Analog TV Transmitter Teardown Teaser - Page 1
Forum section: electronics / general

author: EEVblog
author_rank: Unknown
timestamp: January 04, 2014, 09:17:20 am
content: A teaser video...Dave knocks on the door of the local Sydney TV transmitter facility. Will they let him in?

author: SeanB
author_rank: Super Contributor
timestamp: January 04, 2014, 09:19:14 am
content: More importantly, will they let him take it apart?Live?Keeping the smoke in?

author: hikariuk
author_rank: Unknown
timestamp: January 04, 2014, 09:34:10 am
content: Awww, only a teaser for my birthday? I shall sulk.Looking forward to the full video though - it's going to be awesome.

author: maddhatter
author_rank: Newbie
timestamp: January 04, 2014, 09:50:41 am
content: DO WANT DO WANT DO WANT DO WANT!!!!

author: Towger
author_rank: Super Contributor
timestamp: January 04, 2014, 10:10:15 am
content: Dave, I hope you got shots of the power amps. Nothing better than looking at high power RF 'plumbing'. Are they still going to use the existing final stage amps, what's the output power and are they solidstate or value/ tetrode (correct name sp?)?

author: noisebox
author_rank: Contributor
timestamp: January 04, 2014, 10:11:51 am
content: Looks great, can't wait to see this! Surprised they'd just offer you this stuff though, they don't suspect you of setting up EEVBlog pirate TV station?Great score!

author: EEVblog
author_rank: Unknown
timestamp: January 04, 2014, 10:13:18 am
content: Quote from: Towger on January 04, 2014, 10:10:15 amPlenty of bum crack shots, don't worry.

author: GK
author_rank: Super Contributor
timestamp: January 04, 2014, 10:31:17 am
content: Radio Frequency Systems. I used to personally build and wire those antenna switching frames, in their now no longer existing Broadcast division/factory that was located in Lonsdale, SA.

author: JoeN
author_rank: Frequent Contributor
timestamp: January 04, 2014, 11:07:32 am
content: I think this video so far is just brilliant. In a way, the best one so far. Dave walks into a TV station with an open door and the guy there, who initially look mean as hell, lets him take as much old equipment as he can carry. Even more if he had a truck. Based on being able to talk his way into and out of apparently anything. Unbelievable! Great. Looking forward to the actual opening of this old equipment which was made when I was ten years old.

author: MartinX
author_rank: Regular Contributor
timestamp: January 04, 2014, 11:47:35 am
content: Wonderful! Now put that equipment to use and start broadcasting the EEVblog, no one is using that frequency now anyway.

author: jii
author_rank: Newbie
timestamp: January 04, 2014, 12:16:38 pm
content: Nice! Can't wait for the actual video!I got one old TV-amplifier after the finnish analog TV was brought down (1955–2007 R.I.P.)Image probably below? I added it as an attachment and this is my first post the forums, so I don't knowhow this thing worksThe height of that thing is four car tiresLooks a bit same than what Dave salvaged?Mine is waiting for parts salvaging.

author: open loop
author_rank: Regular Contributor
timestamp: January 04, 2014, 12:58:45 pm
content: As a sound track for a pan shot of the old TX station equipment racks,Sour times by Portishead?Chorus being:"'Cause nobody loves meIt's trueNot like you do"

author: Towger
author_rank: Super Contributor
timestamp: January 04, 2014, 01:21:00 pm
content: Quote from: MartinX on January 04, 2014, 11:47:35 amThrow a dipole up on the roof of EEV towers and Dave should get a range of a few K with just the exciter/pre amp stages. The local old dears will be delighted when their TVs start working again. 560+ episodes without a repeat would be somedoing for a modern TV station.At 34 years old, I would not be surprised if he got the backup TX or even the backup's backup.

author: TheWelly888
author_rank: Frequent Contributor
timestamp: January 04, 2014, 02:18:28 pm
content: The influence of Dave's EEVBlog's YouTube channel in him getting access to the transmitter makes me wonder if the Internet will eventually displace broadcast TV?Looking forward to the teardown!

