-With emphasis on mediumwave reception
-And comparisons to various radios
Purchased From: Anon-co (eBay)
Price: $45.99 + $24.00 shipping ($69.99 total)
Serial#: 369-2010-0202-752 03/2010
The Tecsun PL-380 DSP Digital Receiver is one of the newest offerings in the ultralight-sized category of pocket receivers. It uses the industry's first fully integrated, 100% CMOS AM/FM/SW/LW radio receiver chip, the Silicon Labs Si4734. It tunes the longwave, mediumwave, shortwave and FM bands, and uses the latest in software-based digital signal processing to provide an outstanding choice of filter selectivities of 6 KHz, 4 KHz, 3 KHz, 2 KHz, and 1 KHz, minimizing interference. This little receiver is truly a quantum leap in technology.
Longwave coverage: 153 - 513 KHz
Mediumwave coverage: 520 - 1710 KHz (9 or 10 KHz split)
Shortwave coverage: 2300 - 21950 KHz
FM coverage: 64 - 108 MHz
This review is lengthy and quite technical in places. It is purposely slanted toward the mediumwave DX enthusiast, mainly because I am one and that's why I bought this radio: to further pursue this hobby of mediumwave DX. Virtually all of what is said in terms of functionality and technical specification can also be applied to the shortwave and FM sections of this radio.
SHIPPING AND ARRIVAL
This is my first radio purchased directly out of China (Hong Kong), so I was a little nervous. Seller Anon-co sells these and other radios via eBay. It has been a good experience and exceeded my expectations. Purchase is easy through Pay-Pal. Joyce, the sales agent for Anon-co, contacted me via e-mail within 24 hours of my web purchase introducing herself and asking my preference of color for the radio. Three styles are available: silver, grey, and black. I chose the black one.
The radio was shipped out of Hong Kong within 48 hours via air post. A tracking number was provided for the parcel, shipped by a Hong Kong shipping company. The radio arrived 13 days later in New York via US Postal Service registered mail.
The PL-380 is physically small, fits in a shirt pocket, and is just a little larger (by 5/8 inch width and height) than my Kaito WRX911. It was packed in a Tecsun box, the box itself in a heavy duty bubble-wrap envelope. Radio size is 5-1/4 inch wide x 3-3/8 inch high x 1 inch deep. It arrived in good shape, complete with Hong Kong stamps on the envelope for the stamp collector.
The PL-380 comes with a nicely equipped accessory package. Accessories include a nice zippered cloth case with inside pocket and small foldover pouch for earbuds, an external antenna wire with mini connector and curtain clip, earbuds, 3 NiMH batteries (1000 mAH), a USB charging cord, and a manual.
The manual, in English, contains 29 pages. It is well-written with an acceptable amount of Chinese-English speak. Included in the radio description are many graphics showing how to use the various functions. The inside front-cover has a nicely detailed block diagram of this innovative digital receiver for the technically curious. Studying it, you can see this radio has few parts outside of the Silicon Labs' Si4734 DSP micro-chip. See the accompanying photo in the FILTERS AND SELECTIVITY section showing the radio disassembled and you will see what I mean.
The radio requires 3 AA batteries, like my Grundig YB 300PE. Battery level is displayed on the screen as it is for the PL-600, and is accurate for either NiMH batteries (~1.2 volts) or standard alkalines (~1.5 volts). A simple key press toggles the display between alkaline or NiMH so that your current battery level reads accurately. The NiMH batteries are chargeable right in the radio using the USB adapter cabled to a computer. Charging automatically shuts off when finished. Battery consumption is very low, and batteries should last a long time especially if headphones are used.
Anon-co checks out each radio before shipping to make sure they work, a nice service. The radio also came preset for the North American mediumwave split, 10 KHz. Again, a simple key press toggles between 10 KHz and 9 KHz splits. The long wave band (153 KHz - 513 KHz) was already activated too, and can be activated or deactivated by key press.
The clock is easily set by a combination of a key press and rotation of the tuning dial, done while the radio is off. 12 or 24 hour formats are available. The clock can be made to show while the radio is in operation if desired.
No other setup was required.
QUALITY AND ERGONOMICS
The PL-380 build and fit quality is excellent, and better than the PL-600. The telescoping whip antenna measures 19-1/2 inches when fully extended, and is stout and of nice quality.
