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Bigbob
| | Posted on Friday, September 20, 2002 - 6:50 pm: | 
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What would it take,besides lotsa money,to build one for channel 6? Are there components capable of withstanding such power at 11meters or is it a pipe dream?And just how far would such a station create hate and discontent in other people?I know I'm in the realm of make believe,but these are serious questions and I would like prudent and thoughful answers,please.Oh yes the transmitter would be under ground for safety and closeness to antenna. |
HoosierCardinal
| | Posted on Friday, September 20, 2002 - 8:28 pm: |
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My question is..........................
Why?????????????????????? |
bruce
| | Posted on Friday, September 20, 2002 - 8:51 pm: |
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And how do you power it and if you could how do you pay the bill ??????? |
Taz
| | Posted on Friday, September 20, 2002 - 10:11 pm: |
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Well, lookd like somone is jealous
ok
1,000,000 watts?
During world war 2 the germans used a 3 million watt amplifier to block signals all over europe.
Just take some 3CX25000'S and have one hell of a cooling system with open wire transmission.
 |
bruce
| | Posted on Friday, September 20, 2002 - 10:46 pm: |
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Taz got 2 i can have ???? a 3cx25000 would look good with my 2 lbs ALINCO driving it! |
HoosierCardinal
| | Posted on Saturday, September 21, 2002 - 12:10 am: |
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whos jealous? |
Chris142
| | Posted on Saturday, September 21, 2002 - 12:25 am: |
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I wonder what the power bill would be per minute! |
Taz
| | Posted on Saturday, September 21, 2002 - 2:08 am: |
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Now hes not only jealous hes confused, hehe
Well
I Beleive about 100 thousand watts requires dual 440volt |
bruce
| | Posted on Saturday, September 21, 2002 - 2:38 pm: |
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my luck would be the hospital which is 1200 foot away i would BLACKEN the x-ray flim! |
Taz
| | Posted on Saturday, September 21, 2002 - 4:54 pm: |
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haha |
HoosierCardinal
| | Posted on Saturday, September 21, 2002 - 8:08 pm: |
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Taz..
Whatever...... |
Ncrebel
| | Posted on Saturday, September 21, 2002 - 8:54 pm: |
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Bruce...pacemakes would be out of the questions at the hospital.lol |
Taz
| | Posted on Saturday, September 21, 2002 - 9:07 pm: |
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Hoosier Cardinal..
Whatever...... |
Kirk
| | Posted on Saturday, September 21, 2002 - 9:14 pm: |
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you better have a good job! We run 4.5 million watts visual and aural out of our transmitter for tv and it costs us over $4,000 a month..so.....go for it! |
Bigbob
| | Posted on Saturday, September 21, 2002 - 11:37 pm: |
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Well I asked a dum question... |
HoosierCardinal
| | Posted on Saturday, September 21, 2002 - 11:59 pm: |
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Taz....
*yawn*
This is getting boring so i think ill leave now and leave you guys alone now...
Bye......
LOL! |
Znut
| | Posted on Sunday, September 22, 2002 - 12:06 am: |
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What if you transmitted 25 watts into a 2 element quad made with 1/2 inch tubing?
What is the multiplication? I don't know. I hear the gain is 6db to 8db and the front to back ratio is around 20db.
My favorite solution is antenna VS power.
Znut |
bullet/151 southern Indiana
| | Posted on Sunday, September 22, 2002 - 3:11 am: |
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id say it would talk ok if it were built right,but you arnt going to be excessively impressive with a 2 element at 25 watts. you will most likely sound as loud (out a few miles)as a mobile using a 102 ss whip and a texas star 250. (is my guestamation)
it depends on gain of antenna in question. ball park around 9 - 16 x for a 2 element depending on antennas boom length,element length,spacing. each having its sweet spot for highest gain,bandwidth,and front to back and front to side ratio's. not to mention propogation. |
bullet/151 southern Indiana
| | Posted on Sunday, September 22, 2002 - 4:04 am: |
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at 25 watts,1.5:1vswr,.8dbloss,and 8dbi gain
it figured out at a eirp of 121.333 watts so i was
a bit heavy on my first guess.
a six element quad with 1.5swr,.8 loss,16dbi gain was 700+ eirp.
moonraker4 1.5swr,.8 feedline loss,14.5dbi was around 450 watts eirp |
bruce
| | Posted on Sunday, September 22, 2002 - 8:07 am: |
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Znut a 2 elm quad will give real gain 4-5 DBD gain which is about 3/1 or 75 watts 20 db f/b sounds about right and i TOTALY agree antennas not amps would solve alot of problems. |
bullet/151 southern Indiana
| | Posted on Monday, September 23, 2002 - 11:26 am: |
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"MAXIMUM" gain for a 2 element quad with the parasitic element as a reflector is 8.1dbd; for the parasitic element as a director it is 7.3dbd.
maximum reflector gain occurs at 1.08 wavelengths loop circumferance at a spacing of .15 wavelengths.
