How to combine two or more DAB aerials? and same question for 2 or more FM aerials?
Stephen
Now that I've got my threee Televes Avant 5 units working, I feel a bit of
experimentation coming on....... :-)
You may recall that I live in an area of Northampton where its possible to
pick up 4 different TV transmitters, Sandy Heath, Oxford, Sutton Coldfield
and Waltham. Obviously with 3 Televes Avant 5 units, I am now spoiled for
choice & flexibility on combining various TV transmitters as each unit has
10 programmable UHF filters, giving me up to 30 filter channels
:-))
I have the first programmed up for Oxford, the 2nd programmed up for Sandy
Heath, the outputs are combined together before feeding my two
multiswitches.
I currently have a 12 element DAB aerial pointing at SC and that picks up
from three different TX's (via its side lobes), the 5 DAB ensembles, BBC,
D1, MXR, Now Leicester and Now Coventry from Daventry (MXR), Waltham (Now
Leics), Leamington Spa (Now Cov) and SC for Dig 1 and BBC.
Needless to say the ensembles recieved via the side lobes have higher error
rate and are weaker.
I also have a vertical omnidirectional FM dipole picking up all and sundry,
leaving me with at least three versions of R1, R2, R3, R4 and Classic FM as
well as local radio stations like BBC Oxford BBC Northampton, , 3 counties
Radio, Heart FM etc.
These currently feed into one of the Televes Avant 5's so that leaves the
DAB and FM aerial inputs unused on the other Avant 5 unit.
So could I point an FM aerial at a national FM transmitter to get
R1/R2/R3/R4/Classic FM (horiz pol of course) and a DAB aerial pointing at a
main transmitter giving me the BBC and D1 ensembles, feed that into one of
the Televes unit, and then have a 2nd FM aerial pointing at a regional
transmitter to say get BBC Radio Northampton and 3 Counties Radio from
Northampton TX and a 2nd DAB aerial pointing at Daventry to get the MXR
multiplex? I could in theory extend the idea and use the 3rd Avant 5 to pick
up a 3rd DAB transmiiter and a 3rd FM transmitter.
Obviously I would use directional aerials, and the Avant 5's would do a
reasonable job of equalising the FM and DAB signal levels on a per
transmitter basis during its set up.
I've seen Bill Wright's article on using stub filters on FM so that would be
a good technique for combining FM aerials, but what could be done for the
DAB aerials?
All comment welcome
Stephen
Brian Gregory [UK]
news:jPednc-6DdZ8fijQ...@brightview.co.uk...
Stubs are notches. So, as far as I can see, they would be little use in this
case.
--
Brian Gregory. (In the UK)
n...@bgdsv.co.uk
To email me remove the letter vee.
Graham.
>> So could I point an FM aerial at a national FM transmitter to get
>> R1/R2/R3/R4/Classic FM (horiz pol of course)
Why is it a "given" that you would use the horizontal component? Just wondering?
--
Graham.
%Profound_observation%
R. Mark Clayton
"Stephen" <i.wan...@spam.com> wrote in message
news:jPednc-6DdZ8fijQ...@brightview.co.uk...
> Hi all,
>
> I've seen Bill Wright's article on using stub filters on FM so that would
> be a good technique for combining FM aerials, but what could be done for
> the DAB aerials?
Bill recommended a single vertical FM dipole (this works very well for me
getting FM to 100km+ *), which would just happen to work as a DAB aerial as
well.
If you really want to DX then get a Dressler ARA 2000 [or similar] active
antenna**.
>
> All comment welcome
>
> Stephen
>
>
>
* really only limited by FM capture of nearer transmitters - the whole band
is choc a block.
** not made now, but fabulous performance from my earlier ARA 1300.
Graham.
>
> If you really want to DX then get a Dressler ARA 2000 [or similar] active antenna
You have just got to be kidding.
--
Graham.
%Profound_observation%
Brian Gaff
to flog this multi channel to acable operator!
grin.
Brian
--
Brian Gaff - bri...@blueyonder.co.uk
Note:- In order to reduce spam, any email without 'Brian Gaff'
in the display name may be lost.
Blind user, so no pictures please!
"Stephen" <i.wan...@spam.com> wrote in message
news:jPednc-6DdZ8fijQ...@brightview.co.uk...
Stephen
"Graham." <m...@privacy.com> wrote in message
news:ip4unh$15h$1...@dont-email.me...
R. Mark Clayton
>
>
>>
>> If you really want to DX then get a Dressler ARA 2000 [or similar] active
>> antenna
>
> You have just got to be kidding.
Why?
>
>
> --
> Graham.
