Broadcast Enginers on AM fone?

[W9GT]

My involvement with the broadcast industry was not directly as a broadcast engineer, but as a telecom engineer.  I worked for GTE, which later became Verizon.  I was the radio and video engineer for the GTE-Indiana company.  I was very closely involved with broadcasters in providing network feeds and remote pick-up services, as well as audio program circuits and studio to transmitter links.  I spent many hours in radio and TV stations, as well as at remote pick-up sites working closely with broadcast engineers.

Back in the day before satellites,  we provided video pick-ups via portable 6 GHz and 11 GHz microwave links to the nearest network node (usually AT&T tower locations).

One of our most interesting assignments was our annual provision of a video (microwave) pick-up from Terre Haute, IN covering the Tony Hulman dirt track races from the Vigo County fairgrounds for ABC-TV.  Tony Hulman, who was the owner of the Indy 500 Speedway, required that ABC carry these races as a condition of carrying the Indy 500.  We had to erect a 100 ft. tower at the race track and provide a portable microwave video link back to the AT&T tower in downtown Terre Haute.  Unfortunately, on one occasion a few days before the race, the contractor dropped the tower while erecting it and did considerable damage to the tower itself and some surrounding structures.  Boy, what a crisis!  Somehow we were able to locate another tower and get everything up and running before the race.  It was a blessing that no one was hurt and we were able to provide the network TV pick-up successfully.

We provided national network TV pick-ups from many locations throughout the state of Indiana, including most of the home football and basketball games at Purdue University, some nationally broadcast golf tournaments and other major events.  It was an exciting time.

Most of these pick-ups are now provided by satellite-TV trucks and also fiber optic cables and are relatively routine compared to the "good old days".

73,  Jack, W9GT

[W3NE]

Jack that's a great illustration of how broadcast engineers get things done in the worst circumstances. In many instances it was/is a broadcast engineer's background in ham radio that assists him in, to some extent, surmounting emergency situations. The crucial role of local and regional support for network shows is seldom appreciated by anyone not at the site.

Bob - NE

[K6IC]

Like many high school aged Hams,  my first paying real job was at a local AM BC station.  It was a fun job at a 250 watt small-town station.

Later,  when in college,  got the First Phone with Radar endorsement,  which allowed me to easily get a coveted Union job at KHQ TV - AM - FM,  the NBC affilliate in Spokane,  WA.  This was a show station owned by the local newspaper magnate.  Everything was top-drawer,  and of course,  all RCA,  as this was in the mid 1960s.  Another fun job that paid well.  Was part time,  so the contract specified that a kid like myself got paid a premium over all others who really knew what they were doing,  as PT work was discouraged.

Was able to pay my way through college with 16-20 hours of work per week,  and full time in the Summers for vacation releif.

Later when transferring schools,  was able to get a job at KIRO,  another nice gig.

Left broadcast in 1970 for engineering work in Silicon Valley,  which was fun,  too.

Assume that were it not for my High School having a Science teacher who was a Ham,  and formed a Club Hammie station at the HS,  might not have become a Ham.  And perhaps if not a Ham,  might not have gone into electronics.  So,  Hammie Radio has been very good to me.  AND,  the FCC,  with its requirement for a First Phone ticket to do real,  well paying work at Broadcast stations,  blessed me with a great career that was fun,  too.  Am glad that I left BC engineering when I did,  however.

Feel for the younger folks out there today,  where it is much more difficult in general,  to find good work that pays well,  with some prospect of it lasting for more than  6-12 months.  Great jobs still exist,  just not as many of them as in years past.   Opinions.  HNY  Vic

[W4EWH]

My involvement with the broadcast industry was not directly as a broadcast engineer, but as a telecom engineer. ...
Back in the day before satellites,  we provided video pick-ups via portable 6 GHz and 11 GHz microwave links to the nearest network node (usually AT&T tower locations).

Jack,

You're the perfect guy to ask!

