Radio Attic

Table of Contents

"You see, wire telegraph is a kind of a very, very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? And radio operates exactly the same way: you send signals here, they receive them there. The only difference is that there is no cat." -- Albert Einstein (1879 - 1955)

QRP Contests (and other operating events) (return to top)

QRP ARCI 50th Anniversary, Special Events stations in every state, DC, and Puerto Rico: examine schedule to find when to work AK, KS, ME, MS, NE, ND, & RI

April 2-3, 2011: QRP ARCI Spring QSO Party
August 27, 2011: QRP ARCI Welcome to QRP
October 15-16, 2011: QRP ARCI Fall QSO Party
November 5-7, 2011: ARRL Sweepstakes, CW (rules)
December 1, 2011: QRP ARCI Top Band Sprint
December 3-5, 2011: ARRL 160 Meter Contest (rules)

Original QRP Contest Calendar at the E-PA QRP Club

(Logs and Dupe Sheets for QRP ARCI events are available here.)

QRP Field Events (return to top)

April 23, 2011: QRP to the Field (traditionally the 4th Saturday in April; rules); theme: WPA/CCC/State Park
June 25-26, 2011: ARRL Field Day (always the 4th full weekend in June; rules)
July 31, 2011: ARS Flight of the Bumblebees (always the last Sunday in July; rules)
September 18, 2011: QRP Afield (always the third Saturday in September; rules)

February 4, 2012: Arizona scQRPions "Freeze Your B___ Off" (generally the first Saturday in February; rules)

(Logs and Dupe Sheets for QRP ARCI events are available here.)

Hamfests & Symposia (return to top)

February 13, 2011: Mansfield (Ohio) Hamfest
May 19, 2011: QRP ARCI Four Days in May QRP Symposium
May 20-22, 2011: Dayton Hamvention
August 6, 2011: Voice of Aladdin ARC Columbus Hamfest

Search for hamfests at ARRL

QRP Discussion Groups & Blogs (return to top)

QRP-Tech and sign in
QRP-L at QTH.Net, and the official archives
K5TR’s archive of QRP-L at kkn.net, with good search engine
QRP-L at Yahoo! Groups
W8KC’s qrpl.w8kc.com with QRP-L number look-up.
QRP-L.org

HF Pack and Yahoo! Club (and sign in)

eHam.net

QRPer.com, a blog by Tom Witherspoon, KF4TZK
The QRPer & Trail-Friendly Radio Extra, blogs by Richard Fisher, KI6SN
W2LJ’s Blog -- QRP, Morse Code & Amateur Radio
KC8QVO, a blog by Steve Damico
The Adventures of Rooster and Peanut with Steve, N0TU

Elecraft (return to top)

Elecraft

Reviews in QST at ARRL (Members Only)

K3 (April, 2008)
K3/100 (January, 2009)
K2 & Expanded Report (March, 2000); K2DSP (January, 2005), KPA100 (January, 2005)
K1 (March, 2001)
KX1 (April, 2004)

The Elecraft Owner Online Database

N0SS’s Amateur Radio Page, K2 Section

K2 Mods by W3FPR (new URL)
LA3ZA Unofficial Guide to Elecraft K2 Modifications
Improving the K2’s CW Filter Ultimate Rejection by KO0B

Elecraft K2 & K1 Links by K8ZT

PSK31 and an Elecraft K2 Mod (PDF) by WB4QXE

by G4ILO

Build a Headset for the Elecraft K2
Getting on Data Modes with the Elecraft K2

VA3UXB’s K1 & K2, with mods

K2 Quick Reference Cards:

by W3DX (HTML) at Elecraft
by NS6N (PDF) at Elecraft
by WF4I (PDF) at W3FPR

Rework Eliminator for K2, including Internal Mic Adapter

Heathkit (return to top)

On Heathkit Manuals: In October, 2008, the intellectual property rights to Heathkit legacy products were purchased by Don Peterson of Data Professionals of Pleasanton and it appears Mr. Peterson has been very aggressive in stopping on-line manual downloads and sales. Downloadable Heathkit manuals are no longer available at BAMA (or at the mirror) or from other sources on the web. Data Professionals offers printed copies of some manuals but at this time none are available for any of the Amateur Radio products ever offered by Heathkit.

HW-16 Yahoo! Group (& sign in)

The Heathkit Shop by Mike Bryce, WB8VGE
RTO Electronics, specializing in the repair of Heathkit Amateur Radio equipment
Harbach Electronics--Heathkit, Drake, Collins, and Dentraon parts and upgrade kits
N0JMY’s Hayseed Hamfest--Re-Cap kits

Technology Systems with photos of unbuilt kits and downloadable catalogs and manuals
The Heathkit Virtual Museum
Heathkit Message Board
Heathkit Information at Nostalgic Kits Central

Schematics for Heathkit equipment can be downloaded at Vintage Radio Information

The Benton Harbor Lunch-boxes: the Tener, Sixer, and Twoer

Thousands of these transceivers now in use across the nation, in homes, offices, cars, trucks, boats, etc., attest to their popularity and proven performance. Their neat, compact design, low cost and high versatility make them ideal for use in either mobile or fixed station installations. All feature crystal-controlled transmitters and tunable superregenerative receivers with RF preamplifiers designed for operation on the 2, 6 or 10 meter amateur bands. The highly sensitive receivers pull in signals as low as 1 microvolt and produce complete quieting on reasonable signal levels.

The transmitters with up to 5-watt input are more than adequate for "local" net operations and the communication range of all models is unlimited under "skip" conditions. Other features include: a built-in RF trap on the 10 meter version to minimize TVI; frequency multipliers on the 6 & 2 meter versions to provide straight-through finals from an oscillator using a fundamental crystal in the 8 mc range; built-in final amplifier metering jack, and "press-to-talk" transmit/receive switch on the front panel with "transmit-hold" position.

Kit includes a ceramic element microphone and two power cords, one for use with the built-in AC power supply and one for use with a vibrator power supply such as the Heathkit GP-11 for 6 or 12 volt mobile operation. Transfer from fixed station to mobile operation in a matter of minutes. Handsomely styled in two-tone mocha and beige. Less crystal.