Buttons, though small, give a nice solid click when pressed, and have a stiff spring behind them. A somewhat loud tone is also emitted for each button press, but is easily silenced by a simple key action. Unlike the PL-600, lettering on the radio's buttons is on top of each button itself and it will be interesting to see at what age and usage the lettering begins to wear. The keypad is layed out in correct telephone pad-style format, with the zero key at the bottom center. Brilliantly, there are no tedious menus to wade through when changing core radio settings. Simple 2nd function key presses accomplish this. Excellent design.
A small (1-3/4 inch) front-firing, round speaker is on the left front. Sound through the small speaker is trebley at best. Use headphones, this is not a boom box.
The left side of the radio has a headphone jack and a 5 volt DC input connector, the connector being like those found on many digital cameras. Curious. I'm not sure how you would hook it to another 5 volt power source other than a computer, though a cable from an old digital camera could be stripped and cobbled up.
Two ridged, thumb-wheeled styled knobs protrude edge-wise from the right side of the radio. They are tuning and volume. They each have stepped-detents and seem a bit delicate. Be gentle when using them. I have seen one report in the Yahoo Ultralight group where a user's tuning wheel broke loose off its shaft.
On the back of the radio is a flip stand for elevating the PL-380 if set on a flat surface. The PL-380 also comes with a handstrap. The battery compartment cover is not hinged, but removable, and could be easily misplaced.
THE LCD DISPLAY
The display is clear and easy to read, and contrast is good. Backlighting is yellow, with perhaps a tinge of green, like the PL-600. It can be activated at any time by a key press, or turned on or off permanently.
A key lock button can be pressed to lock all controls on the radio. When locked, a small key is displayed on the LCD.
By pressing the Display button, found just under the Power button, the clock, alarm time, temperature, or received signal strength indicators can be made to show in turn along with the tuned frequency. Stop at the one you wish to be continually displayed.
The clock and alarm read in hours and minutes only, no seconds. A single timer is available which can activate the radio for up to 90 minutes when the alarm is triggered. You can also set the alarm to produce a buzzer-like sound.
A sleep function can turn off the radio after up to 120 minutes. By default, on first power up the radio starts in sleep mode and will play for 30 minutes before shutting off. A "30" will show on the display for the first few seconds. This can be defeated by a key press so the radio stays on permanently after power up.
Temperature reads in either Fahrenheit or Celsius. Cleverly, the software tests the mediumwave split you have selected (9 KHz or 10 KHz), and displays Fahrenheit if you have chosen the 10 KHz split or Celsius for the 9 KHz split.
For the longwave, mediumwave and shortwave bands, received frequency is displayed in kilohertz. For the FM band, received frequency is displayed in megahertz.
Memory operations are displayed in the received signal strength indicator area, at the upper right.
The PL-380, like the other ultralights using the innovative Silicon Labs' Si4734 DSP micro-chip, has a unique signal strength indicator display, the likes of which old radio buffs like me would never have dreamed possible back in the 1950s and 1960s during the waning era of vacuum tubes and analog signal strength meters. Learning of this when the Grundig G8 Traveller and Tecsun PL-300 came out, I was very excited to one day see this in action in addition to wanting to move along and try these new designs. I avoided these initial production attempts due to the so-called soft-mute issues inherent with their design software. The PL-380 has toned down the soft-mute attenuation. But more on that later.
THE RSSI AND SNR DISPLAY
When the PL-380 is tuned to the center carrier frequency of a broadcast station, the carrier strength in dBµV (dB above 1 microvolt) and the signal (+noise) to noise ratio in dB is displayed in the upper right corner of the LCD display. These are commonly called the RSSI (Received Signal Strength Indicator) and the SNR (Signal to Noise Ratio), respectively. The RSSI figure displayed is relative of course, and should not be confused with any published figures of signal strength like those available from V-Soft Communications, or seriously compared with private calculations for receivable stations in your area. Actual received signal strength is highly dependent on local terrain, daylight/nighttime conditions, transmitter antenna pattern gain, receiver antenna, ground conductivity, and other factors which make it impossible to accurately fix through calculation.