My brother is very involved with Emcom (Emergency Communications), and I'm interested in it too, so here are some questions I hope you'll be able to answer. I spent a while on the "Radio Board" at Boston Two for NET&T, and although we had some microwave, it was point-to-point and we never did much more than knife off a marginal link, so I'd appreciate your expertise on the subject of portable microwave.

• Is there any surplus point-to-point microwave equipment available that will work for hams?
• What do TV stations use now for their trucks? Is there any market for older STL equipment that hams could use?
• Most of the demand for high-bandwidth connections for Emcom is for data communications. I know most microwave links are digital these days, but can hams use older analog setups for data?
• I see Gunn oscillators available for sale from time to time, for fairly low prices. Are they a viable way to build an Emcom setup?
• What do the OSCAR satellites and other ham orbiters offer for Emcom data?

I'll think of twenty more questions as soon as I hit "Post", but these will do for now.

Thanks for your help!

73,

Bill, W1AC

[Burt]

I was Chief Engineer at WOCB, built WSDH, KOTZ (in the Arctic) Manager, WNAC-TV, WQRC, built WSDH

[W9GT]

My involvement with the broadcast industry was not directly as a broadcast engineer, but as a telecom engineer. ...
Back in the day before satellites,  we provided video pick-ups via portable 6 GHz and 11 GHz microwave links to the nearest network node (usually AT&T tower locations).

Jack,

You're the perfect guy to ask!

My brother is very involved with Emcom (Emergency Communications), and I'm interested in it too, so here are some questions I hope you'll be able to answer. I spent a while on the "Radio Board" at Boston Two for NET&T, and although we had some microwave, it was point-to-point and we never did much more than knife off a marginal link, so I'd appreciate your expertise on the subject of portable microwave.

• Is there any surplus point-to-point microwave equipment available that will work for hams?
• What do TV stations use now for their trucks? Is there any market for older STL equipment that hams could use?
• Most of the demand for high-bandwidth connections for Emcom is for data communications. I know most microwave links are digital these days, but can hams use older analog setups for data?
• I see Gunn oscillators available for sale from time to time, for fairly low prices. Are they a viable way to build an Emcom setup?
• What do the OSCAR satellites and other ham orbiters offer for Emcom data?

I'll think of twenty more questions as soon as I hit "Post", but these will do for now.

Thanks for your help!

73,

Bill, W1AC

Hi Bill,

Well, I don't know if I am really the best person to answer your questions.  I have been away from the microwave business for 20 years, or so.  I have not pursued microwave operation in amateur radio.

1.  Yes, there is a certain amount of surplus commercial and military microwave gear kicking around, but much of it is difficult to convert for use in amateur bands.  I had a scrapped Lenkurt 76A 6 GHz terminal which consisted of a receiver and a transmitter and some waveguide plumbing, but I ended-up selling it some years ago.  Many commercial users are hesistant to allow hams or other possibly "un-educated" experimenters to get their surplus equipment for fear of injury from misuse.  Some, less than brilliant people have been known to stare down the end of an open waveguide of an operating microwave transmitter.
2. I suppose you could use old analog microwave to carry some digital traffic if you had the necessary digital codecs/multiplexers.  GE and others produced inexpensive 23 GHz digital systems that would handle one or two T-1s.  There are probably a few of those kicking around the surplus market.
3. I have also seen the little GunnPlexer rigs...I do not have any experience with them, but they could provide a cheap and easy way to get a point to point link working for emcomm or any purpose.
4. I have no experience with satellites.

