The May - June 2021 Communicator

110 Pages Of Projects, News, Views and Reviews... 

We're back! The May-June Communicator eZine is now available for viewing or download at https://bit.ly/SARC21MayJun

Read in over 130 countries now, we bring you Amateur Radio news from the South West corner of Canada and elsewhere. You will find Amateur Radio related articles, profiles, news, tips and how-to's. You can view or download it as a .PDF file from:  

https://bit.ly/SARC21MayJun

Previous Communicator issues are at https://ve7sar.blogspot.com/search/label/The%20Communicator

As always, thank you to our contributors, and your feedback is always welcome. 

The deadline for the next edition is June 21st.

If you have news or events from your club or photos, stories, projects or other items of interest from BC or elsewhere, please email them to communicator@ve7sar.net

Keep visiting our site for regular updates and news: https://ve7sar.blogspot.ca    

73,

John VE7TI

'The Communicator' Editor

An Inexpensive Interface Cable for Baofeng Transceivers

Much less expensive than the individual components 

I know many of us have Baofeng and Wouxon transceivers. I recently came across this tip to cannibalize an inexpensive mic for the cable, which can then be easily interfaced to a TNC or other digital device.

The Baofeng UV-5R and similar radios are extremely inexpensive dual band (2m/70cm) HT's that are widely used for FM voice communication. But what about using them on packet radio? Yes, this is possible, but a number of people have had problems with either home made cables are some that were bought commercially. The major problem is that the radio keys, but does not unkey. It seems to be a grounding problem because when you bring your hand close to the radio, it then unkeys. More information on how to fix this momentarily. 

One way to overcome this is to make your own radio/TNC cable using a speaker/microphone that is designed for the Baofeng radio. You then cut off the microphone and just use the cable and connector. This may sound expensive, but as it turns out, speaker/mics are available for the Baofeng on line in the US$5 range. Do a search on Amazon for "Baofeng Speaker" and you will find them. You will also need a 5 pin DIN or 9 pin serial plug for the other end of the cable. 

You can buy these DIN Plugs on the TNC-X web site for $2 and serial plugs are universally available. Locally Lee’s Electronics is my choice for supplier.

Here is the Baofeng Speaker/Mic purchased from Amazon.The pin out for the plug is:

• TX Audio: Ring on big plug
• Ground: Sleeve on small plug 
• PTT: Sleeve on big plug 
• RX Audio: Tip on small plug

In the photo above, the 3 screws that hold the microphone rear plate in place have been removed and it is opened up. You can see that the wires are labelled on the printed circuit board, which makes it easy to figure out which wire is which. On this microphone the connections are as follows:

• Red = TXAudio
• White = Ground
• Black = PTT
• Green = RXAudio

NOTE 1: Some of these mics have the M- (ground) and SP+ (RXAudio) wires reversed. Since these wires are connected to the speaker, this doesn't matter for the operation of the speaker/mic, but it does matter for TNC connections. Typically the white wire is ground and the green wire is RXAudio. To be certain, clip the microphone off the cord and check the continuity between the white wire and the sleeve on the small plug. 

NOTE 2: A few Baofeng speaker/mics don't work.  It is suggested that before you cut the cable, make sure the speaker/mic works with your Baofeng HT.  If it does not work, the cable probably won't work either. 

The next step is to strip the wires and tin them with solder. Notice that the black wire is significantly shorter than the other wires. 

Solder a 2.2K resistor onto the pin where the PTT (black) wire is going to be attached. (This will solve the problem of the TNC getting stuck in transmit. Use as small a resistor as will fit, wattage is not important. Next solder the connector on to the remaining wires. 

Here's the completed cable, ready to go! As you can see it is not a difficult assembly process. However, if you would like to buy one already built, they are available for $20 plus shipping from https://www.tnc-x.com/ This company also sells TNC kits.

 ~ John VE7TI 

   19-02

More on LADD and RR Frequencies for Back Country Communications

 A follow-up

Last August I wrote about the confusion that exists with back-country amateur radio operators who use LADD and RR frequencies, often contrary to terms of their certification. [The Communicator Digital Edition: LADD and RR Frequencies (ve7sar.blogspot.com)].

Given that I frequently hear of this confusion during our Basic Amateur Radio Course [https://bit.ly/SARCcourses] Surrey Amateur Radio Communications (SARC) made it the topic of the April 2021 General Meeting.

That presentation is now available via our YouTube channel at https://youtu.be/SjwCSLSZtXk 

~ John VE7TI

Scientists Warn RF May Disappear Completely by 2040

  

A new study published in the science journal Standing Waves shows that RF signals are disappearing at an alarming rate. Some scientists are going so far as to say that if action is not taken immediately, the airwaves could be completely silent by 2040.

The study’s chair, Dr. Bunsen Honeydew said, “We looked at daily activity on the HF bands from 3.5 to 29 MHz over the last 11 years. For a while the bands were showing healthy growth with plenty of activity, but in just the last five years signals have become much weaker and some have even disappeared completely. Worse hit has been the 10 meter band where we haven’t observed a signal for over two years… the extent of the devastation is breathtaking.”

But what is causing it? Scientists have a few theories but the main culprit seems to be that there are simply too many antennas absorbing a limited supply of RF. As this simple formula shows, RF is depleted at a rate inversely proportional to the square of the distance between any two stations:

Scientists warn that, as cos (1/x) increases, we risk reaching “the point of no return” where RF levels will never recover.

But what does this mean to the average ham? The short answer is we must all help conserve RF. Where hams used to just have one radio, it is now common to own three or even four radios, each with an RF absorbing antenna.

Of course, some of the worst contributors to the crisis are the so-called “Big Gun” stations. These use aluminum farming techniques that have gotten way out of control… covering acres of land with multiple towers reaching up to 100 feet and scooping up every signal that goes by.

The International Amateur Radio Union (IARU) and member societies like ARRL are calling for urgent action and plan to table a number of propositions at the next WARC meeting in Geneva. Among them would be a limit on antenna farming, a program for offsetting RF absorption by deploying more transmitters around the globe, and requiring hams to turn off their receivers when not really listening.

Perilous times.

- Adrian VE7NZ reporting

Hello Adrian, thank you for this enlightening article and for drawing attention to this growing problem. I understand that this may lead to an RF preservation tax much like the carbon tax that is now in place. I for one will be installing reflectors on all my antennas, when they are not in active use, to bounce the RF back into the aether.

I will certainly include this timely article on page 13 of the next issue of The Communicator in the hope that it will spur others into action before its too late.

John VE7TI

Editor ‘The Communicator’
https://ve7sar.blogspot.ca