts an idealized narrowband behavior, but the real implementation might not even be close on that. Sometimes, the coax cable leading to the antenna, is the antenna :-) The gamma match on that antenna, would be "the fiddly bit". Standing next to it, might throw it off (he used a 5pF cap).
The dish will focus anything RF but the receivers at the focus are incredibly narrow band and able to reject most terrestrial junk. The shape of the dish ultimately limits the highest frequency it can use.
VLA offers amongst the widest range of receiver frequencies of any of the worlds radio telescopes:
No, it's because he lives in an area of high DAB field strength.
DAB is all but unusable where I
Let's not start one of those gainsaying DAB discussions. However I did drive from Retford to Rotherham yesterday and GB News didn't drop out once...
Bill
Don't be silly.
Bill
I used to have a van with the aerial on the bonnet on the nearside. It was noticeable how reception would be quite different on weak stations depending on which way you were travelling along a particular road.
Bill
So they aren't TUNED.
The size of the dish, actually.
Most DAB is. Just a couple of tiny, so called 'mini-muxes' that use just a single Tx site
Don't be silly. The grown-ups aren't impressed.
Bill
It hadn't occurred to me, but yes of course they are.
Bill
That's just anti-southern bias. In the South we have areas (notably Kent and Sussex) where provision of some DAB services isn't possible because of French objections (says he with his anti-French bias !)
I live in the South and DAB can only be received using the indoor aerial upstairs and at the front of the house, facing North, and pinned up vertically.
I cut a length of 11mm oval conduit about 25 inches long, and made a slot in the centre by cutting 1/3 of the way through and about 1/2 an inch lomg.
Then I fed the the two arms of the dipole up and down and attached a short length of copper wire at one end and hung it from a pin in the ceiling.
Lowering it down to desk height the radio goes off as it does if the aerial is not vertical.
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