KNOM & DIGITAL AM RADIO

I have seen press releases indicating that KNOM is apparently preparing to convert to digital audio. If this means AM IBOC, they are probably going to be disappointed. AM HD radio in the lower 48 seems to be DOA. Many stations are dropping it. There are no listeners and (except for some vehicles) no receivers.

While the future of FM HD is yet to be determined, there is no consumer interest in AM HD. There are virtually no affordable AM HD table radios, boomboxes, or portable radios being produced, and broadcasting in AM HD can be compared to a bear screaming in the middle of the woods - there's nobody there to hear him. Meantime the station will be paying franchise fees for the privilege of broadcasting to nobody. They need to do some research.

dwtpa97 said:

I have seen press releases indicating that KNOM is apparently preparing to convert to digital audio. If this means AM IBOC, they are probably going to be disappointed. AM HD radio in the lower 48 seems to be DOA. Many stations are dropping it. There are no listeners and (except for some vehicles) no receivers.

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That is incorrect. KNOM has NO plans for digital (IBOC). What IS planned is the modification of the Nautel ND25 to DCC which means "Dynamic Carrier Control". It's in no way digital. DCC is a modulation method very popular in Europe and rapidly coming into use here. It reduces the carrier during periods of relative low modulation. Those who use it testify to power savings (electrical power) of up to 37%. I expect somewhat less when we do the modification next week because KNOM uses a limiter made years ago by CRL and later made, for a short time, under the name "Amigo". It's pretty nasty limiting, as adjusted for extremely narrow bandwidth. Not something I'd recommend for most stations. The point at KNOM is "reach". Pushing the signal as far out as possible since the intent is not to serve Nome with the AM (there's an FM for that) but to reach tiny villages which otherwise would have no service. Given the choice between high quality audio with no signal in your village versus no signal at all then the choice has proven obvious.

But in case KNOM were ever tempted toward digital it wouldn't happen. First, because as you have correctly stated, no audience. Second, because the folded unipole antenna (6 folds on a 230-foot tower, short because of the airport) would not allow IBOC.

I likely won't be logging in here from Nome but will be back to "civilization" in about a week so if anybody is interested in how this all turns out, make note below and I'll do my best to fill you in.

About that limiter: These are very prone to power supply failures. Potted power supplies that can't be field repaired. When CRL issued a "last call" for them about 8-9 years ago I bought several and have them stashed right on top of the limiter chassis so the next person doing the engineering can't miss finding them when needed. Also there is a second (Amigo) limiter of the same type in the same rack. BOTH limiters are fed audio and the output of both limiters feeds the transmitter. There is, however, a relay arrangement which permits only one of them to be powered at any given time; remoted to the studio. That's because the doggone things never fail unless there's a blizzard and 50+ MPH winds at the transmitter site, 3-miles out of town on a seldom-plowed gravel road. Yes, snowmobiles are helpful but not fun in the conditions described. Been there; done that. Forgot to buy the tee-shirt off the polar bear camped out under the generator building. Had other things on my mind at the time. Like getting the H- out of there!

Thanks for the information, VelvetR. It was very informative, and sounds like you and KNOM have made some very good choices. In a vast area like Alaska, signal "reach" certainly is critical. It's reassuring to know that KNOM has its eyes on the road and has very practical goals in mind. Thanks again for the great information.

Re: KNOM & DIGITAL AM RADIO updated

The installation is mostly complete and it sounds just fine. Remote villages report slightly more background noise from passing vehicles but seem satisfied. Based on only a couple of days of operation I'm estimating 20 -25% reduction in power costs. Others report up to 37% but that varies with program material and density of operation.

Downside: Lost about 12 hours of air time and need to replace some relays that were just plain worn out. Until they arrive some risk of further downtime complicated by my having to leave early next week and there being no other engineers within about 1,000 miles. This could yet get ugly. The saving, though, will pay for it all within a few months given incredible electric bills here.

Considering that you are the only technician in the area, presumably the equipment will be more-or-less self-maintaining after all the tweaking and updating is completed?

dwtpa97 said:

Considering that you are the only technician in the area, presumably the equipment will be more-or-less self-maintaining after all the tweaking and updating is completed?

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I'm almost 1,000 miles away which, in Alaska, is considered "right next door".

