Small budget HD

[oldzink]

We're in a small market. We would like to take advantage of the ability to rebroadcast HD2 and HD3 programming on translators. This is our only reason for going HD.
Equipment wise, what is the least expensive way to add HD?

 

[gettinbyagain]

I do not know if there is a very inexpensive way as there are not many manufacturers of HD Transmission equipment, but I would definitely look in to the Nautel equipment. Best bang for your buck and reliable as heck to boot. The Harris products offered now I would stay clear away from.

 

[Tom Wells]

Be aware that addition of HD on FM will make tuning razor sharp/critical/annoying/hopeless for those receiving
your signal in weak to medium areas, if they have analog-knob tuning.

 

[Kmagrill]

If you are not planning to replace your transmitter, the cheap method is to hang a seperate HD antenna and feedline on another leg of the tower at the same height as your main. You then hook that up to a stand alone HD trasnmitter and you're on the air. Since the HD signal is adjacent to yor main, this approach theoretically works. In fact it does work and is pretty common, but there are a lot of problems that you could cause to your main signal. Some of these problems are inherent to HD anyway, but might be made worse by having seperated radiators. Of course, you'll find a lot of users that are prefectly happy this way with no perceived issues. Other approaches include the combined antenna (sort of a more tightly engineered version of the seperate radiator), and various methods of low and high level combining, but these all involve greater expense, sometimes significantly greater.

My only caveat would be to suggest starting out at -20dBc and run it that way for a while before going up to -14 or -10 so that you can assess the effects (if any) of the HD signal to your analog main.

 

[jboyd]

Forget it...JBI

 

[Nostalgia]

Each of these posters approached your question from the technical end, but from the financial end, dont forget the licensing fees from Ibiquity.

 

[WNTIRadio]

If you're only getting it to feed translators, why go any higher than -20dBc? The only reason the HD is existing is to be able to have the translators. No need to splatter your neighbors and raise your own noise floor more than the minimum necessary.

Before we go any further, like most questions asked here, key details are left out! What is your ERP and TPO right now?

 

[xmusicmatt]

We're in a small market. We would like to take advantage of the ability to rebroadcast HD2 and HD3 programming on translators. This is our only reason for going HD.
Equipment wise, what is the least expensive way to add HD?

Are you near any other stations that have HD already? It may be 'cheaper' to lease someone's HD Channels to feed your translators instead of running your own HD. [When you factor in license fees etc with Ibiquity]

 

[nd2023]

It's going to cost at least $10,000. Do you already own or control the programming of the translators? Might be cheaper to either lease another HD station's subchannels or buy a failing AM station.

 

[Chuck]

It's going to cost at least $10,000. Do you already own or control the programming of the translators? Might be cheaper to either lease another HD station's subchannels or buy a failing AM station.

I think it will cost a lot more than that. The Ibuquity license fee is $25,000 plus a part of revenues on a yearly basis. You may be able to get a better deal, but that's retail. For my 3000 watt FM, the quote for transmitter and HD equipment came to almost $60,000 from Nautel. It is questionable that my current antenna would be happy, so that could cost another $40K or so by the time you run new feed line and install it. If you choose to hang a second antenna on the tower and use a separate transmitter for the HD, it would be considerably cheaper up front, but unless you own the tower, your landlord will want more rent. Let's not forget what it cost to put the antenna up. For me, it was cheaper to just buy an under-performing AM station and couple it with a pair of translators. Of course, that may not be an option for you, but in any case, I suspect it will be an expensive adventure.

 

[Kmagrill]

Doing it on the cheap, I'd anticipate between $40k and $70k, not including the licensing fees. Hanging a small antenna and feedline should run you under $10k, unless you're a high powered station on a tall tower. Your biggest cost will be the transmitter and processing equipment. Of course, even spending $100k to launch a new FM station is really pretty inexpensive....

Be sure that the translators' coverages are not just limited to 250W at 32m. Unless you live in a very small community, you'll need more coverage than that to be really effective.

