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Greg Pain

Converting external old vhf antenna to combo fm and dab

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Depends how far you are, line of sight ?.... just a wire will do as all some dab+ radios come with. If little ways out a telescopic whip antenna will do. For us with line of sight either the wire not even uncurled... or whip antenna not even extended does fine. Full reception. If you have a screw f type antenna connector you can pick up a telescopic whip antenna from likes of sangean for $10 posted !

 

if mobile, pure for instance and pioneer also now provide a small stick on antenna both work surprisingly well in dab+ receiving range (check the abc reception charts)

 

as a digital radio early adopter (mobile, portable and in home) even prior to going live and with previous gen trials as well I can attest to capability of all these :)

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Posted (edited)

Obsolete the multi element , try a SOTS "state of the science" omni-directional

https://www.scribd.com/document/396824710/FM-AM-Antenna-Setup-Standard-50-cm-1-8th-wave-Unit

Reasonably much, all frequencies and modulation system widths can be coarsely said to be possible from one antenna as too the data information scheme as DAB has being 128 bit rate CD digital audio mastering computer generated.

The problem is resonance (SWR Standing Wave Ratio) in small receiver elements is massively critical to good operation for the intended purpose of frequency

OR put economically, "how to operate well by tuning with the least construction resource material and thus expenditure" !

The most critical feature of an antenna is impedance (attenuation) and inductance (gain) that are usually conventionally set up by winding the aerial as a coil,

HOWEVER, there are "various other ways" to cause inductance and directional discrimination of signal.

 

 

Edited by theoldnic

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Posted (edited)
On 16/03/2019 at 8:38 AM, Greg Pain said:

Does anyone have plans to convert an old analog vhf tv antenna to pick up fm and dab?

I have an old long range fm antenna with the main central beam about 3m long, and a large fringe vhf antenna which I'd like to convert. It doesn't need to be long range; a director, collector and reflector would be suitable, as it will be roof mounted. 

I'm not even sure if the combination fm/dab is possible. I haven't found anything on the net apart from modified coat hangers!

The only true problem TV antennas have is they are directional and to a lesser extent are also designed to propagate reception with a higher gain dB than an omni-directional ordinary antenna

Of DAB+ or FM , EMR (Electro Magnetic Radiation) in the EMS (Electro Magnetic Spectrum) are all radio waves r.g. "visible light", simply different frequencies.

An antenna is simply a material device that is reactant with EMR with a sub set of design constructed properties that give it good propagative characteristics to cause "induction" of the EMR to produce electric current.

Why some antennas are stipulated for particular frequencies is one of the properties of the antenna called SWR Standing Wave Ration that has good harmonic properties for the induced voltage at the stipulated frequency.

The following is a "city use antenna" that is omni-directional but may need "attenuation" to use on a tv receiver in a city, it is not constructed the normal way an omni-directional antenna is made, and is more unusual of its physics principals than a parasitic element tv antenna.

https://www.scribd.com/document/400632904/FM-AM-long-range-30-cm-housing-1-16th-wave-Antenna-unit-setup

This shows how different it all gets,

tv antennas as most are simply made for both production and resource cost to selling performance.

 

In short, any electric conductive piece of metal is an antenna of any frequency, but there are ways of raising the efficiency for particular frequencies (you seem like you are on the right track...).

 

Edited by theoldnic

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