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Media Bureau Cancels Notice of Apparent Liability for Forfeiture issued to Radio Hatteras, Inc

The Adam Hall Group has unveiled its Palmer brand’s new active studio monitor, the Studimon 5.

The Studimon 5 comes in compact bass reflex housing with wooden sidewalls. It has a 5-inch ferrite custom subwoofer, 0.75-inch neodymium silk diaphragm tweeter, and a frequency response of 70 Hz to 20 kHz.

[Check Out More Products at Radio World’s Products Section]

The two-way monitor, with an output power of two 30 W (RMS) amplifiers is intended for home studios as well as professional audio environments.

The back of the Studimon 5 features a 1/4-inch jack and XLR inputs, and a volume controller for tuning stereo balance.

The Studiomon 5 is priced at $269 each.

Info: www.palmer-germany.com/en/

The post Palmer Releases Studiomon 5 Studio Monitor appeared first on Radio World.

Steve Newberry

Steve Newberry will step down from his role as executive vice president for industry affairs and strategic planning at the National Association of Broadcasters this spring. 

Newberry is leaving the broadcast advocacy association to serve as CEO for ad sync technology company Quu Inc. He will remain with NAB through March 31.

“While we hate to see him leave, we’re delighted Steve will be with us through the completion of our move to a new headquarters this spring. We’re also pleased that Steve will be fulfilling his entrepreneurial passion with QUU, an auto dashboard initiative that uses technology to improve the listener experience and drive higher radio station revenue,” NAB President/CEO Gordon Smith said in the announcement. 

Smith added, “I will miss Steve’s daily presence at NAB and will always be grateful for his friendship and many contributions to the success of broadcasting.”

Newberry became a station owner at 21 years old and went on to serve as a NAB Radio Board chair and NAB Joint Board chair. He also served as president of the Kentucky Broadcasters Association and chairman of the Authority for Kentucky Educational Television, as well as a national board member for America’s Public Television Station. 

Quu was founded in 2007 by Joe Harb, who also serves as chief innovation officer. According to the announcement, Quu’s “technology enables radio stations to take full control of the RDS/HD in-car stereo display with the ability to monetize through ad augmentation.”

The company is based in Mercer Island, Wash., but Newberry will remain in D.C. He will also continue to serve as chairman for Commonwealth Broadcasting of Glasgow, Ky.

The post NAB EVP Newberry Plans Exit appeared first on Radio World.

The author is CEO, Digital Radio UK.

LONDON — It looks like 2020 is going to be another milestone year for digital radio in the United Kingdom with digital listening expected to increase to over 60% of all radio listening.

Ford Ennals

The growth in digital listening is being driven by the continued expansion of national commercial digital stations, with nine new national digital stations added in the last year, the fitting of DAB in just about all new cars, and the rise in online listening in homes driven by the strong take-up of smart speakers.

EXPANSION

This is also the year when the U.K. government will play a key role working with the radio industry on a Radio and Audio Review supporting the long-term health of the radio sector, announced by the Digital Minister in May 2019, and by determining the future of the U.K.’s national and local commercial radio station analog licenses.

The consultation document on analog license renewal published by the Department for Digital, Culture, Media and Sport on Dec. 23 confirms government support for digital radio and the intent to sustain progress. The U.K. government has been a long-term supporter of digital radio dating back to the 2010 Digital Radio Action Plan and the passage of the Digital Economy Act.

Photo Courtesy of Teracom SE

This support was reiterated in the consultation document that highlights the department’s digital radio strategy and the potential options for analog station license renewals. The consultation has been prompted by the fact that the national and local commercial station analog licenses start to expire in 2022 and as government recognize that there “is little prospect of a radio switchover before the mid-2020s,” they will have to take action to support the continued stability of the commercial radio sector and the continued growth of digital radio.

