I've worked on many movie productions and what I think you're receiving is the stage monitor. The wireless mics all feed over various low power channels back to the sound man and his mixing board where they are recorded. There is a separate mix off of the board known as the Stage Monitor and this is likely what you're picking up. They use a higher power transmitter for the Stage Monitor as this audio is what is fed back to the director, producers, DoP, headsets and everyone else that needs to hear what's being said. The Stage Monitors are typically 50 mw ERP out of the box but Techs onset will likely rig up with some better antennas then the rubber ducky that come with the TX pushing out a stronger ERP to keep the producers happy. They love everything wireless onset but it can also cause a lot of problems dealing with interference and this is why they are quick to use solutions like a bigger antenna to keep everyone happy. There could also be a location shoot somewhere in your neighborhood close by that you didn't know about too.

You're measuring the swr with a long antenna cable.... totally a pro. 😂

wireless systems like the Sennheiser ew 100 are small belt-mounted transmitters. they are available in a bunch of frequency ranges. 868MHz being one. They are also used on location. Meaning they could have been literally next door. No need for a studio kilometers away. Great video!

Sometimes filming doesn’t always happen in a studio. Could be something being filmed on-site near you. It’s cheaper to rent an office building or home and film there than to build it all on stage.

@jimbotron70

7 ай бұрын

The most likely explaination.

@VicGreenBitcoin

7 ай бұрын

@@jimbotron70 or its not a 25mW signal.... Most logical explanation.

@jimbotron70

7 ай бұрын

@@VicGreenBitcoin It's unlikely to me that a stage mic, even pimped up, could travel across 20 miles with mountains in the way, but I could be wrong.

@JxH

7 ай бұрын

Ding-dong. "Yes?" "I'm here to fix your boiler..." Etc.

I agree! Might be filming PORN in a home, office, or flat near by.

@paulsengupta971

7 ай бұрын

Do people normally have microphones wired up for that?

There may be a film being made on location nearby, it doesn't have to be a studio.

i think they were making a particular kind" of movie.

Thank's for another great radio-video Andy, I love you and Lewis' videos, and your music at the ends. I always listen all the way out! The best from LB1NH 🙂

Excellent video as always. Very educational. Thanks Andy, looking forward to the LORA videos.

Here in the US in California 866-868 Mhz used to be a public service trunk band (long since abandoned and empty) with analog Motorola and EDACS trunk systems, which included the Oakland Police Dept which also had a simulcast mirror in 982-984 Mhz. Alameda County Sheriff's Dept also used to be in this 866 Mhz range. Today they're on a p25 shared system with three other counties in 772-775 Mhz. I find the Remtronix rubber duck antenna outperforms every other antenna for the 700 Mhz trunking ranges, works well on 800 Mhz and other UHF/VHF and other Low bands. It is specifically cut and tuned in the 700 Mhz band, so it's not a matter of bigger is better at just under 7 inches, the actual element to the BNC connector is shorter. Just solid copper rods in the 6-7 inch range produces the same reception resonance for a proto-yagi within 772-775 Mhz, multi-banded into 450-460-480 & 850-860 Mhz resonances for a well integrated multi band Yagi. Depending on wavelength you can reduce that 6-7 inches down about 3 1/2 inches with about 7-9 turns in a coil. You can use antenna calculators for a rough idea of element lengths, but I tune by ear and observation in signal strengths, like by ear; in old school calibration tuning of radios by ear alone without any equipment.

I believe the data is likely a smart meter for water or power. Could also be for monitoring water systems.

@phungyi4947

7 ай бұрын

This. ^

the big question is - can we decode all of them?

Hi Andy, I have a TTGO TBeam and with this antenna mounted on my car and the TTN LoRa Tracker fw I managed a record of 130 km down in NW Italy!

@andykirby

7 ай бұрын

Wow that is very impressive!

