Episode 265 – Eric Sears – ZL2BMi

Eric Sears, ZL2BMI, who joins me from New Zealand,  is famous for this 80 meter QRP double sideband rig that he designed and documented in the 1980s for his personal use when “tramping”  in the forests and mountains of New Zealand. Eric’s stated design philosophy and rigs proved to be robust and foundational for other QRP rig builders, especially in the southern hemisphere through the years.  ​

 ZL2BMI Links: 

ZL2BMI Double Sideband QRP Transceiver

First License: Zl2UBG, Technician, 2 meters and above

ZL2NBI, Novice license concurrently to operate CW in low bands 

First Rigs:
Pye Hearld tube FM VHF 
ZC1 Transceiver HF, New Zealand war time radio
Ten-Tec Argonaut HF Transceiver

Current Rig: 
Kenwood TS430 HF 
SSB Homebrew rig
Yaesu VX5 VHF 

Favorite operating mode: · 80 meter DSB QRP Backpack portable

ZL2BMI Design Philosophy 

  • Having only very limited equipment and being quite hopeless at most metalwork, the following were important: 
  • Small size and light weight (for tramping) 
  • Simple circuitry 
  • Battery economy ‘
  • Voice’ transmission (with C.W. if required) 
  • Ease of construction. 
  • A.M. was feasible, but heavier on battery and not so compatible with S.S.B. 
  • SSB was too complex to produce. 
  • DSB (at low power levels), is simple to produce and economic in terms of battery drain.

XYL: Mary Sears, ZL2TFS
Mentor: Roger Lawson, ZL2BHG
Bob Sewell, ZL2ASO – Wellington 92 years of age
Bill Meara, N2CQR
Doug DeMaw, W1FB
Peter Parker, VK3YE

Radio Discussed:
Hiker’s One – one tube radio transceiver
Foxhole radio crystal radio
48 Set HF Transceiver 5 mhz. 
Peter Parker’s VK3YE’s DSB rig 
SSB Transceiver using DDS
Elecraft KX2 QRP transceiver

Boy Scouts New Zealand
Semaphore signaling
Morse Code
Blue razor blade
White spot transistors
New Zealand Army Cadets
New Zealand Citizens Band, AM on 26 Mhz
New Zealand Backcountry Hut
Double Sideband suppressed carrier
New Zealand Forest Service backcountry huts
Anglican Church ministry
“Ham Cram” licensing
New Zealand Nation Amateur Repeater System
New Zealand Association of Radio Telephone
Break-in Magazine
Dick Smith Electronics
Covenanted properties
G-QRP Club
SPRAT magazine
NE602 Mixer
Double balanced mixer
Ugly bug electronic construction
Dead bug electronic construction 
Solder Smoke Podcast
80 meter end-fed wire antenna

Greatest challenge facing amateur radio now:   Proliferation of communication, cell phones. 

Most excited by: In an age where everything is regulated, as hams we have the freedom to build our own gear. 

Advice to new or returning hams: Don’t just be an operator. Learn a bit more about simple circuits. 

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ZL2BMI HF Transceiver
ZL2BMI DSB Transceiver Top View
Ten-Tec Argonaut HF Transceiver
ZC-1 HF Transceiver

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