The document details the progress made post the Digital Radio Action Plan and the set of government initiatives announced at the end of 2013. It highlights the development of a “competitive DAB network used by nearly 66% of adults; the expansion of both national and local DAB coverage; the launch of new services; the fitment of DAB in new cars,” and the growth of digital listening to nearly 57%.

DCMS emphasizes that while a “decisive shift to digital has started, progress is not uniform” and that analog still has an important role to play, accounting for more than 40% of radio listening, and with local stations still having the majority of listening on analog.

NEXT STEPS

Consequently government needs to consider what steps to take with regards to commercial analog station renewals and has proposed three options, which range from letting analog licenses expire to renewing licenses for 5–8 years. It is reluctant to support a “do nothing” approach, as it wants to maintain the stability of commercial radio and the incentives to support the further development of DAB in the U.K.

The consultation also looks forward to the launch of new ultra-local small-scale multiplexes, which media regulator Ofcom is planning to license in the U.K. later in 2020, and the potential prospect of some local commercial stations having the option to satisfy their DAB carriage license obligations through distribution on the new small-scale DAB multiplexes.

The outcome of the DCMS consultation on analog license renewal, which closes on Feb. 21 (responses to analoguelicence@culture.gov.uk) and the DCMS/Industry Radio and Audio Review are unknown at this point and will be shaped by industry and stakeholder response and feedback.

What is clear is that in 2020 the government is working to support the development of the radio sector and the long-term transition to a digital future for U.K. radio.

The post U.K. Government Restates Support for Digital Radio appeared first on Radio World.

Fig. 1: A 1960s phasor with commonpoint controls added.

Our previous article “Find Your Modulation Sweet Spot,” published in the Oct. 9, 2019, issue of Radio World, is still available online, just Google that headline. It sets the stage for a two-part discussion of AM directionals, beginning here.

As you surely know, fewer engineers are qualified to work on AM directional antenna systems today. Younger ones who maintain these marvels of engineering may not be as well versed as their predecessors.

If you are a member of the new breed, my advice is to be careful not to do the wrong thing when tackling a problem. Don’t make adjustments without analyzing a situation first.   

PROBLEMS

If you find antenna monitor phase and ratio readings are off more than a few degrees or a tower radio is off more than 5%, don’t start adjusting the phasor to compensate. Keep your cool. Write down all the phasor dial readings for future reference. Do a complete physical inspection, including eyeballing the inside of the phasor cabinet and antenna coupling networks. Look for broken connections everywhere and on lines running to the towers. Go out and measure the monitor points. You may find they are in spec and that your real problem is in the antenna monitor or other part of the sample system. 

Jumping to the wrong conclusion could result in chasing your tail to fix an antenna problem that you don’t have. 

TOO MANY KNOBS

An engineer maintaining a two-tower AM directional antenna station called me for advice recently. He is one of the engineers I am mentoring. 

A station’s commonpoint impedance (RF input to the phasor) was difficult to adjust because the variable commonpoint resistance coil was at one end of its travel. All had been well a few months before. Today’s solid-state transmitters want to see exactly 50 ohms with near zero reactance, as you know, so setting the commonpoint impedance correctly is very important. 

As it turns out, the phasor has phase and ratio controls for both towers. In this case, it was too many knobs.   

The ratio controls could be tweaked on either tower to keep the station in specs. This led to the commonpoint problem when he used both to get the correct antenna monitor phase and ratio numbers. The phasor’s input matching network was looking at a phasor “buss” impedance that was not according to the original plan. 

PHASOR DESIGNS

It’s important to understand how phasing systems are designed and built. A transmitter feeds RF power into a phasor cabinet, where there is a  three-coil impedance matching network. It feeds RF energy to a point called the “buss.” This is where power is rationed out to phase and ratio controls for each tower. The buss is rarely 50 ohms, and it is normal to have the impedance change a bit as an engineer tweaks phase and ratio controls to maintain FCC licensed specifications. The input matching network normally has enough operating range to compensate for these adjustments.    