@stephenjones9153

7 ай бұрын

I was also thinking it maybe from Warner Brother Studios. Also up on 1.3Ghz the record as far as I know was set by M0VRL at 2662Kms on SSB and JT65 record is 18858Kms.

Meshtastic is a lot of fun to play around with. Ive been working with a couple of mates to refine out setups for use whilst camping places where there's no mobile phone coverage. For testing we have them in iur houses and get surprisingly good results with small basic antennas. Id thought of putting one like you bought in my loft but unsure how much my old roof would block the signal. Ill be very curious to see if you use that antenna with meshtastic how well it does.

Fantastic. Time for a drive around? "think it's weight" 😄

Hi, I've often seen those kind of wave shaped SWR fluctuation in case of bad matching in a part of the line (some 75 Ohm coax or adaptor in a 50 Ohm system for instance) There must be a dip every half wave and multiples when the source and the load impedances match.

The signal at 863mhz with the weird pattern is just interference from a power supply. I have them show up all over the hf, vhf, and even uhf bands at my house.

That's cool, now I want an antenna for this band. I did not think about voice transmissions on this frequencies.

the undulating swr curve is due to the coax cable. you can calibrate with the coax in line, then you should only see the antenna.

Looking forward to your Meshtastic review Andy, the units can be configured to repeaters, and come in 433 mhz or 868 mhz for short messages, i was heavily involved with Helium, not to make money but to understand the 868mhz propagation, the plot maps where amazing of who could rx your signal and the distances sometimes where crazy and just didnt make sense, lots of cavity filters, amplifiers and the like available, they set up a massive Meshtastic system at the burning man event in Nevada that was apparently very successful. Loving your videos 😊 Keep up the great work.

@andykirby

7 ай бұрын

Hi, Thanks for the comment, yes I never got involved in Helium but have been following it's progress, I also am very interested in the propagation, especially with LoRa as it seems to do very well against the noise floor. You are right the distances achieved with helium seem impossible! Its very interesting. Also there's a huge amount of infrastructure already there for Helium (antennas on houses) so it would be a huge hassle for one to convert that to meshtastic for a play!

Right on. Thanks for sharing.

At 02:10,.... The Tiny VNA swr Trace "Wiggles" can sometimes be Eliminated by Calibrating (Open, Short, 50 Z Termination) at the Extreme Antenna End of the feed Coax cable Only..... Try & see.....

Sounds like you are listening to a TV station setting up a show .Here in Lancaster Pa. We can listen to what’s happening behind the scenes while advertising is playing over the local TV station . It was about 5 miles from me .

LoRaWan modulation is quite wide on the spectrum..125KHz and there are a few frequencies that are used at random to spread the traffic around (avoid collisions).. Thanks for sharing about the antenna Andy, seems like Helium has left quite a lot of low-cost 868/915MHz gear in the market!, did you check out APRS over LoRa yet? there quite a few doing that in Austria and Europe on 433 MHz, 73

Fascinating!!

If you go to the Smith chart view, you can find the best impedance for the antenna. It could be designed for 75 ohm as it is receiving antenna.

Interesting stuff i must dig out my scanner and have a tune around. Im interested to know whats a Laura signal? Not heard of that before

Nice one Andy, I've used a log periodic in the past to direction find on 868 and have too much hardware left over from mining helium so it would be great if people discovered the what they can do with Meshtastic especially if you want to stay in contact in uncertain times.

As a television sound recordist I can tell you a lot of recordists use this 863mhz band. This is because its free and well away from interfering with the 606mhz band where radio mics in the UK live. You definitely picked up a location shoot, they are more common than you think! Also, the tx's that operate in this kind of frequency are usually outputting 50mw (typically sennheiser) but there are other brands.

@andykirby

7 ай бұрын

Thanks for the heads up! Makes a lot of sense, it's very clear up around 863mhz. 50mw is a very small amount of power so even if it travelled a mile or so that's impressive.

