The Nautel J-1000

I Finished up this installation of a J-1000 in Brookfield, Connecticut for Nossa Radio. That is a Portuguese broadcaster that owns three other stations in the US.

WINE 940 KHz Brookfield, CT

These Nautels are fairly simple affairs; a controller and two RF amps with incumbent power supplies.

Nautel AM-RF and AC mains surge suppressor

Be sure to install the surge suppressor that comes with the transmitter.

The J-1000 is replacing the 43-year-old Harris MW-1A which will function as a backup. Like all new transmitter installations; some things must be done to complete the job.

Harris MW1A

Harmonic measurements out to about the 5th or 6th harmonic need to be documented and compliant with NRSC-2 (AM mask requirements). Although NRSC-2 measurements are required, I don’t see how they can enforce that specification after AM HD radio came into being. Nevertheless, it was measured and passed. With the station carrier power of 680 watts, I used the RF monitor port on the back of the transmitter to make the measurement. Otherwise, I would need to find an empty field somewhere 1 KM away and stand in the middle of it to reduce all of the electrical noise.

Spectrum Mask from a Spectrum Analyzer

The NRSC-2 mask is mainly a function of High-Frequency limitation in the audio processor—certain transmitters, like the aforementioned MW1A did make some contributions to out-of-tolerance measurements.

NRSC-2C AM mask requirements
Harmonics measurements
WINE folded unipole feed point

The antenna is a skirted tower that has many other services colocated on it. At the top is WRKI.

WINE ATU
WINE daytime coverage map

Driving away from this site, I would have to agree with the predicted contour map above, at least on the highway. I think it may be a bit different driving around in town.

The Energy Onix Pulsar transmitter

Engineering Radio: The Oh Dear God Edition.

I have been tasked with fixing one of these glorious contraptions. Aside from the usual Energy Onix quirks; design changes not reflected in the schematic diagram and a company that no longer exists, it seems to fairly simple machine. Unfortunately, it has spent its life in less-than-ideal operating conditions.

Energy Onix Pulsar 1000 in the wild. Excuse the potato quality photo
Energy Onix Pulsar 1000 in the wild. Excuse the potato-quality photo

Upon arrival, it was dead in the water.  Found copious mouse droppings, dirt, and other detritus within and without the transmitter.  Repaired the broken start/stop switches, fixed the RF drive detector, replaced the power supply capacitors, and now at least the unit runs.  The problem now is the power control is unstable.  The unit comes up at full power when it is first switched on, then it drops back to 40 watts, then after it warms up more goes to about 400 watts and the audio sounds distorted.  This all points towards some type of thermal issue with one of the power control op-amps or another composite device.

After studying the not-always-accurate schematic diagrams, the source of the problem seems to be the carrier-level control circuit.  This is based around a Fairchild RC4200AN (U10 on the Audio/PDM driver board) which is an analog multiplier chip.   That chip sets the level of the PDM audio output which is fed into the PDM integrator circuit.  Of course, that chip is no longer manufactured.  I can order one from China on eBay and perhaps that will work out okay.  This all brings to mind the life cycle of solid-state components.  One problem with the new technology; most solid-state components have a short production life, especially things like multiplier chips.  Transmitters are generally expected to last 15-20 years in primary service.  Thus, transmitter manufacturers need to use chips that will not become obsolete (good luck with that), or purchase and maintain a large stock of spare parts.

In the meantime, the chip is on its way from China.  Truth be told, this fellow would be better off with a new transmitter.

Decommissioning transmitters

I was at a transmitter site a few days ago scrapping a Continental 814-R1 transmitter. I started thinking (always a dangerous thing) about how many of these units I have decommissioned over the years.  It turns out, quite a few:

