Are we ready to provide Emergency Communications in South Africa during a Disaster?

The recent severe weather storm that resulted in flooding, deaths, damage etc. was once again proof that the Western Cape is a disaster prone area from time to time.  The question need to be asked whether we as radio amateurs are ready to provide emergency communications in South Africa?  No I am not going to answer this question but in this posting I will rather reflect on the preparedness of radio amateurs in the past during the Knysna Fire Storm in  June 2017.  The reason why I will use the Knysna Fire Storm as an example will be quite clear if you listen to the Podcast.

Podcast file at the bottom of this page.

Herewith a few images of the Knysna Fire.  (Photographers unknown but thanks to them we can now commemorate the event)

 

Listen to the audio file underneath to learn more about the contribution of Amateur Radio especially AREDN during this horrific disaster:

Down Memory Lane: Who remembers Chris ZS3B going Tuk-Tuk Amateur Radio Mobile in South Africa?

                                                    Chris Nagel ZS3B, ZS6BGH (SK)

With all the different activities in Amateur Radio like HOTA, SOTA, POTA etc, I was telling the Amateur Radio 101 Telegram Group about a well known Yellow Tuk-Tuk Three Wheeler that visited the Buffalo Rally in Mossel Bay in 1997.  No this was not an ordinary Tuk-Tuk.  It was the Tuk-Tuk of Chris Nagel ZS3B, ZS6BGH (SK several years ago) which was well known all over South Africa when Chris decided to hit the road.  I once meet up with Chris close to the Buffalo Rally gates in Mossel Bay.  Chris did not participate in the Rally, he decided to look out for radio amateur that might be at the rally.  Needless to say that I spend a few hours with Chris who told many stories of his Tuk-Tuk Adventures. I can remember one of his many stories.  He told me that on one of his trips through the Free State the Tuk-Tuk's front wheel bearings broke and he was left stranded along the road.  Thankfully a farmer stopped and told Chris that he is welcome to stay over on his farm until the Tuk-Tuk is fixed.  The farmer towed the Tuk-Tuk to his farm and in the morning he and Chris ordered a new wheel bearing.  Chris stayed a few days on the farm until the bearing arrived and no he did not stay in the farmers house but in the Tuk-Tuk seeing that it was also Chris's mobile home with a bed and all the necessary things needed. After fixing the bearing problem Chris went on his merry way.  As to all the amateur radio equipment he installed one can view the images.  I regularly spoke to Chris on HF.  Another interesting question that I posed to Chris when he was in Mossel Bay is:  "How do he protect himself man alone against crime?"  Chris was sitting in the Tuk-Tuk at the time and he reached to the roof  pulling out his 44 Magnum Six Shooter.  He indicated that thankfully he never experience any safety issues which necessitated the use of the shooter.

My son and I enjoyed a great few hours with Chris on the day.  Sadly Chris became silent key but the memories live on.  Till today I still miss that very pronounced voice of Chris.

Wonder if somebody will follow Chris in his footsteps by going Amateur Radio Tuk-Tuk Mobile in South Africa in the future?

Images courtesy ZS6PTA:  (Click on the images for larger view.)  

Recent Ping-Pong Loop Incident via the GRHub Network necessitates action to be taken to prevent such incidents in future.

The title of this topic says it all.  What am I talking about?

Let me try to explain.

Firstly if your link, repeater, node, station etc. uses VOX then you are a good candidate to cause havoc on the GRHub- / ZS - Link Network.  Echolink has VOX as a future and on several occasions in the past I had to disconnect stations that lock up the system or causes a Ping-Pong Loop.  PLEASE do not use VOX when linking to the GRHub Network (ZS1I-L).  If I find that your station /link / node is using VOX I will disconnect your station and you will be informed not to use VOX on the Network.  No I do not play policeman, but we need to play the game here.  Your station not only influence the GRHub Network if you use VOX but also all the stations connected to the world wide network.