Hi Andy. I just came across your channel. Great video about the 868 mHz band. Did you realise that some cheap and mass produced satellite and domestic TV amplifiers will work well at this frequency as well as at 433 mHz, where there is an equally intriguing set of signals? They generally need a bias-t power supply to be sent up the coax. Some SDRs, such as the Airspy can provide that power or, you can buy quite cheap power supplies. The one I've had the most success with is called a Mini-Monster from a company called Unispectra in Fareham. They are about 6 quid from their website. It's rated at 30 db amplification, far more than many others which go only to 20db. I live near Elstree studios and regularly pick up productions, but mostly around 440-450 mHz. The Mini-Monster will work up to around 1090 mHz, despite saying it will only go to 862. It will help you with ADSB signals from aircraft, for example, but wont go much beyond that, although there are other cheap amplifiers that will help you receive satellites around 1500-1600 mHz. Best of luck with the hobby!

I am very interested in Radio equipment. and would like to be able to scan around all different frequencies (other than just what my Baofeng UV5R can pickup).... With the hackRF box and software... Do i just require the different frequency antenna's, to be able to pickup a broader range of frequencies?!?! Im gathering the AirSpy software covers all bands / frequencies etc? Its just depending on which antenna you have connected?!?! sorry if this sounds noob... I am haha I just love how people can pickup Russian Signals etc etc..

Great video Andy, thanks for sharing, cheers Garry VK6GLX

Hi Andy thanks for the videos. What is the website you're using for the radio path? Cheers. Dev

Isn't that range used for short range commercial applications? (On the other side of the pond, so it may be different with other countries equivalent of the FCC.) Like the drive-thru window or various intercom systems? The old analog ones could be listened into, but the modern ones that are digital would require knowing how the encoding/encryption works.

It may be just coincidence, but it looked like parts of that signal were reacting to your voice

thanks for the heads up on 868 Mhz. Bunged that into Openwebrx and decoding away. Shame there isnt mmuch for me on 868 Mhz but loads on 434Mhz. Mostly weather stations and car tyre pressure monitors

@-Tris-

7 ай бұрын

Same here. The good thing is, you don't need your own weather station. 😁

@BillyNoMates1974

7 ай бұрын

@@-Tris- saves money too

great music got me dancing around the room trying to keep cool sorry it's 32C here in thailand used synths in many studios in the 70s/80s great radio clip think I'll get a H1 but I dont speak Thai Malay Chinese etc hahaha! I do monitor WSPR here as it's a very quiet rural location

I use radio mics professionally every day. For pro studios like elstree etc, id expect them to be using licences channels in the pmse range. (sandwiched in between TV transmitters in the 500/600MHZ range. Even temporary ad-hoc filming. (TV news etc) would likely use channel 38 (605.5-613.5) .. what you were listening to was channel 70. A license free area 863-865MHz used for radio mics, IEMs and cordless headphones.. it's a very small band and can only fit 4 mics in, so I would guess a local drama group were likely filming something in your area. If it was one frequency, my guess is it would have been an IEM system, relaying mic audio to the room.. likely with a higher gain antenna. Of course it could also have been one of your neighbours watching KZread with cordless headphones.. just my thoughts.. love the videos. :-) Martin M0SGL

I would dearly like to get into this, but have little understanding or where to start ?

The SDR# is a great program and I spent ages getting it to work. I think that the signals that sound like the old dial up tones of the internet are in fact digital voice. I had to install a virtual digital cable to SDR# and my Nooelec dongle to get it working but there's loads of stuff to listen to. . . If you want, you can even decode digital pagers if you were lucky enough to live near a hospital! The local CCTV is on there as well as shop watch etc and it can get a bit lively at times. Local factories are interesting as well as parking wardens, not that I have ever actually done so. . . Love the hobby the whole aspect of just messing around with stuff. 73's

Compared to USA,....Everything in EU seems more Near range, Short distance Located.....Sounds like a rather "Low Profile" home located movie Set production.....Lot's of "Spicy" short movies made in home/Apartments !!

