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50mW for Camera Car


chrisyking

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CK: " My question is this. Will 50mW be strong enough to pick up from TX inside a car, and be picked up in another car following it reliably? "

(right, Jeff:) my answer is: it depends

" Is this something where having a 100mW TX would really help? "...

... as opposed to ..?

let's say, for example:  detachable, magnetic mount antennae (sic) on the outside of the vehicles

constantin: " anything higher than 50mW is not legal anywhere in Europe. "

I don't think CK cares...

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Following my other post, I'm mulling buying a 50mW wisycom or lectrosonics kit. My question is this. Will 50mW be strong enough to pick up from TX inside a car, and be picked up in another car following it reliably?

Is this something where having a 100mW TX would really help?

Speaking from my own experience, car-to-car, even with TX set to 250mw and the trunk open on the camera car, is a total crapshoot. Both sets of aerials are inside big metal boxes and close to working engines both of which can radically affect range. As previously mentioned, you need to think about getting the aerials on the outside of the vehicles.

There are posters on here who have had success without doing this, but it is by no means definitive. More previous experience with their own particular gear and circumstance.

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What often happens is... Things start out OK... Then, for whatever reason, the picture car pulls ahead and pulls away from the follow vehicle... or, makes a turn ...or who knows...   I've been boned more times by what the cars do rather than my initial set up..

 

  Even at 250mW on my lectros it can get interesting...   If you can get the transmitters high, visors or the like it is VERY helpful... buried in someones backside and you will have some issues...  most likely..

 

 Antennas on the receiver side  (some good ones) will help a great deal... try not to use the dinky ones..

 

  Discuss the need for the follow car to stay in proximity if possible, and explain why... you may get lucky... they may actually listen... but, probably not..LOL

 

  You can always let the bag ride along... press record and it's off... your boom op at the other end to shut it off, or you when you pop out from the follow vehicle..

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What often happens is... Things start out OK... Then, for whatever reason, the picture car pulls ahead and pulls away from the follow vehicle... or, makes a turn ...or who knows...   I've been boned more times by what the cars do rather than my initial set up..

 

I've been driven mad (literally) when the setup works perfectly for the first 5-6 blocks, then we run right into a brick wall of localized RFI. And before I can change frequencies, everything comes back. So picking a good working frequency is a huge moving target. I agree that recording within the car is a good option when it's possible.

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50mW should be fine, but antenna placement is a bigger deal. A car is a metal box and the transmitter is kind of hurried in that metal box.

I don't recall hearing any real world user reviews, but *somebody* is/was making a window clip to mount a remote antenna. That is assuming your transmitter allows the antenna to be changed, and camera doesn't have to see the car exterior at the same time.

Like Jack said, Zaxcom recording transmitters are the safest bet.

Many people drop the bag and try to send a monitoring feed to chase car, then check playback after the drive.

I've used this and hidden it at the edge of a window so camera can't see it. If your transmitter has a SMA http://www.lectrosonics.com/US/Antennas/product/140-acoaxtx-specify-block.html

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Yeah, what AFMY and Marc said. I had, what I thought was a well rigged car, my shark fins in the chase van. In the middle of nowhere in rural Pennsylvania. Set off to drive and bam! Garbage interference everywhere. Turned out the driving route was basically laps around some sort of military base with lots of RF.

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As I just mentioned in your other thread, anything higher than 50mW is not legal anywhere in Europe.

 

This isn't true. I don't know about the rest of Europe, but in the UK you can pay to licence radio mics with an output of up to 1000mW (i.e. 1W). The 50mW maximum is often quoted, verbally and online, but you can find out the real rules from the horse's mouth on Arqiva's website (they're the ones who issue UK licences):

 

https://www.pmse.co.uk/equipment/wireless-microphones-and-monitors.aspx

 

The cheapest licence, which most recordists pay for annually, restricts you to 50mW for UHF body-worn transmitters - hence the widespread belief in a 50mW maximum - but you can pay more to use 100mW, 250mW or, indeed, 1000mW transmitters on a per channel, per location basis, and at Arqiva's discretion. It's a question of money and availability, rather than legality. So, if Chris wants to use a 100mW transmitter in his car setup, then - with Arqiva's permission and a suitable bill to production - he can do so with a clean conscience.

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Output power may be legal at 100mW, but deviation/bandwidth at US standard are not. So even if permission is given at 100mW, it must be at EU spec. This applies to Lectro products. I don't know about others.

I have small, tuned, magnetic antennas that dramatically improve car to car range, even if placed off camera. Sometimes they can be hidden in plain sight if they make sense being there. Cop cars, etc. But much more reliable, as mentioned, is recording in the car and broadcasting the less critical monitor feed.

I'd be reluctant to rely on time code stop/start. Just let it run until you can turn it off.

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AR: " I don't know about the rest of Europe, but in the UK you can pay to licence radio mics with an output of up to 1000mW "

I speculate that for the purpose of answering CK's question: " I'm mulling buying a 50mW wisycom or lectrosonics kit. My question is this. Will 50mW be strong enough to pick up from TX inside a car, and be picked up in another car following it reliably? " the higher power licenses are not really in consideration...

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This isn't true. I don't know about the rest of Europe, but in the UK you can pay to licence radio mics with an output of up to 1000mW (i.e. 1W). The 50mW maximum is often quoted, verbally and online, but you can find out the real rules from the horse's mouth on Arqiva's website (they're the ones who issue UK licences):

https://www.pmse.co.uk/equipment/wireless-microphones-and-monitors.aspx

The cheapest licence, which most recordists pay for annually, restricts you to 50mW for UHF body-worn transmitters - hence the widespread belief in a 50mW maximum - but you can pay more to use 100mW, 250mW or, indeed, 1000mW transmitters on a per channel, per location basis, and at Arqiva's discretion. It's a question of money and availability, rather than legality. So, if Chris wants to use a 100mW transmitter in his car setup, then - with Arqiva's permission and a suitable bill to production - he can do so with a clean conscience.

That's interesting, I didn't know that. Although site specific licences are different in other countries, too, they can be higher as well. That 50mW is for mobile applications. Anyway, as I understood the linked information, anything higher than 50mW is for site specific indoor applications. Not sure if I understood that correctly, it seems weird (the indoor bit). However, driving around in a car is usually not site-specific, depending on how they would define that.

And in any case, following on from what Robert wrote, I wonder if such a licence would indeed be granted

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