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Welcome to Catawba Island, Ohio   (US Islands - OH-016L, Grid EN81nn, Ottawa County Ohio)

NOTE:  See separate  W8GNM/8 callsign QRZ page for activation of NPOTA  NM20


Geoff sails a 24' Capital Yachts Neptune sailboat on Lake Erie



One of the many beautiful sunsets



My Catawba Island QTH is about 5 miles South of Put-In-Bay, Ohio



A winter scene of nearby Marblehead Lighthouse


Geoff Mendenhall was born in Johnstown, Pennsylvania and has been an active amateur radio operator for 54 years.

He was first licensed as a novice, KN3VLN in 1961 and soon thereafter as technician class K3VLN, while he was still in Junior High School in Johnstown, PA.   Geoff enjoys the technical side of amateur radio and has built much of his equipment.  He built his first novice CW rig using an 807 tetrode and a power supply made out of parts from a television set.  Later, with some help from Bill Orr, W6SAI, he designed and built a 6 meter band, VHF linear amplifier using an Eimac 4-400A tetrode operating in a cathode driven configuration.  The design of this unconventional amplifier was a high school science fair project that took him all the way to the national JETS science fair in New York City.  While still in High School, Geoff got his First Class Radiotelephone license so he could work as a broadcast technician at WJAC, the local television station.

While attending the Georgia Institute of Technology as an electrical engineering student, Geoff designed, hand built, and FCC type accepted, a 425 Watt FM broadcast transmitter for WREK, the Georgia Tech student FM station. http://www.techatl.com/wrek/docs/gnm_0011.htm

He was also active at W4AQL, the Georgia Tech Amateur Radio Club.  After graduating from Georgia Tech with an electrical engineering degree, Geoff worked for the Comco division of E.F. Johnson designing two way radio communications equipment.

In 1973, Geoff moved to Quincy, Illinois and began designing broadcast equipment for the Gates Radio division of Harris Corporation.  He changed his call sign from K3VLN to W9NEZ in 1973 and spent the next 26 years designing broadcast equipment for Harris and Broadcast Electronics in Quincy.  While living in Quincy, Geoff experimented with the optimization of full size, monoband, Yagi antennas.  He also upgraded the second HF linear amplifier that he originally built in High School.

Geoff's other favorite hobbies are sailing and SCUBA diving.  In the mid 1980's, Geoff combined amateur radio and SCUBA diving in the Cayman Islands operating as ZF2CQ.  He enjoyed being on the other end of pileups while operating amateur radio from the Cayman Islands.

Geoff holds nine US Patents for innovations to broadcast equipment.  In 1999,  he received the National Association of Broadcasters Radio Engineering Achievement Award for his significant contributions to FM broadcast transmitter technology and in 2008 he was named a Harris Fellow.  More than 10,000 FM broadcast exciters in operation around the world utilize technology developed by him.  He is member of the ARRL, The Greater Cincinnati Amateur Radio Association (GCARA), a senior member of the IEEE, the Association of Federal Communications Engineers, and is a Registered Professional Engineer.

Geoff moved to the Harris Broadcast Communications (now GatesAir)  headquarters located in Cincinnati, Ohio where he was most recently, Vice President of Transmission Research and Technology, for the next generation of digital radio and television transmitter systems. (http://www.gatesair.com)   He recently retired from Harris Corporation and started Mendenhall Engineering, LLC to offer RF transmission consulting engineering services.

After moving to Ohio, he said farewell to W9NEZ, his ham call for 28 years and got the new call sign W8GNM.  His past QTH in Cincinnati had restrictions on antennas, so he optimized his "stealth" wire antenna array which enabled him to achieve DXCC on six bands and WAS on 160 meters using only LoTW "paperless" QSL's.

Geoff recently moved to a new QTH located on Catawba Island on the Western basin of Lake Erie near Port Clinton, Ohio.   

Geoff  currently operates using an ICOM 756 Pro-II + his home brew linear amplifier feeding  wire dipoles and delta loop antennas with for the 160m, 80m, 40m bands,  a wire Hex Beam antenna for 20m, 17m, 15m, 12m, 10m, 6m and a J-Pole for 2m.  His Saturn-6 Halo antenna from his high school days is also still in operation on 6m.  A rotatable loop antenna and a home brew, reversible, Beverage antenna system that he designed, help with weak signal reception. Geoff's new multi-mode, reversible, Beverage, BOG, FLAG, or EWE antenna design is being marketed by JK Antennas as the BevFlex-4, which is an updated version of the BevPro-1. 

Check it out at:   http://jkantennas.com/rx-antenna.html

Geoff enjoys modeling and optimizing his antennas with EZNEC software. He uses a dedicated ham radio computer with TRX-Manager CAT software to control his rig, handle station logging, and to implement digital waveform demodulation via a 12kHz IF interface that he added to the ICOM 756 Pro-II.   The audio lineup is Heil PR40 mic into Symetrix 528E voice processor, followed by Orban 9200 digital optimod, driving the direct modulator input to the IC-756Pro-II transceiver.

Geoff is co-manager of the Greater Cincinnati Amateur Radio Association, 1936KHz, net which meets every Thursday evening at 9PM Eastern Time. Although he is currently limited to wire antennas, you can hear him on 160m through 2m from his Catawba Island QTH or mobile using his ICOM 706MK-II when he is on the road or sailing on Lake Erie. 

Geoff's XYL, is W8MNM

LoTW is the preferred method to QSL

PSE QSL via Logbook of the World (LoTW) at:



I also upload log data to my QRZ logbook and to eQSL

7738998 Last modified: 2016-12-05 03:49:14, 7829 bytes

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QRZ Logbook Summary for - W8GNM
Latest Contacts for W8GNM at QRZ.com
dedateband mode grid Country op
KL7TH 2017-04-15 20M SSB BP54KN Alaska Traci A Humphrey
AI4JU 2017-04-15 20M SSB EL86XN United States David J Lawrence
W1IFO 2017-04-15 20M SSB EL95TD United States HANS F SEEBO
K2PEY 2017-04-15 20M SSB EM49HV United States Joseph A Huie
VP5/W3HNK 2017-04-15 20M SSB FM29BT Turks and Caicos Is JOSEPH L ARCURE, JR
M0ZDZ/P 2017-04-14 20M SSB IO90NS England Mike Clark
IU4FIT 2017-04-14 20M SSB JN54MO Italy Armando (Army) Di Martino
SX20MDC 2017-04-14 20M SSB JJ00aa Greece MDXC celebrate its 20th a
KU4FX 2017-04-14 40M SSB EL87UX United States DENNIS E GREEN
W1MGY 2017-04-14 40M SSB FN41XR United States Titanic Marconi Memorial
AC7HU 2017-04-14 40M SSB EL95US United States Elixander Valladares
N9RC 2017-04-14 160M SSB EM79TH United States RONALD E SCHUSTER
W3BFC 2017-04-14 40M SSB FM18TR United States RAYMOND E ALBERT, JR
WQ2N/KP4 2017-04-14 40M SSB FN20TU United States Paul S Whitman

Book Totals: 22452 qso's   4439 confirmed Get a free logbook at QRZ.COM

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