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20W Professional FM Radio Transmitter
- SUPER SILENT
- STEREO WITH AUDIO PROCESSING OPTION
- RDS OPTION
- 12VDC or 90-260VAC OPTION
- USB 192 KHz 24 bit OPTION
- INCLUDES SHIPPING
- 5 YEAR WARRANTY
- EXCEEDS CE/FCC TECHNICAL SPECIFICATION
|
LIMITED WARRANTY |
Suitability
This is a popular choice in Nigeria for campus type university radios that are licensed by the state for 20 watts. Using this 20 watt transmitter with our 4 way stacked dipole is a popular choice producing a total EIRP of approximately 80 watts.
Which Version Do You Need?
These are the two main versions of this transmitter:
◼ Stereo with RDS and Audio Processing Version
◼ MPX Version
These two versions cover 90% of all customer requirements. Other custom versions are available such as stereo only, no RDS, no processing etc. which we can also make if that's what you require.
You will find these two main versions shown in detail in the two following sections with descriptions of what they do and how they work. You should also see the price, INCLUDING delivery, to your country.
If you are still unsure, you are always welcome to contact us at em: info@aareff.com or ws: +1 829 6980733 and we're more than happy to advise you.
Stereo, RDS and Audio Processing Version
If you are not sure which version you want, then you definitely need this version. It is perfect for beginners because it adjusts the audio levels automatically and keeps the 20 watt transmitter within the legal specifications required by the state regulator.
This version is also ideal for professionals who just don't need the all the hassle. This is because it includes everything in one enclosure. The audio processing keeps the audio level 'LOUD', but not too loud whereby it causes over deviation and contravenes your permit. The trick is to get the sound as loud as possible so you can compete with the other stations on the dial, but at the same time keeping your signal legal. This is a tricky balance to maintain, but this version in stereo with our internal audio processers does exactly this.
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In addition, this version INCLUDES RDS. This allows everybody to see your station name and more scrolling across the car radio display.
The RDS is not just ordinary RDS, it is fully programmable dynamic RDS. This means the transmitter can be connected to a PC by a USB cable. The RDS can be changed on the fly in real time by using USB PC CONTROL shown below.
Flat 30Hz to 76KHz MPX Input
We have this version available for Users with experience that prefer straight raw MPX input.
Low frequency audio response is the holy grail for multiband audio processors, they need it.
As you can see from the image, the 160Hz square wave is very square with no tilting making it perfect for use with Orban, Inovonics, Omnia, Stereo Tool and other commercial audio processors.
This setup uses a Hartley-based, lightly coupled push-push VCO that exhibits extraordinary stability, to the point where it deviates by less than 10 kHz from its designated frequency on its own, even when the DSS and PLL are switched off.
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Because this VCO is so inherently steady, the PLL only has to make minor corrections to maintain the frequency within about 300 Hz, effectively just giving it a slight nudge. Consequently, the audio remains very clean, as noted previously, and the PLL’s control voltage can be heavily low-pass filtered to just a few hertz. Such a slow loop filter ensures that low frequencies around 30 Hz are not misread as frequency drift, passing unaltered to the varicap. This preserves the essential low-end audio response needed for high-performance audio processors.
USB PC CONTROL
Download our free PC app that connects 'plug and play' to the transmitter / PLL DDS exciter via USB. You can see the PLL status and change the frequency and power directly from the PC interface. If you choose to add the optional RDS card, you can also change the PI, PTY and scrolling text of the radio from the interface.
Below are the download links for Windows:
https://www.aareff.com/1wpllm/pll14.4/pll14.exe
https://www.aareff.com/1wpllm/pll14.4/pll14.zip
By clicking on these links, Windows may show you a warning that the software is from an unknown publisher. We assure you that we wrote the apps and the files are perfectly safe, virus-free and come from our registered domain www.aareff.com, which you can verify at https://lookup.icann.org/en/lookup
Normal state when the device is connected: the PLL is LOCKED with an output power of 0.85W and a PLL phase of 2.33V
This shows what happens if the device loses its lock. We simulated a failure by placing our fingers on the oscillator coils.
This shows the return to normal with the user command FREQ:106.7 typed in the input box below. A value between 87.5 and 108.0 MHz can be set.
After pressing 'Send:' the display returns UPDATED FREQ 106.7 along with other technical information. This causes the transmitter to change frequency.
This shows another command, RDS-PI:ABCD typed for devices with the RDS card.
After pressing 'Send': the display returns UPDATED RDS-PI:ABCD instantly updating the RDS PI code.
This shows two additional examples of RDS commands:
RDS-TEXT:[write your message here]
RDS-PTY:[number from 0 to 31]
Text is plain ASCII up to 60 chars and valid PTY Codes shown below.
This shows the LOCK-CAL command, which starts a PLL self-calibration sequence. This command is not needed under normal conditions, but can be useful in case of extreme temperature changes (very hot or very cold), repairs or other conditions outside the standard parameters.
Shown below are the current commands available for USB PC Control and also the PTY codes for program type. We will be making further developments, improvements and more useful commands to this app in the near future. Keep checking this page for details.
◼ DEVICE-ID
◼ STATUS
◼ FREQ:[87.5 to 108.0]
◼ DDS-ADJ:[-1,0 or 1]
◼ PWR:[0 to 1]
◼ LOCK-CAL
◼ RDS-PTY: [0 to 31]
◼ RDS-PI: [0000 to FFFF]
◼ RDS-TEXT:[any string up to 60 chars.]
