Curious for the engineers who keep an eye on here. I've always wondered what the monthly power bill would be for a 50kw AM ... and for a 100kw FM? In other words ... what does it cost JUST to toss a signal out in the market each month? (Am ignoring all the hard costs of equipment, site, etc. and all the operations cost -- just wondering how much more expensive a station is than leaving a porch light on for a month!!!!)
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Engineer Input: Cost to keep Xmitter on?
- Thread starter LITTLEBOYBLUE
- Start date
E
eastsidah
Guest
> Curious for the engineers who keep an eye on here. I've
> always wondered what the monthly power bill would be for a
> 50kw AM ... and for a 100kw FM? In other words ... what
> does it cost JUST to toss a signal out in the market each
> month? (Am ignoring all the hard costs of equipment, site,
> etc. and all the operations cost -- just wondering how much
> more expensive a station is than leaving a porch light on
> for a month!!!!)
>
I don't know much about am...but as far as FM goes, just because a station is 100kw, doesn't mean that their actual transmitter output is anywhere NEAR 100kw...far from it most likely. You have to consider things like antenna gain, etc. Cost probably vaires greatly.
> always wondered what the monthly power bill would be for a
> 50kw AM ... and for a 100kw FM? In other words ... what
> does it cost JUST to toss a signal out in the market each
> month? (Am ignoring all the hard costs of equipment, site,
> etc. and all the operations cost -- just wondering how much
> more expensive a station is than leaving a porch light on
> for a month!!!!)
>
I don't know much about am...but as far as FM goes, just because a station is 100kw, doesn't mean that their actual transmitter output is anywhere NEAR 100kw...far from it most likely. You have to consider things like antenna gain, etc. Cost probably vaires greatly.
> > Curious for the engineers who keep an eye on here. I've
> > always wondered what the monthly power bill would be for a
>
> > 50kw AM ... and for a 100kw FM? In other words ... what
> > does it cost JUST to toss a signal out in the market each
> > month? (Am ignoring all the hard costs of equipment,
> site,
> > etc. and all the operations cost -- just wondering how
> much
> > more expensive a station is than leaving a porch light on
> > for a month!!!!)
> >
> I don't know much about am...but as far as FM goes, just
> because a station is 100kw, doesn't mean that their actual
> transmitter output is anywhere NEAR 100kw...far from it most
> likely. You have to consider things like antenna gain, etc.
> Cost probably vaires greatly.
My understanding (OFTEN flawed!!!) is that a 100kw FM station generally has about 33KW of power .... I seem to recall a multiple of 3 being introduced somewhere in the process. But that equation is filed in the same part of brain as "I before E except after C...."
> > always wondered what the monthly power bill would be for a
>
> > 50kw AM ... and for a 100kw FM? In other words ... what
> > does it cost JUST to toss a signal out in the market each
> > month? (Am ignoring all the hard costs of equipment,
> site,
> > etc. and all the operations cost -- just wondering how
> much
> > more expensive a station is than leaving a porch light on
> > for a month!!!!)
> >
> I don't know much about am...but as far as FM goes, just
> because a station is 100kw, doesn't mean that their actual
> transmitter output is anywhere NEAR 100kw...far from it most
> likely. You have to consider things like antenna gain, etc.
> Cost probably vaires greatly.
My understanding (OFTEN flawed!!!) is that a 100kw FM station generally has about 33KW of power .... I seem to recall a multiple of 3 being introduced somewhere in the process. But that equation is filed in the same part of brain as "I before E except after C...."
E
eastsidah
Guest
> > > Curious for the engineers who keep an eye on here. I've
>
> > > always wondered what the monthly power bill would be for
> a
> >
> > > 50kw AM ... and for a 100kw FM? In other words ... what
>
> > > does it cost JUST to toss a signal out in the market
> each
> > > month? (Am ignoring all the hard costs of equipment,
> > site,
> > > etc. and all the operations cost -- just wondering how
> > much
> > > more expensive a station is than leaving a porch light
> on
> > > for a month!!!!)
