Paul Thurst – Page 175 – Engineering Radio

Al Fansome, Call your office

Shortwave Pirate broadcasting has been going on for years. While it is illegal to transmit radio signals without a license, it is not illegal to receive those signals. There is something sort of sneaky like you are hearing something you shouldn’t, part of some underground thing, listening to these guys. I am almost remiss to write something about it because I don’t want anyone to get into trouble.

Anyway, on any given day or night, pirate broadcasters roam the shortwave airwaves. Much of what they do is typical sophomoric humor, such as playing a song where the only lyrics are “god damn you” over and over again. Some of it can be somewhat entertaining. A lot of what they tell as jokes are inside baseball, you have to listen and do a little research to get it, the Al Fansome reference is one. There are no set times or frequencies. It is quite common to hear one guy tuning up and getting ready to go on the air when the current frequency occupant signs off (happens often on 6925 KHz).

Most of these guys build their own transmitters based on designs found on various websites. Power levels vary, but 10 to 50 watts is common. Because of this, a good low-noise receiving antenna is required to pull them out of the noise floor. I have used, with good success, a K9AY terminated loop antenna. We are in a rural area, so it is pretty low noise to begin with. Even so, the coverage with a 50-watt transmitter is remarkable when propagation conditions are good. Sound quality can be quite good for a homemade AM transmitter.

There is a lot of focus on FM pirates these days, that particular setup is likely the easiest to attain for most non-technical types. There are a few AM pirates floating about, those are likely the most difficult to construct and conceal once they are on the air. Both of those broadcast bands have the advantage that there are many kits and or instructions on how to build a pretty good-sounding transmitter. Shortwave seems to be a small cadre of dedicated hobbyists that simply like to fool around on the radio.

In any case, with the FCC stretched thin, it is unlikely that a SW pirate will be busted but not unheard of. One SW pirate station was busted in Florida about a month ago. Even so, that was the first one in almost five years.

For the most part, the activity seems to center between 6850 to 6970 KHz or so. Some others operate around 15055 to 15070 KHz. Here is a brief selection of what one might find on the SW pirate frequencies:

WHYP on 6925 USB “Who Wants To Be A Pirate Radio Operator” at 0156z.
WMPR on 6925 AM “This is WMPR Dancy Party” ID at 0040z.
Captain Morgan Shortwave Radio on 6925AM “Positive Captain Morgan Shortwave ID, email, and twilight zone theme at 2209z.
Radio Ronin Shortwave on 6950AM oriental-sounding interval signal, id at 01:04, Outer Limits intro, “She Blinded Me with Science”, strange version of “SOS”, anti-BP comedy skits, id at 01:19
Indira Calling on 6925AM pop music that I can’t identify, “Rock-It”, Indian music, id at about 00:37, “Beach Party 2000” show, Calcutta mail drop, Beach Boys medley
WEAK Radio on 6925 Shout out to Voice Of Honor. 0048z “Godzilla” 0055z Sabbath.
Channel Z radio on 15067AM 2218z ID and contact info, must be an old show (Blue Ridge Summit maildrop)

And so on. Those call signs are usually spoofs on something. Occasionally, contact information is given out, usually in the form of a mail drop. If so inclined, one might write a letter and receive a QSL card.

There is plenty of information floating around out there about shortwave pirate radio if one cares to look for it. Two of the more popular discussion forums are HF underground and Free Radio Network Grapevines.

Moving the WKZE studio, Part II

The phone company came out and cut over the T-1 circuit on Wednesday, June 2nd. This really kicked things into high gear. By that afternoon we had moved the Prophet systems automation rack up to the new location and started broadcasting from there.

Unfortunately, the backup plan, which was to use the phone company’s DSL circuit to relay audio to the transmitter site, fell through at the very last minute. I think the phone company mistakenly turned off the DSL service to the old studio ahead of schedule. The net result was 2 hours off air in the middle of the day, which we were seriously trying to avoid. Once it was done, however, there was no going back, so we worked extra hard to get back on the air from the new location.

Naturally, while all this is going on, the electrical inspector shows up to do the final electrical inspection for the town building department.

Here is a nice progression on the equipment racks:

After the T-1 circuit was cut over, we began broadcasting from the new location with the equipment rack automation system using the production room as a studio for live elements and voice tracking.

The wiring on the equipment rack is completed.

Completed with phone system and network switch

The equipment rack is completed, the phone system is installed, and the computer network is wired and tested. The yellow light on the top of the rack is a silence sensor.

The old WKZE studio was ripped out on Thursday. The console was removed and rebuilt with a new control surface

New WKZE air studio completed, console is a Radio System millennium 12 — The new WKZE air studio completed, console is a Radio System millennium 12

The production room was completed, speakers hung, etc.

All set and ready to be “customized” by the DJ’s. Monday morning, the staff will roll into their new digs, which is always fun. In comparison to most studio moves and built outs these days, this one was relatively small and simple. The last studio consolidation project involved 5 radio stations and ten studios. That one took place in steps over several months.

Filament Voltage Management

There are still many hollow state (AKA tube type) transmitters floating around out there in the broadcast world. High power, especially high power FM transmitters are often tube types and there are many good attributes to a tube transmitter. They are rugged, efficient and many of the well-designed tube units can last 20-25 years if well maintained.