73,  Jack, W9GT

[K2PG]

I worked in both radio and TV broadcast engineering for nearly 40 years. My latest gig was chief engineer for the Citadel cluster of AM and FM stations in Wilkes-Barre, PA, where I rebuilt their 40 year old Gates AM transmitter after it decided to self-immolate one spring morning. After eight years of service there, I was laid off in November, 2011, after Citadel was acquired by Cumulus Media. I am still looking for a job. I have a temporary clerical job with the Commonwealth of PA, but the pay sucks, there are no benefits, and I am not making enough money to live on. I don't go hungry...I have some chickens in a pen in the back yard and they provide me with plenty of eggs. I eat a lot of them every day. The bright side for the rest of you on this board: If I lose my home, there will be LOTS of AM broadcast gear up for grabs when I dismantle my station. There was no damage from Hurricane Sandy and everything still works.

Deregulation and consolidation have killed broadcasting as a career choice, as a handful of companies now own everything. But I want to get back into that field...it gets into your blood.

Phil K2PG

[K2PG]

As Dinah Washington used to sing, "what a difference a day makes"! I now have two job possibilities in broadcast engineering for mid-January. Wish me luck!

Broadcast engineering is what got me back into AM on the amateur bands after a long hiatus. I used to be active on 2 meter AM from 1969 through the seventies. 145.1 was a hot frequency in the New York metropolitan area and I would chat there for hours. When the FCC expanded the FM repeater subband, that killed the AM activity on 2.

In 1997, I was working for a group of broadcast stations in NJ. The director of engineering asked me if I wanted a large Collins transmitter. It was a 20V, then used as the backup at WNNJ in Newton. I took a ride up there, immediately said "YES!", and, with the help of that station's chief engineer, painstakingly loaded the transmitter into the back of a Dodge pickup truck. Before doing that, I was removing the tubes and wrapping them in paper, the way I would wrap Christmas ornaments when taking the tree down. I ordered a crystal for 1885 and was soon on AM. I have been there ever since.

Phil K2PG

[W4AAB]

Great news, Phil!! 2013 should be a good year for me. I just turned 59 1/2. I remember just after the 2m sub-band expansion, a friend of mine was active on SSB and FM on 2m. One night, he got called by a station in Little Rock, AR who had a kW on 2m AM.I can't remember the call of the guy in AR( we were in north AL at the time).I wonde how many 2m kW stations are still around.I hink this guy's station was all homebrew.

[KL7OF]

I was Chief Engineer at WOCB, built WSDH, KOTZ (in the Arctic) Manager, WNAC-TV, WQRC, built WSDH

When were you in Kotzebue Burt?   I worked out of there in the early 80's building schools and cold storage plants in the interior...KOTZ was the AM station to listen to..(sometimes the only) ...

[N0BST]

One more for the count.  Just turned double-nickels a few weeks ago.  Currently I'm a field engineer for EMF Broadcasting (K-Love and Air-1 Christian music networks) covering WI, MN and the eastern Dakotas.  Even though I'm doing all FM work now, my previous job was three AMs- two directionals and a diplex and I still consider myself very much an AM guy.  Got the ham ticket when I was attending Northwestern Electronics Institute and working at the KSTP (AM) transmitter part time (back when larger stations still had attended sites for improved reliability) back in 1980.

[K6IC]

As Dinah Washington used to sing, "what a difference a day makes"! I now have two job possibilities in broadcast engineering for mid-January. Wish me luck! 

That is great news Phil.  Good Luck - HNY.  73   Vic

[Steve W8TOW]

RCA certainly knew how to compete from the get go! RCA-Victor phonograph records did pretty well even after the 45 rpm escapade.

My late father-in-law (now SK) was at RCA from about '61 until early 70's. First in southern
Ohio, then Camden, N.J. and leaving them after a stint in Indianapolis.
While at RCA, he acquired a few noteworthy patents, one for the 8-Track Tape player,
a Quadrophonic Phono Cartridge and then a speaker design...when cleaning out his
office last year, I ran across the patents, a 8-track player proto-type and a cartridge
proto-type!
He liked some of his work at RCA but left due to frustrations surrounding poor end-design.
"Pete" shared that their final designs were not very service-man friendly, and suffered
from QC...I guess that sums it up for RCA...I did also find an RCA CB radio!!! Probably should
put it on 10m AM

[Burt]

I was Chief Engineer at WOCB, built WSDH, KOTZ (in the Arctic) Manager, WNAC-TV, WQRC, built WSDH

When were you in Kotzebue Burt?   I worked out of there in the early 80's building schools and cold storage plants in the interior...KOTZ was the AM station to listen to..(sometimes the only) ...

