Sunday, May 30, 2010

ESSB: Transmitted Audio Quality on Single Side Band.

Transmitted Audio Quality: If you are a serious SSB operator like I am then you will pay close attention to the transmitted audo quality of your signal. Two black boxes that you basically use for HiFi SSB are the 8 Band EQ and the EQplus produced by Julius Jones, W2IHY. I have found that these two gadgets produce a transmitted audio that is as close as broadcast audio quality as I can get on SSB and Julius did a great job. I get consistently excellent reports on my transmitted audio quality and have also found that with signals that I receive and find with exceptional audio quality that the station on the other side is running the same pair of black boxes.

The equipment used for transmitted audio at my station. [ Visit on details about eSSB]

Following is a photo montage of some of the audio processing equipment and microphone that I use for ESSB:

Saturday, May 29, 2010

Yaesu FT-920 HF Transceiver.


Yaesu's engineers had dedicated themselves to the enhancement of Signal-To-Noise ratio in designing the FT-920. Since recovered audio is the most important consideration at both ends of the communication circuit, the FT-920 is particularly optimized for noise reduction, wide dynamic range consistent with excellent sensitivity, audio tailored to the operators own voice pattern, and ease of operation. The result is an efficient transceiver design without a peer in its price class.

High-Tech Receiver Front End
The FT-920's receiver front end, adapted from the FT-1000D and FT-1000MP legacies, utilizes an up-conversion technique, with a 68.9 MHz first IF being produced by the four-FET doubly-balanced first mixer. Following the first mixer, a four-pole "roofing" filter protects the following stages.

This front-end architecture results in excellent image- and intermodulation-rejection characteristics for the receiver system.

New-Design MOS FET Power Amplifier
Utilizing rugged MRF255 FETs in the final amplifier, the FT-920 produces 100 Watts of clean output power from 1.8 MHz through 54 MHz! Built into an aluminum die-cast unibody chassis, the FT-920's thermal dissipation capability is unnmatched in its class.

High Speed DSP
The audio Digital Signal Processing (DSP) system of the FT-920 runs at a blazing 333 MIPS (Million Instructions Per Second), providing highly-effective filtering and noise reduction with a minimum amount of distortion or "artifacts" that can degrade reception. Noise reduction, bandpass filtering, and auto-notch filters are provided, in addition to a microphone equalizer to boost talk power and enhance audio quality.

Oustanding Digital Mode Features
Easy interfacing to digital modes is yours with the fT-920, and its flexibility for digital operation is beyond compare.Both AFSK and FSK connetinos may be accomplished, and the AFSK line is isolated from the microphone jhack, so you never have to worry about a "live mike" while you're on PSK31. PTT, fixed-level audio output, and squelch status lines are also available.

And for connection to a tape recorder, a convenient "AF OUT" RCA-type connector simplifies audio interconnection, independently from the TNC connections used for digital transceive operation.

CW Operating Flexibility
For CW experts, the FT-920 includes a CW Spot control, for precise alignment of your frequency to that of the station you're working. You also get a CW Tuning Meter, CW-Reverse sideband selection, a CW Pitch control, and a CW Message Memory electronic keyer, with storage and recall access from the front panel.

Advanced Multi-Function Display
The FT-920's Omni-Glow™ display includes a specially-engineered wide-angle lens, to ensure clarity of viewing over a very wide range of angles. The high speed digital metering includes a "peak-hold" feature, to allow easy monitoring of peak signal, power, or SWR values. You also get monitoring of the input DC voltage, speech processor compression level, DSP relative bandwidth, Clarifier offset, and a host of other information including tuning meters for both CW and FM modes.

PA3BFM reviews the Yaesu FT-920

Processed SSB Audio
Those who know me and my transmitted SSB signals know that I care allot about the transmit quality of my signal. I am not one of those local DX'ers who run tons of QRO power and don't care about the quality of their transmitted audio (you know the ones with excessive power, terrible audio, over compression and splattering!).

The constant compliments I receive over the air on the quality of my transmitted audio are a testimony to the efforts put into the front end audio processing.

With the 3 main rigs that I run on HF, FT-2000, TS-870S and the FT-920, I have paid special attention to ensure that the SSB signal is transmitted either in enhanced or extended SSB. But thanks must also be given to many friends on air and off air who are professional broadcasters as well as professional audio engineers who have given me lots of advice in order for me to achieve my ESSB goals.

For the FT-920 it is run in enhanced SSB mode and I use a combination of the KAM RT-1 - Ribbon Tone Dynamic Microphone into a Behringer FEX800 Enhancement/Effects Processor + FEQ800 Equalizer and a Behringer "Shark" DSP-110 Gate/Compressor/Preamplifier:

Here are some videos of what HiFi or ESSB can sound like:

Yaesu FL-2100B HF Linear Amplifier

This is the station Linear Amplifier, it is a Yaesu FL-2100B which operates in Class B grounded grid configuration using a pair of 572B tubes. Max. input power is 1,200 watts PEP.

Additional box fan used for ventilation of heat placed on top of the FL-2100B:

<span class="blsp-spelling-error" id="SPELLING_ERROR_2">Yaesu</span> FL-2100Z
Configuration Class AB2, grounded grid
Frequency coverage 160m - 10m including WARC bands
Plate input power 1200W PEP SSB, 1000W CW, 400W AM/FM/FSK
Plate voltage 2400V (no load)
Drive requirements 100W PEP for full output
Input impedance 50 ohms unbalanced
Output impedance 50 - 75 ohms unbalanced
3rd order distortion products 31dB or better at 1kW PEP
Tube complement 2 x 572B/T160
Cooling system Forced air
Power requirements AC 100/110/117/200/220/234V 50/60Hz
Current consumption (100-117V) 18A
Current consumption (200-234V) 9A
Dimensions 157H x 345W x 326D
Weight Approx 20kg