OK1RR DX & Contesting Page

Ham Radio web site dedicated to CW DX operating and contesting

A Soundcard Digimode Interface

Many years ago I wanted to test RTTY and the new digital modes. Not too seriously, with a simple interface in KISS (Keep It Simple Stupid) style. There is nothing to improve, except my awful PCB design matched to the box I discovered in my junk store. For AF isolation I used small transformers made
Arm strap in action

Drop-Proof Antenna Analyzer

While working on antennas some people have a bad experience with the antena analyzer dropping from the tower etc. An useful solution would be to attach some kind of lanyard (cord, line) and then have the loop end over your head. That way, if this unit were to slip out of a pocket it would just hang at the end of the lanyard. I was also afraid of dropping the unit, or putting strain on the antenna connector of my SARK-110. Here is the solution.


Fake FTDI chips

It was only a matter of time before fake FTDI RS232-USB adapter chips began to appear. http://zeptobars.ru/en/read/FTDI-FT232RL-real-vs-fake-supereal This fascinating page shows how some anonymous Chinese company has created a fake FT232RL chip using a mask-programmable microcontroller, and printed it with the “FTDI” name and logo. Like Prolific (the real Prolific company, that is) FTDI have

Powerpole General Assembly Instructions

Assemble the red and black plastic housings together correctly on the first try, they fit snugly and can be difficult to get apart. See the picture below for ARES /RACES standard orientation. Note that you can assemble the red and black insulated housings in other ways for special applications. Put the connector housings together before

Orion to Yaesu BCD encoder band swicthing

The PDF file OrionBandData which has AD5X design for a encoder which takes the band data output of an Orion and converts to proper levels the BCD data needed to band switching of Yaesu as well as ICOM amplifiers. Thanks to AD5X for the design. Download here.

A Fast and Reliable QSK T/R Relay Control Unit

The antenna changeover relay on most linear amplifiers is rather slow, and when the transceiver keys it, there is an RF spark because the RF power appears before the relay has fully changed over. Many modern transceivers provide a delay of 10 – 15 ms between key-down – or pressing the PTT or transmit button,

An Efficient MW Band-Stop Filter

Reject unwanted MW AM signals from your RX Front End A nearby broadcast AM station in the Medium Wave band can sometimes cause interference to HF receivers over a broad range of frequencies. A band-stop filter can reject the unwanted frequencies and keep them out of your receiver. This design provides a high attenuation between

Yet Another Front End Saver

The KD9SV Front End Saver in a new fashion. If you use a separate receive antenna, you need a Front End Saver to eliminate the possibility of blowing out your receiver’s front end while using an auxiliary receive antenna. Unfortunately, all the radios produced by Icom, Kenwood, Yaesu & TenTec have the same problem –

The S56A SO2R units

Mario, S56A, developed many state-of-art SO2R devices. Look at these hi-tech units! S3O2R – S56A Simple Single Op. Two Radio Interface by Marijan Miletic, S56A, N1YU SO2R category is becoming very popular in HF contests. Several PC programs support operation via LPT and COM ports. Commercial switching boxes were recently introduced by two USA manufacturers.

The BCC Joker Switch

Why this reprint? You may get some goals here: Download PC boards ready to foil print Download complete data sheet of the relay used Get more construction details This reprint is made under kindly permission of the author, Thomas Moliere, DL7AV [reprinted from the CQ Contest November 1998, p. 8-13] The BCC Joker Switch Here