Menu
What's new
By:
Advanced search...

DAB Options

There are many types of diversity in communication, a phased array is the most simple version.

I could pull up some images of compact UHF yagi stacks I have installed , as well as the experiments with inserting remote local oscillators to two and three C band LNBs on 1.8m offset dishes, to recreate the characteristics of a 2.7m where space - and neighbours - wouldn't allow it. In the end I got away with a bit of camouflage, and the client plied next door with three bottles of scotch

Fading however is limited to lower band stuff where trophospherics (sp) can impact upon the audio.
 
I have tried to take pictures - but you can't actually see anything.
And, now that I think about it, I know what diversity means - I just hadn't put 2 and 2 together to make 4

Doh
 
Channel Hopper said:
There are many types of diversity in communication, a phased array is the most simple version.

Fading however is limited to lower band stuff where trophospherics (sp) can impact upon the audio.
Click to expand...
Yep there are many types of Diversity, but it's the antennas on the 7th and 8th gen Accord that we're talking about.

But I think you need to read up on fading ;)
 
Almost forgot, I have a dual Yagi array on the roof of this house for combining horizontal and vertical polarities, I tested signal fade in heavy precipitation a few years back and used to receive other transmitters by eliminating Crystal Palace with partial phase change when there were regional programmes (before satellite and the postcode checker on freesat).
 
NugentS said:
I have tried to take pictures - but you can't actually see anything.
And, now that I think about it, I know what diversity means - I just hadn't put 2 and 2 together to make 4

Doh
Click to expand...
Since you have an 8th gen saloon, and since I've not seen one close up, have a look at the "wires" particularly where the connectors are. It depends on how they've done it on the saloon as to how many connectors you'll see, but if you see two of the connectors with identical patterns of short straight "wires" then (without seeing it myself) that would confirm the use of Diversity.
 
freddofrog said:
Yep there are many types of Diversity, but it's the antennas on the 7th and 8th gen Accord that we're talking about.

But I think you need to read up on fading ;)
Click to expand...
I am unsure what causes fading on FM, I've not been asked to deal with a particular problem on terrestrial services, but a dual array would actually create more issues owing to the distance the two antennas would have to be placed apart. The Triax 7 element used to be the weapon of choice but they appear to have discontinued it.
 
Channel Hopper said:
I am unsure what causes fading on FM, I've not been asked to deal with a particular problem on terrestrial services, but a dual array would actually create more issues owing to the distance the two antennas would have to be placed apart. The Triax 7 element used to be the weapon of choice but they appear to have discontinued it.
Click to expand...
Everything that I have written in this thread and the other thread is direct from memory (not based on anything I have read on the subject in the last few years), but I spent 20 years in RF comms in several countries using models and making surveys using expensive equipment (costing tens of thousands)

I've just had a look in wikipedia, start here https://en.wikipedia.org/wiki/Fading it represents a fraction of what I have read and been told

edit: but this is the wrong thread, why not discuss it in your own thread /
 
Will do, I answered only because of the earlier Matsus hita reference (which I will be receiving the pertinent detail overnight, the company owns most of the patents to the technology used), then the question over 'diversity'.
 
Channel Hopper said:
Will do, I answered only because of the earlier Matsus hita reference (which I will be receiving the pertinent detail overnight, the company owns most of the patents to the technology used), then the question over 'diversity'.
Click to expand...
well yes it would be interesting if you have access to info that mentions precisely what the two inputs are for on the HU.

As you can see in #25, one is "Main" the other is "Sub" , which indicates Diversity (and I think that the "Main" also carries MW RF from an FM/AM combiner on one of the RF amps). But as I keep saying, it's close examination of the antenna patch/mesh that reveals what the arrangements are.
 
freddofrog said:
well yes it would be interesting if you have access to info that mentions precisely what the two inputs are for on the HU.

As you can see in #25, one is "Main" the other is "Sub" , which indicates Diversity (and I think that the "Main" also carries MW RF from an FM/AM combiner on one of the RF amps). But as I keep saying, it's close examination of the antenna patch/mesh that reveals what the arrangements are.
Click to expand...
I shall try and take photos on Friday (11th) when I (well my fitter) gets the thing apart

Sean
 
freddofrog said:
Without looking at the antennas on the 8th gen I can't be certain but, to cut a long story short, going by the circuit diagrams for the 8th gen Premium system there should be two FM antennas. If the receiver has the technology, with two antenna inputs it can use them to reduce fading caused by multipath interference. The two antennas will either give "space diversity" or "pattern diversity". If this is the case, then the 8th gen Premium system is far better than on the 7th gen, so I'd leave it as it is.