> > >
> > I don't know much about am...but as far as FM goes, just
> > because a station is 100kw, doesn't mean that their actual
>
> > transmitter output is anywhere NEAR 100kw...far from it
> most
> > likely. You have to consider things like antenna gain,
> etc.
> > Cost probably vaires greatly.
>
> My understanding (OFTEN flawed!!!) is that a 100kw FM
> station generally has about 33KW of power .... I seem to
> recall a multiple of 3 being introduced somewhere in the
> process. But that equation is filed in the same part of
> brain as "I before E except after C...."
>
It really varies depending on a LOT of factors...Line Loss, antenna efficiency/gain...a 100kw ERP can certainly be had with a 33kw transmitter and the right antenna combination...some need a more powerful amp, I think I've heard/seen a few that used less than 33kw as well.
>
> > > always wondered what the monthly power bill would be for
> a
> >
> > > 50kw AM ... and for a 100kw FM? In other words ... what
>
> > > does it cost JUST to toss a signal out in the market
> each
> > > month? (Am ignoring all the hard costs of equipment,
> > site,
> > > etc. and all the operations cost -- just wondering how
> > much
> > > more expensive a station is than leaving a porch light
> on
> > > for a month!!!!)
> > >
> > I don't know much about am...but as far as FM goes, just
> > because a station is 100kw, doesn't mean that their actual
>
> > transmitter output is anywhere NEAR 100kw...far from it
> most
> > likely. You have to consider things like antenna gain,
> etc.
> > Cost probably vaires greatly.
>
> My understanding (OFTEN flawed!!!) is that a 100kw FM
> station generally has about 33KW of power .... I seem to
> recall a multiple of 3 being introduced somewhere in the
> process. But that equation is filed in the same part of
> brain as "I before E except after C...."
>
It really varies depending on a LOT of factors...Line Loss, antenna efficiency/gain...a 100kw ERP can certainly be had with a 33kw transmitter and the right antenna combination...some need a more powerful amp, I think I've heard/seen a few that used less than 33kw as well.
D
dickfry
Guest
> Curious for the engineers who keep an eye on here. I've
> always wondered what the monthly power bill would be for a
> 50kw AM ... and for a 100kw FM? In other words ... what
> does it cost JUST to toss a signal out in the market each
> month? (Am ignoring all the hard costs of equipment, site,
> etc. and all the operations cost -- just wondering how much
> more expensive a station is than leaving a porch light on
> for a month!!!!)
>
Modern transmitters are roughly 50% efficient. Some say they can do 60%, but they probably exaggerate their efficiency. So assume that if you put in 100,000 watts of electricity you get 50,000 watts of RF out. The rest is lost as heat in the transmitter shack. Think of having 50 1000 Watt space heaters running all the time in your living room and you get a feeling for how much energy is wasted.
Assuming it's an AM station, the FCC doesn't figure the antenna gain, no matter how tall or short the antenna is. So 50,000 watts is 50,000 watts, minus some small percentage loss in the transmission line. Unlikely to be more than 5 to 10% loss.
So figure out how many hours it's on the air in a month and multiply by the cost per kilowatt hour. I don't pay the power bill here, but let's assume it's about $0.10 per kW/hour.
For 24/7 operation figure total hours in a 30 day month as:
24x30=720.
50 kW station Power use = 100 kw x 720 hours = 72000 kilowatt hours.
72000 kW/hours x $0.10 kilowatt hour = $7200 a month to keep the transmitter fed.
If the price of electricity is different at your house, remember, it's just an estimate and just go with the exercise. Plug in your own power cost and get your own answer. Big power users are able to negotiate their own rate with the power companies.
---
An FM station is different from AM because the antenna gain determines the effective radiated power. More bays of antenna = higher power.
With a high power station, it's a fair assumption that they're getting a 3x or 4x gain from their antenna. So assuming a 100 kW FM, it's fair to assume 30 to 40 kW coming from the transmitter, depending on coax loss and antenna gain.
Let's say 35 kW divided by 50% efficiency gives 70 kW coming out of the wall.