Not all phasors have a front panel adjusted ratio control for the reference tower. That is for good reason. The reference tower normally gets more power than the other tower or towers. There is normally no need to adjust power to the reference tower after the station is initially tuned and licensed. It is the standard/reference that the other towers or towers are compared/referenced to. 

I told the engineer to carefully adjust the reference tower ratio control to full, or close to full on, while keeping the other tower ratio and phase correct. Then, don’t touch the reference tower radio control again. Mark it as “don’t adjust.” That solved his commonpoint problem. He then had good resistance and reactance control because the buss impedance was as expected in the design. Also, running both ratio controls down to their lower ends could cause some phasor components to run hot. 

DESIGN EVOLUTION Fig. 2: Commonpoint controls were added to this phasor.

Phasor systems did not typically have front-panel adjustable input matching networks years ago when tube transmitters were the norm. That changed when solid-state transmitters came along. Now input resistance and reactance controls are required to keep reflected power low and transmitters happy. 

Fig. 1 shows a 1967 vintage Gates three-tower phasor. It did not originally have an input matching network that is adjustable from the front panel. I added those knobs to help control the input impedance and transmitter power when switching from 5 kW non-directional day to 5.4 kW directional night. One control is for resistance, which is tweaked to keep the input at the licensed 50 ohms. The other is commonpoint reactance. Fig. 2 is the dial I normally adjusted to get the transmitter to make just the right amount of power at night. 

In this case, the day non-directional antenna coupling unit has clips on fixed coils for adjustments. Once set, it was good to go. The maintenance procedure is to get the transmitter running at the correct power level in the day mode, then switch to night and adjust the night commonpoint reactance control to get the correct directional antenna power. It is that simple.

You’ll also note there are FCC-required operating parameters listed on the front of the phasor and transmitter. They are right where needed most.     

Yes, that is a Gates BC-5H Transmitter next to the phasor. It has been in full service, running 5,000 watts day and 5,400 watts night since 1973. That’s 46 years! This transmitter is on its third high-voltage transformer, third set of AC contactors, fifth set of high-voltage rectifiers and the solid-state audio driver section has been rebuilt four times on site without sending it to a factory for repair. The transmitter lives on, but will likely be replaced by my engineering successor when the next serious failure occurs. Fortunately there is a Collins 5 kW AM to back it up. Both are excellent tube designs. 

ANTENNA EFFICIENCY

Can you assume that all is well when the monitor points are below FCC limits? Not necessarily. You might have serious impedance mismatches and power divider mismatches, as described above. RF power could be turning to heat. 

You can get a readout on antenna efficiency by going to the original proof of performance documentation and making six or more measurements in the major lobe or lobes. The readings should agree, although there are seasonal variations. RF travels better over frozen ground so winter signals are inherently a bit higher. It is not a big deal in the first couple miles from the transmitter. Ground loss changes become more apparent the further out you go, especially at  20 miles and beyond.

OOS, OOM

Just because the phasor doesn’t have active components, that doesn’t mean it should be ignored. Rodents get in sometimes and need to be dealt with. Loose hardware is common on RF contactors because they are usually operated twice a day with plenty of vibration in the process. RF contacts wear and should be replaced before they fail completely. 

HEAT

Get one of those infrared temperature meters and go through the phasor, then antenna coupling networks looking for hot spots. Use it around electrical load centers too. You might be amazed to find hot electrical contracts and wires that are about to fail. Best to take care of the problem before it causes an off-air emergency at a bad time.      

PAPERWORK Fig. 3: Keep good records.

Keep good visit-to-visit documentation on an AM directional (Fig. 3). It is a history of how the system has been behaving. You don’t just log that everything is OK. AM directionals have many parameters to keep track of. That includes phase and ratio readings on each non-reference tower, dial settings on the phasor, transmitter PA readings, commonpoint current and monitor point readings. along with date and time. You’ll likely see seasonal changes on monitor point measurements.