The ripple in SWR as you sweep frequencies comes from the antenna not being quite perfectly matched, and the length of the coax passing through 1/4 and and 1/2 wavelenths relative to your tuning frequency. On odd multiples of 1/2 wave, the impedance of the antenna simply "clocks through" to the end of the cable. On odd ultiples of 1/4 wave, there is a different transformation. None of that is very important to your reception in this case.

Could be something from Leavesden Studios nearby?

These frequencies will actually find ways to terrestrially propagate. 800 and higher will surprise you . Keep up monitoring for new exciting reception on your SDR receiver

Andy Meshbyyyy

Would that be a collinear dipole?

what site is that where you can plot your line of sight and see the terrain in between the 2 spots?

thanks for the link for the antenna ill give it a try. no ebikes? >:)

P25 Trunked systems carry around those freq's if Im not mistaken

Bro get a 9 dBi McGill antenna,that`s the MAGICAL antenna for 868Mhz

210Mhz to 220Mhz has some very interesting pulse transmissions that seem rather rhythmic.

Andy do you have a university / college near you that perhaps has media/drama studies. Maybe students ??

Swr I thaught didn’t matter when only receiving. It’s more important though when you are transmitting. Receiving, you don’t have final amplifier stages, transmitting, you do. That signal btw is pocsag paging.

Can the digital signals be decoded

my sony wireless headphones work on 868mhz its probably someone local listing to the telly

Music is 🔥

I was listening to the bbc news and I could hear the guy talking to the news reader. She was talking and then you could hear the guy saying 2 minutes kate,then like 30 seconds Kate. The band is on all the time but nothing broadcasting 442.275 not heard it again since the other night. Not sure what time I heard it but still turning on every time the news is on but idk

Andy, that was probably Elstree studios, far closer to your receiver location?

@phungyi4947

7 ай бұрын

I noticed that too. Wondered why he didn't mention it.

I think the 845 Mhz frequencies are used for cell and utilities in the US? 😊

@stlouisx50

7 ай бұрын

The usa has 806-812 mhz input for trunked systems and 850-870 mhz is P25, p25 trunked, Motorola trunked I and II

Got to be Hoddesdon Studio. They are filming The Silo there.

@andykirby

7 ай бұрын

Yeah I heard this.

Music at the end good! Who is it

Andy, I watched your video on the TinySA ultra last week, do you know of a device that does the same thing but in the form of a USB device that you plug into a laptop, possibly like a dongle?

@andykirby

7 ай бұрын

I believe you can use a £20 RTL SDR dongle and there's a spectrum sweep application that sweeps large chunks of spectrum. I can't recall what it was called and might be Linux only.

Waves on nanovna are course of staning waves.

Ofcoms favourite channel

You see how small the wire on your dongle is love? I think if we can bump that up to a 10 gauge, we should be able to receive¡

If you want to see some VERY strange signals, come on out to our ranch in Arizona. We are seriously far off grid where you wouldnt typically find many signals but last year we started picking up 740.440 which had a power to it ive never seen. When its active it totally destroys alot of other bands its bleeding onto all the way down to 440.000 we've tried everything to fox hunt it down but its been impossible to target exactly but we have honed in on the exact area atleast. Personally I think its actually coming from below ground as crazy as this sounds. The other odd things is we often hear deep rumbles all around the area that have zero mechanical vibration. Im an engineer and geologist by trade, and I gotta say I have no idea what this could be outside of a DUMB ( deep underground miltary base) or some sort of underground rail system. If your interested in these VERY strange singals and much more check out Shea Road, outside of Parker AZ. I will warn you though, be careful. Theres things out in that desert, dont go out there alone and certainty not past where the pavement ends to dirt roads!!

Hey Andy! Have you thought of picking up a KrakenSDR? That might help you locate them :P

@andykirby

7 ай бұрын

Yeah I like the look of that!