I was there in 1978 was Chief Engineer and manager. I visited there in 2003, saw Brad Reeve and Ernie Norton. I also taught at Kotzebue High School for the Northwest Arctic school district

[WB2EMS]

I dabbled in broadcasting some in college in the frozen north country of Potsdam in the 70's. i started out as a weekend DJ for the FM station on campus WTSC, then got involved in the tech support for the carrier current station WNTC. Got my 2nd class and became a transmitter engineer with the privilege of XC skiing out to the transmitter shack a few times a week to take transmitter readings.    Later I got my first and radar endorsement. Having been a ham for about 7+ years at that point, I had more working knowledge of the hardware than many of the more senior folks at the station.

Some of those carrier current transmitters in the basements of the dorms over at the SUNY school in town would have made great AM rigs. I recall sets of 811's being modulated by 810's or some such and at least one that had an 813 in it. I think we had about 500 watts of carrier power out of some of them. We basically had one of those in each of the tower dorms on that campus and a number of minor ones scattered around town all tied together with phone lines.

There was a minor FCC flap a couple of years before I got there where 'somehow' one of the distribution feeds for a building accidentally managed to get coupled to a couple of acres of copper roofing on the old main building complex, which markedly improved the coverage. Apparently the FCC heard about it when someone about 150 miles away in the Hudson valley complained of interference with a local AM station. They were said to not be amused...

While I was in college I also worked for a manufacturer of land mobile radio equipment during the summers and all breaks and got to prototype handheld radio modules, mobile radios, and pagers and do most of the first article testing as an engineering tech as well as run our home brewed antenna test range. I also got to design test fixtures for the first major run of an electronic video game, Coleco's 'Pong' game on the run up to Christmas in 1975 or so. We built a zillion of those. I think I still have one of the pc boards in my junque pile. 

The engineers I worked with there passed on their knowledge and combined with my ham radio Elmers, equipped me with a working education in how radio and electronics worked which led to a career in electronics. My college courses were much less useful!

That career has involved VHF/UHF land mobile,  HF radio system engineering and construction, then a stint in specialty computer hardware, 10 years as a programmer for automated testing systems, then s shift into network video engineering including video conference systems and an early deployment of an IPTV system and now a focus on wireless networking at a large university.

A lot of my focus in the last 20 years has been to support in house production or capture of video for distribution on campus, though that has been spun off into another group now. But I'm often involved in engineering solutions that support things such as getting feeds out for campus sporting events, other special events, and any other special requirements such as a network feed for our 'hawk cam', including anything that involves RF (such as cellular DAS systems), up to 60 Ghz so far. 

On the side I kept my hand in with some of the broadcast gear with a friend who was heavily involved supporting a local FM station, and working on the local club repeaters. Plus helping an ISP get started in wireless networking and building some of their longer wireless links.

All that early exposure to broadcasting and AM probably contributed to my interest in the AM segment of the hobby, although a lot of it comes from listening and talking to folks who actually know what goes on inside the boxes! And a lot of it comes from the magic of listening to AM radio, especially some of the clear channel stations on long winter drives to and from college. Though I dabbled for a while listening to FM in my rock and roll era, AM has always been the companion on the road.

And even though I've been captured lately by the 'smug' radios, I'll always have a soft spot in my heart for the warm glow and sound of tubes.

 

[W2PFY]

Some of those carrier current transmitters in the basements of the dorms over at the SUNY school in town would have made great AM rigs. I recall sets of 811's being modulated by 810's or some such and at least one that had an 813 in it. I think we had about 500 watts of carrier power out of some of them. We basically had one of those in each of the tower dorms on that campus and a number of minor ones scattered around town all tied together with phone lines.