The downside of a tube transmitter is tube replacement. Ceramic tubes, like a 4CX20,000 or 4CX35,000C cost $6-9K depending on manufacture. A well-maintained tube and last 3-4 years, I have had some lasting 8 years or more. My personal record was for a 4CX35,000C that was a final PA tube in a Harris MW50A transmitter. The tube was made by EEV (English Electrical Valve, now known as E2V) and lasted approximately 84,000 hours, which is 9.58 years. When it finally came out of service it looked like it had been through a fire, the entire metal plate body was dark blue. I took it out because the power was beginning to drop a little and it was making me nervous.

This was not an accident, I did it by maintaining the filament voltage and keeping the tube and transmitter clean. The tube filament supplies the raw material for signal amplification. Basically, the filament boils off electrons, which are then accelerated at various rates and intensities toward the plate by various control grids. The plate then collects the amplified signal and couples it to the rest of the transmitter. When a tube goes “soft,” it has used up its filament.

I had a long conversation about this one day with Fred Riley, from Continental Electronics, likely the best transmitter engineer I have ever known. At the time, the consensus was to lower the tube filament voltage by no more than 10%. On the 4CX35,000C, the specified filament voltage is 10 volts, therefore, making it 9 volts was the standard procedure. What Fred recommended was to find the performance “knee,” in other words, where the power began to drop off as the filament voltage is lowered. Once that was determined, set the voltage 1/10 of a volt higher. I ended up running that EEV tube at 8.6 volts, which was as low as the MW50’s filament rheostat would go.

The other important thing about tubes is the break-in period. When installing a new tube, it is important to run only the filament voltage for an hour or two before turning on the plate voltage. This will allow the getter to degas the tube. New tubes should be run at full filament voltage for about 100 hours or so before the voltage is reduced.

Tube changing procedure:

Remove power from transmitter, discharge all power supply caps to ground, hang the ground stick on the HV power supply.
Remove the tube, and follow manufacturer’s procedures. Most ceramic tubes come straight up out of their sockets (no twisting).
Inspect socket for dirt and broken finger stock. Clean as needed. Finger stock, particularly in the grid section, is important for transferring RF. Broken fingers can lead to spurs and other bad things
Insert new tube, follow manufacturer’s recommendations. Ceramic tubes usually go straight down, no twisting.
Make all connections, remove grounding stick, half tap plate voltage supply if possible, close up transmitter
Turn on filaments and set voltage for manufacturers’ recommended setting. Wait at least 90 minutes, preferably longer.
Turn on plate voltage and tune transmitter. Tune grid for maximum current and or minimum reflected power in the IPA. PA tuning should see a marked dip in the PA current. Tune for dip, then load for maximum power.
Turn off transmitter, retap plate supply for full voltage
Turn on transmitter and plate supply, retune for best forward power/efficiency ratio.
After the 100-hour mark, reduce filament voltage to 1/10 volt above performance knee.

Of course, every transmitter is slightly different. There may not be a dip in the plate current if the transmitter is running near its name plate rating, in which case one would tune for maximum forward power.

This system works well, currently one of the radio stations we contract for has a BE FM20T with a 4CX15,000A that has 9 years on it, still going strong.

FCC authority to conduct warrentless searches of Private Property

I was this interesting tidbit on the Radio World website the other day. The question is, how much authority does the FCC have to conduct a search of a private residence? The Electronic Frontier Foundation wanted to know therefore they sent a FOIA request to the FCC seeking documents supporting this claimed authority.

The documents received seem to be redacted and some are mostly blank, such as the training module on how to obtain permission to enter private property is supposed to take 6 hours to complete, but consists of 3 paragraphs and 2 questions. Hopefully, that is redacted and does not reflect on the quality of agents the FCC is employing these days. The upshot seems to be the agent either needs a warrant or permission.

It may be surprising to some citizens, however, the FCC does have the authority to investigate radio signals, whether they are intentionally generated, as in a pirate broadcaster, or unintentionally generated, as in a piece of gear gone bad.

According to federal regulations, an FCC agent may request entry to inspect a private building anytime he/she believes there may be a device emitting radio frequency energy. This includes anything with an FCC part 15 sticker, which can be computers, TV remote controls, garage door openers, WiFi network routers, etc. This basically covers every house in the US as well as most businesses. Those rules were written when most homes and businesses did not have any RF generating devices and there was little to indicate that they ever would.

The consequence of failure to allow an FCC field agent into a residence or business appears to be the issuance of a citation in the form of a threatening letter. Continued intransigence would be met with a NAL (Notice of Apparent Liability) followed by a forfeiture notice also known as a fine. The typical FCC fine these days seems to be $10,000.00. If it is a repeated and willful violation, the equipment can be ceased and the perpetrator arrested.

In instances where the safety of life is in question, then every step necessary to disable the offending device needs to be taken. Things like transmitters spurring into aircraft frequencies or TV antenna amplifiers running wide open, also interfering with aircraft frequencies come to mind.

One of the examples given details a field agent trying to track down a noisy cable TV amplifier. From the FCC field agent’s perspective, the homeowner appears to be a royal pain in the ass. In this day and age when everything has a computer and most of them generate RF, tracking down interference can be a painstaking process, especially where housing is dense. Uncooperative homeowners, especially dumb ones, who have no idea what they have plugged in only make things worse.

Still, there is the issue of fourth amendment rights, which, if the above law was misinterpreted, misused, or applied with the wrong standard would likely be trampled. In these days of extra-constitutional activity, giving Los Federales entry into one’s house might invite unwanted scrutiny by other agencies. As far as changing the rules, with the current group of scoundrels and rouges in the legislative branch, one might end up with something ten times worse than before.