It is important to note that the RSSI indicator (marked dBµ on the display) is not the same measurement as dBu, the figure commonly used in recent years by the FCC for measuring electric field intensity of AM broadcast stations at prescribed distances. dBu [lowercase "u"] is electric field intensity, always in decibels above one microvolt/meter (and the same as dBµV/m). dBµV, on the other hand, using the Greek letter µ ["mu"] instead of u, is voltage expressed in dB above one microvolt into a specific load impedance, commonly 50 ohms. The PL-380 measures and displays dBµV, not dBu-dBµV/m.
Signal to Noise Ratio (SNR) is the ratio of (a) the power of the desired signal plus the noise to (b) the power of the noise. The (S+N)/N ratio is usually expressed in dB.
RSSI indications, as displayed on the PL-380, can range from 15 to 63 dBµV. Per Scott Willingham, one of the Si4734's designers, "The RSSI readings are referred to the pins of the chip, which are the inputs to the LNA. In the Tecsun radios operating in the MW band, this is also the voltage across the loopstick. In SW bands, the Tecsun ULRs use a preamp/LNA on the circuit board between the whip antenna and the Si4734. In that case, the RSSI readings reflect the signal at the output of Tecsun's external LNA."
Displayed SNR indications can range from 0 to 25 dB. About SNR measurements, Scott Willingham related that, "The SNR figure is calculated by a proprietary DSP algorithm, and neither the RSSI nor audio output directly play a role. The input to the algorithm is the filtered IF signal before audio demodulation. It is really more of a carrier-to-noise ratio than directly an audio noise measurement. Obviously, in AM it is bounded between 0 and 25 dB. The motive for computing and providing the number comes from implementing better station search capabilities; the display is just a nice byproduct."
At 0 dB SNR, a weak signal at best, soft-mute is at maximum attenuation according to the Si4734 programming manual. A great discussion thread on PL-380 soft-mute exists on the Yahoo Ultralight group.
Soft-mute, a further lowering of the audio level of the received signal when it drops below a prescribed strength, is undoubtedly meant to provide a more comfortable listening experience for the casual listener and not the DXer. The idea is to relieve the listener from all that nasty low level "static" and "interference", or as Silicon Labs states: "The soft-mute feature is available to attenuate the audio outputs and minimize audible noise in very weak signal conditions."
Long suffer the mediumwave DXer, as static and interference and low level signals are his bread and butter and the secret to gaining new DX. Luckily for him a weakly received signal is still there, though attenuated, and may in fact be perfectly readable if not for the soft-mute. How do we recover it?
A general consensus indicates that tuning 1 or 2 KHz off frequency and advancing the volume control will compensate for the muted audio. This is the theory: When you tune off the center frequency of the carrier it causes the signal to noise ratio to drop to zero (in fact it does), and the software responds by fully engaging the soft-mute, stabilizing any pumping audio possibly caused by multiple and different strength stations on the same frequency. At that point the volume is manually raised to counteract the soft-mute reduction.
Sometimes it works. Sometimes not, in my experience. Raising the volume also raises the background noise level and sometimes I don't see any beneficial signal recovery. Many times I have found if you stay tuned on frequency, wait a few seconds and rotate the radio around a bit to either peak the desired signal or null the offending one, the soft-mute seems to settle down and disengage, allowing reception of the weak signal. So try this too.
Maximum soft-mute attenuation for the PL-380 is 6 dB. As measured, the soft-mute threshold is actually 3 dB (SNR reading) and the slope is 2 dB/dB. This means that there is no soft-mute effect at all for SNR readings of 3 dB or more. Below 3 dB SNR, the audio is attenuated 2 dB for every dB decrease in SNR, up to a maximum of 6 dB when SNR reaches its minimum reported value of 0 dB, as such:
3 dB SNR: 0 dB audio attenuation (the threshold)
2 dB SNR: 2 dB audio attenuation
1 dB SNR: 4 dB audio attenuation
0 dB SNR: 6 dB audio attenuation
On a separate issue, a different person in the same group reported a generally high and somewhat constant RSSI value (dBµV) across segments of the mediumwave band. I have noticed the same effect here in the general frequency neighborhood (let's say plus or minus 40-50 KHz) of the local powerhouse stations, where RSSI values will hang at a value of perhaps 20-40 dBµV with an SNR of 0. I can only attribute this to a kind of front end "desense", ahead of the filtering, as I don't know what else might cause it. When you get far enough away in frequency from the overly-strong signals, the effect vanishes.
