autocinema audio transmitter options

[William Kucharski]

I disagree with the need for a compressor, but a limiter, yes.

Note that BW Broadcast is a UK company, and though they WERE closed due to COVID, they look to be up and running again.

[Stefan Scholz]

The drive ins that I installed them at always had people show up with big sound systems in cars and vans. The broadcast sound from the BW's was really impressive to say the least.

True, Mark. I also had spectacular results from BW broadcast transmitters.
And they always stayed within legal modulation limits, with their built in modulation optimizer.

The Chinese $50 boxes, they work, but do not expect any legal output spectrum. Nasty on some, they use reverse TNC antenna connectors, that are hard to find on short needs.
Plus, these days they are only available from Chinese warehouses, with not plannable delivery time.

[Marin Zorica]

The Chinese $50 boxes, they work, but do not expect any legal output spectrum. Nasty on some, they use reverse TNC antenna connectors, that are hard to find on short needs.
Plus, these days they are only available from Chinese warehouses, with not plannable delivery time.

I would not recomend those on any way! They are just basic VCO with wideband amp based on BH ic......i had chance to hook it up on my Anritsu analyzer and that thing is everywhere on band, it easy can be overmodulated and pll unlock, plus no filtering on output so you can easy end up above 110MHz which is air band and regulation agency are very sensitive to any noise in that part of spectrum!

[Dustin Grush]

I have been tasked with updating our FM transmitter at the Drive-In and have come for advice. I've been given the go-ahead to order the BW Broadcast 5-30W system, as it seems the most recommended, and am wondering if there are recommendations for attenuation to get the power below the 1W that we will likely require. I've read another post here about antenna choice being one possibility. Google tells me that an in-line attenuator is another. We will be replacing everything from the transmitter outward - cables, antenna, mounting, etc. What would you recommend for antenna brand (or DIY, using an online calculator?) and method of attenuation? Is there a go-to place to purchase that I should know about? Should I also get a SWR meter and/or other test gear to go along with this, and if so, a recommendation on the lowest cost/acceptable performance scale would also be appreciated. Thank you all in advance.

[Sean McKinnon]

AFAIK these are almost impossible to get right now.

[Juan Jose Garcia Calvo]

Hello!!!
About the compressor, what will be the recommended settings to feed an FM transmitter in a Drive In cinema setup?
Thresold, Ratio, Attack time, Release Time, ...
Thanks!

[Mark Gulbrandsen]

I never used a compressor, just a limiter. The BW transmitters have that processing built in....

[Mete Tunca]

Has anyone tried audio over wi-fi option ? Like below item.

https://www.listentech.com/listen-everywhere/product/listen-everywhere-2-channel-server/

On paper this should work but I'm not sure about latency and risk of loosing w-fi connection or bandwidth usage.

[Sean McKinnon]

There is an awful lot of dynamic range in modern digital soundtracks for a random car stereo to handle. I am afraid that without a compressor the quieter parts of the soundtrack will just get lost. Maybe its not an issue but with a DSP platform like q-sys it costs nothing to add to the design and one can simply bypass it unless they decide they need it.

[Carsten Kurz]

Wifi is not able to sustain enough users. The trouble is, there is no 'real' broadcast/multicast in Wifi - you can not send a packet once over the air and expect all connected clients to receive that one packet. Over the air, every single packet needs to be transmitted individually to every connected client. That saturates the air interface already with a rather low client count. Then there are many additional latency issues. I wish someone would have thought about a radio-type transmission standard on Wifi frequencies, but, no one established one.