HW-19, HW-29A, & HW-30 at the Heathkit Virtual Museum
HW-30 "Two-er" at Richard Post’s Boat Anchor Pix

FT-243 crystals are available from AF4K--$12 plus shipping
search eBay for FT-241 & FT-243 crystals

The 6m and 2m lunch-boxes cost $44.95 in 1964 and 1967. (1964 catalog page & lunch-boxes_ad_nov1967.jpg">Nov 1967 QST ad)

Hotwater QRP: the HW-7, HW-8, and HW-9

Whether you use it for standby, camping, emergency operation, or your primary rig, the Transceiver will prove its worth. Band changing and tune-up are easily accomplished with pushbutton band selection and single-control Tuning. The light-weight and compact Transceiver has pushbutton crystal transmit provisions for the novice or QRP roundtables. Main tuning is accomplished through a 6-to-1 vernier that is virtually backlash free. A Relative Powermeter, built-in sidetone, and carry-along size make the Transceiver a pleasure to operate.

ARRL Product Reviews on ARRL’s Members Only site:

HW-7 (January, 1973)
HW-8 (April, 1976)
HW-9 (July, 1985)
HFT-9 Antenna Tuner (July, 1984)

KK4KF’s HW-7/8/9 Information Page
Michael Bryce’s Repairing the HW-8 at The Heathkit Shop
WB6FZH’s HW-8 Page & HW-8 Modifications, Repairs, & Recollections
K8YTOs Index of HW-7, 8, and 9 Modifications in Excel 97 spreadsheet format

The Freq-Mite from Small Wonder Labs is ideal for incorporation within an HW-7 or HW-8. (See notes here about installing a Freq-Mite in the HW-8.)

In HW-8 Handbook, First Edition (1994), Michael Bryce recommends replacing the MPF-105 front-end in the HW-8 with a 2N4416 for a significant increase in sensitivity. He notes, "The extra pin of the 2N4416 grounds the case, and it may be done with a small hole drilled into the PC board nearby the new unit, or the ground simple (sic) may be left ’floating’ with no noticeable loss in performance." (This suggestion was not included in the Second Edition of the book.) The 2N4416 is available for $2.50 each at RF Parts. The 2N4416A is available at Mouser for $2.00 each. (Note: RF Parts has a $25 minimum order; Mouser has no minimum order.)

Classic Heathkit Stations:

DX-60: The DX-60 Amateur Transmitter with its many design features offers more in quality, performance, and dependability than any other unit in its price and power class! Superbly designed throughout, the DX-60 with its high quality components, clean, rugged construction and thoughtful circuit layout makes it an ideal "first" transmitter for the novice. Construction proceeds smoothly from start to finish with the complete, informative instructions furnished. All parts are easily identified and a precut, cabled wiring harness eliminates much of the tedious wiring. The completed unit with its neat, functional panel layout provides for maximum ease of operation.

Circuit-wise, the DX-60 features a built-in low pass filter for harmonic suppression, neutralized final for high stability, grid block keying for excellent keying characteristics and easy access to crystal sockets on the rear chassis apron. A front panel switch selects any of four crystal positions or an external VFO. Controlled-carrier modulator and silicon diode power supply are built in. Single knob bandswitching for 80 through 10 meters and pi network output coupling provide complete operating convenience. A high-quality panel meter shows final grid or plate current to aid in tuning. In every way, the DX-60 represents an outstanding amateur "buy." May be run at reduced power for novice operation. Less crystals.

Recent Equipment: DX-60 Transmitter Kit (July, 1961 QST) by George Grammer, W1DF, in QST Archives at ARRL
DX-60 at Heathkit Museum
DX-60 at Rich Post’s Boat Anchor Pix
DX-60 catalog page can be viewed on page 33 of the Christmas 1961 Catalog available at Technology Systems
DX-60 catalog page can be viewed on page 22 of the 1963 Catalog available at Technology Systems
Re-Cap Kits for the DX-60, DX-60A, & DX-60B are available at Hayseed Hamfest

HR-10: This handsomely-styled amateur receiver is a perfect match for the DX-60 Transmitter, providing complete high-performance station receiver facilities at low cost!

The HR-10 is designed for amateur band coverage only on 80 through 10 meters, for maximum accuracy and stability. Each band is separately calibrated on a large, easy-to-read slide-rule dial. The tuning dial is illuminated and provides over 6" of bandspread for precise frequency settings. A carefully-designed diode detector, plus BFO, tunes AM or CW and SSB signals. The 7-tube superheterodyne circuit features an RF stage for added sensitivity and employs a half-lattice crystal filter for excellent selectivity characteristics...a necessity with today’s crowded band conditions. Two IF amplifiers operating at 1680 kc provide good image rejection. Other features include: "S" meter to aid in tuning and determining relative strength of received signals; a 3-gang tuning capacitor to assure proper tracking of all circuits rather than "Broad Banding"; a front panel dial calibration control and provision for a plug-in 100 kc crystal calibrator to provide accurate dial calibration at any 100 kc point across the band. Other panel controls consist of: antenna trimmer, bandswitch, tuning, BFO tuning, RF gain, AF gain w/AC on-off switch, xtal. calibration on/off, STBY/RCV, BFO on/off, AVC on/off, and automatic noise limiter on/off. An accessory socket is provided on the rear chassis apron for receiver muting, etc., and a speaker jack is provided for use with any 8 ohm PM speaker. 21 lbs.

Recent Equipment: HR-10 Receiver (July, 1963 QST) by George Grammer, W1DF, in QST Archives at ARRL
HR-10 Receiver at Heathkit Museum
HR-10B Receiver at Rich Post’s Boat Anchor Pix
HR-10 catalog page can be viewed on page 33 of the Christmas 1961 Catalog available at Technology Systems
HR-10 catalog page can be viewed on page 24 of the 1963 Catalog available at Technology Systems
Re-Cap Kits for the HR-10 & HR-10B are available at Hayseed Hamfest
Reviews at Eham indicate the HR-10/HR-10B is an extremely poor performer; a Drake 2-B with 2-BQ would be a much better choice

Recent Equipment: Heathkit Model HG-10 VFO (October, 1963 QST) by Edward Tilton, W1HDQ, in QST Archives at ARRL
HG-10 VFO at Heathkit Museum
HG-10 VFO at Rich Post’s Boat Anchor Pix

Recent Equipment: Heathkit HW-16 C.W. Transceiver (January, 1968 QST) by George Grammer, W1DF, in QST Archives at ARRL
HW-16 Novice Transceiver at rigpix.com
Re-Cap Kits for the HW-16 are available at Hayseed Hamfest

HP-23 AC Power Supply at Heathkit Museum
Rebuild an HP-23 with the HP23R (~$65) or HP23RL (~$56) by Michael Bryce or the HP-23D (~$63) by Old Heathkit Parts
Note: The HR-10 and DX-60 each feature a built-in power supply and don’t need an HP-23.