720 hours x 70 kW = 50400 kW hours in a 30 day month.
50400 kw hours x $0.10 =$5040 a month for electrons.
Older transmitters are less efficient, so they tend to get replaced fairly quickly in high power stations because it's cheaper than paying the power bill on the wasted energy every month, year after year.
Given a choice, it's cheaper to leave the porch light on. And considering what some of these stations are used for, a working porch light is probably a better investment.
-Dick
> always wondered what the monthly power bill would be for a
> 50kw AM ... and for a 100kw FM? In other words ... what
> does it cost JUST to toss a signal out in the market each
> month? (Am ignoring all the hard costs of equipment, site,
> etc. and all the operations cost -- just wondering how much
> more expensive a station is than leaving a porch light on
> for a month!!!!)
>
Modern transmitters are roughly 50% efficient. Some say they can do 60%, but they probably exaggerate their efficiency. So assume that if you put in 100,000 watts of electricity you get 50,000 watts of RF out. The rest is lost as heat in the transmitter shack. Think of having 50 1000 Watt space heaters running all the time in your living room and you get a feeling for how much energy is wasted.
Assuming it's an AM station, the FCC doesn't figure the antenna gain, no matter how tall or short the antenna is. So 50,000 watts is 50,000 watts, minus some small percentage loss in the transmission line. Unlikely to be more than 5 to 10% loss.
So figure out how many hours it's on the air in a month and multiply by the cost per kilowatt hour. I don't pay the power bill here, but let's assume it's about $0.10 per kW/hour.
For 24/7 operation figure total hours in a 30 day month as:
24x30=720.
50 kW station Power use = 100 kw x 720 hours = 72000 kilowatt hours.
72000 kW/hours x $0.10 kilowatt hour = $7200 a month to keep the transmitter fed.
If the price of electricity is different at your house, remember, it's just an estimate and just go with the exercise. Plug in your own power cost and get your own answer. Big power users are able to negotiate their own rate with the power companies.
---
An FM station is different from AM because the antenna gain determines the effective radiated power. More bays of antenna = higher power.
With a high power station, it's a fair assumption that they're getting a 3x or 4x gain from their antenna. So assuming a 100 kW FM, it's fair to assume 30 to 40 kW coming from the transmitter, depending on coax loss and antenna gain.
Let's say 35 kW divided by 50% efficiency gives 70 kW coming out of the wall.
720 hours x 70 kW = 50400 kW hours in a 30 day month.
50400 kw hours x $0.10 =$5040 a month for electrons.
Older transmitters are less efficient, so they tend to get replaced fairly quickly in high power stations because it's cheaper than paying the power bill on the wasted energy every month, year after year.
Given a choice, it's cheaper to leave the porch light on. And considering what some of these stations are used for, a working porch light is probably a better investment.
-Dick
> Given a choice, it's cheaper to leave the porch light on.
> And considering what some of these stations are used for, a
> working porch light is probably a better investment.
>
> -Dick
THANK YOU VERY MUCH, Dick .... You answered some basic questions I had, which were (a) Is FM cheaper than AM? (from your example above it seems a well-maintained facility would be somewhat less expensive than the AM example); and (b) Seems like a ballpark to run power for a transmitter either way is maybe $5K to $15K range per month (ignoring the rate discounts you mention); (c) Why do vendors keep showing up at NAB hawking high-priced equipment (because it seems now that efficiency xmitters pay for themselves, and expensive automation systems eliminate human resources costs).
So hard costs of just running the transmitter would equal several bodies who are jamming something INTO the transmitter...and it also gives a handle on how many spot-dollars need to be gathered JUST to stick ANY programming out there. So now I'm confused as to how companies like Salem can have so many stations they pay to operate, marginal content on there, marginal spot rates ... yet keep the whole operation running year after year??? Some other revenue stream must be helping to subsidize that -- and I would have to assume the payback is through more intangible measurements.
> And considering what some of these stations are used for, a
> working porch light is probably a better investment.