You could have amateur dramatics in a local community hall. Wireless mics can be inexpensive.

Have a bunch of different 800mhz systems around here in Canada for public safety. I really miss how the old 800Mhz motorola systems, they sounded a whole lot better than how the P25 Systems sound now

@jplacido9999

7 ай бұрын

Because they were analog. Great audio... Digital radios have terrible audio.....what a shame....😢

I'm jealous. Here in Jamaica, other than HF and FM broadcast, all I get is Airband at 120-130, and taxis in Kingston in the 145-155 MHz range. Otherwise, nada.

Like to know more about you'r ARM MINI PC!

Looks like you found a wireless mic of some sort.

Maybe location..... Easy to find. Normally a lot of commercial and caravan vehicles parked in the street and people wearing radios and eating all the time😅. Try to monitor unusual activities in the PMR range

Also remember how far you can get on seriously low power on vhf.😊

What frame rate are you filming at? Its mega stuttery.

Smart meters

Might be the petrol station modem or a bookies for the beeps and bleeps

You are not picking up 25mw from 8KM away. They are wither transmitting several watts or they are in your backyard.

How about fast-food drive thru windows ???😮

What's helium minor?

Mmm reminds me of 1999 to 2004 trance.

@GamingKing545

7 ай бұрын

i thought the same thing

Picking up sounds of filming you say 🤔 What a way to discover your innocent looking neighbours run a porn production company from their loft 🤣

I’ve heard of some people buying old Motorolas (800mhz versions) from the 2000s on eBay (they think that because it’s unpopular, there’ll be less interference) and just crack on.

Do you ever pick up baby monitors?

i have to mesh nodes andy and im near milton keynes we use it all the time

@andykirby

7 ай бұрын

Is it meshtastic? Are you using default freqs and settings so there is an open channel to communicate on? you never know one day when lift conditions come up there's a chance we could receive each others beacons.

@m7ncnnigel391

7 ай бұрын

@@andykirby yes im using meshtastic and default freqs would be good if we could

Keep monitoring that audio... See if they mention a Plumber

That massive CME we are having could have a lot to do with it, depends on when you recorded this video

@CrownJewelzMusicGroup

7 ай бұрын

Was just gonna say maybe the solar flares..they sayin the solar winds million+ mph

@fungo6631

7 ай бұрын

LMAO no. Just no.

Probably a Sun spark. It's no good what that star is doing at the moment.

This is some wizardry of spying 😂

In Chinese quansheng is pronounced more like chew-N shung. Not exactly, but that's a lot closer than the English reading.

Solar flare

There is Sky Studios Elstree at Rowley Ln and Loverose Way? Could it be from there? Love your videos Mr. Kirby. Thank you, educational without being condescending. 73's from Dallas Texas

I am looking forward to the next video where you will be recanting yet another 'Angy from Borehamwood' berating you for 'Making a mockery' of their 'ham radio licence they worked so hard for........'

Listen to some of the lines the actors are saying; google search with portions of those lines in quotes and see if somebody posted a script.

bleeding over. LOL

Probably a co linear

4 minutes: it's POCSAG , i'm pretty sure !

@andykirby

7 ай бұрын

Good shout but no it's not pocsag. Don't know what it is though!

If you only receiving you don’t have to worry about SWR

@andykirby

7 ай бұрын

SWR is a good indication of the performance of an antenna and the VNA gives you a complete snapshot of an antenna system so you can spot potential problems before you try using it.

@RA-II

7 ай бұрын

@@andykirby only if you going to transmit and recieve . If it’s a receive only it doesn’t matter

@RA-II

7 ай бұрын

For receiving, SWR has little impact. It is associated with resonance and impedance, so a very bad match may degrade performance. For transmitting, think of standing waves being reflected back to the transmitter. This has to be dissipated as heat so a bad match can cause PA failure.

they speak Dutch

Have you never heard of filming on location lol