Maybe take good quality and clear pictures of the patch/mesh on the rear screen of the saloon ?

yep I agree ...but you're now adding to it :lol:
Click to expand...
The Premium system on the tourer has one FM, and one AM aerial mounted one in each rear quarter window.
 
smokingman said:
The Premium system on the tourer has one FM, and one AM aerial mounted one in each rear quarter window.
Click to expand...
ahhh I hadn't thought of looking on the 8th gen Tourer.

The sketches of the windscreen for the CU3 are not very clear in any respect, but I've now checked the CW3 and it's much clearer.


The first two bear out what the circuit diagram indicates (8th gen saloon and Tourer, Premium Sound system), which is that the 8th gen Premium does have diversity antennas for FM

LHS
CW3_antenna_lhs_1.jpg


RHS
CW3_antenna_rhs_1.jpg



The setup is very different from on the 7th gen Tourer, because the sketches indicate that LHS on the 8th gen is FM (only), and the RHS on the 8th gen has AM and FM.



The next two are closeup of each antenna sketch

LHS
CW3_antenna_lhs_2.jpg


RHS
CW3_antenna_rhs_2.jpg



The equivalent sketches of the 7th gen Tourer are very different from on the actual 7th gen Tourer, and the latter is not the same anyway. Do the above resemble the actual 8th gen Tourer ?
If so then one side (RHS in the sketches) has an AM plus an FM antenna (and the apertures of mesh antennas are not obvious without expensive equipment, although it is possible to guess the basic design by measurements of a couple of the sections of wire geometry)




These two show the RF amplifiers on the 8th gen Tourer


LHS (sub)
CW3_antenna_lhs_3.jpg


RHS (main)
CW3_antenna_rhs_3.jpg



The 7th gen only has a coil on each side, whereas the 8th gen has active amplifiers. Note that the "sub" amplifier on the LHS is FM-only and it looks like the lower geometry may be a reflective ground-plane (similar to the 7th gen FM antenna).



Finally, note that there are differences on the 8th gen circuit diagrams for the antenna inputs to the Premium and to the non-Premium systems, yet there is no differentiation on the components on the vehicle.
So it is also possible that the non-Premium does not have antenna diversity i.e. mesh antennas different to the above (possibly same as 7th gen).
 
I'll be passing by the local Honda dealer tomorrow so will take close up pictures of the windows if there are 8th gen vehicles there.
 
Pot luck as to whether they have any 8th gen Tourers. The antenna mesh on the saloon (8th gen included) is squished along the top, so it might just look a very jumbled geometry on the saloon.
 
Thamse Ditton parts said they had a silver Gen 8 at the showroom earlier today, but upon driving over there it appears to have vanished so I couldn't get any images of the glass. There are none parked up on the way home either but then most new cars look the same to me.
 
Damn I thought there'd be pictures LOL

There's quite a big Honda dealer in Nottingham, next time I'm over that way I'll take a look ;)
 
Channel Hopper said:
I'll ask the MOT station - nicely - if they have a local client with one on their books tomorrow.
Click to expand...
and then you'll get arrested for stalking :lol:
 
Facelift 8th Gen Tourer. Any help? Edit: Premium audio with Nav

Passenger’s Side:
8thTourerPassenger_zpsejsj2329.jpg


Driver’s Side:
8thTourerDriver_zpsjorfskvv.jpg
 
crikey 2nd picture looks like a Martian fighting machine is about to attack (War of the Worlds) :lol:

But those are excellent pictures, confirms that the sketches in the ESM are very representative.

They are also substantially different from the 7th gen Tourer and it's difficult to make any guess as to the directivity of the Band 2 elements. I'll keep looking for one in a supermarket car park ;)
 
And apologies from me again.

Kit is in and working - and working extremely well.

Fitter was in the garage and he had everything done and buttoned up before I remembered the photos. He did however say he couldn't easily connect the FM part ofthe new antenna to the radio so left it disconnected

Ah well only need FM for Classic - carrying TMS

Sean
 
Yup I do

Its got extremely good reception - on autodab its a maximum star arial. There was always the possibility of not being able to use the FM part but if I ever need to change the radio for some explicable reason - I can use the arial if needed

And it works - I just hope the hole don't go rusty
 
Hi Sean.

I think if I had just drilled a hole in my car I would have repainted the area, then put some Waxoyl just to stop the possibility of any rust. Good to know you got good results with the DAB unit.
 
Hi again Sean.

So other than the aerial you mentioned earlier what other parts did you need to purchase, obviously a coax cable from the aerial to DAB box and maybe an adapter or two, if so what did you get?

John
 
You must log in or register to reply here.
Top