author: Radio Tech
author_rank: Frequent Contributor
timestamp: January 04, 2014, 02:48:59 pm
content: Dave that is sweet!Cant wait to see the tear downI had a chance to go in the old channel 7 place here in North Carolina many years ago when they shut it down after building the new one. It was great. Had no camera at the time though. Funny thing was I grew up in the shadow of the 1500 foot tower in a old farm house.Pics of ithttp://pages.suddenlink.net/w4ydy/witntv.html

author: (In)Sanity
author_rank: Regular Contributor
timestamp: January 04, 2014, 03:33:54 pm
content: As a general class licensed HAM I have to say I just love the RF stuff. Can't wait.Jeff

author: Frantone
author_rank: Regular Contributor
timestamp: January 04, 2014, 03:38:39 pm
content: Quote from: EEVblog on January 04, 2014, 09:17:20 amLOL! Brilliantly done! Just walked through the door....winkwinkLooking forward to the rest.

author: N2IXK
author_rank: Frequent Contributor
timestamp: January 04, 2014, 04:26:56 pm
content: Can’t wait to see this one!Hope you at least got some shots of the guts of the power amps and the HV power supply, since you didn’t take them with you.This is a GREAT subject for a teardown, as most electronics folks have never seen or worked with multi-kilowatt RF gear, or “modern” equipment that still uses vacuum tubes. Coax feedlines that look like copper pipes, water cooled dummy loads, all kinds of neat stuff at transmitter facilities, and it is always nice to look at gear that hasn't been built down to a price point, but designed to run 24/7 for years, often unattended.

author: electronics man
author_rank: Frequent Contributor
timestamp: January 04, 2014, 04:43:11 pm
content: Dave, what was that guys reaction when he founed out who you were and what you wanted.im looking forwerd to the teardown lots of high power stuff and lots of RF magic.

author: Unknown
author_rank: Unknown
timestamp: January 04, 2014, 05:02:09 pm
content: Quote from: electronics man on January 04, 2014, 04:43:11 pmWell, if you watch to the end of the video I'm sure you will work it out.

author: KarlosVandango
author_rank: Contributor
timestamp: January 04, 2014, 05:04:58 pm
content: Hi Dave,Looking forward to the teardown... What a cheeky tease!!!

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: January 04, 2014, 05:12:41 pm
content: Awesome! Can't wait!

author: wss
author_rank: Newbie
timestamp: January 04, 2014, 05:22:19 pm
content: I can't believe they just gave the equipments to you, AWESOME! Can't wait for the videos!!! Really exciting!

author: free_electron
author_rank: Super Contributor
timestamp: January 04, 2014, 05:34:02 pm
content: We really need to get you a new car.. that dinosaur-extact driven thing could use a Mr.Fusion …I must say i am a bit disappointed though. I was hoping for sledgehammers, discgrinders and other heavy equipment to tear down the power endstage ( especially those huge vacuumtubes. I'd love the sound of those being crushed by a large hammer ) , and maybe a backhoe or two to bring down that large tower ...

author: calexanian
author_rank: Super Contributor
timestamp: January 04, 2014, 05:34:45 pm
content: A friend of mine had been the engineer at the local ABC station for 30 years. He also worked for the other local tv and radio stations who could not afford full time staff. When Disney bought all the abc stations they cut people from every department and since he was the only one, out he went. Nothing more than a computer generated boiler plate letter saying don't let the door hit you on the way out. Now they pay somebody to come up from LA.

author: calexanian
author_rank: Super Contributor
timestamp: January 04, 2014, 05:37:54 pm
content: Quote from: free_electron on January 04, 2014, 05:34:02 pmDinosaur extract if fine. Just something more effecient.. I think they need a jetta TDI or an Audi A3 diesel sports wagon. I get 46+ mpg highway and 36+ mpg in town in my jetta, and it feels like a real car.

author: Unknown
author_rank: Unknown
timestamp: January 04, 2014, 05:44:59 pm
content: Quote from: free_electron on January 04, 2014, 05:34:02 pmSteady on, digital services are still on, and I'll bet it's also a repeater station as well, and it will have some mobile cells on it.Have you been nearthis one?

