WELCOME!

Welcome to the BMG Engineering, Inc. Home Page. Besides SuperDF product Info you will find here a lot of useful and interesting information. Browse and download or make copies of what interests you. You may publish or give away copies. Contact us with your questions, comments, suggestions, or requests. Note: The page will be growing in the future, so come back! Thanks for the visit! . . . . To see what's new, look at our Change Log. Last Update was done on 1 Oct 1999.

The SuperDF business is for sale!

I and my wife have reached a point in our lives where we wish to do other things, so we have decided to end our direct involvement in making and selling The SuperDF. Because the product is so extraordinary, I would like to see it continue. Therefore we are looking for a person or small company who would like to carry on The SuperDF product. See details.

Present or future owners of SuperDF need not be alarmed. We will keep this web site up as a Tutorial site. It will have appropriate references to whoever might buy the business. We will personally support buyers who have questions which the new owner may not able to answer. We will also honor the guarantee on all units we have sold, including KITs.

BMG Engineering Suspends RDF Sales

I have taken a job as a school teacher! Teaching has been a life-long passion of mine. I am teaching Computer Literacy for 5th through 8th grade at a Christian school, and helping out with K through 4th. Needless to say, this is a very demanding edveavor. I have spent much of the last summer writing the curriculum and dramatically improving our classroom. Now I do not have the time to support SuperDF sales. I am still hoping to sell the product line.

I intend to leave this site up, as a community service, because of its large tutorial content.

I don't know if or when I will resume sales. My best advice is to periodically check this Web Site.

CONTENTS

Active Links are shown underlined. Inactive (yet to be uploaded) links are not underlined. An * indicates the item is listed in more than one "Contents" section. FAQs -- Home Brew Articles -- Tutorials -- Jammers and Other "Problem" Signals -- About SuperDF -- Price List and Order Sheets -- Links to other Pages -- Let us develop your Web page for you -- Resume' of George R. Andrews

Home Brew Articles

Here are some pieces of RDF equipment you can build.

• Adcock Antenna for HF RDF* Learn about the Adcock antenna usable on the HF bands. Some information on building one.
• Attenuator, indestructible. Here is an attenuator good up to at least 5 GHz, lots of attenuation, and it can't be damaged by transmitting.
• Attenuator, pot. Quick and easy RF attenuator, from the junk-box.
• Automatic Gain Control (AGC) system that can be added to some receivers. On the author's receiver its meter reads full scale 10 feet from 10 Watts. No need for an attenuator! Recommended for advanced builders only.
• Quad Beam. Made from PVC pipe.
• Remote S Meter. Its nice to have a large S meter sitting on the dashboard.
• Adding an RF Gain Control. On the author's receiver, he could DF a 1 Watt transmitter 1 foot in front of a 4 element Quad beam!
• RF Sniffer with Tone Output. No need to look at it. Just listen to it. No tripping over stuff!

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Go to: FAQs -- Home Brew ... - Tutorials - Jammers ... - About SuperDF - Price List ... - Links - Resume'

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Tutorials

• Adcock Antenna for HF RDF* Learn about the Adcock antenna usable on the HF bands. Some information on building one.
• Balloon Tracking and Recovery*
• Buildings, Hunting Inside of. OK, we found the building, but where inside is the transmitter?
• Comparing SuperDF* with other RDF systems. (Text & a chart).
• "Dirty" tricks! Here are some things you can do to "scramble the brains" of hunters when you are hiding.
• Discussion of Propagation, Multipath, and Antennas as Related to Radio Direction Finding Yes, its a long title, but so is the discussion! But don't worry, its broken down into digestible pieces. (This Link leads to another "Contents.")

Doppler Explained

• Theory of the Amateur Radio Doppler.
• The "Doppler" is not a Doppler. A discussion on why the Amateur Radio Doppler is not a real Doppler.
• Doppler Weakness.

Emergency Locator Transmitter (ELT) hunting

• Hunting AM Signals with SuperDF*
• Hunting an ELT on the ground
• Hunting an ELT in the Mountains. An example.
• Setting up an ELT Hunting Team.

