ATS-909 Modification and Alignment
Article Index --- click here to unfold ---
Newest Pages
NEW: Ubuntu PPAs for AlacrittyNEW: Trumpists Kicking the Hornets Nest
NEW: Introduction to Catbird Linux
NEW: Skywave Linux Updated to ver 4.1
i3wm: Using i3-ipc to Float Windows
How to Record from WebSDR and OpenWebRX Sites
Programmatic RTL-SDR Frequency Claibration
Public KiwiSDR Lists
Malaysia Airlines Flight MH17: Simply Mass Murder
The Anonymous Cathay Pacific Employee Letter to Hong Kong
For For Cathay Crews Crossing Borders With Electronics
Photo Gallery 9: The New Life Movement in China, 1944
E Pluribus Unum: From Many, One, Dammit
HFGCS Quick Tune SDR List
The Robert Mueller Iron Triangle Speech
A Rant About One Party Rule
Best OpenWebRX and WebSDR Servers
SDR School via YouTube
ADALM-PlutoSDR on Linux Systems
MOFO Linux: Defeating State Censorship and Surveillance
Linux: Distros, Code, and Nifty Software
NEW: Introduction to Catbird LinuxNEW: Skywave Linux Updated to ver 4.1
NEW: i3wm: Using i3-ipc to Float Windows
Skywave Linux: HPSDR, WebSDR, and RTL-SDR ready to run.
Siduction Linux with the Cinnamon Desktop
Siduction Linux with the LXQT Desktop
Andy's Ham Radio Linux 15 and QtRadio
Booting Multiple Linux Disc Images with Grub2
Porteus Linux Hard Drive Installation
UPDATED: MOFO Linux - For Unrestricted Internet
Aptosid with LXDE
Asus EeePC 1215N with Linux
Autostart Tweaks for KDE3 and KDE4
Broadband Speed Tweaks For Linux
Fixing the Firefox 3 Rendering Bug
Linux on Solid State Drives
Linux Wireless Interface Driver Updates
Setting Polkit to Automount USB Devices
Sidux with LXDE
Fixing Skype Inverted Video
SLAX Remix - kernel upgrades
Flash Drive Linux - Introduction
Flash Drive Knoppix 5.3 - Part 1
Flash Drive Knoppix 5.3 - Part 2
Flash Drive Knoppix 6.0 - Part 1
Flash Drive Knoppix 6.0 - Part 2
Flash Drive SLAX - Part 1
Flash Drive SLAX - Part 2
Flash Drive Bluewhite64 - Part 1
Flash Drive Bluewhite64 - Part 2
Flash Drive Linux - Basic Customization
SLAX Customization - Part 1
SLAX Customization - Part 2
Bluewhite64 Customization - Part 1
Bluewhite64 Customization - Part 2
Long Range Wi-Fi
Basics of Long Range Wireless NetworkingLinear Focus Parabolic Wi Fi Antenna
High Gain Wi Fi Dish Antenna
High Gain Helical Wi Fi Antenna
High Gain Yagi Wi Fi Antenna
High Power Wireless Adapters
Wi Fi Extender Antenna for Routers
Belkin F5D7050 External Wi Fi Antenna
Linksys WUSB54GC External Antenna Mod
Compat Wireless Linux Drivers
Installing WPA_Supplicant for Wi-Fi Security
Linux Wireless Interface Driver Updates
Linux Wireless Interface Driver Support
NetworkManager and Consolekit
RT73 Wireless Drivers for Linux Kernel 2.6.27+
RT2860 Wireless Drivers for Linux Kernel 2.6.27+
Radio: Amateur Radio, Aero Radio, Shortwave, etc
NEW: Programmatic RTL-SDR Frequency ClaibrationNEW: Public KiwiSDR Lists
NEW: GHFS Quick Tune SDR List
UPDATED: Best OpenWebRX and WebSDR Servers
UPDATED: Skywave Linux: HPSDR, WebSDR, and RTL-SDR ready to run.