The RSSI and SNR displays update every two seconds, however the radio itself responds to realtime changes much faster than this. For example, when rotating the radio to null a station's signal, you may notice that soft-mute kicks in before the SNR display reaches 2 dB. This is because the display has not reached its update cycle yet. This is not a problem, but just something to be aware of if you are using the displays for positioning the radio.
The PL-380 employs a rather short ferrite bar antenna (3-1/8 inches in length) for the LW and MW band frequencies. FM and shortwave employ the telescopic whip antenna. Signal nulling is excellent and as good as any radio I own, as good or better than the renowned WRX911.
Interestingly, WRX911 nulling was improved dramatically here by the removal of the telescopic whip antenna's connection to the circuit board which was found to be interacting with its ferrite loop and worsening its ultimate nulling capability. Per the block diagram, the PL-380 also connects its whip to the AM tank circuit, as the AM side of the Si4734 chip is also used for shortwave AM tuning. The connection is made through a so called "SW LPF" (low pass filter), funneling the shortwave band signals to the AM tank circuit. I wondered if there would be interaction with the whip causing a degradation of mediumwave nulling and maybe some false "signal enhancement".
I did an experiment by taking the PL-380 outside away from household noise and attaching about ten feet of wire to the telescoping whip. Tuning to distant outlet WGY-810 in Schenectady, NY (186.3 miles distant), the signal to noise ratio (and audible signal strength) increased by a factor of 7 dB when the wire was attached to the whip versus when it was not. It seems there is at least some interaction between the whip and mediumwave reception, as was the case with the WRX911. In the case of the PL-380, however, even with the whip extended a full 19-1/2 inches it is probably minimal, a matter of a couple of dB and hardly noticeable.
Further, coupling this unit to a passive loop to enhance sensitivity is a rather strange experience, and unlike any other ultralight or other radio I own. Passive loops seemed to tune rather broadly, making it a bit difficult to find a signal peak. Loose coupling seems to work best, and finding the "sweet spot" of best signal transfer is difficult.
My homemade Q-Stick device, the 4-Inch Tunable Ferrite Bar featured on RADIO-TIMETRAVELLER last September, couples even more poorly than the passive loop does to the PL-380. Again, in close proximity, tuning is upset and even more skewed and undefined. I often can't find a signal peak at all when tuning the external ferrite bar. All in all, the PL-380 exhibits some strange coupling tendencies. You will have to experiment with your passive loop or ferrite tuning device to see what works best for you.
Reports in the Yahoo Ultralight group suggest that Tecsun has tweaked the stock AVC for the Si4734 chip so much that it results in "unvarying volume over many conditions", which in turn makes it hard to determine a signal peak when coupling to passive devices. See this discussion.
The sensitivity of the PL-380 is good and markedly better than my little Sangean DT-400W ultralight. It approaches the PL-600's sensitivity throughout the mediumwave band, though it tends to be down a little more at the lower end. Reports speak of the low tank coil inductance as curbing sensitivity on this unit, particularly at the lower frequencies. Ranking four radios for sensitivity, arbitrarily ranking the Kaito 1103 at a ten since it is the most sensitive, they would rank thusly:
Kaito 1103: 10.0
The PL-310, on the other hand, a previously manufactured DSP ultralight receiver using the same Si4734 chip, had a longer loopstick and better sensitivity than the PL-380, as witnessed by others. Unfortunately, reports of its heavy soft-mute signal attenuation have steered me away from it.
So what to do if you want more sensitivity? Short of using a cranky passive loop or Q-Stick device, the answer for improved sensitivity seems to be hacking into the unit and replacing the PL-380's ferrite bar with something longer and tuned correctly. This has been hashed about in many posts in the Yahoo Ultralight group. A 7.5 inch ferrite bar has been used with very good results.
All-in-all, I don't find the PL-380's sensitivity that bad. It is certainly not dead, and better than many other ultralight receivers. It is obviously no Kaito 1103 or even a Tecsun PL-600, but it can hold its own with many others.