Fig. 4 shows a phasor adjustment crank. Note that normal counter dial reading is labeled nearby for easy reference. This is one more way to prevent an “oops” from becoming a major problem.

You should keep accurate phasor schematic documentation on hand at the transmitter site. Designs and “as built” are often a bit different. I recommend you pencil any changes on the original schematic. Also, mark down the number of active turns on each coil in the system. As you know, silver-plated straps with clips are used to short out unused turns on fixed coils. They are set once and then normally not touched again. It won’t take but an hour to do the documentation and will save a lot of headaches in the future. Lightning can blow up a coil or capacitor beyond recognition. Having parts values and settings on a schematic diagram can be a life saver.

Fig. 4: Mark your normal dial settings for easy reference.

A nearby station was visited by vandals one night. Somehow they got into the antenna coupling networks and pulled clips off the fixed coils. No other damage, just mischief. It took the engineer only an hour to put the coil clips back in the right spots, plus do a little tweaking, to get the antenna system working properly again. Imagine trying to start from scratch to get the system operational without that knowledge. Ouch! 

By the way, spare parts and equipment manuals belong where the equipment is, not back at the studio. That includes books and programming information for remote control systems. 

The best is yet to come. Stay tuned for an upcoming issue, where you’ll find a real-life story about a 197-foot tower that came down in the parking lot at a directional AM station.

Comment on this or any article. Write to radioworld@futurenet.com.

Mark Persons, WØMH, built four new AM directional systems, from the ground up, using only schematic diagrams and parts. He is an SBE Certified Professional Broadcast Engineer and was named SBE Engineer of the Year in 2018. Mark is now retired after more than 40 years in business. His website is www.mwpersons.com.

The post Best Practices for AM Directional Systems appeared first on Radio World.

Breadboarding the circuit.

Ever get a song stuck in your head that you don’t necessarily mind being there? My latest benign earworm happens to be “Frankenstein” by the Edgar Winter Group; probably due to what’s been going on at my workbench lately. 

In our first installment, we walked through the audio circuit of “THAT Thing,” a mic preamp design built around THAT Corp. ICs.

POWER SUPPLY Gathering the parts.

In this “episode,” we start with the power supply. It’s a fairly common, straightforward design. The audio chips require bipolar DC power at a maximum of ±20 Volts. A +48VDC rail is needed for phantom power.

We start with an AC transformer that takes 120VAC from the wall and steps it down to 48VAC with a center tap, 24VAC for each side of the bipolar supply. 

Following rectification through BR1, we get two pulsing DC rails. From there, the pulsing DC goes through a set of electrolytic capacitors, C101-C104, to level out the bumps. Then, the actual regulation occurs with U101 and U102, positive and negative 18VDC regulators. Next, each rail gets another dose of filtering through C105-108 to take out any remaining ripples. 

Etched PCBs

C109 and C110, a pair of polyester capacitors, remove any RFI sneaking in through the power rails. D101 and D102 are there to ensure that the positive and negative rails stay that way. Any negative voltage appearing on the positive rail shunts to ground and vice versa. D103 and D104 protect the regulator ICs by ensuring that the output voltage never exceeds the input.

Finally, LEDs 101 and 102 in combination with their respective current limiting resistors, R104 and R105, indicate the presence of actual voltage on each rail to show that the supply is functioning correctly, a good aid in troubleshooting.

Power supply board

For the phantom power section, the entire 48VAC secondary winding of the transformer is used. After filtering and rectification through C111, C112 and BR2, we’re left with about 70VDC. Additional RF and ripple filtering is accomplished by C113 and C114. Regulation is performed by U103, a TL783 adjustable regulator. R101 and R102 determine the output voltage of the IC, and C116 filters out any output noise. 

Additional stability is provided by C115 and R103. 48VDC phantom power must be ruler flat to prevent any noise being introduced at the mic inputs, where the audio circuit is the most sensitive.

BREADBOARDING Curt etches the PCBs.

