AF6DS - Peter

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Disclaimer:  The  projects presented here are for informational and educational purposes only.  The author is not responsible nor liable for direct, indirect, consequential, incidental loss or damages to equipment and/or bodily injury resulting from the information provided here.
Always think safety first, and use common sense !

No endorsement of any product is expressed or implied.
Details  •  Documentation  •  Dissemination
Updated:
October 24, 2010

Contents

  1. 1 Amateur Radio
    1. 1.1 Go-kits (for emergency or portable communications) using Pelican and B&W cases
      1. 1.1.1 VHF operation w/packet - Pelican model 1400
      2. 1.1.2 VHF operation - Pelican model 1150
      3. 1.1.3 HF operation - Pelican model 1400
      4. 1.1.4 APRS beacon - B&W International model Type 5
    2. 1.2 HF projects
      1. 1.2.1 Yaesu MH-59A8J DTMF microphone modification (W1AEX) - for improved low-end frequency response
      2. 1.2.2 MFJ-347 "HF Stick" mini-dipole mount design modification
      3. 1.2.3 HF 1:1 RF current air choke (to eliminate feedline radiation) - intended for 15 or 20 meters
      4. 1.2.4 Isotron 15 meter antenna enhancements
      5. 1.2.5 Venetian blind headrail HF indoor antenna (patio door aluminum frame as counterpoise)
      6. 1.2.6 Inverted-V antenna (using MFJ-1620T 20 meter "HF Stick"s, reused from a MFJ-2220 kit)
      7. 1.2.7 PSK31 setup for Yaesu FT-857D and PC/laptop soundcard, with fldigi / gMFSK 
      8. 1.2.8 Yaesu FT-857D CAT interface circuit (for use with LDG YT-100 tuner)
      9. 1.2.9 LDG YT-100 tuner/radio interface cable 8-pin mini-DIN insertion force issue
      10. 1.2.10 HF RFI from 120VAC LED lamp
    3. 1.3 Packet radio projects (including APRS)
      1. 1.3.1 Presentation "APRS Packet Digipeating via the ISS"
      2. 1.3.2 OpenTracker+ (OT1+)
      3. 1.3.3 Packet TNC / radio interface cable wiring
    4. 1.4 ARRL General License Class (2007-2011) course presentation, sections 4.5 - 4.7
    5. 1.5 Reviews @ eHam.net
    6. 1.6 Equipment
    7. 1.7 License
    8. 1.8 Emergency Preparedness Training
  2. 2 Misc (non-ham projects)
    1. 2.1 Embedding Google Map KML data into Google Sites
    2. 2.2 Telescope - Meade SCT OTA conversion
    3. 2.3 Itty Bitty (Radio) Telescope - IBT or IBRT
    4. 2.4 HDTV Yagi antenna (WA5JVB), with copper wire and PVC pipe
    5. 2.5 PVC pipe earthquake brace for a LCD TV
    6. 2.6 Mounting GPS receiver on bicycle handlebar
    7. 2.7 Telephone LED ringer
    8. 2.8 Universal Scalability Law (Gunther) analysis with R

External reference links are italicized.

Amateur Radio

Go-kits (for emergency or portable communications) using Pelican and B&W cases

Note: The Pelican cases shown here are no longer waterproof / watertight, since holes have been drilled into them - for mounting, to allow antenna cables to feed through, etc.  The cases are more than just for storing equipment, they're an integral part of equipment operation.

VHF operation w/packet - Pelican model 1400

Yaesu FT-1802 mobile transceiver, Kantronics MT1200 1200-baud packet TNC, and homemade blue LED reading lamp:
This is the equipment and setup that I use to digipeat APRS packets with the ISS (ground plane antenna not shown).

VHF operation - Pelican model 1150

Yaesu FT-1500 mobile transceiver, and homemade white LED reading lamp (w/740 ohm 1/2 watt series resistor):

HF operation - Pelican model 1400

Yaesu FT-857D HF portable transceiver, with external 1mA analog meter (the Pelican 1400 go-kit fits nicely inside a backpack):
Cheat sheet for Yaesu FT-857D:
  • PDF - 2 pages
  • ODP - OpenOffice source document

APRS beacon - B&W International model Type 5

Argent Data OpenTracker+ (OT1+), USGlobalSat BR-355 GPS module, Yaesu VX-6R, Red-Dee-2 Connect PS-4.  Items are mounted with cable ties to a 1/4" thick plastic sheet.  Plastic sheet is then attached to case with Velcro Extreme strips.
[The Yaesu VX-6R can be powered solely off of external 12 volt source without any battery installed - no damage observed yet!  Make sure that supply voltage never drops below 8 or 9 volts, else HT and OT1+ will go into transmit spasm (as observed with a weak 1.2 Ah SLA battery).
This project was originally developed for the May 2010 Maker Faire in San Mateo, CA for an APRN (SSTV-enabled APRS) demo at the amateur radio booth - it has since been disassembled and now being reused for interfacing with a Yaesu FT-8900R.

