RFI Site survey – Part II, interpretation

Posted on February 5, 2018 by Dave

Overview:

Annotated 40 meters showing various RFI events

Annotated 40 meters showing various RFI events

This is part II in a series of articles which will cover how I interpret and use SDR captured spectrograms as they relate to my RFI mitigation efforts.  See Part I, Using a SDR as a Site Survey Tool for how I setup and use the SDRPlay RSP1 as my SDR of choice, while using HDSDR as the radio control program.  The concept was to view my RFI environment as a whole, not in real time, but across long periods of time, and very wide frequency spans.  Once you have looked over part I, and part II, take a look at the RFI Samples page.  This page presents various forms of RFI so you might be able to tell what is causing your RFI issues.

Real world examples of RFI will be used here showing how I can infer what appear to be disparate RFI sources, as related sources.  Part I covered my choice, installation and setup of HDSDR, and an SDRPlay RSP1 SDR for use as a site survey tool. Read more »

Categories: I have RFI: Series, Info, RFI Mitigation, SDR as Site Survey tool | Leave a comment

RFI Snapshots

Posted on January 20, 2018 by Dave

Grow lights on 80

Grow lights on 80

If you click the image at the left, or here, you get to a set of pages containing snapshots of the various categories of RFI generating devices.  Once you arrive at the category page, you will find another set of images, each representing some form of RFI.  Clicking on any of the images on the RFI category page will take you to yet another page, which contains any number of RFI signatures.  This may be helpful in identifying a source of RFI.  While it is not a a RFI fingerprint, it is an indication of what may be causing your RFI.  These indications can help in the location of RFI.  For instance, if you see something here like a street light, and it matches what you see at home, then you can reasonably suspect streetlights in your area, and watch them.  There are many types of RFI, not all of them will match, so do not expect to find an exact match…  For more information on locating RFI see the “I have RFI” three part article located here.

 

Important:

If you have any sort of KNOWN RFI signatures, please send them to me, with a note as to what they are.  If you have an audio sample please include it.  My email is good on QRZ.COM.  Clicking the QRZ link will open a tab, you can get my email there…

Categories: I have RFI: Series, Info, RFI Mitigation, RFI Signatures | Leave a comment

Notes on tuning a Hustler 6BTV

Posted on July 24, 2017 by Dave

80 Meters, no choke, 8 radials.

80 Meters, no choke, 8 radials.

Overview:

I thought I would share a few of my notes on tuning up a 6BTV antenna, and constructing a radial field.  I have been using a GAP Challenger DX, (review here), for the past fifteen years, unbeknownst to me, and over that time, water had been slowly seeping into the tuning harness of the antenna.

The harness finally gave up the ghost one day, presenting a dead short to my Solid State ALS-1306 amp, (review here), as I increased power.  At about 800 watts CW, the harness shorted out, killing the ALS-1306, and necessitating the amp make a trip back to ALS-1306 heaven, (Ameritron), to have a replacement RF output device installed.

Replacing the Challenger was one of the options on the table, but I did not want to do a new install of a Challenger– I remember the last install.  The entire phasing harness installation process is not fun, nor is it easy, so– given there were a few things about the Challenger I was not happy with anyway, I began looking for a different antenna.

Read more »

Categories: 6BTV, Antenna Reviews, Construction, Info | 13 Comments

Using a SDR as a RFI site survey tool

Posted on September 7, 2016 by Dave

Overview

Twenty Four hours of RFI on 80 Meters

Twenty Four hours of RFI on 80 Meters

This is Part One of a multi part article dealing with setting up a SDR as a RFI site survey tool to assist in RFI detection, location, and mitigation.  Further, part one will set the stage for how captures of the RFI were accomplished, and visualized.  Part one will also  touch upon some of what can be seen and learned from this data.  Methods I used to locate RFI can be found here.  Also some RFI sources signatures have been captured here.

Part two will deal with interpretation of the SDR spectrogram.  Part two can be found here.  Part three will deal with actual location methods, using that portable SDR tool.

Read more »

Categories: Cleanup, I have RFI: Series, Info, RFI Mitigation, SDR as Site Survey tool | 13 Comments

Review of the Palstar AT2KD Tuner

Posted on April 29, 2016 by Dave

AT2KD Tuner, front view

Palstar AT2KD Tuner

This review of the Palstar AT2KD tuner will start off with a few comments about tuners in general, and will not get too technical.  There are many other places to find technical reviews of this device…  eHam ratings indicate that it is a 4.8 out of 5, which is a pretty darn good rating, and some pretty good technical reviews there as well.