FT-243 crystals are available from AF4K--$12 plus shipping
search eBay for FT-241 & FT-243 crystals

Heathkit Citizen-Band Walkie-Talkies:

The GW-31/31A "Hand-Held Transceiver" is a single-channel rig with superregenerative receiver and crystal-controlled 100mW (input) transmitter.

The GW-21/21A "Deluxe Hand-Held Transceiver" is a single-channel rig with superheterodyne receiver and crystal-controlled 100mW (input) transmitter. It features a squelch circuit and external antenna and earphone jacks. The GW-21/21A is significantly larger than the GW-31/31A. Click here for schematic of the GW-21A.

The GW-52A appears to be a GW-21A with internal rechargeable batteries.

WD8RIF has a pair of GW-21 transceivers and a GW-31 which he may move to ten meters.

GW-21/21A: The receive crystal is 455kc higher in frequency than the transmit crystal.

The GW-21 & GW-31 were designed for the NEDA #1602 carbon-zinc battery which is 9 volts and 850mAh; see Energizer No. 246. Modern, smaller, 9v alkaline batteries have approx. 625mAh capacity; see Energizer 522; a pair in parallel would have 1250mAh capacity.

Ten-Tec (return to top)

ARRL Product Reviews:

Argonaut 505 (November, 1972)
(Apparently, the ARRL never reviewed the Argonaut 509 or 515...)
Agonaut II (January, 1992)
Argonaut V Model 516 & Expanded Report (April, 2003)

Omni D (January, 1980)
Omni V (November, 1990)
Omni VI (January, 1993)
Omni VI Plus & Expanded Report (November, 1997)
Omni VII (July, 2007)

TenTecWiki

The W8KC Virtual Ten-Tec Museum

Power Mite by VE3JC
Power Mite manual in .PDF format

The Odyssey of the Argonauts by Anthony Luscre
WB6FZH’s Argonaut 505 portable station in a tube caddy

Argonaut 509 Schematics courtesy of Rob Frohne

According to Paul Clinton, WD4EBR, Ten-Tec Service Manager (email), the dial string for the Argonaut 509 is $1.50 and the PTO kit is $25.00. Shipping is $6.00.

The NorCal VE3DNL Marker Generator would work well as a crystal calibrator for the Argonaut 509.
The NorCal FCC-1 Frequency Counter looks ideal for an external digital display for an Argonaut 509.

From The Second Coming of the Argonaut, November, 1971, CQ:

Long-time readers of CQ will recall the original "SSB Argonaut" built by W6AVA for W6UOU in 1957 and sent around the world in an effort to give many DX stations an opportunity to put their country on the air with the then-new mode of s.s.b. It is fitting, therefore, that a new low-power portable s.s.b. rig under development at Ten-Tec, Inc. should also be dubbed the Argonaut...

In today’s highly mobile society, the need for a small, light, portable rig is rapidly increasing. Reciprocal licensing, low-cost travel trailers, popularity of camping, proliferation of summer (and winter) homes all call for personal ham gear that is easily set up and takes little space.

For emergency service, stand-by equipment that can operate independently of commercial power is often a lifesaver.

Low power operation (QRP) is a growing facet of Amateur radio. Thousands of hams are finding an exciting challenge in conquering distance with a few potent watts.

With these applications in mind, work started several years ago to create an entirely new miniaturized transceiver that would be (1) ultra compact, (2) easy to service, (3) operable on s.s.b. and c.w., (4) usable at maximum power that can be reasonably supplied with a 12 volt lantern battery, (5) to operate on the ham bands, 80 through 10 meters and (6) to include features that make operating easy and convenient. The Argonaut fulfills these objectives.
Argonaut 509 at RigPix Database
Argonaut 515 at RigPix Database
Argonaut II at RigPix Database
Argonaut V at RigPix Database

Omni D at RigPix Database
Corsair II at RigPix Database
Omni VI Plus at RigPix Database

On powering older Ten-Tec 100-watt transceivers with non-OEM power supplies:

Michael Bryce’s Remote Power Controller (approx. $20) allows older Ten-Tec 100-watt transceivers to be powered by non-OEM power supplies or batteries while retaining functionality of the transceivers’ front-panel power switch. This device was described in the September, 2007 issue of QST and is available from Michael at his Heathkit Shop. (Currently, Michael’s website doesn’t have a page for this device; email him for cost and availability.)

Early Ten-Tec 100-watt transceivers lack SWR-foldback circuitry and rely on a fast circuit breaker in the power supply to protect the transmitter from high SWR. For use of these rigs with non-OEM power supplies or batteries, Ten-Tec recommends the use of an Airpax T11-1-20.0A-01-11C-V fast trip magnetic breaker. This device is available at Poco Sales. Price is one at $25 each, two at $12.50 each, and three at $9.25 each. Minimum order is $25. Paul Clinton, Ten-Tec Service Manager, says these are also available at marine shops--they’re used in charging circuits for trolling motor batteries.

R.L. Drake return to top)

R.L. Drake Virtual Museum
2-B Receiver & 2-BQ "Q Multiplier"

Manuals at BAMA

K2TQN’s Drake Novice Station, with 2NT transmitter and 2B + 2BQ receiver

WWII Command Sets (return to top)

The Command Set Story by Gordon Elliot White, from November, 1964 CQ (.pdf)
The Entire ARC-5 & B29 Radios at U.S. Military Aircraft Avionics from 1939 to 1945
The ARC-5 Pages at Glowbugs
AN/ARC-5 at Wikipedia
SCR-274-N by WA6IKJ
AN/ARC-5 Airborne Communications Systems
Command Sets at Ray Robinson’s Communications Museum
Command Set Transmitter SCR-274-N at Kurrajon Radio Museum

ARC-5/BC-455 Modification Notes by Phil Salas, AD5X (.pdf)
N3FRQ’s B-17 Aircraft ARC-5 Communication System
Photos of radios in B-17: here, here, & here
B-17 Radio Operator
B-17 Crew Requirements and Standard Operating Procedures, including Radio Operator
B-26 Radio Operator Compartment
Rich Post’s ARC-5 Navy Receiver
K5MBX’s WWII Military T-21/ARC-5 Transmitter
BC-696 schematic

KF6NUR’s BC-224 and BC-348 Aircraft Radio Receivers
BC-348 at Wikipedia
The Irrepressible BC-348 Receiver by WA2CBZ
Rich Post’s Signal Corps BC-348Q Receiver
BC-348 FAQ
AC7ZL’s Restoring the BC-348-Q
BC-348 by James Moorer
BC-348 at Kurrajon Radio Museum

rec.radio.amateur.boatanchors FAQ

Manuals are available in the "military" section of Boat Anchor Manual Archive (BAMA) ( and mirror)

Transmitters:

BC-696 (Navy T-19): 3 - 4 Mc
BC-457 (Navy T-20): 4 - 5.3 Mc
BC-458 (Navy T-21): 5.3 - 7 Mc
BC-459 (Navy T-22): 7 - 9.1 Mc

Receivers:

ARC-5/BC-453: 190 - 550 Kc
ARC-5/BC-454: 3 - 6 Mc
ARC-5/BC-455: 6 - 9.1 Mc

"Resurrecting a Command Set Transmitter" by W8KGI appears in January, 2009 QST.
"Bring That WWII Command Set Receiver Back to Life" by AD5X appears in January, 2009 QST.

