Newbie to DAB radio here

Back door Dave

Novice Member
Hi Guys.. Newbie here with a question and hopefuly a simple fix.

Recently purchased a DAB receiver stand alone unit and out door aerial.
The reception is rubbish in my garage so I stuck the aerial up outside and ran a coax to the F connector.
Its an omnidirectional aerial that is supposed to be positioned vertically but I found better reception was with it positioned horizontally pointing toward thee North East which might be Ally Palace.
So I can now get great dab fadio in nearly all stations.
The signal strength is great but the problem is that when I scan up to the end of the channel list like Union Jack and Virgin I cant received them but the signal strength shows nearly maximum..

Any ideas ??
 

Rodders53

Distinguished Member
ALL DAB transmissions are VERTICALLY polarised. Put that antenna vertical!

What is the antenna you have bought? (Hopefully not one with an amplifier in).
What is the receiver you bought?

DAB is actually designed to work indoors in areas like London especially, with reception from more than one transmitter site working to, effectively, reinforce signals. (Especially useful on the move in vehicles)>

AP is a DAB site, along with CP or Croydon on some ensembles, plus other microsites for some (e.g. BT Tower).

The aerial might need 'adjusting' in position to receive some of the problem stations? It's unlikely that too much signal is overloading the tuner but may be worth considering if antenna relocation doesn't help (amplified aerials are :censored:) ?
 

Back door Dave

Novice Member
ALL DAB transmissions are VERTICALLY polarised. Put that antenna vertical!

What is the antenna you have bought? (Hopefully not one with an amplifier in).
What is the receiver you bought?

DAB is actually designed to work indoors in areas like London especially, with reception from more than one transmitter site working to, effectively, reinforce signals. (Especially useful on the move in vehicles)>

AP is a DAB site, along with CP or Croydon on some ensembles, plus other microsites for some (e.g. BT Tower).

The aerial might need 'adjusting' in position to receive some of the problem stations? It's unlikely that too much signal is overloading the tuner but may be worth considering if antenna relocation doesn't help (amplified aerials are :censored:) ?
Hi Rodders..thanks for the reply!

Ok here we go.. The aerial is an outdoor DAB digital version..No amplifier. Comes as a kit with coax and an F connector and a small length of tube to act as a stand off.

The Dab receiver is an Acoustic Solutions CDAB-1 DAB/FM reciever.

So ye I can reorientate it vertically but it wont work
The garage where I am setting all this up is low down and the M11 motorway embankment could be a hinderance. I know it plays havock with our mobile phone signal.
What gets me is that with the element in the horizontal it works great ..or am I still missing something?
1619449239578.png
 

Rodders53

Distinguished Member
If you are anywhere near the M11 then AP is to the West of you! Not NE (and SW with nulls at NW/SE where the tips of the folded dipole point)...

Relocate, re-orient and try the problem stations again?

RF is a bit of a black art and polarisation can be skewed by diffraction off ridges and such like but it's unusual to find it that far off that it works better when 90 degrees out.
Such skew will vary by frequency, too - albeit all DAB ensembles are pretty close together 211-229 MHz mostly (excluding local trial stuff).

Horizontal should reduce the aerial pickup but may allow direct cable pickup if not double-screened and an open weave cheap cable).

Tests of FM and DAB aerials - A.T.V. Poles, Brackets, Clamps & Aerials is a pro installers take on DAB aerials.

Mobile phone frequencies are much higher 900MHz/1.8GHz etc.,. and from completely different places and using different transmission parameters so not at all comparable.

It's possible you are in one of those 'not spots' for good reliable DAB reception of all ensembles if low lying and shielded from the obvious local transmitters ? Certainly bits of Central London were appalling before the BT Tower came on air.

The two stations are on the SDL National ensemble so a different frequency to the others you seem to get OK.

External aerials generally need to be high up in the clear to benefit fully from the signals available.

Signal strength/level is one measure, quality/bit-error rate is another - sadly your receiver doesn't support such data being displayed. Too many errors result in the stations being muted, typically.
 

Back door Dave

Novice Member
Ye my mistake.. the aerial is pointed NNW toward AP or thereabouts but the M!1 on its embankment runs right across its reception path.
Yep cheap coax was supplied.. a bit of multi strand and a foil overlay..not like the pure copper dense weave i've seen before.
Ok so I adjusted the aerial back to vertical and alls good but not the pesky stations like union jack and all of the virgin stations. I still cant receive them.
The bit that is bugging me is that the signal strength is full bars..
Like you say I can basically receive no matter where I position the antenna but NNW/NW toward AP is the best but I still cant get those statios mentioned..
I dont think the signal strength is a problem.
Something to ponder on is that if I take my cheapo DAB portable toward the garage and place it near the aerial it will receive union jack and virgin..all it hAS got is the standard telescopic stick...

Maybe the Acoustic solution tuner is naff?
 

A1944

Active Member
Sometimes you can get a problem with an aerial at one spot and perfectly good with it moved just a few inches in one direction or another. Maybe a bit of experimental tweaking of the aerial’s position is what you need.
 

Back door Dave

Novice Member
Sometimes you can get a problem with an aerial at one spot and perfectly good with it moved just a few inches in one direction or another. Maybe a bit of experimental tweaking of the aerial’s position is what you need.
Hi A1944 ..
Thats a good shout. I will try moving the location slighty. seems weird that a small portable dab set will work close to the arial installation.
 

atthecoast

Novice Member
Hi A1944 ..
Thats a good shout. I will try moving the location slighty. seems weird that a small portable dab set will work close to the arial installation.
Does your DAB tuner receive DAB+ stations? It might be that the portable does and the tuner does not?

Union Jack and Virgin Radio Anthems / Chilled are DAB+ stations. My micro hi-fi shows DAB+ stations like Union Jack but if you tune into them they are silent.

You could try tuning into Planet Rock and Scala Radio which are on the SDL National multiplex but are the older DAB type. If these work, but Union Jack and TalkRadio do not it could be that the tuner isn't compatible with DAB+?

Other DAB+ stations are Heart 70s and LBC News if it found them?
 

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