Equipment List. What do I need to hunt?

• Minimum equipment to get started
• More advanced equipment to add later

Grading RDF system types*. (Text & a chart)

How to hide a transmitter

• Terrain shielding
• Signal strength
• Remote control automatic transmitter
• Transmitter ID
• Beams

How to use:

• A compass
• A beam
• A Doppler
• A SuperDF Hand-Held*
• Signal strength information
• A map

• The "Ideal" RDF*. A Talk given at a convention of the Association of Public-safety Communications Officers (APCO).
• Personal Safety*. Its NO fun if you get hurt or get dead!!
• Search and Rescue* . . Learn about some of the SAR applications.
• SuperDF Used in Helicopter Search and Rescue*. Talk about being able to "Home In," this is the ultimate!

Jammers and Other "Problem" Signals
Be SURE to read the section "Personal Safety*."

• Accidental signals
• Catch A Jammer
• Catch A Mobile Jammer
• Dealing with malicious disruptions to repeaters
• Personal Safety!* The purpose is to stop the problem, not get hurt or get dead!!
• Spiral-In hunting technique
• Triangulation
• Interference Committees
  • Setting up your own
  • Training material
    • xxx
    • yyy
    • zzz...

About SuperDF

• Accuracy plot of SuperDF.....WOW!!
• AM Signals*, hunting with SuperDF
• Applications for SuperDF: A few are listed.
• Balloon Tracking and Recovery* with SuperDF
• Comparing SuperDF with other RDF systems. (A chart)
• Documentation: A few words about ours.
• FAQs   Frequently Asked Questions.
• Grading RDF system types. (Text & a chart)
• Hand-Held DFing
• The "Ideal" RDF. A talk given at a convention of Association of Public-safety Communications Officers (APCO).
• Kits are Guaranteed*
• Low Frequency operation (below 100 MHz)
• Multipath, Motion, and SuperDF
• Search and Rescue* . . Learn about some of the SAR applications, and the problems that SuperDF solves.
• Sensitivity Explained. How SuperDF can perform so well!
• Specifications & Features
• SuperDF Product Flier, SD...series
• SuperDF PRO Product Flier, PRO...series
• SuperDF PRO Pictures. OK, OK! ... But what does it look like? (Warning. Lots of graphics. Loads slow.)
• SuperDF Used in Helicopter Search and Rescue*. To the Rescue! Fast!
• Training Course flier
• Users of SuperDF. Who are the people or organizations who have bought and use SuperDF?
• Warranty, Service, and Customer Support. -- Kits are Guaranteed*

Frequently Asked Questions

• Can I build my own antenna for SuperDF?
• Can I remove the lower whips to make the antenna set lower on the car?
• Is there anything special about hunting above 550 MHz?
• Can I use a PVC cross-boom?
• Can I transmit while using SuperDF?
• Does SuperDF have a computer interface?
• What equipment do you recommend for a Radio Service company.
• Is there any benefit to using PIN diodes in the antenna switch assembly instead of the 1N4148's specified?
• Can I use an Adcock antenna on VHF or UHF?
• Can I hunt ELT or other AM signal?
• Would SuperDF be suitable for use in a Marine Environment?

Price List and Order Sheets

• USA Customers Link Removed During Suspension of RDF Sales
• Canadian Customers Link Removed During Suspension of RDF Sales
• Other countries

Resume' of George R. Andrews
NO, I'm not looking for work.

About this Home Page

This page has been referenced times.
To see what's new, look at our Change Log.

Busy? Let us develop your Web page for you

George R. Andrews (Russ, K6BMG)
BMG Engineering, Inc.
9935 Garibaldi Avenue
Temple City, CA
91780, USA

Voice 1(626)285-6963
Fax 1(626)285-1684 (24 hour automatic)
America OnLine: Grandrews
Web: http://members.aol.com/bmgenginc

(30 May 1998)

Send E-mail to grandrews@aol.com. (A message window will open.)