Get up early some morning just before sun up and take the PL-380 outside and away from household noise. Put your headphones on. You will find a world of distant DX stations fighting with each other for dominance on nearly every channel. And better yet, use the 2 and 1 KHz filters to slice that interference and IBOC nastiness out of existence.
No chuffing or dropout is apparent when tuning the radio, and tuning is very smooth once you get used to the detents on the tuning dial. The days of chuffing and signal masking while tuning are about gone for digital radios, I hope.
Two tuning speeds are available, slow and fast. They are as follows:
Longwave/slow: 1 KHz per detent
Longwave/fast: 9 KHz per detent
Mediumwave/slow: 1 KHz per detent
Mediumwave/fast: 9 or 10 KHz per detent, depending on split
Shortwave/slow: 1 KHz per detent
Shortwave/fast: 5 KHz per detent
FM/slow: 10 KHz per detent
FM/fast: 100 KHz per detent
Slow or fast tuning speed kicks in automatically depending on how fast you spin the tuning wheel. It takes some getting used to, to get the feel for how fast you can spin the tuning dial before the radio goes into fast tuning mode. It is annoying at first and will catch you off guard till you learn the feel.
Direct entry tuning couldn't be easier. Punch in a frequency, like 8-5-0, and it instantly tunes to 850 KHz without having to press an additional "enter" key, or a "period" key twice. Such a simple feature makes a huge difference. Kaito, Eton, are you listening?
General shortwave band selection is done by the "carousel" method. Press the "up" or "down" arrow keys to take you to the band you desire. Or, just punch in the frequency on the number pad once you have arrived on a shortwave band. It is simplicity at its best.
The PL-380 has several different scanning modes. See the MEMORIES AND SCANNING section for a further description.
FILTERS AND SELECTIVITY
Selectivity is nothing short of astonishing on this little radio. Five selectivity widths are available, digitally filtered of course - 6 KHz, 4 KHz, 3 KHz, 2 KHz, and 1 KHz. Gone are the days of ceramic filters, good. The AM Bandwidth button at lower left controls the filter setting using a carousel type method.
Audio recovery of weakly received signals is excellent and intelligible even in the 1 KHz bandwidth setting of the filter. And the benefit of using the lower bandwidths of 2 and 1 KHz are better signal to noise ratio, thus better signal recovery when receiving weak DX. I have tuned signals with this radio that were very weak but perfectly intelligible in the 1 KHz setting when they were not apparent in either the 4 or 6 KHz filter settings. So use the 1 or 2 KHz filter width when scanning for weak DX.
Offset tuning can sometimes be used to pull in a weak station that can't otherwise be received on frequency, perhaps due to adjacent channel interference or muddled audio. Switch to the 1 KHz or 2 KHz filter and detune the station by 1 or 2 KHz. The audio will brighten, usually imparting better clarity. Raise the volume some, to counteract the soft-mute. There are few receivers that I have known which can carry off intelligible audio at such narrow filter widths. The PL-380 can.
Audio quality is fair with the speaker and good using headphones. Don't expect to set this radio on a garden table and get yard-filling, full range volume. Use your boom box for that. Headphones are the key. They are the DXer's choice.
MEMORIES AND SCANNING
The PL-380 has 550 memories. Longwave, mediumwave, and FM each have 100. Shortwave has 250. Memory operation is simple. Tune to a station, press the memory key (VM), press again to reconfirm and store. Use the tuning wheel to scroll through memory slots when in memory mode.
Easy Tuning Mode (ETM) is an automated band scan type of operation which automatically scans and stores receivable channels into the Easy Tuning Mode memory, separate from regular memory. The manual states that the longwave, mediumwave, and FM bands have a total of 100 storage slots, and shortwave 250. While in the band of your choice, hold the ETM button down until the scan starts. Stations above a prescribed strength will be saved in ETM memory. A handy function, but almost identical to ATS, below.
Auto Tuning Storage (ATS) automatically scans and stores stations just like Easy Tuning Mode does, only uses regular memory. Makes me wonder why they even included ETM as another scan type operation. The difference appears to be that you have a full range of 100 memory slots for each band (longwave, mediumwave, FM) versus 100 total. Shortwave is the same, at 250.
Scanning within any band is simple, and fairly effective, though the lock thresholds are set a bit high. Press the VF key to start/stop.
Memory scanning is also available through the VM key.