author: free_electron
author_rank: Super Contributor
timestamp: January 04, 2014, 06:09:01 pm
content: Beam it form satellite. no need for multi megawatt transmitters to get 100 miles of range. much more energy efficient. and the satellite is solar powered !

author: N2IXK
author_rank: Frequent Contributor
timestamp: January 04, 2014, 06:20:16 pm
content: Those satellites probably use vacuum tubes in the output stages of their transponders, as well....http://en.wikipedia.org/wiki/Traveling-wave_tubeFar enough above the earth to be safe from your sledgehammer and side grinder, though...

author: OrangeJacketGuy
author_rank: Contributor
timestamp: January 04, 2014, 06:26:03 pm
content: Damn tease was right -- there's all kinds of hardware porn there, and that shot there with Dave and the rails was just too good...

author: Jon86
author_rank: Frequent Contributor
timestamp: January 04, 2014, 06:49:34 pm
content: I hope that first bit was scripted?

author: PA0PBZ
author_rank: Super Contributor
timestamp: January 04, 2014, 06:56:34 pm
content: Quote from: Jon86 on January 04, 2014, 06:49:34 pmYes it was.

author: electronics man
author_rank: Frequent Contributor
timestamp: January 04, 2014, 08:24:31 pm
content: I grew up ne'er in the shadow of the alexandra palace transmitter where the worlds first tv signal was transmitted the bbc was there until the 60s. I wonder what old equipment they have there hmmm......

author: atw60444
author_rank: Contributor
timestamp: January 04, 2014, 08:29:38 pm
content: Quote from: Jon86 on January 04, 2014, 06:49:34 pmYeah, I think the station Tech. needs acting lessons!

author: jmcdonald
author_rank: Contributor
timestamp: January 04, 2014, 11:33:46 pm
content: Quote from: free_electron on January 04, 2014, 05:34:02 pmor at least repair the roof lining.http://youtu.be/-MmT72NDtTswould make a good repair video for the Altzone youtube channel

author: EEVblog
author_rank: Unknown
timestamp: January 04, 2014, 11:38:55 pm
content: Quote from: free_electron on January 04, 2014, 05:34:02 pmHow do you think a crowd funding campaign to get me a Tesla would go down?I'm surprised my POS Vectra got me there and back

author: notsob
author_rank: Frequent Contributor
timestamp: January 04, 2014, 11:45:58 pm
content: perhaps we could get vincent to take a photo of a cardboard cutout of dave sitting in his tesla, just to give dave some inspiration, or make him even more jealous of vincent.

author: calexanian
author_rank: Super Contributor
timestamp: January 05, 2014, 12:24:17 am
content: Quote from: EEVblog on January 04, 2014, 11:38:55 pmYou would have to get the extended range battery. We had one for a few days at the adam carolla podcast and we all had a chance to try it out. Not a bad car. By the time you get the top end battery though you were looking at $120,000 or so! Its still a first adopter type thing.

author: NiHaoMike
author_rank: Super Contributor
timestamp: January 05, 2014, 06:02:03 am
content: Get as much of the high power RF stuff as you can. The ham radio operators can make use of it.

author: calexanian
author_rank: Super Contributor
timestamp: January 05, 2014, 06:59:53 am
content: Quote from: EEVblog on January 04, 2014, 11:38:55 pmNot exactly the same, but close enough. Only top gear could do it..

author: vk6zgo
author_rank: Super Contributor
timestamp: January 05, 2014, 07:39:29 am
content: Quote from: free_electron on January 04, 2014, 06:09:01 pmThe Earth Station isn't!They cost as much to run as TV transmitters any day of the week!The EIRP of City TV Analog Transmitters in Australia is around 100kW for VHF,a bit more for UHF,but that isn'trealpower,as the antenna array has around 10dB of power gain within its coverage area.The CH7 Tx in Perth WA produced 13kW sync tip power (same as PEP,but easier to measure!),allowing for transmission line losses & antenna gain,it came out as right on 100kW EIRP.The CH2 Tx had two 10kW units in parallel,as the lowband antennas had less gain.The quoted output from FM & DAB transmitters is also EIRP.Contrast this to MF AM,where if you want 55kW.you have to generate it,there is no antenna gain to help you.

