The Low Power Station
- HF QRP CW Pedestrian Portable -

JL3AMK's Web Site
"May the Morse be with you!"
http://www.jl3amk.org/ or http://www.jl3amk.net/

[Top/English/Japanese]

Created: October 1, 2002

JL3AMK's Radio Kit Building Service - I will build your KX1 or K1.

Contents

• Self-Introduction
• Operation Style
• Elecraft K1 Mods
• Membership
• Links

Self-Introduction

Welcome to my web site. Let me introduce myself.

My name is Harry. I was born in February 1969 and I have been a radio amateur since 1983. It was summer when I was a junior high school student, I got a no-code (4th class) operator's license, and got a station license in fall. I was 14 years old. I got a Morse code (3rd class) operator's license when I was a high school student in spring 1985, age of 16. After that, I had enjoyed DXCC hunting and contesting, especially on 15m/10m CW. The propagations were not so good because it was around the bottom of the Solar Cycle 21, but the weak signals from Europe on 15-meter CW were exciting me. Around 1990, Sunspot Numbers were increasing, but I was not excited because so many stations were on the band and they were so strong. In addition to that, I found employment and moved, so almost QRT on HF until 1997. I had enjoyed amateur packet radio on 70cm/25cm during 1989 and 1994, and portable operation on 6m CW/SSB during summer in 1994 and 1995. I sometimes QRV'd on 12-meter CW with long-wire from 1997 to 2000.

In 2001, the new century, I bought an FT-817, small portable QRP transceiver from YAESU - Vertex Standard, and several telescopic antennas. I live in the apartment so I have been on the air from somewhere; a park, a mountain, or other places. Its RF output power was not big, maximum only five watts. I was very excited when I could contact with overseas stations. For example, I could QSO with KH2/Guam, with only 500 milliwatts, it was about 5,000 kilometers per 1 watt. T8/Belau, also 500mW, it's about 6,000km/W. The best 'km/W' was with V6/Micronesia, 500mW again, it's abount 7,000km/W! It's fantastic! I might be with the FORCE! If I had a big antenna, I won't be excited, but my antenna was just a small telescopic whip. The most exciting QSO was with W3/Pennsylvania in fall 2002. It's distant over 11,000 kilometters between Osaka and Penn! At that time, power was five watts, so it was about 2,000km/W, but the propagations were over the North Pole. Another U.S. station I had worked was in W7/Washington, it was about 9,200km, using 1 watt into a dipole antenna on a tripod. These QSO's were had on 17m/15m/12m bands CW.

I know a pleasure for building kits noadays. I built Small Wonder Labs' Rock-Mite 20 in 2003, Elecraft's KX1 in 2004, and again Elecraft's K1 in 2005. From late 2006 to early 2007, I built Elecraft's K2. I'm currently active on CW on HF high bands with my K2.

Operation Style

equipments

I usually use simple wire antennas like: telescopic whip, telescopic dipole, random wire with fishing rod, etc.

at home

I live on the first floor of an apartment. I can't fix the antenna, so I set it temporarily as a photo below.

Photo: 15-meter band whip antenna, as of February 2004. Apartment facing to south-west. (click picture to enlarge)

I usually operate from the living/dining room. My "shack" is on the dining table...

Photo: L-R: KX1, Gel-Type Battery (12V 2.6Ah), K1, Clock (receives JJY which sends a time signal from atomic clock and it adjusts time automatically), SHARP Zaurus PDA (for web browsing). As of September 2005.

portable

I usually use KX1 or ATS-3B to enjoy park bench portable operation or pedestrian mobile. Antennas are telescopic whip or random wire with fishing rod, or telescopic rod dipole.

Elecraft K1 Modifications

• AGC Problem Solved
• LCD Backlight Kit Added
• 160m Band Filter Board Module
• BFO Changed to USB
• VFO Spread Out
• Power Increased
• SSB Mod
• 12m/10m Mod

AGC

When the strong signals came into my receiver, I was very surprised because of the loud sound. So I changed some capacitor on the RF Board of my K1.

• C31 to 1uF (from 2.2uF)
• C67 to 0.1uF (from 2.2uF)

References:
K1_AGC_Notes (from Elecraft Reflector)
[Elecraft] K1 revisited

LCD Backlight

Elecraft now presents K1BKLTKIT, the LCD backlight mod kit. I put it into my K1. So I can operate even if it is dark. Not so bright, but easy to read.