 

[oldzink]

If you're only getting it to feed translators, why go any higher than -20dBc? The only reason the HD is existing is to be able to have the translators. No need to splatter your neighbors and raise your own noise floor more than the minimum necessary.

Before we go any further, like most questions asked here, key details are left out! What is your ERP and TPO right now?

We're 24kw erp 7750 tpo
That's what I was thinking..can we go below 020dBc?

 

[Dr. Bob]

If you're only getting it to feed translators, why go any higher than -20dBc? The only reason the HD is existing is to be able to have the translators. No need to splatter your neighbors and raise your own noise floor more than the minimum necessary.

Before we go any further, like most questions asked here, key details are left out! What is your ERP and TPO right now?

We're 24kw erp 7750 tpo
That's what I was thinking..can we go below 020dBc?

We need some more information to help you arrive at the best solution. How old is your present transmitter? Some recent transmitters can be converted to common amplification.

Your three choices are space combining with a separate antenna, high level combining and common amplifications (I'm not considering a backfed combiner as they are rare). Each has pluses and minuses. High level combining wastes 90% of the power of the digital transmitter, 10% of the power of the analog transmitter and (generally) locks you into no HD power level above -20 dBc but it does not require a separate line and antenna. It may be the lowest cost solution since you only would need an HD transmitter capable of 775 watts, a 10 dB injector, and a dump load. You do need the headroom for a 10% output increase in your analog transmitter.

Common amplification eliminates the separate antenna and line issues and allows increased digital levels in the future with the addition of another transmitter. It may be the best solution if keeping programming on the translators is important as you could use combined common amplification transmitters. If one fails, you are still on the air with analog & HD (feeding the translators) at 1/2 power by switching the good transmitter into the antenna.

Space combining with a separate antenna has been covered except that your installation may or may not require additional filtering if the isolation between the two antennas is not sufficient to prevent intermod between the analog and HD transmitters. The digital antenna must be between 70 and 100 percent of the height of the analog antenna. Operation is only allowed between -20 dBc and -10 dBc (see 73.404) so I would say that less than -20 dBc is not allowed but run it past your communications attorney for an expert opinion. Your present antenna/line combination has a power gain of 3.1 so I'm guessing it's something like an eight bay with 1-5/8"? If you could install another eight bay with the same line loss as you have for your analog, you would need a 77.5 watt HD transmitter for -20 dBc. Eight bays and 1-5/8" line is a pretty big windload increase (guessing about your present tower) so a perhaps a four bay antenna with 3 dB more line loss for smaller, cheaper, line and something line a 310 watt HD xmitter might be closer to the lowest cost solution for space combining. Whatever your tower situation, you will need to find out how much extra load your present tower can take.

Put together a cost analysis for each by getting quotes from the various manufacturers then make an informed decision based on your unique situation. Good luck.

Bob

 

[rfry]

>... Eight bays and 1-5/8" line is a pretty big windload increase (guessing about your present tower) so a perhaps a four bay antenna ...

Another consideration with space combining is the match of the az/el radiation patterns of the separate analog and digital antennas, especially from different radiation centers on the tower.

The relative field patterns of the two antennas as installed need to match each other for the expected A/D ratio to be correct at the receiver.

Reception problems are produced when the antenna patterns do not match closely -- especially closer to the transmit site where the elevation patterns of an 8-bay and a 4-bay (for example) are considerably different.

 

[secondchoice]

Do not know the local area, but it might be cheaper to LMA an AM (s) with sufficent daytime coverage for your tranlator(s).