◼ RDS-ON
◼ RDS-OFF
| PTY Code | Europe | United States |
| 0 | None | None |
| 1 | News | News |
| 2 | Current affairs | Information |
| 3 | Information | Sport |
| 4 | Sport | Talk |
| 5 | Education | Rock |
| 6 | Drama | Classic Rock |
| 7 | Culture | Adult Hits |
| 8 | Science | Soft Rock |
| 9 | Variable | Top 40 |
| 10 | Popular Music (Pop) | Country Music |
| 11 | Rock Music | Oldies Music |
| 12 | Easy Listening | Soft Music |
| 13 | Light Classical | Nostalgia |
| 14 | Serious Classical | Jazz |
| 15 | Other Music | Classical |
| 16 | Weather | Rhythm & Blues Music |
| 17 | Finance | Soft Rhythm & Blues Music |
| 18 | Children’s Programs | Language |
| 19 | Social Affairs | Religious Music |
| 20 | Religion | Religious Talk |
| 21 | Phone-in Talk | Personality |
| 22 | Travel | Public |
| 23 | Leisure | College |
| 24 | Jazz Music | Not assigned |
| 25 | Country Music | Not assigned |
| 26 | National Music | Not assigned |
| 27 | Oldies Music | Not assigned |
| 28 | Folk Music | Not assigned |
| 29 | Documentary | Weather |
| 30 | Alarm Test | Emergency Test |
| 31 | Alarm | Emergency |
Antennas
On delivery the equipment is ready to plug in and use with any suitable 50 ohm antenna system such as our:
• SINGLE DIPOLE
• 4.8dBi 2 DIPOLES
• 7.8dBi 4 DIPOLES
• 10.8dBi 8 DIPOLES
• 4.8dBi 5/8 ANTENNA
• -0.8dBi CIRC. DIPOLE
• FOLDED DIPOLE
Our system package the 20W EIRP system includes this transmitter with a dipole antenna and very low loss LMR400 cable to give you a full system that will comply with the regulations of the European Union and most other countries in the world.
Reliability
Like all our products, we over engineer them, this is no exception. This uses a 45 watt transistor, for 20 watts output. basically you can throw any amount of reflected power at this unit and it will laugh in the face of it. Basically this transmitter, is not super, not ultra, it's HYPER reliable
Construction
The enclosure is made in strong 16 gauge steel, powder coated and baked in satin black. This leaves a tough, durable surface that will never rot or corrode and be cleaned to shine for decades. The front panel is 19 inch across and 2U (3.5 inch) high with a depth of 12 inches, so it will fit with ease into a standard rack. It is very strong and difficult to damage even under extreme handling.
Configuration
When we test this unit we need to test it at some frequency, it's obviously better if we test it at the frequency you want to us it on, then you can use it straight out of the box on delivery. But if you don't know the frequency, that's okay, the frequency, FM deviation and power is easy to set in a few minutes on the underside panel controls.
Compliance
The stereo version with audio processing and limiting meets all the regulatory standards required out of the box and pre configured. In fact if you send us a copy of your permit and it's conditions, we will set it up exactly to the specification. This equipment complies with EU/CE harmonised standards and FCC technical requirements for FM broadcasting. More information HERE
RF Specification
All stated measurements were made at 220VAC at 27 Deg. Celsius ambient temperature unless stated.
| Power Output | Adj. 1-20 Watts into 50 ohms |
| Spurious Emissions | Less than -75 dB ref to carrier |
| Harmonic Emissions | Less than -70 dB ref to carrier |
| Freq Stability | +/- 1 KHz max. typ. +/-300 Hz |
| Deviation Sensitivity Stability | +/-2 % max |
| Freq Fine Adj | > +/- 1000 Hz |
| Freq Range | 87.5 to 108 MHz in 100 KHz steps |
| Out of Lock RF Muting | Less than -70 dB ref to carrier |
| Residual AM | Less than 0.5 % |
| Synchronous AM | Less than 0.5 % |
| RF Ruggedness | Any VSWR phase or length of time |
| Output Connector | N-Female |
| Operating Temp | -20 to +40 Deg C |
AF Specification
| Pre-emphasis | (50 uS/ 75 uS/ None) Selectable | |
| Audio Input Connector | Phono/ RCA type unbalanced sockets | |
| Audio Input Sensitivity | +4 dBu for +/- 75 KHz dev. | |
| Version | MPX | Stereo and Audio Processor |
| Signal To Noise Ratio | 80dB | 65dB |
| Frequency Response | 30Hz-76KHz | 30Hz-15KHz |
| Audio Distortion | Better than 0.1% / 60dB THD | Better than 0.1% / 60dB THD |
AC Specification
| Input Voltage | 90-264 V AC 135-370 V DC 47-63 Hz |
| Input Power | 40W for 20W RF OUT with RF SWR less than 1.5 |
| Working Humidity | 20-90% RH non-condensing |
| Safety Standards | UL60950-1 TUV EN60950-1 BSMI CNS14336 CCC GB4943 J60950-1 approved |
| EMC Emission | Compliance to EN55022 class B EN61000-3-2 3 FCC PART 15 / CISPR22 class B CNS13438 class B GB17625.1 |
| EMC Immunity | Compliance to EN61000-4-2 3 4 5 6 8 11 light industry level criteria A |
