Got to play with some BIG radio's today.

[Snowizard]

How about something different from all the election anxiety.?

Here's what I did after I voted today.
A lot of people probably never get to see the expensive end of a broadcast station.

The tower crew was re-tensioning guy wires and re-lamping the beacons on this commercial FM site.
Our local "ham radio" club has both a VHF and UHF repeater equipment at this site, and antennas on the shorter tower.
Our antennas are fed separately from the big broadcast transmitters (for obvious reasons. LOL)

As long as the crew was there, we hired them to change out both of the "ham" antennas with better quality ones.

Here's a couple pics of the type of hardware that broadcasts the tunes you listen to on FM radio. This equipment is pretty typical of what you would find almost anywhere.


Combiner cavity filters. Multiplexes both 93.3FM and 106.7FM into a single antenna.

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93.3 machine on the left, 106.7 machine in background. The final output stage runs at 5,000 Volts DC, at 6 Amps!

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Station manager Dave, shuts the transmitters off the air so its safe for the tower climbers.

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Reverse view of air cooled tuned cavity-combiner filters. The heavy coper pipe is actually coaxial cable. It needs to be that size to handle total 50,000 Watts to the antenna.

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200,000 Watts of Country+Contemporary Rock comin' at ya'. Antenna pattern "gain" increases Effective Radiated Power.
(And to think I used to climb towers like these 30-35 years ago. ) 400ft. left, 300ft,right.

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[sledhead699]

damn looks sweet the guy on the phone i bet he gets good service there to. ahahah

 

[Ex-Member]

Very nice. Kinda makes the 50W in my truck look like a drop in a bucket.

Biggest i've played with is a 6.5kW DX10. Nothing quite like the sound of one of those chuggin away.

BTW, that shack is surprisingly clean Needs moar cables on the wall, papers on the desk, etc

 

[racingpit]

Very cool photos, something that I have never seen before.

 

[Snowizard]

..............
Biggest i've played with is a 6.5kW DX10. Nothing quite like the sound of one of those chuggin away...........

BTW, that shack is surprisingly clean Needs moar cables on the wall, papers on the desk, etc

The noise level in that building is incredible. There is a tremendous Cubic Ft./Minute of air moving through the transmitter cabinets from internal squirrel cage blowers, then there's building exhaust fans, and sometimes the air conditioning kicks on.

You literally have to yell to a person standing only 10-15 feet away to carry on a conversation.
The air temperature coming off the final output stage is 140*F !! No building heet needed in winter.

 

[Ex-Member]

STL a T1 link to the towers?

 

[Snowizard]

STL a T1 link to the towers?

T-1 line.

FYI others, a "STL" is a Studio to Transmitter Link, that involves sending the studio programming via a short hop radio path, on FCC a assigned channel usually in the 450MHz or 900MHz band.

A "T-1" is a digital dedicated telephone link direct to the site. Can be copper wire, or fiber optic.
T-1 lines are preferable, but not always available everywhere.

 

[black swan]

Yep, that looks like just another day at work, except you didn't show any sleds under the tower.

200,000watts huh...nice! I actually had a PBS tower in hutch KS at 1400ft that caught fire 10ft from the top. New kid, decided to oftset the relfection with more wattage..........bad idea since the hardline 6"dia coax not the fancy copper plumbing.....burnt a 4ft section clean in half...........1100 ft off the ground........yep took me 2hrs to climb up there.

those self cooling cavaties are friggin awesome!!

ray
radio RULES!!
kd0chn

 

[Snowizard]

Clarifying a couple items.

.....you didn't show any sleds under the tower.
........200,000watts huh...nice!

.....those self cooling cavaties are friggin awesome!!

Sleds, eh? We are still about 5-6 weeks away from the possibility of that around this neck of fly-over country.

The site is actually at the top, of the local ski hill.
200KW is ERP from the antenna array. I could have been more specific. Actually around 50KW combined going up the coax TO the antenna.

Those white circular objects on top of the cavities are cooling fans.

The tower crew couldn't finish our ham antenna work that day, since the WX went to h*** a couple hours after I shot these pics.
Now its been raining for the past 2 days. We need the moisture, just not right now. LOL.

Maybe I can post a couple more pics when we get back there, next week maybe?
Roger.
w0wug.

 

[Ex-Member]

Nothing like workin on the mountain with a thunderstorm on the horizon... Antennas make great lightning rods

I didn't think UHF was used for STLs.... Most that I've seen are PTP microwave...
I think the switching equipment to go between the T1 and microwave is crazy... switches between the two in fractions of a second.

The squaw mountain site out here is pretty difficult terrain... mostly fire breaks to get up there. Generator crapped out 2 or 3 years ago after a huge snowstorm... sled or snowcat is about the only way to get to those towers.

good to know there's a few radio geeks on snowest...

K7AIH

 

[Snowizard]

^^^^
As far as uplinking to broadcast sites around MN, just about every kind of technology is used.
In my former town (Willmar) one of the local FM's uses two analog channels.
L and R stereo, one on 450.000MHz, the other on 455.000MHz. Has been working great for decades.
ANother station is using a 960MHz multiplexed hop.
Of course, years ago dedicated metallic (copper) broadcast equalized phone lines were used.
( wouldn't be surprised if some still are in use.)

At cellular sites, and BC sites, where possible, back-up T-1's are preferred. One run may come from the north, for example, and the back-up from the south, to the site. Both are 100% active and reduntant, and can switch in an instant w/no loss of signal continuity.

As tech's joke, this is in case "two leg'ed gophers dig up one of the runs doing underground utility construction.

 

[black swan]

backhoe fade??? lol

here in the colo mtns, 80% of my sites are fed via microwave-ISM or 5.3.
no copper avail due to terrain, and even if the cable was buried the distances are ridiculous and failures were daily so MW is the only solution.

No real reduntantcy, just primary ESF spans and a lot of luck.

FM=fancy magic

Some of our Ops peeps only travel via heli, $1200/hr. I prefer the sled or atv takes longer but the company toys rock! And the boss would shiat over a heli bill.

 

[Ex-Member]

looks like we've scared just about everyone else out of this thread... lol