CubicSDR on Debian, Ubuntu, and Linux Mint
Dump1090 for Linux Mint 17.1 and Siduction 2014.1
Software Defined Radio - An Introduction
QS1R Direct Sampling SDR
Chaining SDR Audio Interfaces
FLEX-6000 Direct Sampling SDR
UPDATED: RTL2832 Software Defined Radio
WebSDR Digimode Reception
Enabling FLASH in Jack Audio
Realtime Software Audio Processing
Liberation Technology
MOFO Linux - For Unrestricted InternetVeracrypt Encryption for Linux
Veracrypt Encryption for Windows
Using Google Within China
Popcorn Time and Flixtor for Uncensored Streaming Media
DNS Encryption using DNSCrypt
Galaxy Nexus Privacy and Robustness Enhancements
Galaxy SIII Privacy and Robustness Enhancements
Flash Drive Encryption for Linux
Flash Drive Encryption for Windows
Multihop VPN Connections for Strong Internet Privacy
Open and Free DNS Server List
OpenVPN Cloaking against Deep Packet Inspection The Serval Mesh Phone Project
Skype's Robust Security
Man in the Middle Wireless Security Risks
Wireless Security and Surveillance
Digital Audio
Adjusting Audio Dynamics in VLCBacking Track Prep Guide
Ipod Music Processing Guide
How To Record Record Live Music Performances
Realtime Software Audio Processing
Chaining SDR Audio Interfaces
Aerospace Radio, Aviation, Pontification, and Opinion
NEW: Trumpists Kicking the Hornets NestNEW: The Anonymous Cathay Pacific Employee Letter to Hong Kong
NEW: For For Cathay Crews Crossing Borders With Electronics
NEW: E Pluribus Unum: From Many, One, Dammit
NEW: HFGCS Quick Tune SDR List
NEW: The Robert Mueller Iron Triangle Speech
NEW: A Rant About One Party Rule
Captains Authority Versus Autocratic Airline Management
Malaysia Airlines Flight MH17: Simply Mass Murder
Malaysia Airlines Flight MH370 - A Media Circus
High Gain Air Band Antennas
Apollo Unified S Band Communications
Chinese Anti-Stealth VHF Radar
Oceanic Communications - Procedures, Equipment, Voice and HFDL
Boeing 737NG Radio Equipment
Boeing 767 Radio Equipment
NAOC-TACAMO Monitoring
My Flight on 9/11
Joshua Chamberlain's Leadership Tips
Special Operations Forces Truths
TWA 800: Just Give Me Some Truth
Photo Gallery
Aviation Photo Gallery 1: Snapshots From My JourneysAviation Photo Gallery 2: On the Road With ATA Airlines
Aviation Photo Gallery 3: More ATA Airlines
Aviation Photo Gallery 4: Southwest Airlines is the Borg Empire
Aviation Photo Gallery 5: Starting Over, Moving On...
Aviation Photo Gallery 6: More Viva Macau
Aviation Photo Gallery 7: Mainland China Airline Flying
Aviation Photo Gallery 8: Chinese Smog and Fog
NEW: Photo Gallery 9: The New Life Movement in China, 1944
Broadcasting
BBC Radio Blooper - Adolf MerckleTV DXing the World Trade Center
New York TV after 9/11
Live Music Recording
Adjusting Audio Dynamics in VLCBacking Track Prep Guide
Ipod Music Processing Guide
How To Record Record Live Music Performances
Radio Circuit Modifications
ATS-909 ModificationsATS-909 Manuals
ATS-909 Alignment Procedure
ATS-909 Alignment Spectrograms
The ATS-909 / DX-398 is certainly one of the great portable shortwave receivers ever made. It performs reliably, has many fine features, and is widely available at a reasonable cost. Countless people use it as a source for news, information, and entertainment around the world. The radio performs better than many full-sized tabletop receivers of years past. It well outperforms my old DX-160, and does more than my Heathkit HR-1680. Despite this, there is room for improvement.
I will not repeat the numerous improvements to the ATS-909 that may be found on other modification websites, such as davemoison.org but will limit my comments to a few changes that mean the most in my shortwave listening experience with the receiver. I first obtained this dandy radio in 1995, and have taken a soldering iron to it numerous times. It is not a difficult radio to work on, but one must be careful with its surface-mount components. There are a few cables and delicate connectors that should be handled with care. Considering those factors, I suggest making changes described below.
- Anti-Chuffing
- Beep Removal
- Finer SSB tuning (makes steps smaller, but you lose some ability to tune between 1 kHz increments); parallel SVR5 with a 4.7k resistor for 10 Hz steps
- Replace ceramic filter CF6 with a narrower one for better adjacent channel rejection on FM
- Restore segments of FM tuning range (diode change enables TV audio in the USA and some assisted listening devices). D310 on tuner board.
- Short resistor R7 to ground - allows gain reduction to zero
- AGC mods as described here; IF clipping mod not necessary
- Audio bandwidth enhancement
Improved AGC response:
- Popular modification sites on the web have suggested reducing capacitor C57 (on Pin15 of IC1) to a value of 10 uF. I disagree, and have had better results leaving it at 22 uF.
- Capacitor C11 should be verified to be 4.7 uF.
- The radio does not exercise enough control over strong signals. Local amateur and utility signals frequently slam the S meter to full scale and distort badly. I have solved the problem by increasing R181 to 470K. This slows the rate at which C11 recharges and also allows a more effective control of IF circuit gain.
AGC Schematic:
|
AGC Parts Layout: |
Audio Modifications for Better Bass Response:
To achieve a low end rolloff around 15Hz,
coupling
capacitors should be increased as
indicated:
- C67 and C68 (output from product detector) 4.7uF
- C80 (AM / SSB audio into IC3)
- C93 and C94 (input to audio amplifier IC6)15uF@10v
- C106 and C107
(input to the L and R power amplifiers IC4 and IC5)10uF@10v - C116 and C117
(output of L and R power amplifiers IC4 and IC5)1000uF@10v - C132 and C133
(output of auduo amplifier IC6) 10uF@10v
Product Detector Schematic |
Product Detector Layout |
For better oscillator frequency alignment without a counter, connect the audio to your computer sound card and follow this ATS-909 alignment procedure and refer to the ATS-909 circuit board images and alignment pectrograms.. Tags: ATS-909, DX-398, receiver mods, radio hacks ©2005 - 2020 AB9IL, All Rights Reserved. About, Contact, Privacy Policy and Affiliate Disclosure, XML Sitemap. |