Getting Your ARC-5 Transmitter Running Without Hacking it Up (PDF) at Glowbugs
Command Set Receivers for All Frequencies (PDF) at Glowbugs (CQ, January, 1967)
ARC-5 Receiver Mixer-Mod (PDF) at Glowbugs
The Command Set Roundup (PDF) at Glowbugs
AN/ARC-5 Military manual (PDF) at Glowbugs
Command Sets (PDF) at Glowbugs (CQ, 1957)
Guide to ARC Sets (PDF) at Glowbugs

Complete 80-Meter CW Station Using Surplus Units (PDF) at ARRL (June, 1960)
Vacation Special (PDF) at ARRL (May, 1967)
Single-Control Transmitter-Receiver (PDF) at ARRL (May, 1953)

Converting Surplus Transmitters for Novice Use (PDF) at ARRL
Keying the BC-696 (PDF) at ARRL (July, 1951)
Operating the BC-696 in TV Fringe Areas (PDF) at ARRL (December, 1953)
Crystal Control for the BC-457 and HC-459 (PDF) at ARRL (November, 1959)
Better Keying for the Converted BC-457 (PDF) at ARRL (March, 1953)
100 Watts on 160 Meters, Using a BC-458 (PDF) at ARRL (October, 1972)
"All-Band" BC-458--A Heterodyne V.F.O. for S.S.B. (PDF) at ARRL (February, 1953)
Improved Keying for the BC-459 (PDF) at ARRL (June, 1963)
Using the BC-459 With the V.H.F. Overtone Oscillator (PDF) at ARRL (December, 1957)
Simple Heterodyne Exciter for 10 Meters (PDF) at ARRL (November, 1953)
ARC-5 Transmitter Modifications: 14-Mc Output from the BC-459-A (PDF) at ARRL (June, 1948)
ARC-5 Transmitter Modifications: 14-Mc Output from the BC-459-A (PDF) at ARRL (June, 1948)
ARC-5 Transmitter Modifications: Eliminating Ripple in the BC-459-A (PDF) at ARRL (June, 1948)
ARC-5 Transmitter Modifications: NFM Added to the BC-459-A (PDF) at ARRL (June, 1948)
ARC-5 Transmitter Modifications: Improved Keying (PDF) at ARRL (June, 1948)
ARC-5 Transmitter Modifications: Making Use of the Tuning Eye (PDF) at ARRL (June, 1948)
Crystal Adapter for ARC-5 Transmitters (PDF) at ARRL (December, 1952)
TVI-Proofing the ARC-5 VHF Transmitter (PDF) at ARRL (November 1950)
Deluxing the ARC-5 Transmitter (PDF) at ARRL (September, 1960)
Putting the ARC-5/T18 on 160 and 80 Meters (PDF) at ARRL (February, 1963)

Two-Band Coverage with the BC-454 (PDF) at ARRL (January, 1960)
Getting Started with the BC-454 (PDF) at ARRL (January, 1959)
80 Through 6 with the BC-454 (PDF) at ARRL (May, 1959)
Command Set Receiver for 6 and 10 (PDF) at ARRL (September, 1953)
ARC-5 and 274N (PDF) at ARRL (April, 1959)
ARC-5 Triple Superhet (PDF) at ARRL (August, 1959)
Super-Simple 80-20 Receiver (PDF) at ARRL (April, 1972)
New Life for the Q5-er (PDF) at ARRL (February, 1951)
BC-453 "Q5-er" reception (PDF) at ARRL (August, 1950)
Bandspreading the BC-455 (PDF) at ARRL (April, 1959)

BC-348 Alignment (PDF) at ARRL (July, 1959)
Note on Surplus Type BC-348 Receivers (PDF) at ARRL (September, 1957)
Double Conversion Using the BC-348 (PDF) at ARRL (June, 1954)
Modifying Tuning Range of the BC-348 (PDF) at ARRL (January, 1952)
Curing Backlash in BC-348 Receivers (PDF) at ARRL (January, 1951)
Eliminating Back-Lash in BC-348 Receivers (PDF) at ARRL (February, 1948)
Broadcast-Band Coverage with the BC-348-Q (PDF) at ARRL (September, 1949)
"Q5-er" for BC-348 Owners, by Adding Series Padders (PDF) at ARRL (June, 1948)
"Q5-er" for BC-348 Owners, Building a Simple Converter (PDF) at ARRL (June, 1948)
"Q5-er" for BC-348 Owners, Modifying the Calls (PDF) at ARRL (June, 1948)
"Q5-er" for BC-348 Owners, Converting with an External Oscillator (PDF) at ARRL (June, 1948)
Converting the BC-348-Q (PDF) at ARRL (January, 1947)
Servicing Xtal Filters in the BC-348 (PDF) at ARRL (August, 1947)
More on the BC-348-Series Receivers: Modifying the BC-348-O (PDF) at ARRL (November, 1947)
More on the BC-348-Series Receivers: Calibrating the BC-348 (PDF) at ARRL (November, 1947)
More on the BC-348-Series Receivers: Curing Noise-Limiter Troubles (PDF) at ARRL (November, 1947)
More on the BC-348-Series Receivers: A Further Note on the BC-348-Q (PDF) at ARRL (November, 1947)

CW and Keys (return to top)

Radio Amateur Education Society with The Art & Skill of Radio-Telegraphy course
RadioTelegraphy.net
K7QO Code Course
LB3KB’s Just Learn Morse Code
W1AW Morse Code Practice Files & archive, sorted by code speed

How to use an "English Key" by WB8DQT

The Vibroplex Collector’s Page
Parts List, Machine Drawing, & Adjustments of Vibroplex Champion, at Vibroplex
Slow a speeding bug with a The BugNapper by WB9LPU

RadioTelegraphy.net

The Sparks Telegraph Key Review
Stewart Johnson, Les Logan, EF Johnson, & Wm. M. Nye keys by N0UF
Radio Telegraphy -- Straight Keys to Bugs at Western Historic Museum
The KK4DW Telegraph Key Collection

History of keys called "Speed-X":

1927 - Electro Manufacturing began making a key that would later be known as the Speed-X
1934 - Stuart (Stewart?) Johnson purchased Electro Manufacturing and named the key "Speed-X"
1937 - Les Logan bought Speed-X
1947 - E.F. Johnson bought Speed-X
1972 - William Nye bought E.F. Johnson
Both E.F. Johnson and Nye-Viking appear to have made Speed-X oval-base straight keys with sprung anvil.
(Information gleaned from N0UF and The Sparks Telegraph Key Timeline.)