"Maximum" radiator gain occurs at a cirumferance of 1.2-1.4 wavelengths.
maximum director gain occurs at .95 loop circumferance and a spacing of .1wavelength.
minimum back radiation with reflector is -12.1 db this is nearly the same over the range of reflector sizes from 1.1 to 1.15 wavelengths circumferance,and the range of spacing from .1 to .25 wavelength."maximum" front to back ratio occurs at a circumferance of 1.1 wavelength and a spacing of around .1 wavelength and is around 20 db.
these are "optimum" spacing and loop figures for maximum performance in a given area. and come from
bob haviland's book the quad antenna.(who is a subject matter expert on quads)
most company's dont build optimized antennas in one area (gain,front to back,bandwidth) but try to
make a compromized design to please the masses.and in this case you will see the lower gain figures, its a trade off.
i hear alot of guys on the radio that think if a beam talks out the back much at all its junk. they like alot of front to back, but"maximum" forward gain is not realized when your beams set up for high front to back ratio's.
thats why i said it depends on how it is built in my first post.and the eirp figures were from a online antenna system calculator. |
HeHe
| | Posted on Friday, October 25, 2002 - 4:28 pm: |
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TAZ has a 1000,0000 watt mouth. |
Alsworld
| | Posted on Friday, October 25, 2002 - 6:00 pm: |
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I don't get it. Was that a compliment because of the awesome station he runs?
Or was it a slam?
Hmmmmm
We've got your back Taz.
Alsworld
Alsworld & Taz,
I approved that post as I figured it was a compliment.
Around here we have what we call $(dollar) Radio Techs and the only problem is when they get done talking (giving you their expert advice) you always have to give them change back as you never get your doller's worth.
So I assumed that when he said Taz's mouth was worth a million that was a compliment. 
Lon
tech808
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Znut
| | Posted on Friday, October 25, 2002 - 6:25 pm: |
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I like my 2 el. quad. I see s-units over the A-99, when someone I'm talking to is flatside especially. There is a guy about 20 miles away that runs horiz. on AM (a ch 6'er). I get a 5 on him on the 99 and almost full scale on the beam on the backside, keeping in mind the quality of the s-meter on a 2510, haha. Only a 6 or 8 from the side. It works great DX and has bandwith to spare. I guess that's 'cause of the 1/2 inch tubing. Yes I cut it shorter to account for the diameter.
Znut |
Bigbob
| | Posted on Friday, October 25, 2002 - 7:29 pm: |
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I think HeHe's comment was in poor taste and he's not registered,augh!!!!You weren't 15 or 16 once,hehe,hah! |
bruce
| | Posted on Friday, October 25, 2002 - 9:15 pm: |
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Bullet NEVER have i seen any gain figuras of 8DBD for a 2 el quad NEVER if this is some model on a computer modeling softwhere thats fine but REAL world gain id 4 to 5 DBD about 6-7 DBI if your number were true then a 3 elm quad would be about 10 DBD and i dont EVER remember anyone claming that kind of gain. Now you are correct max gain and frount to back do not always go together but 8DBD i would like to see a real antenna measuer that gain.
bruce |
Tech808
| | Posted on Friday, October 25, 2002 - 10:38 pm: |
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TAZ,
KEEP UP THE GOOD WORK!
ENJOY YOUR POST's, HUMOR, KNOWLEDGE, and JOKES.
KEEP IT UP!
Lon
tech808 |
Znut
| | Posted on Friday, October 25, 2002 - 11:09 pm: |
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WT*?
Znut |
Taz
| | Posted on Friday, October 25, 2002 - 11:51 pm: |
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Thanks guys.