author: vk6zgo
author_rank: Super Contributor
timestamp: January 05, 2014, 07:57:27 am
content: Quote from: free_electron on January 04, 2014, 05:34:02 pmIt would have to be a quite serious hammer,& it might be a bit dangerous,as those tubes use beryllium internally (not in the external ceramic,but for thermal coupling inside).Bring down the tower?--Some backhoe!!Another problem,that thing is right in the middle of suburbia,unlike the Perth ones which are up on the Darling Scarp,well out of the way.

author: Jon86
author_rank: Frequent Contributor
timestamp: January 05, 2014, 12:21:24 pm
content: Quote from: atw60444 on January 04, 2014, 08:29:38 pmI agree!

author: electronics man
author_rank: Frequent Contributor
timestamp: January 05, 2014, 12:59:04 pm
content: He should make a second journey ther too get even more stuff. He shouldn't tear it all downe because that stuff could be quite valuable in the future.

author: Unknown
author_rank: Unknown
timestamp: January 05, 2014, 03:33:11 pm
content: Quote from: electronics man on January 05, 2014, 12:59:04 pmThat's the exact reason a lot of the members of this community have piles and piles of worthless shit that they can't get rid of, me included!

author: (In)Sanity
author_rank: Regular Contributor
timestamp: January 05, 2014, 04:09:11 pm
content: Quote from: EEVblog on January 04, 2014, 11:38:55 pmI think Practical and efficient would go over better. I went from an SLK (non practical) to a Golf TDI, and loving every minute of it. Plus now I can go to a ham fest and load all the crap I want in the back without issue. All while getting 40+ mpg.P.S. I got surprised and smoked by a Tesla model S while driving the SLK. I left some vehicle behind and before I could realize it I had a silent whoosh go by me. I then realized what I had passed was a Tesla. It was topic for conversation at work that morning. Nice cars.Jeff

author: tom66
author_rank: Super Contributor
timestamp: January 05, 2014, 07:54:16 pm
content: Quote from: EEVblog on January 04, 2014, 11:38:55 pmI'd personally contribute to see you tear down a wrecked Roadster -- including some lovely photos of all of the power and system electronics!!I have seen them go for as "little" as £10k if the battery pack is dead/bricked (0 miles for 3+ months.)

author: free_electron
author_rank: Super Contributor
timestamp: January 05, 2014, 10:22:20 pm
content: Quote from: EEVblog on January 04, 2014, 11:38:55 pmI'll chip in my 5$ ( to offset the complaints from people that think the tax break comes out of their pocket )

author: calexanian
author_rank: Super Contributor
timestamp: January 05, 2014, 10:26:32 pm
content: Lets just do a electric upgrade on that Vectra. What year is it?

author: Unknown
author_rank: Unknown
timestamp: January 05, 2014, 10:27:22 pm
content: Quote from: calexanian on January 05, 2014, 10:26:32 pm1985

author: free_electron
author_rank: Super Contributor
timestamp: January 05, 2014, 11:16:30 pm
content: Here ya goplus : fold the rear seats down, combine it with the 'frunk' and you can drag in massive hauls of equipment (in style)

author: calexanian
author_rank: Super Contributor
timestamp: January 05, 2014, 11:40:23 pm
content: Quote from: Lurch on January 05, 2014, 10:27:22 pmno.. it cant be that old! Interior looks too good.

author: (In)Sanity
author_rank: Regular Contributor
timestamp: January 05, 2014, 11:41:03 pm
content: Quote from: free_electron on January 05, 2014, 11:16:30 pmLOL, same color as the one that blew past me in my former SLK. Ok, I miss the power. But love the MPG. Better off with MPG. I actually thought about buying a Model S until I realized I would just be trying to compensate for something. Better off spending the extra money on more solar power and/or solar hot water.Jeff

author: dr.diesel
author_rank: Super Contributor
timestamp: January 05, 2014, 11:41:44 pm
content: Quote from: free_electron on January 05, 2014, 11:16:30 pmYou mailing your new ride to Dave?