The update is technically complete and working OK but there are a couple of little issues unresolved. There are some parts on the way that may overcome those and enough local talent to just plug them in. If it goes beyond that then it's time for a factory technician to do a run-through. After that I'd expect another 5-years with only small annual cleaning and checking screws, nuts and bolts before there are any troubles. It's a Nautel ND25 that's 17 years old with NO transmitter caused downtime in all of those. Power failures and STL link problems don't count. The desire is to replace it with a current generation transmitter in about 2 years but I think that's economically unrealistic and, in fact, foolish since there's to much potential life left in this one. I can be back there in a day if needed but, at my age, wouldn't encourage that. It's looking like the projected power saving will be closer to 30% than to either the originally guessed 37% or my personal projection of 20%. I like being wrong that way....

It's good to know you're "only" 1000 miles away! But I know Alaskans are used to that.

Since KNOM is a non-profit and presumably is partially or in whole dependent on donations, it's nice to hear that these changes will bring about those kinds of savings. Thanks for the info -

First month power cost saving using DCC: 26.7%! And that being a comparison to a month of days that were a couple of hours shorter so the saving was more, just not easily calculated. Zero reports of signal loss.

Certainly was worth doing.

Time to sell one's stock in the Nome power company

Impressed, not surprised. Glad to see it.

w9wi said:

Time to sell one's stock in the Nome power company

Impressed, not surprised. Glad to see it.

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Me too! Power costs in Nome are incredibly high. There is no "Nome Power Company" - electricity is sold by a city department, Nome Joint Utilities, which also provides water and sewer service.

Generation is by huge Wartsilla diesels running on fuel oil priced around $5/gallon (perhaps higher now) which is the cheap bulk purchase price. Not all that many years ago we produced our own power (were at 10 kW/day, 5 kW night) back then. We did that because city power at the time was so "dirty" (spikey, low voltage, wandering frequency) that tubes in the original Collins transmitter lasted about 3-4 months. Once we started rolling our own that more than tripled but generator maintenance was an ongoing hassle. Now there's a 66 kVA John Deere out there and it runs only about 40/50 hours a year when the long line to the edge of town is storm damaged.

This has been an interesting discussion. Congratulations on the power savings!

Re: KNOM & DIGITAL AM RADIO updated

VelvetR said:

The installation is mostly complete and it sounds just fine. Remote villages report slightly more background noise from passing vehicles but seem satisfied. Based on only a couple of days of operation I'm estimating 20 -25% reduction in power costs. Others report up to 37% but that varies with program material and density of operation.

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Had you discussed with KICY regarding their success in deploying this technology? Was it a factor in KNOM's decision to move forward with the installation? Did the 37% savings figure come from KICY, or was it a projection from Nautel?

Re: KNOM & DIGITAL AM RADIO updated

sloux said:

Had you discussed with KICY regarding their success in deploying this technology? Was it a factor in KNOM's decision to move forward with the installation? Did the 37% savings figure come from KICY, or was it a projection from Nautel?

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The discussion began when some (state owned) public stations experimented with DCC and saved some bucks. At that time some sort of FCC waiver was required but that was easily granted on an experimental basis. Seems like there were other experiments going on as well and the process became simple. KICY management was attentive to those initial state experiments so the seeds were sown at about the same time. Nautel was brought into the conversation because there was no "kit" for the ND series but they agreed to create one. Sometime during all that KICY went with the Harris package (for which there wasn't much of a wait) with success. I'm not certain whether the order was placed with Nautel before or after KICY went with DCC but there is good communication between the stations so it could easily have been either way.

The (up to) 37% savings estimate came out of various publications and a Nautel "seminar" at an NAB convention. That was the upper end of a projected range and it's clear that a lot depends on any given station's format, how they're handling their audio chain and even the transmitter make/model and perhaps even the individual transmitter. The 26.7% first-full-month saving throughly pleased me given the way KNOM hammers modulation levels.

I'm hoping the current rate of saving is maintained through the wide spread of daytime/nighttime operations. The dollar savings will, of course, be at their lowest when the days are about 4 hours long and power consumption is about 2/3 per month than when the days are 20+ hours long. Even considering that it looks like the payback may take only a couple of years.

Latest DCC saving figure: Down 30.2% from the same period in 2011. Slightly better than the previous month but the city utility varies a day or two in reading meters so there's no real certainty. All savings are very much appreciated and have proved the value in doing the conversion.