 

[OKCRadioGuy]

"Reception problems are produced when the antenna patterns do not match closely -- especially closer to the transmit site where the elevation patterns of an 8-bay and a 4-bay (for example) are considerably different." Fry speaks very good advice. As you have heard from some posters earlier in this thread, sometimes HD signals CAN mess with the host. I feel im most all cases this is actually due to POOR implementation on FM HD more so than the technology itself. Avoid anything that uses seperate antennas or coax runs. Any "spacial combining" or "it combines in the antenna with the other antenna rotation" stuff is subject to providing a poorer HD radio experience, mainly to your bread-winning host FM signal. I would either generate both HD and analog out of the same transmitter OR combine. Keep in mind that ERI and some others have now come out with filter-combiners to take the HD and analog signal and combine them with MUCH less loss than the 3db combiner method that burns 10 percent of analog and 90 percent of digital. So, do some fresh research with costs of either a bigger transmitter to simply generate it within the transmitter OR go with the new technology of filter-combiners. Either method are a clear and good path towards making your system do what you want it to do without loosing listeners.

 

[nd2023]

There are a few HD2 translator stations that stay on the air even when the parent station's HD is off.

 

[Kmagrill]

There are a few HD2 translator stations that stay on the air even when the parent station's HD is off.

As long as the translator's service contour is entirely within the primary station's sevice contour (a fill-in translator), it's okay for the translator to remain on the air for periods of time when the primary is off the air. I don't know if there's a time limit for FM fill-ins, but in the AM service, the translator generally cannot be on the air for more than 24 hours after the primary has been off. By inference, I would expect this policy to also cover HD carriers.

 

[Dr. Bob]

"Reception problems are produced when the antenna patterns do not match closely -- especially closer to the transmit site where the elevation patterns of an 8-bay and a 4-bay (for example) are considerably different." Fry speaks very good advice. As you have heard from some posters earlier in this thread, sometimes HD signals CAN mess with the host. I feel im most all cases this is actually due to POOR implementation on FM HD more so than the technology itself. Avoid anything that uses seperate antennas or coax runs. Any "spacial combining" or "it combines in the antenna with the other antenna rotation" stuff is subject to providing a poorer HD radio experience, mainly to your bread-winning host FM signal. I would either generate both HD and analog out of the same transmitter OR combine. Keep in mind that ERI and some others have now come out with filter-combiners to take the HD and analog signal and combine them with MUCH less loss than the 3db combiner method that burns 10 percent of analog and 90 percent of digital. So, do some fresh research with costs of either a bigger transmitter to simply generate it within the transmitter OR go with the new technology of filter-combiners. Either method are a clear and good path towards making your system do what you want it to do without loosing listeners.

And while I agree that you need to be careful, I know of one station with its analog on a panel antenna. They leg mounted a seven bay conventional antenna on a 12' face tower to implement HD and, even at -14 dBc, don't seem to have self interference issues. They must be lucky or living right (or carefully engineering).

As for the new technology combiners, get ready to pull out your wallet. I priced a combiner for a 100 kW ERP station (25 kW TPO) and it was close to $60k. It also has the problem of limiting the implementation of the extended HD carriers. Real world filter slopes aren't infinite. Would mostly appeal to stations who are high level combined (HD transmitter already) at -20 dBc but want to go to -14 dBc at the lowest additional cost. That's why I suggested the 10 dB combiner; it may be cheaper to implement if you are never going above -20 dBc.

Bob

 

[nd2023]

There are a few HD2 translator stations that stay on the air even when the parent station's HD is off.

As long as the translator's service contour is entirely within the primary station's sevice contour (a fill-in translator), it's okay for the translator to remain on the air for periods of time when the primary is off the air. I don't know if there's a time limit for FM fill-ins, but in the AM service, the translator generally cannot be on the air for more than 24 hours after the primary has been off. By inference, I would expect this policy to also cover HD carriers.

Isn't that only for daytime AM stations that have to go off at night? I thought FM and HD translators have to go off the air when the parent station goes off, or when the parent HD transmitter goes off. There was an HD translator that stayed on for months while the parent's HD transmitter was off.

If this were the case, a station like KYLI 96.7 which has its main 100000 watt transmitter in the desert and its booster in Las Vegas. They would love to keep that 100000 watt transmitter off the air, because they have to bring diesel fuel to its transmitter site to power the generator since there's no commercial power. The 100000 watt main has no listeners, the 340 watt booster is the moneymaker.