author: Driver
author_rank: Unknown
timestamp: January 06, 2014, 08:14:16 am
content: Long time viewer, first time poster... Good to see ch7 give away the gear like this!Any ETA's for broadcast?

author: williefleete
author_rank: Regular Contributor
timestamp: January 06, 2014, 03:53:46 pm
content: Can't wait to see all the high power RF porn, dave was practically creaming his jeans at the rails on the rack mount stuff

author: echen1024
author_rank: Super Contributor
timestamp: January 06, 2014, 04:40:31 pm
content: What Dave REALLY wants is the Model X SUV. That way, he can haul all types of gear, and, with the top battery, he won't have the embarrassment of saying "This oscilloscope is more expensive than my car."

author: DeepThought
author_rank: Newbie
timestamp: January 06, 2014, 04:47:01 pm
content: EEVBlog pirate radio FTW

author: singera
author_rank: Contributor
timestamp: January 06, 2014, 10:10:03 pm
content: climbing to the top of the antenna

author: calexanian
author_rank: Super Contributor
timestamp: January 07, 2014, 02:02:40 am
content: No thank you! I am so glad we have mountains here in California to put our antennas on!

author: vk6zgo
author_rank: Super Contributor
timestamp: January 07, 2014, 03:34:27 am
content: It's more than 14 years since I've delved into these beasts,so I might have forgotten some points,but here goes:-I am most familiar with the NEC Transmitters at TVW7,which have Sync Tip Output Powers of 13kW to allow for various losses in the feed system.In this generation of NEC's high power Transmitters,the Sound (“Aural” in “NEC- speak”) & the Vision RF signals do not pass through the same amplifier chain,but are passively combined at the output of the Transmitter.Valve/Tube PA:-(Vision)Big tetrodes like the NEC 8F76R can easily provide around 13dB of power gain in Television service,with a Sync Tip Output power of around 13kW.13dB is a convenient figure,as it translates to a power gain of 20times.,so 13kW output requires 650W of drive to the valve PA.TRPAs:-Normally,there is one TRPA driving the Vision (Valve) PA,having in this case an output of 650W,& two,(in TVW7's case) or more TRPAs operating in parallel to provide the Aural Output .The total output power of the sound carriers combined is approx-10dB w.r.t. Vision Sync Tip power.The TRPAs are also designed to deliver around 13dB of gain,so in each case require around 32.5W of drive from the exciter.NEC had extensive experience with BJT RF PAs in their lower power Transmitters,so these TRPAs are extremely reliable in service.Modular Construction:-NEC used modular construction extensively in this series of Transmitters.An example is the TRPAs &.their power supplies..These are situated “back to back”,so that if the power supply fails,it may be removed & replaced with a spare without delving deeply into the “innards: of the Transmitter.If a TRPA fails,it can simply have the RF connections removed,& be pulled out of the mounting slot.Note on Sync Tip Power:-Analog TV systems,except for very early ones,notably the British 405 line system use so called “Negative Modulation”,where the most negative part of the Video signal,the Sync Tips,corresponds to maximum RF Output Power.This is very convenient when measuring Transmitter Output Power,as a “peak hold” voltmeter may be used .It is simple to produce such a device which is hardly affected by the 64uS time between Line Syncs.The reading is reallyPEP,but it is much easier to perform in this case,than with SSB.The relationship between Vision & Aural power can also be determined easily using the same meter,as PEP & Average power of an FM signal is the same.(It does get a little bit messier with the 2 carrier Stereo Sound system used in Australia,but is still pretty close!)Average power can be determined with greater accuracy using a water cooled Load,with the Transmitter modulated with Blanking & Syncs.To obtain an accurate figure for Sync Tip Power using this method,however,it is necessary to very precisely set the modulation,so correction factors may be applied.I have used "around" & " approx" a fair bit,as no components are perfect,or perfectly stable in their characteristics over time,especially large Power tubes.A tube may have more than 13 dB Power gain when brand new,& require less drive than it will 20000 hours later!