160m Band Filter Board

The K1 covers 80m to 15m (4-band or 2-band), but Don, W3FPR modified two-band module to 160m. My K1 can be on 160m running 9 watts RF output.

Reference:
Re: [Elecraft] 160M K1 band option

BFO Changed to USB

The BFO of K1 is LSB but I usually use 17m/15m filter board, so I changed the BFO to USB from LSB by removing and jumpering RFC1 on the RF Board. I can listen to the SSB (USB) stations.

• RFC1 removed
• and jumpered

Special Thanks:
A staff of Elecraft support team told me how to modify. TNX.

VFO Spread Out

I added a 68pF capacitor in parallel with C2 (120pF) on the RF board to make the VFO range spread out because I want to listen to SSB QSOs. VFO covers about 267kHz, but it is difficult to tune. I'm looking for 100k-ohm 20-turn potentiometer.

p.s.
I removed a cap. because it was so critical to tune.

Power Increased

The output power of my K1 was four watts on 15 meters, so I added a 0.001uF capacitor (as a bypass) in parallel with R30 on the RF board.

160m: 10W (not changed)
80m: 10W (not changed)
17m: 7W (from 6W)
15m: 7W (from 4W)

SSB Modification

I'm planning to modify my K1 to be a CW/SSB rig. Giuliano, I0CG designed SSB board.

Reference:
I0CG K1 transceiver page

12m/10m Modification

Special Thanks to Stephanie, VA3UXB
for her suggestions on component values

Parts

• a KFL1-2
• four T37-6 (yellow) cores (if no KBxx band modules)
• a FIL-J1 and a FIL-J2 (if K1 has KAT1)
• capacitors (listed below)
• crystals (listed below)

Component Values

Mods

Additional mods I did were almost same as Stephanie's:

• 220pF capacitor added to J7 on the RF board, between pin 7 and 8 of J7.
• R11 on the RF board changed from 82-ohm to about 33-ohm (56-ohm added in parallel with 82-ohm).
• Compressing the windings on T3 on the RF Board.

In addition to above mods, I added a 0.001uF capacitor in parallel with R30 on the RF board to increase the RF output power.

ATTN: VFO range must be 150kHz or more because K1 covers 12-meter band starting 24.800MHz, but this band begins from 24.890MHz.

RF Output Power

References

[Elecraft] K1 on 10 meters: helpful advice (by Wayne Burdick N6KR @ Mon Dec 26 14:44:01 EST 2005)
[Elecraft] 10 meters on K1 - component values (by Stephanie Maks VA3UXB @ Sun Jan 1 12:57:13 EST 2006)

Additional Info: [Elecraft] 4-band K1 module covering 10-20 meters? Also: less-expensive 10/12 m crystals (by Wayne Burdick N6KR @ Sat Jan 7 14:13:04 EST 2006)

Membership

• 10-10 International Net, Inc. (10-10#50402) [U.S.A.]
• A1 Club (A1C#311) [Japan]
• Adventure Radio Society (ARS#2121) [U.S.A.]
• Alaska QRP Club (AK/QRP#735) [U.S.A.]
• American Radio Relay League [U.S.A.]
• Club 72
• Croatian Telegraphy Club (CTC#2564) [Croatia]
• CW Operators' QRP Club (COQC#711) [Australia]
• European CW Association (EUCWA)
• FISTS EAST ASIA; East Asia Chapter of FISTS CW Club (FISTS#15002) [Europe, North America, Down Under and East Asia]
  http://www.feacw.net/ or http://www.fists-ea.org/
  a.k.a. the International Morse Preservation Society.
• G-QRP Club (G-QRP#11804) [U.K.]
• Hawaii QRP Club (HI-QRP#527) [U.S.A.]
• Japan Amateur Radio League [Japan]
• New England QRP Club (NEQRP#678) [U.S.A.]
• New Jersey QRP Club (NJ-QRP#488) [U.S.A.]
• North American QRP CW Club (NAQCC#0540) [U.S.A.]
• QRP Amateur Radio Club International (QRP-ARCI#12260) [U.S.A.]
• Russian QRP Club (RU-QRP#110) [Russia]
• Straight Key Century Club (SKCC#1045) [U.S.A.]
• WARC Century Club (WCC#472) [U.S.A.]

Links

Japanese Callsign System (by JJ1WTL)

Frequency Allocations in Japan (JARL Web Site)

Japan's Awards published by JARL

Copyright © 2002-2009 by JL3AMK.{org,net}. All Rights Reserved.
mycallsign atsign mycallsign dot org or dot net (try arrl.net if error)