>
> -Dick
THANK YOU VERY MUCH, Dick .... You answered some basic questions I had, which were (a) Is FM cheaper than AM? (from your example above it seems a well-maintained facility would be somewhat less expensive than the AM example); and (b) Seems like a ballpark to run power for a transmitter either way is maybe $5K to $15K range per month (ignoring the rate discounts you mention); (c) Why do vendors keep showing up at NAB hawking high-priced equipment (because it seems now that efficiency xmitters pay for themselves, and expensive automation systems eliminate human resources costs).
So hard costs of just running the transmitter would equal several bodies who are jamming something INTO the transmitter...and it also gives a handle on how many spot-dollars need to be gathered JUST to stick ANY programming out there. So now I'm confused as to how companies like Salem can have so many stations they pay to operate, marginal content on there, marginal spot rates ... yet keep the whole operation running year after year??? Some other revenue stream must be helping to subsidize that -- and I would have to assume the payback is through more intangible measurements.
> > Given a choice, it's cheaper to leave the porch light on.
> > And considering what some of these stations are used for,
> a
> > working porch light is probably a better investment.
> >
> > -Dick
>
>
> THANK YOU VERY MUCH, Dick .... You answered some basic
> questions I had, which were (a) Is FM cheaper than AM?
> (from your example above it seems a well-maintained facility
> would be somewhat less expensive than the AM example); and
> (b) Seems like a ballpark to run power for a transmitter
> either way is maybe $5K to $15K range per month (ignoring
> the rate discounts you mention); (c) Why do vendors keep
> showing up at NAB hawking high-priced equipment (because it
> seems now that efficiency xmitters pay for themselves, and
> expensive automation systems eliminate human resources
> costs).
>
> So hard costs of just running the transmitter would equal
> several bodies who are jamming something INTO the
> transmitter...and it also gives a handle on how many
> spot-dollars need to be gathered JUST to stick ANY
> programming out there. So now I'm confused as to how
> companies like Salem can have so many stations they pay to
> operate, marginal content on there, marginal spot rates ...
> yet keep the whole operation running year after year???
> Some other revenue stream must be helping to subsidize that
> -- and I would have to assume the payback is through more
> intangible measurements.
>
Dude, I think you would be AMAZED at what Salem's income really is.
> > And considering what some of these stations are used for,
> a
> > working porch light is probably a better investment.
> >
> > -Dick
>
>
> THANK YOU VERY MUCH, Dick .... You answered some basic
> questions I had, which were (a) Is FM cheaper than AM?
> (from your example above it seems a well-maintained facility
> would be somewhat less expensive than the AM example); and
> (b) Seems like a ballpark to run power for a transmitter
> either way is maybe $5K to $15K range per month (ignoring
> the rate discounts you mention); (c) Why do vendors keep
> showing up at NAB hawking high-priced equipment (because it
> seems now that efficiency xmitters pay for themselves, and
> expensive automation systems eliminate human resources
> costs).
>
> So hard costs of just running the transmitter would equal
> several bodies who are jamming something INTO the
> transmitter...and it also gives a handle on how many
> spot-dollars need to be gathered JUST to stick ANY
> programming out there. So now I'm confused as to how
> companies like Salem can have so many stations they pay to
> operate, marginal content on there, marginal spot rates ...
> yet keep the whole operation running year after year???
> Some other revenue stream must be helping to subsidize that
> -- and I would have to assume the payback is through more
> intangible measurements.
>
Dude, I think you would be AMAZED at what Salem's income really is.
K
Khafre
Guest
Having no choice and owning a station, it sounds like it would be best to have a medium powered AM on in 600-800 KHz (superior range for the channel at any power), and or a medium powered FM in any city.
> Given a choice, it's cheaper to leave the porch light on.
> And considering what some of these stations are used for, a
> working porch light is probably a better investment.
>
>
> -Dick
>
> Given a choice, it's cheaper to leave the porch light on.
> And considering what some of these stations are used for, a
> working porch light is probably a better investment.
>
>
> -Dick
>
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