At this stage, I began breadboarding the circuit to test a few component choices and layout. Here’s where I found out firsthand the importance of filter caps C7-C10. 

Without those critical components in place, the circuit made a nice white noise generator, especially in the unprotected environment of the workbench! 

I also found that I had pretty wide latitude in my choice of C6, the high-pass filter capacitor. I settled on 1 µF because it offered, to my ears, the best balance between getting rid of rumble and being able to go high enough for extreme roll-off, if necessary. Anything — even as high as 47 µF — will work, as long as the gain is high enough.

Once I was through experimenting with circuit topology, I imported my schematic into ExpressPCB and worked on the circuit boards. In order to maximize flexibility, and to be able to possibly repurpose the design, I opted to keep the power supply and each audio channel on separate boards. 

Once I had all the correct parts together and etched the boards, I was able to bench test the finished power supply and one completed channel. Surprisingly, the only issue was that I had wired the phantom power LED on the audio board backwards! An easy fix for a change! It was only mounted directly to the PCB temporarily, anyway. Its intended location is the front panel with the other controls.

Testing the preamp assembly with a microphone. Testing the power supply assembly.

Speaking of which, while thinking about how I was going to house this creation, I came across an abandoned 1RU chassis that was just right. I stripped out the guts and replaced the front panel with a 1RU blank that could be punched and drilled specifically for this project. I put the input XLR jacks on the front panel, taking a cue from a previously built kit in my studio. The output jacks are 1/4-inch TRS for easy interface with my 1/4-inch TRS patch bay.

CONSIDERING IMPROVEMENTS

Never one to leave anything alone if I think there’s room for “improvement,” I started thinking of potential modifications to this design. Looking at some of the design notes from THAT Corp., and discussing this project with other DIYers, I settled on two relatively simple things to try. 

The faceplate after drilling.

First up, an alternative to the gain pot is a rotary switch with several positions, each position providing a different fixed gain. The advantage here is better component matching between channels, which translates to more accurately repeatable settings between channels. High quality reverse log pots of this resistance value can be hard to find at reasonable prices. Besides, more precise adjustments can be made further down the signal chain, or in the mixing/editing stage.

The other modification I looked into was replacing the initial input stage with a transformer. While I suggested in the first installment that transformers are expensive compared to capacitive coupling stages, this is a case where the custom build aspect and its benefits perhaps outweigh the added cost. 

True, the concept behind chips like the THAT1512 is to obviate the need for a transformer, which is perfectly valid, if one is building numerous preamp stages or a 16-channel mixer. On the other hand, a transformer provides way better common mode rejection, kills RFI, eliminates hum loops and also mitigates against any phantom power faults possibly cooking the ICs. Placing a transformer on the input eliminates several other components: C3, C4, R3, R4, R5, R6, R7 and D1-D4 all go away.

VERSION 2 The version 2 preamp assembly with transformer installed.

In version 2 of THAT Thing, I went ahead with the input transformer and the rotary gain switch with six positions.

The transformer I used is OEP’s A262-A3E, which I borrowed from a tube mic preamp in my rack. It’s much less expensive than a Jensen or a Lundahl and, hey, it’s what I had! Good thing it was cheap because while desoldering it from the other preamp’s PCB, I somehow managed to fry the secondary winding. Oops! It had a good run. R.I.P.

Once the replacement arrived from www.Newark.com, I set about testing it within the circuit. It’s important to consider that the input transformer adds some gain of its own to the circuit, about 16 dB. It took some experimentation to settle on the gain levels for the rotary switch, but I ended up with a range between 19 dB and 50 dB.

Looking inside.

So, how did it sound? Super clean, and the transformer definitely adds some character. Either version works very well with just about every mic I tested, from a Shure SM58 to an MXL ribbo n mic, to an Audio Technica AT4040. Two to four channels of “THAT Thing” would nicely compliment a Mackie 1202 or 1402 mixer’s line inputs, should you find yourself running short of mic inputs. Or connect it straight to a PC’s sound card input.