Wow, I never knew they ran that sort of power? I have a carrier current transmitter mfg by LPB and it puts out about 30 watts. I have hooked it up to a computer for audio feed and I can make it sound better than local BC stations. I need a matching network to drive the neutral line in the house. Some say your supposed to drive the "HOT" leg of the line?

[K3ZS]

During my first year at Penn State, all freshman had to stay in the dorms.   Since this was 1962, there were not many FM stations or FM receivers.   The dorms had lousy reception for AM, you could receive the one and only AM station broadcasting at night, and they didn't have the programming to satisfy our ages craving for rock music.     I converted an AM radio to an AM transmitter, cathode modulated the local oscillator with the receiver's audio stage.   We coupled it to the power line and were "on the air" throughout the half of the dorm building that was fed the power line.   PSU had a rule about not having transmitters in the dorms, but this was OK.    A few of us decided to go "nation wide", we set up a wire antenna, and built a tuner for the transmitter.   One cohort had every 45 that was popular at the time, his clothes closet was full of 45 rpm records and his clothes was piled up all over the rest of the dorm room.    He also had a good audio setup, and we added a microphone to the setup.    We used the call WBTW, the initials stood for an obscene phrase that was popular at the time.   We went on the air every evening and set up a request line.   We usually had whatever was requested.   Apparently we were heard all over a good part of the campus, that local oscillator must have been powerful.  Of course it was AM and FM at the same time.    After about a week of broadcasting,  three Penn State officials came in and put us off the air.    I was put on probation for the term and that ended my career in AM broadcasting.

[W7TFO]

Most LBP transmitters are designed to connect directly to the power line. 

Those that do have their own internal matching network, so there ought to be three 3AG fuses and a terminal strip inside.

One hot leg to each (120 or 240 or three-phase 208) and ground or neutral.

If you TX has just the 50Z output, you can get data from LPB on what they have in their external matching networks. 

They use toroids and fixed SM caps with a decade selector switch and SWR meter.

73DG

[WD5JKO]

In 1974 I got my Advanced ham ticket, and 1st phone within a week of each other. I went in for the Phone 3rd class, part of my high school broadcasting class. So it was only a couple of dollars more to go for the 1st, so what the hell...I took that test cold...and passed! All those questions about towers and light regulations...had no idea, but eanie meanie miney mho worked well for me...Then as a Freshmen in college (Ferris State) I became the assistant chief engineer of WFRS, a carrier current station with 17 transmitters; one in each dorm boiler room.

These were mostly 5 watt LPB transmitters coupled into the dorm 3 phase grid. The LPB's had a pair of 6AD10's inside, and worked pretty well. There was a couple of home made rigs though with an 807 modulated by a pair of 6L6's. These were throttled back to 5 watts as well. Over Christmas break, I took one of those home, bridged the power supply, and made it a 50 watt (INPUT) transmitter. Added a little audio negative feedback, and the thing rocked at Kramer Hall (11 story dorm). I made a mistake though, and the output matching network had a 'Q' that was too high. The load varied from day to night, so dipping the plate was best done at dinner time. I remember going into the boiler room, and without turning on the light, I could see that red plate 807. I'd walk over there, and dip the plate for minimum red (no meter), and head out. I wonder what ever became of that rig over the year following my graduation....807's are tough, but not that tough. 

I had a LP FM station as well my second year. Amazing how a transistorized modulated oscillator + PA (maybe 100mw input) got full campus coverage with a ground plane antenna on the dorm roof. The quality was decent too considering. This went on for a couple of months, taking calls through the dorm desk, and broadcasting every Saturday night. We called ourselves, WRFP "Radio Free Puterbaugh".

Jim
WD5JKO

[W4EWH]

... The load varied from day to night ...

I'm curious: did you find out what caused that?

