Misc. Net Technical Topics

From time to time the presenter of the Weekly Net Technical topic provides a summary of their presentation -- which will be posted here for your review.

A Technical Topic about GRID SQUARES was presented by Dot AC4HH


Some of this is from the ARRL Handbook, ARRL’s website, an old issue of QST, and some from Wikipedia.

I feel sure you all know what a grid square is, but tonight I thought I’d go a little deeper into the subject. If you listen to the low end of any VHF band, one of the first things you will notice is that most QSOs include an exchange of "grid squares." Grid squares are a way of defining your general location anywhere on the earth. Before we get too far into grid squares, let's take a quick look at one of the more common methods used to define locations. If you have a globe or map, look at it and you will see the lines that run north to south (Longitude) as well as east to west (Latitude). . These lines divide our entire planet into a system of coordinates. Any point on the globe can be defined by the intersection of two ordinate lines.

Tonight we are going to discuss the Maidenhead Locator System, a.k.a. QTH Locator and IARU Locator. Ham radio uses the Maidenhead Locator System which replaced the QRA Locator System which was limited to describing European locations. The new system was originally devised by John Morris, G4ANB, and adopted by a meeting of the European VHF managers in Maidenhead, England in 1980 From which came the Maidenhead system name. Out of 20 different proposals. Mr. Morris’s was deemed the best. The Maidenhead system compresses latitude and longitude into a short string of characters, which is similar in concept to the World Geographic Reference System. The chosen coding uses alternating pairs of letters and digits like so: BL11bh16.

The first letter represents longitude and the second letter represents latitude—traditionally called a FIELD—designated by the letters AA to RR. The entire earth’s surface was divided into 18 X 18 squares making 324 grids altogether, dividing the globe into 18 zones of longitude of 20 degrees each, and 18 zones of latitude of 10 degrees each.

The second pair of numbers called a SQUARE, uses a base number of 10, and is designated by the digits “0” to “9”. Each of these squares represents 2 degrees of longitude 1 degree of latitude and measures approximately 70 X 100 miles. So they are not squares but rectangles.

For additional precision, each square can be sub-divided further, into SUBSQUARES, designated by the addition of two letters, often (but not always) presented in lowercase. These more precise locators are used as part of the exchange in some contests. Each of these 576 subsquares measures 5 minutes longitude and 2.5 minutes latitude, roughly corresponding to 4x3 miles in the continental US.

These letters are “a” through “x”. For even more precise location, two additional digits were proposed and ratified as an EXTENDED LOCATOR, making it altogether a string of eight characters, and dividing subsquares into even more smaller ones.

In summary:

1. Character pairs represent longitude first, then latitude

2. The first pair (FIELD) represents a base of 18 and the letters “A” to “R”

3. The second pair (SQUARE) represents a base of 10 and the digits “0” to “9”

4. The third pair (SUBSQUARE) represents a base of 24 and the letters “a” and “x”.

5. The fourth pair (EXTENDED SQUARE) represents a base of 10 and the digits “0” to “9”

6. And we are not going to discuss the fifth and subsequent pairs—which are not formally defined

However, you might hear of something like BL11bh16oo66

All you really need to know is your location, such as EM75 and EM75hc, the identifiers of my location.

For additional study, go to ARRL’s home page and type in “grid square” in the search box. And if you want to know your grid square and subsquare, you can go to Google and type in your address. You can also install an app on your phone to find grid squares.

A Technical Topic about RST Signal Reports was given by KK4EAO

R S T Signal Reports

When you are talking on the radio (mainly HF Transmissions) during Field day or in personal conversations or in contests -- you might get a report that "you are a 5 9" or some other combination of numbers. What does this mean?

Well, they are telling you how clear (or not clear) your signal is -- and they expect a report from you in turn about their signal.

So what is a Signal report (also known as a RST Report) -- you ask.

Well, the R stands for READABILITY and applies to both Voice and CW (Morse Code) Transmissions. There are 5 categories for R.

1. = UNreadable

2. = Barely readable, occasional words are distinguishable

3. = Readable but with considerable difficulty

4.= Readable with almost no difficulty

5. = Perfectly Readable

There are are no meters or dials on your radio to give you this information. It is up to your ears and brain to judge Readability.

The S in the RST report stands for SIGNAL STRENGTH and also applies to both Voice and CW transmissions.

There are 9 Categories for S and they are:

  1. Faint barely perceptible signals
  2. Very weak signals
  3. Weak signals
  4. Fair signals
  5. Fairly good signals
  6. Good signals
  7. Moderately strong signals
  8. Strong signals
  9. Extremely strong signals

The S meter on the front of your HF radio will show you the signal strength so you don't have to use your ears or brain (though, of course, you can if you want to.)

The T in the RST Report stands for TONE and only applies to CW (Morse Code) transmissions.

The T (Tone Report) also has 9 categories ranging from 1 which is awful (Sixty cycle a.c or less, very rough and broad) to 9 (which is Perfect tone, no trace of ripple or modulation of any kind)

During the YL Net when this information was given, KE4RP (Betsy) provided us with a link to a webpage that has the 1-9 Definitions for TONE as well as the R and the S Definitions. She suggests printing the page with all 3 definitions and keeping the page close to your radio. Here is the link

And one more thing --

if you are using Morse Code (CW) and get a 5 9 9 C report --

the C means CHIRPING which means your signal is Unstable or Chirping -- and this is probably due to an inadequate power supply or you are operating on a Low Battery.

So now you know what it means when someone gives you a RST Report. Here's hoping you get lots and lots of 5 9 reports -- which indicate you have a Perfectly Readable (the 5) and an extremely strong signal (the 9)