SIGNAL SPURS AND IMAGES
As noted by others, the PL-380 has some spurs. The one usually reported is the strong one, a 2 KHz heterodyne on 620 KHz. I found numerous other heterodynes of low to medium strength on 560, 820, 850, 880, 920, 1010, 1280, 1420, 1430, and 1570 KHz.
Also, I'm hearing some sort of broad digital hash between 570 and 580 KHz, and a strange digital mixture fighting with a weak station on 590 KHz.
I have not detected any images in the MW broadcast band.
The PL-380's LCD display is fairly clean. Touching the display produces a barely perceptible amount of digital hash, about the same as the Tecsun PL-600. The Sangean DT-400W produces a noticeable amount of hash when you touch the digital display with your thumb.
RFI susceptibility is about the same for the three radios. Moving the radio about the house near sources of RFI produced the usual buzz in all. A computer will introduce a sizable amount of digital hash into all three radios.
THE PL-380 IN USE
As stated, the PL-380's sensitivity approaches the PL-600's throughout the mediumwave band. However, you will never notice it by hurriedly flipping through the band. If you take your time in tuning, use the narrow filters, rotate your radio and allow soft-mute to settle down and disengage, you may be as pleasantly surprised as I was.
First, let me say that sensitivity comparisons were done near mid-day to avoid any enhanced nighttime propagation.
At the high end of the MW band, usually weak CHTO-1690, Greek Multicultural Radio Toronto (1KW at 98.4 miles), is perfectly receivable on the PL-380, and about equal to the PL-600. Conditions on this one vary greatly throughout the day. I have had occasion where the PL-380 had the stronger signal by a small margin.
At the low end of the MW band, CIAO-530, Brampton, Ontario (1KW at 120.1 miles) is weak but readable, and the PL-600 excels here. WJR-760, Detroit, MI (50KW at 286.2 miles) is barely readable, but above the noise, a good catch for an ultralight without help from a passive loop. Neither the 530 KHz or 1690 KHz channel (let alone WJR-760) can be received at all on the Sangean DT-400W ultralight without help from a passive loop.
Nulling signals on this receiver can be an interesting experience if the station's signal strength at maximum null results in an SNR of 2 dB or less. At the 2 dB threshold the soft-mute kicks in and the signal drops off most abruptly, giving a false sense of having nulled the signal. Keep your eye on the SNR display when nulling, or tune 1 or 2 KHz off frequency, turn the volume up and null again, listening for the center of the fade. Remember, the SNR display may lag a little before it catches up.
Now for the selectivity test. A major problem here is local station WYSL-1040, which beams a whopping 20KW daytime signal in here with a level of some ~76 dBu - the strongest signal on the MW band here at the farm. With an antenna pattern pointed roughly northward, at some 4.25 dB gain in that direction, its effective radiated power is equivalent to some 53 kilowatts aimed right at me, and less than five miles away. It literally overwhelms receivers plus or minus 20-30 KHz either side of its frequency.
CP24 Radio 1050 (KHz), Toronto, Canada (50KW, ex-CHUM), across Lake Ontario, a distance of 105.0 miles, is the only station even capable of putting a up a fight with WYSL. All the rest are either too weak or too distant. I can usually detect the presence of CP24 in the WYSL splatter with the PL-600 using the narrow filter (4 KHz), however identification is difficult to impossible. Using the PL-380 and nulling WYSL carefully, it is perfectly readable using the 2 KHz and 1 KHz filters. This is an astonishing feat which impressed me very much!
The Tecsun PL-380 is a technological wonder in a small package, and all for $45.99 + shipping. It is an experimenter's playground if you are into high technology, and a keeper for me.
Sensitivity is adequate in my opinion, and if you are patient with a passive loop it can make a positive difference. Remember, overall it is no Tecsun PL-600 or Kaito 1103 in the sensitivity department, but it is way ahead of a lot of other standard ultralights.
Selectivity is unmatched, perhaps in any radio under $1000 except for other Si4734-based receivers. Nulling is excellent. Audio is good. Ergonomics are simple, and the receiver is easy to use without tedious menus to navigate. 550 memories, not that you will use them, but they are available.