Bill, W1AC

[WB2EMS]

Wow, I never knew they ran that sort of power? I have a carrier current transmitter mfg by LPB and it puts out about 30 watts.

Yeah, the modern units all run around the power range and there's a lot more knowledge about how to build a good matching network for the line feed. The folks who had homebrewed those old carrier current systems in the late 60's or early 70's were using link coupling and a series cap as I recall - probably not very well matched, so add power! ("Antennas by Eimac" was a popular phrase back then) 

The big transmitters were only used in the major dorm towers. I think there were two or three of these big dormitory buildings on the SUNY campus, about 11 or 13 stories tall, with hundreds of rooms, so we needed a lot of drive to be heard well on the upper floors. For more normal residence halls, we had smaller transmitters with an 807 or 6146 in the final, probably running 50 watts or less.

It was a real kludge of a system that had grown organically through the years with various temporary staffers cycling through the school for a year or two till they lost interest and the next guys came along. I doubt by the time I was there that anyone had a system diagram of what was where. But it worked, and good enough is the enemy of better.   

[W7TFO]

Since the load was the local grid, any and all devices on it varied the reactive component. 

As night fell, lighting loads changed and industrial equipment went offline.

All this played hob with trying to keep a match, so most CC units were designed to handle substantial VSWR.

73DG

[WD5JKO]

... The load varied from day to night ...

I'm curious: did you find out what caused that?

Bill, W1AC

Yes all those incandescent light bulbs, space heaters, etc. that came on in the evening changed the load as seen by the transmitter looking into the 3 phase building power.

Jim
WD5JKO

[KA3EKH]

I did carrier current stuff back when I when I was in college, lots of dry pair phone lines to dorms and at that time we were using all solid state LPB transmitters and couplers in the dorms that were all in the boiler rooms connected to the big three phase panels. They were always connected to the high side of the lines and the grounds connected to the neutral or ground of the system. 20 and 50 watt transmitters were most common. Years later when I left full time broadcasting and started working full time for a university they at first had a carrier current system but they went to a LPFM and that works way better then the old carrier current systems ever did, now twenty years later do not think any of the kids today have any idea what or how to receive AM radio or maybe FM too. Although where I am working we have a 50 kW and  25kW NPR stations and a 100 w student run station all on FM think most kids today don’t listen to radio. In my other job for the Evil Empire I have an old LPB 50 watt transmitter that we have for a daytime only AM station (WJDY) as a backup transmitter. That station runs 5 kW daytime and a whopping 49 watts at night.  On this subject I have a technical question on something I cannot understand. Why is it on the old tube broadcast AM transmitters that they would always design such a stupid system for reduced power operation of switching in additional resistance into the output of the plate supply for operation in your nighttime or low power mode?  Example: you have a RCA 1 kW daytime transmitter and have to go to 250 watts at night so they would have a relay that dumps a huge amount of resistance in series with the output of the HV supply to reduce voltage to the PA and modulator. The transmitter still consumes the same amount of AC power and now produces a lower power output and a lot more heat output. I have a RCA BTA-1 that’s on 1.885 and wanted to run reduced power. The book tells you to stuff a bunch of resistance in series with the output of the HV supply but I did not want to do something like that so what I did was put a autotransformer on the input of the HV transformer and vary the HV that way with out dissipating lots of heat and wasted energy but often wondered why that was never the approach for broadcast service?

[W7TFO]

"The book tells you to stuff a bunch of resistance in series with the output of the HV supply but I did not want to do something like that so what I did was put a autotransformer on the input of the HV transformer and vary the HV that way with out dissipating lots of heat and wasted energy but often wondered why that was never the approach for broadcast service? "

Simple...it still had to make the distortion & noise specs called for by the FCC.

Really tough to pull a big, plate modulated rig down in power to 1/4 and make the operation still 'linear'.  It was found far simpler to just let the power supply run normal, drop it thru Ohms, and move the bias a bit on the modulators.

73DG