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| Next Bunny Hunt:
TBD |
Location: To be determined |
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| New Links! | RDF
T-Hunts around Puget Sound Area: KLICK
HERE courtesy of Art Jury, KF7GD Lots of T-Hunt info here: www.thunt.org Check it out. Nice story from the ARRL: http://www.arrl.org/news/features/2006/05/05/1/ |
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| General RDF info | The "Homing IN"
website has lots of RDF general information.
IMHO... it leaves just enough out to make me wanna buy the book. http://members.aol.com/homingin
Note: This website does not allow frames and may seem
to take over your web browser so you can't return to the this page by using
your BACK button. |
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| Tape Measure Yagi | Build the
Tape Measure Yagi (thanks Joe
Leggio, WB2HOL)... plans here: NEW for 2008: on kr7w.org website: www.kr7w.org/TMY.pdf
http://home.att.net/~jleggio/projects/rdf/rdf.htm |
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| Yagi Attenuator | You'll need an
attenuator for your Tape Measure Yagi (or your antenna of
choice) The idea is to
"de-sensitize" your Handy-Talkie so the S-Meter is effective (not over
loaded) The methodology is
known as an "off-set attenuator" The attenuator gizmo contains a local
oscillator that mixes with the antenna's received signal and changes the
output frequency to to your HT to be some value above or below the Fox/Bunny's transmit
frequency. i.e. If the Bunny was transmitting on 146.565 MHz... and
the active attenuator has a local oscillator freq of 4.0 MHz.... then your HT
would be tuned to 142.565 or 150.565. This method works well to keep the
bunny/fox's signal from sneaking into the HT thru the battery connection or
keypad or some other backdoor way... if you are close to the hidden transmitter.
This type of attenuator is much easier to build than a passive attenuator
that uses many resistors and slide switches in shielded compartments. Here's the recommended attenuator unit from the Homing In website: [Note... I am pretty sure that this is the one that Art Jury demo'd at the RCT meeting] http://members.aol.com/joek0ov/offatten.html It uses a 4 Mhz oscillator package available from Jameco electronics (another good place for the experimenter to shop). Ordering details are in the text. Here's another off-set active attenuator. It uses a 1.000 MHz crystal as the local oscillator frequency. From Joe Leggio, WB2HOL [the tape measure Yagi guy].
NEW for 2008:
KR7W design Active Attenuator:
KLICK HERE for Article (from
4/2008 Bark) |
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|
The Fox or Bunny's XMTR Controller/ IDer |
Want to build your RDF Hidden Transmitter? [AKA "bunny" or "fox"] ...Then
you'll need a transmitter controller of some sort to key up the HT (presuming
your Fox/Bunny will be a Handi Talkie)... Remember, you must ID your signal
every 10 minutes. More often would be better in RDFing. PicCon Transmitter Controller... was the unit that Art Jury (our guest at the meeting) was using. It can be bought as a kit ($42.00) or built and tested ($66.00) at Byonics. http://www.byonics.com/piccon/ This unit uses the touch tone dialing pad of your HT to send tones to the controller to program it. Another Transmitter Controller,
the ID-O-Matic, kit only, can be obtained from Dale Botkin N0XAS for way
less money ($20.00) and seems easier to program by connecting your PC's
serial port and making menu choices. Also you gotta add a small amount of
circuitry to key up your HT with a 2.2K ohm resistor. Personal note:
I've purchased from Dale... and I like doing business with him. Also, if
you like to experiment and build your own stuff... this site has useful
miscellaneous parts. |
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