When did the model 310 straight key appear?
According to Western Historic Radio Museum both the models 322 (rectangular base) and 310 were available from Les Logan from 1937 to 1947.
Morse Express says the model 322 has been available since 1937 and was manufactured by Les Logan, E.F. Johnson, and Wm. M. Nye.
Tom French (Artifax Books) thinks my older Speed-X is an early Wm. M. Nye piece; Logan and Johnson number-schemes were different.
N0UF identifies Speed-X HS15.682 keys as being products of the William M. Nye Company.

Military CW Keys:

J-37 & J-38 Keys by K6IX

Artifax Books sells old keys and replacement knobs for old keys

The book "Keys IV... and More--the Finale" by K4TWJ (SK) is available in PDF format as a free download here: K4TWJ

Amateur Satellite (return to top)

AMSAT.org

Work an FM VHF/UHF Satellite with an HT:

AMSAT-OSCAR 51
12 Suggestions for Success Working AMSAT-OSCAR 51 (Echo) on a Handheld Transceiver

AO-27 & SO-50 FAQ
Working Your First Amateur Satellite (SUNSAT SO-35)
Working the Easy Sats (PDF)
How to Work AO-51 with Your HT (PDF) by K6LCS

Arrow II Satellite Antenna at ArrowAntennas.com

"Down-to-Earth" Satellite Communications (PDF), by N1ASA
mp3 audio file by N1ASA of nine QSOs made through AO-51 at 76º elevation, Arrow antenna w/preamp, and 20-watts

Amateur Satellite Articles at EB4DKA

The "IOio" Antenna (pdf)
The "CJU" ANtenna / The Magic Antenna (pdf)
The Arrow Antenna and the Satellites (pdf)

K6LCS’s How to Work Satellites with Your HT

Orbitron satellite tracking software

Visible Satellite Flybys at SpaceWeather.com

Winlink (return to top)

Winlink 2000
Get Started
Winlink for Dummies online course

APRS (Automatic Packet Reporting System) and GPS (Global Positioning System) (return to top)

Southeast Ohio APRS Development by W8KVK

FindU.com

mobile: WD8RIF & with timestamps
home QTH: WD8RIF-1 & with timestamps
check APRS messages on-line: http://www.findu.com/cgi-bin/msg.cgi?WD8RIF-1; change callsign and SSID as needed
internet-to-APRS text messaging: http://www.findu.com/cgi-bin/entermsg.cgi
      (APRS station must be on the air and in range of I-Gate; full callsign and SSID required)

Google APRS Maps with zoom and scroll

mobile: WD8RIF
home qth: WD8RIF-1

APRS World APRS database and information

TinyTrak forum at Yahoo!Groups (and sign in)

Amateur Radio High Altitude Ballooning, with launch announcements

A Guide to the Global Positioning System (GPS) at Radio Shack
About GPS & GPS for Beginners at Garmin
GPSInformation.net by Joe Yeazel N4TEB, Jo Mehaffey W2JO, & Dale DePriest

APRS.org & direct URL by Bob Bruninga, WB4APR (& symbols table)
APRS & GPS at TAPR.org

Automatic Packet Reporting System (APRS) at ARRL
Automatic Packet Reporting System (APRS) at ARRL (sidebar to QEX article)
Position Reporting with APRS at ARRL
Build an APRS Encoder Tracker at ARRL, in PDF format

UI-View32 APRS client for Windows (and registration)

Convert Lat/Long between various formats

grab topo maps at TopoZone.com
instructions on importing to GPS (and APRS software?) here: GPS and Adventure Radio by VE3JC

Review of Delorme EarthMate GPS Receiver by Joe Mehaffey (W2JO) & Jack Yeazel (N4TEB):
This $150 receiver (can come bundled with Street Atlas 8) is a 12 channel receiver/antenna combination, but has no display. It is "rain resistant" and so may be itself mounted on your car’s roof. The EarthMate GPS receiver is designed specifically to work with Delorme’s Street Atlas 4/5/6/7 software and unless connected to a laptop with SA running, the EarthMate shuts down and provides no data. This unit acquires reasonably quickly and maintains lock not quite as well as most other 12 channel parallel receivers. Overall, it is among the lowest cost GPS receiver/software packages, but its lack of a stand alone display, and the fact that it only works with Delorme Mapping software products makes it less desirable than others. Speed capability is reported as 900 kph. The Earthmate and Tripmate have been reported to be among the least accurate of the low cost GPS receivers. (found in Low Cost GPS Review)
DeLorme Earthmate Serial:

at DeLorme.com:
USB-to-Serial Adapter Driver for Windows
Using HyperTerminal to Test Earthmate

Use the serial Earthmate for APRS by N9UUR using the GST-1 GPS Sentence Translator

serial Earthmate initialization software: InitEartha.zip
TinyTrak3 configuration software and documentation: TinyTrak3.zip

Use a DeLorme Tripmate with a TinyTrak3 by KD5OM
limited serial Earthmate support can be found at Delorme

Bicycle-Mobile APRS

(See Bicycle Combined With Amateur Radio within this document for more on use of radio on bicycles.)

WD8RIF and the ACARA provide APRS support to the Athens (Ohio) Marathon
ACARA Marathon Communications Planning Page
a thread at BMHA about bicycle-mobile APRS

The Athens Marathon will be using chip-timing in 2009.

They will be using Runners’ High system.
They will have systems at finish and both turn-arounds.
Both Full- and Half-Marathon runners will be tagged.
Runners will wear visible numbers in addition to tags.
Tags will not be used for "real time on course" tracking so ACARA lead/last runner reports will remain valuable.
Learn more about RFID tracking: IPICO Sports.