Since energy cost is such a big factor, why doesn't KNOM use a higher tower (which would allow them to lower their wattage)? I know from other posts that they can't go any higher at the airport, but surely there are other sites available. If they could cut their wattage in half, wouldn't that result in some savings?

dwtpa97 said:

Since energy cost is such a big factor, why doesn't KNOM use a higher tower (which would allow them to lower their wattage)? I know from other posts that they can't go any higher at the airport, but surely there are other sites available. If they could cut their wattage in half, wouldn't that result in some savings?

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Going back to the beginning:

Land availability. At the time (1970-71) Nome was landlocked by The Bureau of Land Management. It took a lot of congressional delegation involvement to get ANY land.

Power availability. If you check a Google Map, follow the coastal road to the East of Nome. The KNOM transmitter is just before the Nome River Bridge on the right side of the road. Very nice ground conductivity, being up against Nome River right at Norton Sound (salt water). City power extended only about a mile more to the East to the FAA Vortac/outer marker site. The folded unipole design produces very nice groundwave coverage at the expense of sky wave but that's exactly what's needed for the area.

Alternate sites? To the North, mountains (very close). To the East the road moves somewhat inland and is a little higher and more dry. Plus, no power available. To the west no road, no power. Power was installed a little to the Northwest in the last few years but, again, dry higher ground that is even closer to the airport than the present site.

Airport. There are two airports at Nome, both of them on the opposite side of the city from the KNOM (also KICY) transmitter site. The KNOM site is slightly East and South of The KICY site. They're both very close to the flight path to the primary airport's instrument runway. In fact twice KICY lost a tower to aircraft impact.

KNOM dealt with the tower height limitation by using a folded unipole antenna which was a continuing problem until the original 3-fold design was changed to 6-fold a few years ago. Once some initial problems with the modification were fixed it's been much more user friendly.

For about 20 years 10 kW day/5 kW night covered the desired area but as villages got "city" power, added electrical appliances and started buying motor vehicles the noise floor rose and, to be heard, the power was upped to 25 kW days; 14 kW nights just to stay even. The noise floor is still rising (we're talking 200+ mile listening area) and it would be nice to up to 50 kW days. With a new, more efficient transmitter and DCC it might be affordable but it would be a daytime improvement only and consider the length of days up here. Super long in summer and measured in minutes in Winter. So higher nighttime power would solve that, right? Yeah. If The FCC would allow it. But they won't because of a crescent shaped interference zone with a station in Seward. That station is willing to waive because the zone is on an uninhabited glacier. Apparently somebody in D.C. thinks global warming might someday turn that ice into prime subdivision territory and won't budge on anything more than the current 14 kW night power.

Oh yeah, I left out the wind loading of a higher tower. The present 230-foot tower is of 1.75 inch solid rod stock with four levels of guys. Ice often builds to another 3 inches (plus) and that's when the wind kicks up to 70 MPH on a nice day. Taller would....well, you can imagine.

Good questions, though, and nice to sort through memories to address them. Thank You!

Thanks for such a thorough - and very interesting - reply. It shows how solutions that sometimes look simple can in fact be very complicated. It sounds like the problems there are formidable, to say the least. I really enjoyed reading your reply, and can really appreciate the challenges that you broadcast engineers face up there. Thanks again!

dwtpa97 said:

Thanks for such a thorough - and very interesting - reply. It shows how solutions that sometimes look simple can in fact be very complicated. It sounds like the problems there are formidable, to say the least. I really enjoyed reading your reply, and can really appreciate the challenges that you broadcast engineers face up there. Thanks again!

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Pls check your private messages for a link to some photos and more.

KNOM update

Power update:

After several years operation the DCC is running perfectly and power savings confirmed at average 30% reduction.

In addition, tower just inspected, plumbed and trued. LED beacon and obstruction lights are still 100% and light output not notably diminished. Manufacturer had suggested a 7 year life expectanty; these are now over 10 years old and show no sign of weakening. Saving in power costs alone (electric costs keep on rising) are over $80,000 and the $15-20 thousand inspection/lamp changout that used to happen every year now happens at 3-4 year intervals depending upon how severe the winter has been. Paint is going on eight years and holding up very well. No chipping or peeling; colors still very close to samples kept in the dark indoors. Sadly the paint is no longer available - the in-state company that made it with a fish-oil base has been sold and the new owners (out of state) want a huge minimum order to prepare a new batch.

Thanks for the update on KNOM...... its been interesting to read this and follow.

Les, that you? We haven't talked in ages Hope you're well.. you have my email address, I think.. if you wanna say Hi.

walkerbroadcasting at gmail dot com