Taz
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bruce
| | Posted on Saturday, October 26, 2002 - 6:53 am: |
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I just went back through a pile of books and the highest number ive seen is 7 DBD now thats fine on a computer but the REAL world the best is closer to 6DBD So the get real i can measure number is about 6..... ok now we hear ground enhansment and all the other poopy-puck but when all is said and done if your geting 6 DBD your in high cotton. It's nice to come up with all these max numbers but a quad at 50 toot with trees and houses and power wires and so-so ground reflection is what the REAL world is all about.
Bruce |
Znut
| | Posted on Saturday, October 26, 2002 - 11:09 am: |
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Bruce,
Real world is right. I wish it was at 50'.
The real world part I like is that when I flip the antenna switch to the beam I see more s-units and get a stronger sounding signal, unless the other station is a local base or mobile with a vertical antenna. That's what I have the A-99 for!
Znut |
Karatebutcher
| | Posted on Saturday, October 26, 2002 - 8:24 pm: |
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TAZ sorry for the delay in my post, I just got to this colum, may I say, stay the way you are, good ,and funny at times, honest all the time, interesting, concerned, and in all ways, there to help, you have a $10000,0000 heart.
Don't be picking on OUR pal |
Taz
| | Posted on Sunday, October 27, 2002 - 12:55 am: |
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Thanks for the kudos Karatebutcher.
Taz |
Tech833
| | Posted on Sunday, October 27, 2002 - 12:28 pm: |
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Taz,
Just FYI, you would not likely use open wire transmission line at high power. There is too much chance that a moist day or a stray bird could cause problems, and maintenance is much too labor intensive. Almost all high power SW, MW, and LW installations use Heliax or hardline for cable runs.
According to Tessco, at 30 MHz., you could use 4 inch cable and run an average (carrier) power of 1 MW and still have a safety margin of several KW. Heliax is available all the way up through 6 inch and even larger sizes with air cores and can handle HF power levels well in excess of 1 MW.
Also, for high power, we do not parallel a lot of smaller tubes (like they do in CB and amateur amplifiers). Instead, we employ single and (rarely) dual tube designs that are more than capable of twice the intended power. For instance, one transmitter I recently worked on runs 115 KW (115,000 watts) carrier and uses a single IOT. The IOT in that transmitter is actually capable of nearly 500 KW (1/2 million watts) running at peak. However, it is run at substantially less than peak by design so the tube lasts longer (about 5-8 years continuous duty).
Another type of large power tube is the Klystron. Klystrons are mostly used for T.V. and long range radar work. Klystrons are slowly giving way to the IOT. Klystrons are available in power levels exceeding 1 MW (one million watts). The cooling system for Klystrons is typically liquid. The liquid cooling works just like the radiator in a car. Air is used to cool fluid (water with anti-freeze) in a large radiator outside the building which is then pumped back into the transmitter where it is heated and returned to the cooling system.
Sometime, you should contact one of your local T.V. stations and ask for a tour. Most stations are happy to take a smart young lad through the place. I believe you would look at C.B. transmissions through a new light after a tour of a professional plant. Knowledge is power! (pun intended). |
Taz
| | Posted on Sunday, October 27, 2002 - 1:10 pm: |
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307, I have actually been through one. Channel 3 is one of the news stations here in arizona. Very very cool stuff in that place. |
Taz
| | Posted on Sunday, October 27, 2002 - 4:56 pm: |
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hmmm, i meant 833 |
Bigbob
| | Posted on Sunday, October 27, 2002 - 7:26 pm: |
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Tech 833&Taz,wgtu tv has a 10meg transmitter,uhf,it's in the "blue room",it has 2 tubes,one on all the time,one on stand-by in case first one goes down.I was told the tubes are quite large. |
bullet
| | Posted on Monday, October 28, 2002 - 3:53 am: |
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bruce,
id say you better contact bob and tell him he's been wrong all this time. im sure he would want to retract that from his book's since you dont agree. |
Kirk
| | Posted on Monday, October 28, 2002 - 12:11 pm: |
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Taz, If you lived up near me I could take you thru a TV Station. We are a UHF Station that just went online with what 833 is talking about (single IOT, but we have a redundant set-up, so we run 2 IOT's at 50% per). We just de-commissoned out Klystron based transmitter (RCA) and it's headed for the scrapyard. The tubes are about as big as a person. We used one for visual, one for aural. The visual power output was much higher than the aural and would literally shake in it's socket because it was used close to maximum output. Truly an awesome sight. |
bruce
| | Posted on Monday, October 28, 2002 - 12:55 pm: |
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Bullet
Computer modleing is fine its a great way to work out things without hours of cutting wires However now we go to the real world a antenna can have 8 dbd gain on a model but what will it do in the real world I went out on the net and research his book nice book but again i cant find a single measured gain of 8 DBD not DBI for a 2 elm quad
Im not realy being all that picky but if that was a fact the antenna makers would be out there clameing it.