author: dmm
author_rank: Newbie
timestamp: January 07, 2014, 10:29:49 am
content: Quote from: GK on January 04, 2014, 10:31:17 amI was at RFS at Lonsdale as well between 1995 and '98. I designed the wiring for the interlock system on the RF power switch panels, amongst other things. Worked for RFS again in 2003 in their Kilsyth facility.dmm

author: Ed.Kloonk
author_rank: Super Contributor
timestamp: January 07, 2014, 11:33:19 am
content: Tease Me...Tease Me...

author: SeanB
author_rank: Super Contributor
timestamp: January 07, 2014, 03:51:24 pm
content: Camel toe song? Don't worry, I do not really want to link to it. GIY if you want.

author: Nickk2057
author_rank: Regular Contributor
timestamp: January 12, 2014, 04:23:55 pm
content: question.... when you went into the place what did the guy ask you and such? made me think that you are not allowed to be inside that place and he may cite you on a trespass warning or something..... sure fooled the hell out of me... lol

author: rolandpenplotter
author_rank: Regular Contributor
timestamp: January 12, 2014, 04:42:47 pm
content: Sooooo... Dave.... when are we to expect this amazing video?

author: station240
author_rank: Unknown
timestamp: January 12, 2014, 11:34:18 pm
content: 5 ton truck you say, you mean like the types you can hire for a hundred something bucks a day that come with a tailgate ?Fair point about the beryllium warning, same stuff in microwave magnetrons.

author: rolandpenplotter
author_rank: Regular Contributor
timestamp: January 13, 2014, 11:46:16 pm
content: Considering that "Teardown Tuesday" is normally released on a Tuesday, and that tomorrow is Tuesday, I think (and I hope) that this episode will be released tomorrow.The suspense is too much!

author: electronics man
author_rank: Frequent Contributor
timestamp: January 15, 2014, 08:01:48 pm
content: So when's it coming dave it was Tuesday yesterday we are still waiting

author: rolandpenplotter
author_rank: Regular Contributor
timestamp: January 15, 2014, 09:01:10 pm
content: Quote from: electronics man on January 15, 2014, 08:01:48 pmDave is a busy chap - patience is an amazing virtue. He has said, on YouTube comments:(The comment was under video #568)

author: electronics man
author_rank: Frequent Contributor
timestamp: January 15, 2014, 09:49:49 pm
content: Well it's nice to have lots of brilliant vidios over a long time to look forward too

author: rolandpenplotter
author_rank: Regular Contributor
timestamp: January 15, 2014, 10:01:36 pm
content: Quote from: electronics man on January 15, 2014, 09:49:49 pmYupIf my desire for electronics is high, but my concentration for practical work is dying off (midnight to 5am), I'll type "EEVblog teardown" or "EEVblog repair" into YouTube, and re-watch some of the many hundreds of videos our Dave has shot over the years; they NEVER get boring. Dave is a man with a family and a young child, and he also manufactures things, and does many other "real life" things which we have no right to know about, since it's his personal business. We all want "more more more!" from him because he is SUCH an amazing teacher... but patience is a REAL virtue, and it's SO easy to forget that what we see of Dave on YouTube is about 1% of his whole life (if that?) - I have to constantly remind myself

author: CRCasey
author_rank: Newbie
timestamp: January 16, 2014, 11:53:55 pm
content: I have to say that teaser photo at the end of the video is total wave-guide porn!Thanks Dave.

author: vk6zgo
author_rank: Super Contributor
timestamp: January 21, 2014, 06:57:48 am
content: Quote from: station240 on January 12, 2014, 11:34:18 pmI may have led you astray with the beryllium.Eimac/Varian & others do refer to beryllium as an internal component of their tubes,but It may be a blanket "protect your butt" thing,as I seem to remember the older documentation specifically referred to its use inwater cooledtubes.There does not appear to be any necessity for its use in external anode air cooled tubes,as there is no requirement to have an insulating material of high thermal conductivity.The Anode is what gets hot & the fins are directly connected to it,so no thermal link is required.There is also no requirement for such material in the external insulation,as transfer of heat from the anode to the other elements is not desirable.