HF projects

Yaesu MH-59A8J DTMF microphone modification (W1AEX) - for improved low-end frequency response

Not shown is enlarged microphone port opening, and internal baffle removal.
Yaesu FT-857 mic gain set to 15 (of 100) after a VHF audio test with other local hams.  W1AEX recommends a setting of 20.

MFJ-347 "HF Stick" mini-dipole mount design modification

HF 1:1 RF current air choke (to eliminate feedline radiation) - intended for 15 or 20 meters

Isotron 15 meter antenna enhancements

Venetian blind headrail HF indoor antenna (patio door aluminum frame as counterpoise)

  • Installed using sliding window lock attached to patio door frame, and coax center conductor clip attached to venetian blind headrail
  • Construction details, patio door mount
  • SWR is approximately 4.4:1 on 20 meters, and 2.3:1 on 10 meters - as measured with Autek Research VA1 analyzer.  This antenna setup is probably best suited for 10 meters, where the background S-meter noise is the lowest.  FYI: venetian blind headrail is 8 1/2' long, and patio door is 8' wide x 6 1/2' tall.
    [ With this antenna, I made a 20 meter CQWW DX contest contact ! ]

Inverted-V antenna (using MFJ-1620T 20 meter "HF Stick"s, reused from a MFJ-2220 kit)

PSK31 setup for Yaesu FT-857D and PC/laptop soundcard, with fldigi / gMFSK 

Interface cable
Ubuntu 8.04 (Hardy Heron) Linux w/gnome
Slackware 13 Linux w/fvwm, using fldigi

Yaesu FT-857D CAT interface circuit (for use with LDG YT-100 tuner)

      • schematic (PDF), interface box, gEDA/gschem file (Linux)
        [This circuit seems to be noisy (birdie heard) when the FT-857D frequency is adjusted every second by gpredict software for satellite doppler shift tracking, but no switching noise is heard when changing frequency with fldigi software - laptop or grounding issue?  Maybe a Yaesu CT-62 cable will work better.]

LDG YT-100 tuner/radio interface cable 8-pin mini-DIN insertion force issue

  • Comparison photo sharp-edged, rectangular ended pins on the 8-pin mini-DIN makes it difficult to insert the LDG supplied 14" cable into either the LDG YT-100 tuner or Yaesu FT-857 CAT port.  A Sun Microsystems 6' keyboard extension cable (P/N 530-1442-02) has slimmer, round-ended pins for easier insertion - and hopefully has less wear on the radio or tuner CAT connectors.  This cable is shielded, fully pinned, straight through, for compatible tuner operation with the radio!

HF RFI from 120VAC LED lamp

  • S-meter noise reading indicating HF RFI from 120V LED lamp, as picked up by 15 meter Isotron located 12 feet away -  whereas incandescent light bulbs do not have this problem.  [Note: have not re-investigated the issue using my 15m Dunestar filter.]

Packet radio projects (including APRS)

Presentation "APRS Packet Digipeating via the ISS"

(Earlier editions of this presentation were titled:  APRS via the ISS - A Quick Tutorial)

  • PDF - 46 pages (~ 1.6 MB)
  • ODP - OpenOffice source document (~ 800 KB)
    February 11, 2009, Rev. 6
Permission granted to distribute, modify, and/or pilfer - provided appropriate credit is given, thanks!