Four different scanning options. Two tuning speeds, and a real volume control. The display is bright and easy to read. If I could change a couple of things, I would add some up and down frequency slew buttons and perhaps beef up the tuning dial to be more like the PL-600 or Kaito 1103, getting rid of the detent. The detent is fine for the volume control.
Soft-mute is at a minimum in this radio, and I didn't find it objectionable once I got used to it. 6 dB of audio reduction is not a lot and can be defeated with some finessing of the radio, making it a non-issue in my opinion.
The radio has a fair amount of spurs, and some digital hash on a couple of channels. These are annoying. This is not the cleanest radio.
All-in-all, the PL-380 may be the ultimate ultralight receiver as of this writing, and a competitor to some larger models for mediumwave reception. The first company that produces a radio using this Si4734 chip with the soft-mute defeated, the thresholds lowered, AVC adjusted, and includes a matched, 6 to 8 inch ferrite rod is going to have a real DX machine on their hands.
For the technically curious, an excellent treatise on calculations and measurement of electric field intensity, received voltage, and power density, see:
Calculations and Measurement
A excellent description of signal to noise ratio can be found here:
Signal to Noise Ratio
Saturday, June 19, 2010
Saturday, June 5, 2010
A belated story from Sunday, May 23.
Tuning across the MW broadcast band with the Tecsun PL-600 early Sunday afternoon, I discovered local powerhouse station WYSL-1040 (20KW, 4.9 miles distant) off the air for some reason. What an opportunity! WYSL normally overloads the receivers here plus or minus 20 to 30 KHz either side of 1040. I grabbed the 24-inch loop and headed for the backyard away from household noise to see what I could hear on 1040 KHz and adjacent frequencies.
20 KHz up, across the Appalachians and coming in nicely with good strength was KYW-1060, Philadelphia, PA (50KW) at a distance of 232.0 miles.
Stronger yet, 10 KHz down on 1050 KHz was CP24 Radio 1050, Toronto, Canada (50KW, ex-CHUM), across Lake Ontario, a distance of 105.0 miles. Approximately 50 miles of this distance is over water, giving a certain amount of signal enhancement due to the lower path loss. On a good day I have heard this station in the spill-over of WYSL with a narrow filter. This signal enhancement axiom seems to be true of all signals coming across the Great Lakes, from Montreal at the east end of Lake Ontario to WJR-760, Detroit, MI, clear across the west end of Lake Erie, nearly 300 miles distant.
On 1040 KHz itself was an ESPN Radio station, at least it was identifying as such. It appeared to be in the New York City area from the talk heard, and at good signal strength. Although they never did give their call letters, the odd thing was that they identified their frequency as 1050 KHz on several occasions! One possibility exists here in that the station might be WEPN-1040 (50KW), 238.6 miles, out of New York City. It is an ESPN Radio station. Very weird that it should identify as transmitting on 1050 KHz when it was most definitely on 1040 KHz. I even had to check the dial several times to make sure I was correct on this.
1030 KHz was vacant, not totally surprising. The only two possibilities here would be WWGB, Indian Head, MD (50KW) at 304.5 miles, and WNJE, Flemington, NJ (15KW) at 217.7 miles, but neither was making the grade. WBZ-1030, Boston, MA (50KW), has a regular appearance at night when WYSL switches to lower power.
Tuning down another 10 KHz, pointing the loop south brought in the obvious in KDKA-1020, Pittsburgh, PA (50KW), at a distance of 200.9 miles with good signal. This oldtimer also comes in well at night after WYSL switches to lower power.
Local WYSL-1040 puts in a daytime 20KW signal here in the neighborhood of ~76 dBu and is the strongest signal on the MW band here at the farm. With an antenna pattern pointed roughly northward, at some 4.25 dB gain in that direction, its effective radiated power is equivalent to some 53 kilowatts aimed right at me, and less than five miles away. WYSL also runs critical hours and nighttime power levels of 13.2KW and 500 watts respectively. Even at the 13.2 KW level during critical hours, its signal is a whopping ~74 dBu. The next closest contender, WHAM-1180 in Rochester, NY (50KW), at 11.2 miles distant, booms in here at some ~64 dBu.
By the way, all the distant stations documented above were also received on the Sangean DT-400W ultralight. With the Tecsun PL-380 just arriving yesterday, it will be interesting to see how it performs in tests against these two powerhouse stations.