TRY IT YOURSELF Inside closeup

For anyone willing to take a stab at this, I’m happy to provide the schematics, PCB layouts and other notes. 

“THAT” Thing in the rack.

You’ll need to download ExpressPCBPlus (free at www.expresspcb.com) to read and print them out. All parts except the input transformers are available from Mouser Electronics or most other suppliers. The transformers, as mentioned earlier, can be ordered from Newark.com.

Happy soldering!

Curt Yengst, CSRE, is a contributor to Radio World and an assistant engineer with WAWZ(FM) in Zarephath, N.J.

Email us with your own DIY ideas at radioworld@futurenet.com.

The post Let’s Finish Our Solid-State Mic Preamp Project  appeared first on Radio World.

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Announcing comment and reply comment dates for Cable Service Change Notifications NPRM, MB Docket Nos. 19-347, 17-105, 10-71

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The author is membership program director of the National Federation of Community Broadcasters. NFCB commentaries are featured regularly at www.radioworld.com.

Amid tensions with Iran simmering, the ongoing impeachment impasse in the national consciousness, and the election season looming, radio listeners are turning to stations as never before. They want coverage from their trusted source: noncommercial radio.

New demands may create stress at stations, but this interest offers incredible opportunities as well.

How significant is all the attention? Radio Research Consortium, the nation’s purveyor of audience data for noncommercial radio, issued a study this week into impeachment broadcast listenership. RRC’s numbers show a spike in audience for stations airing impeachment hearings and analysis.

[Read: Community Broadcaster: The Last 2019 To-Dos]

“[F]or 50 full-time noncommercial news stations across 44 PPM metros, the six days containing special coverage saw more total AQH listening than any of the 14 days absent of special coverage,” the team notes. “Not only did the six days with special coverage outperform the 14 days without special coverage on a day-by-day basis, listening was higher for this set of stations on an hour-by-hour basis, as well.”

Off to the side, many stations are skittish about interrupting their regularly scheduled programs, especially their most popular ones, for what can seem like dry Robert’s Rules of Order procedurals or blatant grandstanding by lawmakers. Nothing could be further from the truth, it seems. Audiences love their regular programming but in times of urgency and uncertainty, the numbers indicate these listeners crave more the context and clarity your station can provide.

“All well and good,” you may say, “but how can a lightly staffed or an all-volunteer station compete with the giants in doing this breaking coverage?”

My encouragement to everyone in community radio in these moments is to stop thinking about competition and focus on, realistically, what you can provide to your community. That’s a hard pill to swallow for many of us, because we have been raised around the idea of outdoing others, beating others to whatever we’re racing toward, and with winning. Noncommercial radio should always assert itself, of course, but community service is really our goal. Unlike for-profit media, community radio does not need to chase whatever winds the markets are blowing in. In fact, no matter what you do, collectively or individually, you will discover someone is always bigger, better, more resourced and quicker. So why not instead place your energies in how your station can serve its listeners and signal area best?

Perhaps your station can collect voices in your community with area reactions to the issues of the day. Candidate forums or one-on-one visits with candidates in a given race might give your audience a chance to cast an informed vote, or even to find common ground with perceived opponents. How are your Congressional representatives responding to the matters facing the nation now? These are all avenues your station can take to deliver coverage that do not demand tons of resources.

Some nonprofit media organizations are seeing tremendous returns with partnerships that pool resources and deliver coverage jointly to everyone. Especially for thinly resourced stations, collaboration is a fantastic way of delivering what audiences want without undercutting the rest of your operations.

2020 is shaping up to be a tremendous year for radio. The presidential election, races for House and Senate seats marked by several prominent retirements, and natural disasters mean community radio still has a big role to play. We can make a real impact, but such will require fresh thinking and commitment.

 

The post Community Broadcaster: Community Radio Relevant as Ever appeared first on Radio World.