>
>
Bill Wright
positions where they are in the same general field and they have their
outputs combined without a frequency-selective device of some kind, the
results will be heavily dependent on the phase relationship on any given
frequency between the signals received on the two aerials. This will
greatly affect the overall polar response and in fact may be the
dominant factor in determining it. Certainly there will be deep notches
in the response. These can be defeat the object of the exercise, or they
can be put to good use for discrimination purposes. The phase
relationship can be varied by moving one aerial towards or away from the
relevant transmitter. See
http://www.wrightsaerials.tv/articles/whatsat-phased-arrays.pdf
and even, as a blast from the past
http://www.wrightsaerials.tv/reference/resources/eliminating-ghosts.pdf
More specifically looking at FM and DAB, reception of distant signals is
often (usually?) limited more by CCI than by signal strength per se.
Thus after a reasonable signal has been obtained on a good directional
aerial, attempts to combine the output of that aerial with another will
often degrade reception severely.
Applying different levels of amplification to the two feeds before
combining is a difficult balancing act. If it's done though, variably
attenuate each feed AFTER each amp.
Bill
Stephen
bros filter clusters, is it possible to do the same with DAB?
E.g pick up DAB ensembles 11D and 12B (Digital 1 and BBC) and MXR on 12A,
from an aerial aligned to Daventry, then a 2nd DAB aerial aligned at
Leamington Spa to get Now Coventry on 12D, a 3rd aerial on Waltham/Copt Oak
to pick up Now Leicester on 11B from Copt Oakand and Now Nottingham on 12C
from Waltham?
Now what could I pick up on 11C? :-) Oh yes, CE Birmngham from Lichfield.
I could also try for Zouches Farm to give me 5 ensembles, and a 2nd DAB
aerial at Membury to get Now Swindon from Membury and Now Reading from
Hannington (both are in the same direction from Northampton)
"Bill Wright" <bi...@invalid.com> wrote in message
news:ip6kl1$6pp$1...@speranza.aioe.org...
Stephen
bros filter clusters, is it possible to do the same with DAB?
E.g pick up DAB ensembles 11D and 12B (Digital 1 and BBC) and MXR on 12A,
from an aerial aligned to Daventry, then a 2nd DAB aerial aligned at
Leamington Spa to get Now Coventry on 12D, a 3rd aerial on Waltham/Copt Oak
to pick up Now Leicester on 11B from Copt Oakand and Now Nottingham on 12C
from Waltham?
Now what could I pick up on 11C? :-) Oh yes, CE Birmngham from Lichfield.
I could also try for Zouches Farm to give me 5 ensembles, and a 2nd DAB
aerial at Membury to get Now Swindon from Membury and Now Reading from
Hannington (both are in the same direction from Northampton)
"Bill Wright" <bi...@invalid.com> wrote in message
news:ip6kl1$6pp$1...@speranza.aioe.org...
Bill Wright
> Ok, given that its possible to get channel filters for UHF, eg the Taylor
> bros filter clusters, is it possible to do the same with DAB?
No. Passive filters can't discriminate between adjacent DAB channels,
which are only 2MHz wide. They can't for that matter discriminate
between adjacent TV channels which are 8MHz wide.
>
> E.g pick up DAB ensembles 11D and 12B (Digital 1 and BBC) and MXR on 12A,
> from an aerial aligned to Daventry, then a 2nd DAB aerial aligned at
> Leamington Spa to get Now Coventry on 12D, a 3rd aerial on Waltham/Copt Oak
> to pick up Now Leicester on 11B from Copt Oakand and Now Nottingham on 12C
> from Waltham?
>
> Now what could I pick up on 11C? :-) Oh yes, CE Birmngham from Lichfield.
>
> I could also try for Zouches Farm to give me 5 ensembles, and a 2nd DAB
> aerial at Membury to get Now Swindon from Membury and Now Reading from
> Hannington (both are in the same direction from Northampton)
By the time you've finished aligning and combining you'd be better off
just putting up a single vertical dipole really high (much higher than
you'd be able to put all those beams). Alternatively, you could have
some fun with a single good beam (a yagi I mean) on a rotator.
Bill
Stephen
> Stephen wrote:
>> Ok, given that its possible to get channel filters for UHF, eg the Taylor
>> bros filter clusters, is it possible to do the same with DAB?
>
> No. Passive filters can't discriminate between adjacent DAB channels,
> which are only 2MHz wide. They can't for that matter discriminate between
> adjacent TV channels which are 8MHz wide.
I presume you mean TV filters in Band III as opposed to band IV & V
otherwise the TCFL's would not work.....?