Make/ModelYear new*Year removedStationDisposition
GE BT25A19481994WPTRDonated/scrapped
Gates BC5P19602004WWLODonated
Harris MW5A19822000WLNAScrapped
Gates BC1T19612001WLNADonated
Harris FM20H319722001WYJBScrapped
RCA BT1AR19602001WROWDonated
Harris BC1G19722001WDFLAbandoned
Harris FM20H319712005WHUDScrapped
BE FM30A19882005WHUDCannibalized
Harris FM5G19722008WSPKScrapped
Mc Martin BF3.5K19762011WCTWScrapped
RCA BTF-10ES19782011WRKIScrapped
Gates BC1T19642011WINEScrapped
Continental 315F-R119852013WVMTDonated
Collins 813F19752014WKXZScrapped
RCA BTA1AR19652014WCHNScrapped
Collins 813F219782015WKXZScrapped
Collins 830D-1A19682014WKXZScrapped
Harris FM20H319722013WYJBScrapped
Harris BC5HA19732013WROWScrapped
Harris FM10H19712013WMHT-FMScrapped
Harris FM2.5H319732015WEXTScrapped
Mc Martin BF3.5K19722014WSRKScrapped
CCA FM5000G19802015WTBDScrapped
RCA BTF1E19722016WZOZScrapped
QEI 695T3.519962015WBPMScrapped
QEI 695T519962015WBPMScrapped
Harris HT3.519972015WUPE-FMScrapped
Harris Z5CD19972015WXPKCannibalized
Energy Onix SSA100020002015WDHICannibalized
Harris MW119822016WPUTAbandoned
Mc Martin BF1K19822016WSULScrapped
Mc Martin BF3.5K19822016WSULScrapped
Continental 814R119802016WDBYScrapped
Broadcast Electronics FM35A19862017WEBECannibalized
CCA FM-1000D819732018WDLAScrapped
Collins 828E19782018WSYBScrapped
Gates BC-1H19712018WHUCScrapped
Gates BC-1J19542019WBECScrapped
Gates BC250GY19692019WSBSScrapped
Nautel V-7.520092021WSPKCannibalized
Nautel V-1020072023WHUDCannibalized
Nautel V-1020072023WHUDCannibalized
Harris FM1H319702024WBEC-FMScrapped

*In some cases the “Year New” is a guess based on when the station went on the air.  Before you write me and say “But model XYZ transmitter wasn’t made until 19XX, I did not look at every nameplate and write all the information down as I did this.

Like everything else, there is a process to this.

RCA BTA-10U AM transmitter
RCA BTA-10U AM transmitter

First, if the transmitter was made before 1978, the possibility of PCB capacitors and transformers exists. In the case of the GE BT25A, massive amounts of PCBs needed to be disposed of properly. According to current federal laws, ownership of PCBs and PCB-contaminated items cannot be transferred. Thus, the transformer casings were cleaned and taken to Buffalo to be buried in a PCB-certified landfill.   Otherwise, most other transmitters, such as the RCA BTA-10, may have a few PCB capacitors and perhaps the modulation transformer.  Those items can be disposed of by calling an authorized environmental disposal company like Clean Harbors.

The rest of the transmitter is stripped of any useful parts.  Things like vacuum variable capacitors, rectifier stacks, blower motors (if they are in good condition), HV power supply contactors, unique tuning parts, whole control and metering boards, tube sockets, etc.

The remaining carcass is then disassembled and hauled off.  I have a guy that will do this for relatively little money.  He takes the transmitter back to his warehouse cuts it up, sorts the various metals out, and then takes it to the scrap yard.  This includes cutting all the windings off of transformers and power supply chokes, sorting out the brass and copper tuning parts, etc. Thus, most of the transmitter is recycled. Things like vacuum tubes, circuit boards, and other plastic parts are disposed of as e-waste.

Village seeks repayment from Energy Onix

This saddens me a little bit.  Apparently, the Village of Valatie, NY is seeking repayment of a $500K loan from Transmitter Manufacturer Energy Onix.  Since the passing of Bernie Wise, the company has basically folded.

The village may foreclose on the building if necessary, said Mayor Diane Argyle.

Located at 1306 River St., Energy-Onix was founded in 1987 by broadcast pioneer Bernard Wise, who is known for bringing the “grounded grid” to radio broadcasting. The company designed, manufactured and sold radio transmitters and tubes.

More from the Columbia-Greene Register Star.

Sadly, there goes support for many Energy Onix and CCA transmitters still in the field.  I know of several of those old CCA transmitters that are still cranking away, 40 or more years after they rolled out of the factory in Gloucester, NJ.   I have tried, several times, to call Energy Onix since Bernie passed last year and the phone goes unanswered.  I wonder if we could pick up the field support and service for these units.  I wonder if there are any spare parts left at the old factory building?