Logitek has added Ravenna-compatibility to its JetStream Plus and Jet67 AoIP audio routing engines, according to a press release.

In the announcement, Logitek President Tag Borland says the company “has always looked for better ways to manage audio” and described Ravenna’s solutions as “world-class” in terms of quality and performance standards.

[Check Out More Products at Radio World’s Products Section]

JetStream Plus and Jet67 AoIP can already use Dante, AES67, LiveWire and, of course, Logitek’s own JetNet solutions to connect to other broadcast equipment, the company says. The company also touts the devices’ small footprint and high-density routing technologies.

Ravenna is an open networking standard developed by ALC NetworX for real-time distribution of audio and other media in IP-based networks.

 

The post Logitek Beefs Up AoIP Engines With Ravenna appeared first on Radio World.

Jeff Welton

A recent RW ebook asked, “Have You Bought Your Last Tube?” It included a Q&A with Nautel’s Jeff Welton, a recipient of the Association of Public Radio Engineers Engineering Achievement Award and the Society of Broadcast Engineers James C. Wulliman Educator of the Year Award.

These are excerpts; read the free ebook at https://www.radioworld.com/ebooks.

 

RW: Do you find that many users are attached to their tube systems, both because of familiarity as well as cost factors? 

Welton: Very, very few — and it’s a rapidly decreasing number. 

There are some who are quite apprehensive about the cost of acquiring a new box, as it’s a big number. However, in a lot of cases, especially if you amortize it over the period of a lease or bank loan, the overall savings can actually outweigh the acquisition cost. 

I’ve had situations where a station leased a solid-state transmitter to replace a tube rig, and the savings in operating costs actually made the lease payments. Obviously that’s not always the case, but it’s something to consider, especially if the current rig is eating you out of house and home, electrically speaking!

RW: What considerations then should an engineer or manager use to assess the ROI on a new purchase?

Welton: It’s not enough to just look at purchase price. Look at the power bill now — and get the manufacturer to use that to provide you with a ballpark of what it would be with the new rig. Remember that this will just be an estimate — demand costs and overage charges can be hard to calculate without an intimate knowledge of the specific utility.

Also factor in the amount of time your engineer spends doing repairs — or if you have a contract engineer, what it’s costing in emergency calls. Don’t expect engineering costs to go away; if you’re not doing maintenance, it’s the same as owning a car and never changing the oil … it’s not if you’ll have a failure, but when. However, you can factor in the cost of emergency repairs and tube costs; those alone can make up several thousand dollars a year. 

Also look at air handling; if you’re air conditioning, you’ll need less of it as a rule. Forced air is less a concern. Obviously you should look at extra costs that may come with a new rig, also; liquid-cooled systems, for example, tend to have much higher installation costs associated with the plumbing. That’s a one-time thing, but it does need to be considered. 

If you are using air cooling, you may decide to switch from forced air to air conditioned; that’s also an impact on ROI. 

Remember that manufacturers will typically be leaning toward the solutions they provide, so get a couple of different opinions, even if you already think you know what you are leaning toward.

RW: What’s the expected life of a tube these days?

Welton: It varies, a lot. Some of the more popular systems out there are lucky to get 11 months out of a tube anymore, even with careful filament voltage management. Others are still good for a couple of years. I think the days of seeing 50,000 or more hours on a tube are pretty much gone. Part of that is systemic — the folks who know how to manage tuning for maximum tube life are slowly leaving us — and part of it seems to be related to material factors, but that’s not an area I’m proficient in, for obvious reasons.

RW: How much more efficient are solid-state designs?

Welton: For the most part, overall efficiency of a solid-state FM transmitter is around 72% these days — that’s AC to RF. For tube transmitters, efficiency can vary from less than 50% for a grounded grid design, to 65% or higher for some of the other designs, so the efficiency of a solid-state design will be somewhere between 10 and 50% higher than that of the tube system, as a rule.

The post Factors to Weigh in Your Tube Talk appeared first on Radio World.