Experimentation of two transmitters EasyDab v2 in complete SFN configuration, at short distances 10m ...

[fredinp...@gmail.com]

Hello,

I did tests in SFN but short distance with a power of about 4mw and a distance of 10m.

I realized that the mini "SFN plate" but did not work.
Indeed, the constellation is very noisy at mid-distance and the receiver is disconnected.

I'm looking for people who have done these tests.

When I use a single transmitter whether it is one or the other the aperture is good and so there is no problem.

I made SFN plates in DVBT on big cities and so on a large scale, but I never realized this kind of test in workshop.

Moreover I noticed, when a SFN plate was made (in DVBT), there was always a transmitter with a delay of 0 μs and the other one with - + 100 to 250 μs, taking care to stay in the interval of guard (a master and the other slave)

What I find curious is that there is not this kind of setting in EasyDab V2.

Thank's for advance.

Pascal

[Matthias Brändli]

Hi Fred,

not sure what you mean by "SFN plate", I guess "SFN lab test".

One remarks that is not specific to the easydab: If you run two
transmitters in SFN, without time offset, and you're placed half-way
inbetween getting about the same amount of power from both, you will see
deep and wide-frequency fading.

If you run a lab setup, always play with the timing and observe what you
receive. I don't know what timing settings the EasyDAB offers. You
actually need the ability to set such an offset when you operate a SFN.

mpb

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[fredinp...@gmail.com]

Hello Mpb,

And thank's for respond,

An "SFN plate" is two or more SFN transmitters that cover an area.

In my workshop I resimulate with small power this type of configuration.

Actually by looking at the menus of EasyDab V2 transmitters, we have the time settings

of the flow of the mux but apparently no time adjustment of the emission.

Regards,

Pascal

[Rene Stevens]

Last year I try to transmit two transmitters about 5 meter from each other, both GPS locked. In the middle of the transmitters the receiver has troubles. Drop outs, quality bar drops to zerro etc. 

Later I set the same transmitters with amplifier about 10km from each other and listen with a car radio, it was good. 

Transmitters has 25 Watt out, at the first test about 4 mWatt

Op donderdag 16 augustus 2018 14:27:16 UTC+2 schreef fredinp...@gmail.com:

[fredinp...@gmail.com]

Rene,

Thank you for the information and your test,

Pascal