As a point Cubex gain is for its 2 em quads 9 DBI which is 6.8 DBD and they are a leader in thoes antennas. I ran a 11 elm 2 meter quad for years it was a fine antenna and out did a beam but measured gain was about 13 dbd. That type of modleing can be used on yagis too and ive seen 3 elm beams in the 8 DBD class but try and build one ? This works for me safe rule is this always figure 2 db less and you would't be disapointed |
Tech833
| | Posted on Tuesday, October 29, 2002 - 12:10 pm: |
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Kirk,
I just de-commissioned an old VHF 1970 RCA myself. We installed a new Harris IOT and I love it! Of course, the power supply for the Harris is larger than the RCA was so we had to reconfigure the room (including relocating the auxiliary transmitter, which meant being off the air- which meant working from after the news was over until 5 AM!). Someone found the old signoff tape with the National Anthem and ran it. Nostalgia!
Anyway, my impression of our new Harris is that it has a lot of CMOS to go wrong. It's like having a computer connected to the end of a lightning rod. The Harris came up just fine, but I'm waiting for the day when a CMOS component clamps and the transmitter goes BANG! because of it (we in the business refer to it as 'crowbar-ing').
I'm still happy to be rid of the old RCA. That transmitter was becoming very unreliable. It would burp at least once every two weeks or so and require paying Comark's unrealistic prices for parts not available anywhere else. This on the number one station in two markets! Needless to say, the G.M. was excited when corporate approved the new transmitter purchase. |
Insider
| | Posted on Tuesday, October 29, 2002 - 3:41 pm: |
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Tech 833
At the radio station I work for, we use a BE (Broadcast Electronics) transmitter as the primary. It's all solid state and has lots more protection systems in it than the Harris tube job we have as a back up.
One weekend, of course this kind of thing has to happen when I'm on the clock, the transmitter burned up. Literally, the power supply had exploded and several of the power modules been on fire for a brief period. I'm still not sure what was more impressive: being on duty whent the transmitter burned, or the engineer bringing one of the burnt modules over to everyone and saying "Check this out. Look at how the top of that transistor's all mangled and charred from the flames, or see that streak running up the circuit board? That's where a flame shot across and melted a hole in the plastic insulator on the backpanel." He,he,he.
Ironically the engineers found that the transformer that supplied the voltages to the protection systems had an open in it and the transmitter was essentially running with no regulation. Hopefully BE will anticipate that type of failure in the next revision. |
Tech833
| | Posted on Wednesday, October 30, 2002 - 1:39 am: |
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I have installed 3 BE AM transmitters and 3 BE FM transmitters myself! BE is my hands down favorite radio transmitter.
I personally own a newer BE 1.5 KW FM with the FX-50 exciter. I use it as a go-anywhere standby. I also own a solid state P-Tek 1 KW rig (yuck). It has blown up a couple of times, but only when I needed it to save a client's station of course.
I just installed a new FM1C a couple months ago at one of the FM's I am C.E. of. Marvin Steelman left BE last month, so I am back to dealing with John Abnour now. John's a good guy too, but he can't seem sharpen his pencil as good as Marvin could.
The AM10 at the X-band I built two years ago has had 3 modules go out in it. At the last NAB, I spoke with one of the engineers and discussed the problems. BE has since made modifications. Despite all that, BE has the most reliable FM transmitter by far in my opinion.
I am C.E. of 13 stations and assist 8 others. Transmitter count:
BE- 7
Continental- 3
Harris- 3
Collins- 4
Gates- 1
Elcom Bauer/Sparta- 3
Nautel- 2
QEI- 1 |
Insider
| | Posted on Wednesday, October 30, 2002 - 2:14 pm: |
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Impressive count Tech833.
I'll have to remember to pay closer attention to the model number of the transmitter. The C.E. of the station I work for made some modifications to the transmitter. BE was impressed, so they took the transmitter back, copied the mods and sent the atation a new unit with the mods as part of the finished product. |
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