WD8RIF bicycle-mobile APRS configuration:

DeLorme Serial Earthmate => Byonics GST-1 => Byonics TinyTrak3 => Icom IC-02AT

TinyTrak3 GPS Encoder for APRS by Byonics

rig-specific cables from Byonics
TinyTrak3-to-radio wiring diagrams
TinyTrak3 in QST in PDF format
KD5OM’s Building and Configuring the TinyTrak3 in PDF format
KD5OM’s Configuration Connector for the TinyTrak3
external power for the serial Earthmate (5-6vdc to pin 9; ground is pin 5)
external power for Earthmate and GST-1 at Byonics
TinyTrak at Yahoo!Groups (and sign in)
Shorting J7 in TinyTrak3 will provide power to GST-1 through pin 4 of the serial port.
TinyTrak3 draws approximately 6.6mA plus 3mA for each lit LED at 12v; GST-1 draws approximately 8.5mA.

Second APRS stations under consideration:

Byonics GPS2 => TinyTrak3+ => Icom IC-2AT: $111
Byonics HT2P interface cable w/PowerPoles: $ 19
Byonics Null Modem Gender Changer: $8

Byonics Micro-Trak AIO (FA 10w 2m TX w/TinyTrak3 chip w/GPS & antenna) + programming cable : $275
Byonics GPS2 => Micro-Trak 8000 (FA 10w 2m TX w/TinyTrak3 chip) : $259+

Aeronautical-Mobile APRS

APRS forum at VansAirForce.net

HP iPAQ HX2415 Pocket PC:

Intel PXA270 Processor 520MHz
Integrated 802.11b & Bluetooth
Integrated Compact Flash type II (CF) and Secure Digital slots (SDIO)
3.5" transflective TFT QVGA with 64k color LED backlight display
Microsoft Windows Mobile 2003 Second Edition

Support at HP
HP and Compaq iPAQ Pocket PC -- Using ActiveSync at HP
ActiveSync at Microsoft

description at Amazon.com
description at T1 Rex

PocketGEM, free mapping software for PocketPC and external GPS

PDA to GPS: Using a Handheld Computer as a Navigation Tool (Palm OS)

Cabling DeLorme Earthmate (serial) to PocketPC

Serial Adapter for HP iPAQ with power ($29.95) & without power ($19.95) at Gomadic
Syncable Solutions--serial cables for Palm OS PDAs
Serial (RS232) Interfaces for PDA at PC-Mobile

In an email dated 2007-07-2 DeLorme confirmed that Street Atlas USA 2008 DVD works with PDAs with touch screen and running either Windows Mobile 5.0 or Palm OS.

In an email dated 2007-04-04 DeLorme confirmed that Street Atlas USA 2007 contains what used to be called Street Atlas Handheld.

GlobalSat BC-337 Compact Flash GPS

review at Geekzone
at Amazon.com
at Semsons.com

Bicycles Combined with Amateur Radio (return to top)

(See Bicycling & Canoe Links for more links about bicycling.)

Bicycle Mobile Hams of America site & Yahoo! Club
GOBAHams.org (and alternate URL)

How to Wire a Bike for Ham Radio (PDF), by Bill Sharp, W8HI
Bicycles and Radios at ARRL, by Dick Arnold, AF8X
Bicycle-Mobile Antennas at ARRL
The Jurassic Duck--a 2m J-Pole antenna inside PVC, by WX2NJ
2m J-Pole by AA1EP
2m J-Poles by N6VNG
Bike ’n Hike Special antenna described by WB8ERJ
The Perfect HF Bicycle Mobile Antenna by Bonnie Crystal, KQ6XA on the HFPack Yahoo! Group (logon required)

Steven K. Roberts, N4RVE:

Nomadic Research Labs
Computerized Recumbent Bike Adventure
Winnebiko & BEHEMOTH Specs
Microship Wordplay and kayak Bubba
Shacktopus--BEHEMOTH in a pack, only more so

G4AKC HF Bicycle and Pedestrian Mobile
K2 Bicycle Mobile by N8MX
QRP Plus & K2 CW Bicycle Mobile by VE3JC
CW Bicycle Mobile by KB8U
HF Bicycle Mobile by N0LX, with FT-817
CW Bicycle Mobile - Field Day 2004 by KC4AUF, with Yaesu FT-900
Recumbant HF & VHF Bicycle Mobile by N1RWY
SGC-2020 Bicycle Mobile by NW7DX
SGC-2020 Bicycle Mobile by GØSBW
Bicycle Mobile by AF8X (2m FM and HF)
Bicycle Mobile, from a Beginner’s Point of View by KD7S (20m CW)
Bicycle Camping Adventure and pictorial by AC6XK (HF CW)
IC-703 Bicycle Mobile by N0MLZ
W9XS Bicycle Mobile by Ron Baran--100-watt HF CW & SSB (and alternate URL)

Bicycle Mobile by K4MBE (2m FM)
Bicycle Mobile by N8AVR (gone?)
2m & CB Bicycle Mobile by VO1MDS
An article on 2m FM bicycle mobile by AA6WK
Bicycle Portable by K6WEB (2m FM)
Riding the Airwaves, bicycle mobile by KE4WMF (2m FM)
Mountain-Bike Mobile by N7QJP (2m/70cm FM)

Articles at BHMA (in JPG format):

"The Perfect HF Bicycle Mobile Antenna", by Bonnie Crystal, KQ6XA: pages 1 | 2
Mounting the Antenna on the Front of the Bike by Skip La Fetra, AA6WK
Dressing for Cold Weather Riding by Scott Farrell, KE4WMF
"Q-R-Pedaling - K2/Gary Fisher Style", by John Cumming, VE3JC: pages 1 | 2
"Double the Fun While QRP" by Scott Farrell, KE4WMF: pages 1 | 2
Ham Bike has HT, GPS, APRS, & Packet! by Dave Reed, WA1ZWG
Varner’s "Coaxial Antenna" Easy to Build by Jim Varner, AE6N
Headset vs. SpeakerMike by Bob Murdock, WX2NJ
Indexes:
Antennas
Gear
Bits and Pieces

According to W8HI (link), a half-wave antenna wants to see feedline that’s an odd multiple of 1/4-λ long. Three 1/4-λ is about 57" at 2m. Larson sells GBR-1 in this length with NMO on one end and BNC on the other.

Build a Bluetooth Headset:

Build a Bluetooth Headset by K7SFN & K7AGE video on YouTube
Jabra A210 Bluetooth interface
BlueParrott B150 Headset
Jawbone noise-canceling Bluetooth headset (might not handle wind-noise well: link)

Canoes / Kayaks Combined with Amateur Radio (return to top)

(See Bicycling & Canoe Links for more links about canoeing and kayaking.)

Kayaking the Grand Canyon with a K-1 by WB6ZFG
QRP + Kayak = Outdoor Adventure by W8BHK
QRP with a Sea Kayak by AA4XX
QRP with a "Catacanoe" in the Adirondacks by N2XE
Canoe-portable QRP, German-style
Guide to Canoe/Kayak-mobile QRP by AE3C
Kayak-Portable by WV9I
Rowboat HF Mobile by N0LX

(See also the sites by Steven Roberts, N4RVE, above.)