This presentation was given at:

OpenTracker+ (OT1+)

Modification

Motivation for the modifications

  • OT1+ modification schematic to prevent GPS super-cap reverse surge (when source power is removed or shorted), thus protecting the LM7805 voltage regulator and microcontroller.  The R11 value was changed from 10K to 3K ohm to provide better serial port levels to the microcontroller.  Additional protection circuitry added to the serial port input FET for static and over-voltage.  RFI reduction, with 10K pullup resistor, to Transmit Now.
    A GlobalSat BR-355 serial GPS receiver (    +/- 5V RS-232 voltage swing) is being used with the Argent Data Systems OpenTracker+.
  • OT1+ modification photo showing: surge protection diodes soldered in on top of the LM7805 voltage regulator, low-voltage drop Schottky diode "jumpered" onto +5V and Vext on JP1 (pins 6 and 8), Transmit Now 10K pullup to +5V, 3K @ R11, serial port protection circuit.
    Earlier modification photo.
  • OT1+ COR_In 10K ohm pulldown to prevent false CD prior to FW 54908, using 10K 0805 size SMT resistor (photo and modfication schematic shows old value of 1.1K ohm).

Yaesu interfacing

Packet TNC / radio interface cable wiring

ARRL General License Class (2007-2011) course presentation, sections 4.5 - 4.7

    • PDF - 44 pages (~ 800 KB)
    • ODP - OpenOffice source document (~ 1.3 MB)
      April 29, 2010 - FYI, not a complete treatise due to preparation time constraints

Reviews @ eHam.net

Equipment

License

  • KE6SIO (March 1995 No-code Tech & June 2007 General class upgrade - Cupertino, CA)
  • AF6DS (July 2007 Amateur Extra class upgrade - Milwaukee, WI)
I got my license thanks to Gordon West's (WB6NOA) study guides.  I also briefly reviewed/proofread a few chapters of Gordon's Extra Class Study Manual 2008-2012.

Emergency Preparedness Training

ARES (Amateur Radio Emergency Service) member
CERT (Community Emergency Response Team) trained - not really ham radio related

Misc (non-ham projects)

Embedding Google Map KML data into Google Sites

Telescope - Meade SCT OTA conversion

De-forking the Meade LX50 8" SCT, and modifying the OTA (Optical Tube Assembly) for GEM

The goal is to make the Meade LX50 telescope more manageable for transporting and handling - so the original fork mount is detached from the OTA, and a dovetail is attached to the OTA for GEM use:
The original LX50 fork mount and OTA assembly weighs 36 lbs.  Without the 25 lb. fork mount, the OTA weighs only 11 lbs. - making it much lighter and less bulky.

The large 10" diameter hose clamps were bought from a marine/boating store, since the heating/airconditioning stores only had clamps of maximum of 7" diameter.

Itty Bitty (Radio) Telescope - IBT or IBRT

A science project found on the Internet using a small 18" satellite dish (DirecTv or Dish Network) for detecting ~12 Ghz radiation from the sun, trees, human body, etc.  For more info, do a web search on: Itty Bitty Telescope.
Satellite finder meter adjustment - aim dish to get lowest meter reading, adjust meter gain knob until mid-scale reading, then aim at various objects which should get full scale deflection.

HDTV Yagi antenna (WA5JVB), with copper wire and PVC pipe

Here's a homemade Yagi antenna for HDTV use - thanks to WA5VJB.  WA5VJB's Popular Communications article (PDF) .

Materials are:  3/4" schedule 40 PVC pipe, #8 AWG solid copper wire, 75 ohm RG59 coax cable, 60 watt soldering iron, PVC cement, super glue (to glue copper wire to PVC pipe), hot glue (to prevent stress on soldered connections), drill, cable ties.  Note: a 60 watt soldering iron was needed to properly melt the solder on #8 gauge copper wire.
The antenna is being used indoors, and with a Digital Stream DSP7500T DTV converter box.  Find where to point the antenna at: antennaweb.org

PVC pipe earthquake brace for a LCD TV

The PVC pipe contraption secures the back of a LCD TV (wall mount bracket holes) to a TV stand.  The TV pedestal itself is not secured to the stand.  Careful alignment and assembly can be challenging especially when dealing with 45 degree PVC sections and quick bonding PVC cement.  [One section of pipe ended up a bit short, so it had to be re-patched with a salvaged PVC T-section].

Mounting GPS receiver on bicycle handlebar

Cable ties secure a Pelican 1010 case (with a Garmin Nuvi 260 receiver inside) to the bicycle handlebar.  Holes are drilled in the case where the cable ties feed through.  Some portion of the rubber liner insert was removed to make the GPS unit fit inside when the cover is closed.

Telephone LED ringer

Universal Scalability Law (Gunther) analysis with R


© 2009-2010 Peter Chow.  All Rights Reserved.
email, eQSL.cc
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