Over time I have had both auto tuners, and manual tuners.  I have used differential tuners, and standard tuners…  I always return to manual tuners, using roller inductors, and large caps every time…  An auto tuner is simpler to operate, but the power levels just are not there yet for me on anything I can afford, nor have I been able to get an autotuner, (of the ones I have used), to tune to an exact 1:1, every time, on every band.  It is always something like 1.x:1, I have seen as high as 1.7:1, which can cause issues with the new solid state amps, such as the ALS-1306, which I own.  See the section under “Conclusions”, for more on that subject. Read more »

Categories: Accessories reviews, Info, Palstar AT2KD, Reviews | 2 Comments

Adding an external keypad to the K3

Posted on January 21, 2016 by Dave

Genovation KeypadThis article on adding an external keypad to the K3 was created to make it simpler for the next poor sod down the road to add a Genovation CP48USBHID, 48 key keypad, or the Genovation CP24USBHID, 24 key device to their K3/P3 devices.  I initially learned about the Genovation keypads on the Elecraft mail list.  It sounded to me like several people were talking as if they had them working, so I asked how to set one up, and got nothing back…  I asked again a few weeks later, only this time on both the Elecraft, and the Yahoo mail lists.  I received several replies, all saying they would like to have one of these working as well.  I did get one lone reply from a person who said, “yes, but I did it a year ago, and have now forgotten how”.  From that I concluded I was on my own in getting these two devices connected.  Given I agreed with the general premise that having a keypad available to send macros to the radio would be good, I decided to move forward with this project and see how far I might get.  I contacted the Elecraft support team first, and got, “only the listed keyboards will work”, response.  However, in the discussion, I got what would later turn out to be a vital piece of information in making the connection between these two devices work. Read more »

Categories: Elecraft K3, Info, K3: External Keypad, Reviews, Setups, Software information, Station | 36 Comments

I have RFI, now what– Locating it

Posted on December 20, 2015 by Dave

FFT of RFI showing 10 hours of noiseAs the name suggests, this article, “I have RFI, now what– Locating it”, will show how I located several RFI sources in my area.  This is part three of a three part series–  Part one covered what tools I needed to locate RFI, while Part two covered internal removal of RFI sources within the shack, and finally, Part three covers how I located a number of RFI sources external to the shack, and how I got them corrected.  A new section has been added to this site, showing the SDR based signatures of various RFI events, or look over the entire RFI series here.

Over the past few years, I have been plagued with RFI on 40 and 80 Meters.  Most of it has been Horticultural lighting, (read that as Grow Lights), and most of it has been pretty easily located.  In fact most have been found in under 15 minutes!  For the most part the folks I have contacted have all been decent types, and have all to a fault, done what it takes to either remove the RFI, or stop generating it.  For that I am thankful to them, it saves me the time in getting the Federal Communications Commission, and the ARRL involved.  It also saves the person generating the RFI, the problem of federal involvement.

I suspect a lot of this “good luck” has been because I never threaten, or wave the Federal Communications Commission at anyone.  I simply tell them, in writing, what I will do to get the RFI to stop, by giving them a handout our club created, which approaches the entire issue in a kind, friendly manner.  The goal is to solve the RFI problem at the lowest possible level, not just go straight to the Federal Communications Commission, but to give the person a chance to solve the issue locally, so I don’t have to involve the Federal Communications Commission. Read more »

Categories: ARRL, Direction Finding, DX, I have RFI: Series, Info, Legal Actions, MFJ: MFJ-856, Quantification, Reviews, RFI Mitigation, Setups, Software information, Station, W8VVV: S-meter Lite | 2 Comments

Review of Ameritron’s ALS-1306 Amplifier

Posted on June 29, 2015 by Dave

Ameritron ALS-1306 Front view

ALS-1306 (Front)

This review of Ameritron’s ALS-1306 was prompted by my selling my older ALS-82 in order to get a no tune amp.  This will not be a technical review, as there are many of those around, and the amp is based on the older designed ALS-1300, with some protection added.

I decided that I wanted an auto tuning amplifier, as opposed to the manual tune, AL-82 I was using.  So I sold the old AL-82, (see my review here), and purchased an Ameritron ALS-1306.   Read more »

Categories: Accessories reviews, Ameritron: ALS-1306, Info, Radios reviews, Reviews, Service reviews, Setups, Station | 46 Comments

Review of “DX World”

Posted on May 3, 2015 by Dave

 

DX World Logo

DX World Logo

 

Introduction:

Several months ago I did a review of “The Daily DX“, and now it is time to do a review of “DX World“.  One is for pay, and one, (DX World), is free.  Yes, free, “DX World” is totally free to the user.  I did not want to do a review without having actually used DX World for a bit, so I started using DX World on a daily basis the day I did the review of Daily DX.

Read more »

Categories: DX, DX World, Info, Propagation, Reviews, Service reviews | 2 Comments

Review of Ameritron’s RCS-4 Coax Switch

Posted on March 16, 2015 by Dave

RCS-4 by Ameritron

RCS-4 by Ameritron

This is a a review of Ameritron’s RCS-4 Coax Switch, covering its use and mounting.  I purchased the RCS-4 several years ago from HRO thinking I would get it outside sometime soon, that didn’t happen.  Two years later it was it was still installed inside the shack, on my feedline, switching between a dummy load, and my feedline run outside.  I recently, decided to add a 4-Square for 30 meters, completely redo my antenna feed system, and replaced my trusty 756 PRO III, with a new Elecraft K3!  This seemed like a good time to really just redo everything in the back yard, and the shack, moving the RCS-4 outside as well.

My GAP Challenger was giving me a bit of trouble anyway, and it was time to rebuild it as it had not been looked at, or touched in a any way, for maybe 10 years or more.  The feedline was getting water in it, and the phasing harness needed replacement, and the three radials needed to be redone from scratch.   Read more »

Categories: Accessories reviews, Ameritron: RCS-4, Info, Reviews, Station | 1 Comment