WD8RIF Two-Way QRP Worked All States (return to top)

States needed: Alaska, Kansas, Maine, Mississippi, Nebraska, North Dakota, & Rhode Island.

map of WD8RIF two-way QRP WAS -- sometimes the map takes a long time to load...
(map generated at World66)

Miscellaneous (return to top)

Why Ham Radio Endures in a World of Tweets by David Rowan

Sherwood Engineering

Receiver Test Data in tabular format
Roofing Filter, Transmitted B/W, Receiver Performance (video)

QRPSpots.com

Announced DX Operations by NG3K
Active DX, by Date at Radioham.info
DXScape; spots can be filtered to just those from US hams and by band
DX Summit; click "Custon Spots" to find QRP DX

Railroad Depots on the Air

KØS Strange Antenna Challenge (new URL)

Moxon Antenna Project

Make-Your-Own Portable End-Fed Wire Antenna on a Spool, as discussed on QRP-L:

(The original QRP-L postings describing this are gone.)
a look at a commercial version at DWM
a dipole version is described (with photos) here, by AA2VK
a variation here on eHams
KD1JV’s matched end-fed half-wave, with photos (at archive.org)

Ultra-light Antennas Based on a Panfish Pole by Bruce Grubbs, N7CEE
WA3WSJ Black Widow Vertical Antenna 20m, 30m, & 40m without a tuner

MiniBac antenna (Minimalist Backpacker Antenna System) by KQ6XA

Joe Everhart, N2CX, has had good luck using a Black-Widow supported 40m end-fed half-wave wire with counterpoise for QRP NVIS work. See January, 2000, QRP Quarterly

Portable Antennas by N0LX:

20’ Toroid 20-30-40m with switchable band taps
shortened 20’ half-wave vertical with toroidal loading coils
end-fed inverted-v for 17-20-30-40m

Dollar Store Special Antenna by WB3GCK

Sooper-Shooter by Robert Hightower, NK7M
The HyLaunch, Build a Compact, Integrated Antenna Launching System by Bill Jones, KD7S
Antenna Launching for Serious Practitioners by Russ Carpenter, AA7QU

B&W AP-10A & AP-10B Window/Balcony Portable Antenna; instructions: AP-10A | AP-10B

NVIS Ionospheric Map -- US (and tinyURL version)
75/60/40m NVIS Portable Antenna by W4CNG

55’ Irrigation Pipe Push-Up Mast by Bob Bruninga, WB4APR

Build a Tiger Tail Counterpoise by W1CAR

VHF/UHF J-Pole:

2 Meter Half-Wave J-Pole Antenna from 450 Ohm Ladder Line (pdf)
The DBJ-2: A Portable VHF-UHF Roll-Up J-Pole Antenna (& correction) by Edison Fong, WB6IQN (pdf; ARRL QST Archives)
An Easy Dual-Band VHF/UHF Antenna by Jim Reyante, KD6GLF (pdf)
A Backpacker’s Delight--The Folding J-Pole (& correction) by Michael Heiler, KA0ZLG (pdf; ARRL QST Archives)
Build a Weatherproof PVC J-Pole Antenna by Dennis Blanchard, K1YPP (pdf; ARRL QST Archives)
Tuning a Wire J-Pole Antenna (pdf; ARRL QST Archives)

N7VE SWR Indicator

A Bright Idea for Wrestling With SWR in the Field by Richard Fisher, about the N7VE SWR Indicator
The N7VE SWR Indicator/Bridge kit at Hendricks QRP Kits

Novice Historical Society
The Museum of Radio & Technology in Huntington, WVa
K2TQN’s Old Radio and Radio History Website with QST Column additional items
The Xtal Set Society

CAT Repeater Controllers

Michael Burkhardt’s W8MHB.com--download question pool; generate practice exams and flash cards

Amateur Radio Today video with Walter Cronkite (for purchase or 70MB download) at ARRL
Voice of Victory (1944): Part I | Part II at Internet Archive

Boat-Anchor Nightlight (PDF) by AD5X

LED Station Lights:

LEDs for Low Power Station Lighting Ideas by KB1DIG and KB1GTR
LED Circuit Tutorial
LED Current Limiting Resistor Calculator by Jani ’Japala’ Pönkkö
(Look in Fall 2004 "QRP Quarterly" for more ideas on LEDlights.)

Anderson Powerpoles:

Correctly Install PowerPoles at West Mountain Radio
Anderson Powerpole Ideas by KB1DIG & KB1GTR
Powerpole Instructions by WB3W

West Mountain Radio--Powerpoles, crimp tools, and accessories
PowerWerx.com----Powerpoles, crimp tools, and accessories

Powerpole Polarity Tester by WB3GCK
More Fun with Powerpoles (PDF) by VE3FFK
Surface Mount Powerpole Connectors (PDF) by AD5X
Compact Voltage Conditioner/Fuse Assembly for 100-watt Transceivers (PDF) by AD5X

Powerpole Chassis Mount and Distribution Boards (zip) by W1GHZ

Emergency Power:

"Practical Battery Back-Up for Amateur Radio Stations" by George Thurston III, W4MLE:
Part 1: March, 1990 QST, pp. 34-37 (PDF ARRL Members Only)
Part 2: April, 1990 QST, pp. 32-35 (PDF ARRL Members Only)
Part 3: May, 1990 QST, pp. 25-27 (PDF ARRL Members Only)
"Emergency Power at W1ZR" by Joel Hallas, W1ZR: December, 2003 QST pp. 41-44 (PDF Members Only)
"Emergency Power at W1ZR" by Joel Hallas, W1ZR, Technical Correspondance: February, 2004 QST p. 82 (PDF Members Only)

Battery Manual at Power-Sonic
Battery University & Batteries in a Portable World by Cadex Electronics, Inc.
Batteries & QRP by AE5X
The Care and Feeding of Gel Cell Batteries by WB3GCK
Battery Care (PDF) at EMRG
12-volt Battery Case with Powerpoles (PDF) by VE3UNW

LED Voltage Monitor (zip) by W1GHZ

kits are available from WA3IAC;
cost is $15.95 each plus s/h of $2.00 for the first kit, $0.50 for each additional kit, First Class mail.