>> E.g pick up DAB ensembles 11D and 12B (Digital 1 and BBC) and MXR on 12A,
>> from an aerial aligned to Daventry, then a 2nd DAB aerial aligned at
>> Leamington Spa to get Now Coventry on 12D, a 3rd aerial on Waltham/Copt
>> Oak to pick up Now Leicester on 11B from Copt Oakand and Now Nottingham
>> on 12C from Waltham?
>>
>> Now what could I pick up on 11C? :-) Oh yes, CE Birmngham from Lichfield.
>>
>> I could also try for Zouches Farm to give me 5 ensembles, and a 2nd DAB
>> aerial at Membury to get Now Swindon from Membury and Now Reading from
>> Hannington (both are in the same direction from Northampton)
>
> By the time you've finished aligning and combining you'd be better off
> just putting up a single vertical dipole really high (much higher than
> you'd be able to put all those beams). Alternatively, you could have some
> fun with a single good beam (a yagi I mean) on a rotator.
I've already tried a vertial dipole, I have two issues. the first is that
the signals are too weak to resolve and secondly, the Zouches
Farm/Membury/Hannington Ensembles are co-channel with
Daventry/Waltham/Lichfield and Leamingto Spa so hence the reason why I was
using a 12 element DAB aerial aligned to the midpoint between the 3 DAB
transmitters I can actually swivel round and have a load of
London/Reading/Swindon centric DAB stations or have a load ot West
Midlands/Leics/Cov/Notts Centric radio stations.....
J G Miller
William Wright explained:
> Alternatively, you could have some fun with a single
> good beam (a yagi I mean) on a rotator.
What is your opinion of the quality of Blake antennas?
GBP 54,95 at
<http://www.moonraker.EU/TV-and-FM-Radio/FM-Dab-Antennas/DAB-12-DIRECTIONAL-DAB-YAGI-ANTENNA>
GBP 59,59 at
Stephen
"J G Miller" <mil...@yoyo.ORG> wrote in message
news:ip6qe0$sk3$5...@dont-email.me...
I have the ABM 12 aerial as it happens, its a big beast, over 2m long.
It does the job in getting the weaker ensembles for more distant
transmitters and rejects the weaker transmitters behind it.
If I use a vertical dipole as suggested by Bill, I only get the BBC and
Digital 1 ensembles.
Stephen
Stephen
they will get possed iff if I start swivelling the DAB array to a different
Tx via the motor............... :-)
Bill Wright
> "Bill Wright" <bi...@invalid.com> wrote in message
> news:ip6ovb$iku$1...@speranza.aioe.org...
>> Stephen wrote:
>>> Ok, given that its possible to get channel filters for UHF, eg the Taylor
>>> bros filter clusters, is it possible to do the same with DAB?
>> No. Passive filters can't discriminate between adjacent DAB channels,
>> which are only 2MHz wide. They can't for that matter discriminate between
>> adjacent TV channels which are 8MHz wide.
>
> I presume you mean TV filters in Band III as opposed to band IV & V
> otherwise the TCFL's would not work.....?
against an adjacent channel. 0dB at the near edge; maybe 15dB at the far
edge if you're lucky.
Bill
Bill Wright
if they cover the whole band from 175 to 240 Fairy Cycles they are too
wideband to have much gain. The European aerials meant for BIII TV and
are tuned for 210 to 240 Fairy Cycles are much better.
The little four element wideband ones have negligible gain over a dipole
with a reflector only.
Bill
J G Miller
> I have the ABM 12 aerial as it happens, its a big beast, over 2m long.
During tropospheric propagation conditions, have you been able to receive
any very long distance transmissions using this antenna?
Graham.
"R. Mark Clayton" <nospam...@btinternet.com> wrote in message news:WPKdnX3OeLuxUyvQ...@bt.com...
It's a piece of damp string with a built in amp.
Any gain figure quoted will be the gain of the amp.
--
Graham.
%Profound_observation%
Graham.
"Brian Gaff" <Bri...@blueyonder.co.uk> wrote in message news:ip5u2g$mh7$1...@dont-email.me...
> You are wonderfully loopy, is all I can say. Maybe after all this you need to flog this multi channel to acable operator!
>
> grin.
>
> Brian
At one time I had aerials for Winter Hill,Emley Moor and Moel-y-Parc.
I tried various methods of combining the three ITV channels including
modified mechanical UHF tuners housed in Tupperware boxes.
None of which were entirely successful.
--
Graham.
%Profound_observation%
Bill Wright
earoles belted for that!
Anyway, I used the mechanical tuner trick and it worked for me.
Bill
Stephen
Aaaawwww, a man after me own heart! *big grin*.......
Stephen
Silk
If it were me, I'd listen online.