A Long Haul H-T Battery System (PDF) by Thurman Smithey, N6QX, at ARRL Archives

Note: Figure 2, Voltage Regulator circuit, has incorrect pin-out shown for LM317T
correct pin-out for TO-220 package is 1-Adjust, 2-Output, 3-Input
LM317T datasheets are available here

Three-Terminal Regulators by N0AX at Hands On Radio (PDF, Arrl Members Only)

Improved 9.6V Compact Fast Charger (PDF) by AD5X
Simple In-Line Current/Voltage Monitoring Fixture (PDF) by AD5X

BatteriesAmerica.com (and replacement packs for Icom)
NiCD Lady

WD8RIF has battery packs for Icom IC-2AT & IC-02AT handhelds:

BP-2 (converted into 9.6v NiCD R/C battery adapter)
BP-3 (one converted into DC-1 clone; two condition as-yet unknown)
BP-4 six-AA holder (qty 3) -- 9v with alkaline cells; 7.2v with NiCD/NiMH cells
BP-5 10.8v 450mAh NiCD (qty 2) dead
BP-7 13.2v 450mAh NiCD (qty 2) dead
BP-8 8.4v ???mAh (Mr. Nicad clone; condition unknown
BP-8sh 8.4v 1800mAh (Mr. Nicad clone; condition unknown
DC-1 10v DC-converter for IC-2AT (qty 4)
IC-8 eight-AA holder -- 12v with alkaline cells; 9.6v with NiCD/NiMH cells (qty 4)

WD8RIF has a Maha MH-C801D smart-charger for NiCD/NiMH AA/AAA cells.

Notes on AA cells:

Zinc-Carbon AA cells are nominally 1.5v at 400mAh to 900mAh.
Alkaline AA cells are nominally 1.5v at 1700mAh to 3000mAh; high internal resistance causes capacity to drop as load current increases.
Nickel-Cadmium (NiCd) are nominally 1.2v 700mAh to 1100mAh.
Nickel-Metal Hydride (NiMH) are nominally 1.2v 1650mAh to 2700mAh.

NiMH cells self-discharge in about 15 days; NiCD cells self-discharge in 30 to 60 days. (source)

Panasonic Oxyride AA cells:

1.7v initial voltage
2x to 3x longer battery life than with alkalines in high-current use
cost is comparable to alkaline
Looks very good for HTs and power-packs for portable HF
Oxyride at wikipedia
Can a New Disposable Battery Change Your Life? Parts of It, Maybe. at NY Times
New Consumer Primary Battery Chemistry Introduced After a 40-Year Dryspell
Panasonic Oxyride Editorial Review -- The Revolution in Battery Power at techlore.com

Quantaray Super Z by PowerGenix (Nickel-Zinc):

1.6v, 2000mAh
PowerGenix
Nickel-Zinc Rechargeable Batteries Make Their Debut
Quantaray Super Z Rechargeable Battery Features PowerGenix Technology

Build a Dummy AA Cell forum topic

N1HFX 100kHz (or 50kHz) Crystal Calibrator: HTML & PDF formats

design uses 8MHz HC49U microprocessor crystal: $0.40 each at Mouser

Hand Soldering and the Impact of the RoHS Directive (PDF)
Repair of RoHS Equipment at Hardware Secrets

recommends use of "99C alloy" (99.7% tin, 0.3% copper) solder

Make Mine to Go by Anthony Luscre -- build a portable station

Cabbage Cases

Foam is available in 0.5", 1", 1.5", 2", 3", and 4" thicknesses.
Prices vary between $0.50/ft2 for 0.5" to $4.15/ft2 for 4" thicknesses.
Sales: Michael Hannah (email)
Business hours: 8:30-4:30 Mon-Fri
Pelican Cases
Midwest Case Company--Columbus, Ohio

Aviation Headsets:

General Aviation: microphone ~150ohms; headphone 150Ω to 600Ω (source: 1 | 2)
Military Aviation: microphone and headphones 8Ω to 20Ω (source)
Use David Clark military headset in general aviation:
#40880G-01 Headset Adapter (~ $134), or
M-1/DC Amplified Dynamic Mic (~ $78), or
M-7A Amplified Electret Mic (~ $78)
Make an adapter for David Clark headset: sockets for PJ-068, PJ-055, & U-174/U plugs (PJ-068 is 0.206"; PJ-055 is 0.250")
Part numbers for panel-mount socket for U-174/U four-conductor jack: M9177/4-1, JB-11F-PM, TJT-102; $16.95 here
K5ALQ’s circuit to interface a civil-aviation headset to amateur transceiver can be found in December, 2003 QST, page 57
K0IZ’s circuit to interface a civil-aviation headset to amateur transceiver can be found in April, 2010 QST, page 65


My headset is a David Clark H10-76 military headset:
description
parts list
specifications
M-87 dynamic microphone impedence 5Ω +/- 20%
M-87 dynamic microphone sensitivity 0.05-0.11 mV
M-87 dynamic microphone will not operate when a DC bias voltage is applied
headphone impedence 10Ω (19Ω each, wired in parallel)

Partstore.com has parts, including earcups, for Sony MDR-V4 headphones

The Carl & Jerry Stories from Popular Electronics

Radio-Adventure Books by Walker A. Tompkins, K6ATX (SK):

CQ Ghost Ship
Death Valley QTH
DX Brings Danger
Grand Canyon QSO
Murder by QRM
SOS at Midnight

Unless otherwise indicated, all photos copyright 1995-2011 William Eric McFadden

Disclaimer:

This is a collection of links that I have found useful or interesting, either professionally or personally. It is maintained for my own use, and is subject to change at any time. No claims are made to completeness, accuracy, or competence. No endorsement of any site, individual, product, or corporation is intended. With these caveats, anyone is welcome to browse these links or to use this page.

Attributions:

Heathkit Lunch-Box paragraph found at the Heathkit Virtual Museum.
Inside-view photographs of Heathkit Lunch-Box found at the Heathkit Virtual Museum.
Photo of HW-7 chassis from manual; scan found at Boat Anchor Manual Archive.
Paragraph about HW-7 from Heathkit manual.
Paragraphs about and photo of DX-60 found at the Heathkit Virtual Museum.
Paragraphs about and photo of HR-10 found at the Heathkit Virtual Museum.
Heathkit walkie-talkie catalog page found within Heathkit 1961 catalog scan found at Technology Systems.
Heathkit walkie-talkie catalog page found within Heathkit 1963 catalog scan found at Technology Systems.
1979 Ten-Tec Omni D advertisement found at RigPix.com.
Ten-Tec Omni D Series C advertisement found at TenTecWikie.

Radio Collections, Galleries, & Home Pages

Clubs & Organizations

Publications & Reference

Commercial Pages

Ham Radio & Short Wave Listening

Old Time Radio

Other Antiques Sites

Other Favorite Web Sites