Secondly if your link, node or repeater has a long "tail" (squelch burst often heard at the end of a transmission as the PTT is released) please adjust this tail to be as short as possible or switch the tail off. The best squelch "tail" elimination method is when the tone stops just before the hang timer unkeys,this works well with all brands of equipment.  Most good repeaters or controllers have the option to select the tail off or on.  I do understand that some repeater custodians  prefer to have a tail on their repeater.  If you do link to the network then please make this tail as short as possible.

A long "tail" if not setup correctly will cause endless ping-ponging.  More on this below.

Early repeaters used relays to key the transmitter in response to the receiver detecting that a signal is present. Some propagation effects, such as mobile flutter, or picket fencing, would cause the repeater transmitter to cycle on and off as the receive signal experiences fading and restoration of received signal. This cyclic operation would result in premature failure of the transmit relay. Further, the delay in keying the transmitter may itself be responsible for rendering a signal unintelligible when compared to leaving the transmitter keyed during periodic momentary signal fading conditions.

These problems were mitigated by implementing a squelch tail timer. As soon as the receiver detects a valid signal, the transmitter is keyed immediately. When the received signal drops out, a timer is started and the transmitter remains keyed until that timer times out. The squelch tail timer duration is longer than most periodic signal fading conditions, and is able to avoid un-keying the transmitter in instances of periodic fading conditions.

Secondary to this function, the squelch tail serves a second purpose in providing a queuing signal to indicate when a user station may begin transmission. Stations may begin transmitting after the repeater squelch transmitter drops. This can be identified by the sound of the repeater squelch decaying being re-transmitted by the repeater transmitter when the receive signal drops out of the repeater receiver, followed by a delay that is equal to the duration of the squelch tail timer, and then the sound of the squelch decay heard directly on your radio when the repeater transmitter drops. Although the squelch tail timer duration typically is approximately 1.5 seconds long, shorter and longer squelch tail delays may be present on a given repeater system.

This double decay of squelch circuits, resulting in short noise bursts that are separated by a 1.5 second delay, is often referred to as a ker-chunk sound, or simply the squelch tail (it is not a come-back).

The squelch tail is used in repeater operating protocol to indicate first, that the transmitting station has ceased transmission as evident by the first squelch decay noise burst, and second, that the repeater transmitter has stopped transmitting as evident by the second squelch decay noise burst. Conversing stations should not start transmitting until the second squelch decay noise burst occurs. Breaking stations should transmit in the interval between noise bursts, as conversing stations will be standing by to wait for the repeater transmitter to drop, in order to make their presence known.

This is very important when two repeaters are linked to each other, to prevent endless ping-ponging of one repeater bringing up the other.  

Thirdly I request that a station do not connect to more than one station/node that is already connected to a specific station on the network.  This will also result in ping-ponging and audio loops.  Always check who is connected to who before connecting to a station, repeater, link etc.

Fourthly - If at all possible connect the Internet to your repeater, node, link etc. on site. That way, there is no hang time to propagate back into the network.  Alternatively connect the Echolink/AllStar node to a link port on the existing repeater controller, which has the advantage that if the AllStar/Echolink box dies, you still have local repeater functionality. The other advantage of having the node at the repeater is better audio quality. You can successfully setup a link on the user frequency, but you need to take steps to ensure that the hang time is not seen by the node, such as using CTCSS gated by the receiver's COS.

Finally:  The above might sound cumbersome and technical but unfortunately this is the only way to prevent the dreaded Ping-Pong Loop effect.  Either we do it right or don't do it at all.  A half-baked system is not going to work effectively and will only lead to frustration and bad operating practices, nothing that we need or want in amateur radio.  We must be proud and professional in this regard.  Let's play the game and enjoy the ZS Link Network in South Africa.

More information and links:

1.   The use of "AND Squelch" to eliminate those annoying squelch bursts.  By Kevin Custer W3KKC 

2.  Echolink Sysop Settings  By K1RFD

3.  Repeater Linking Tips. By K1RFD  

4.  Repeater Linking. By Kevin Custer W3KKC  

UPDATED 25 Sept 2023: Amateur Radio Activities in the Garden Route- , Southern Cape- and other Areas

In this specific topic you will find information, images, videos about amateur radio activities in the Garden Route-, Southern Cape- and other Areas.  I would like to thank everybody who send me information in this regard.  Other regions of the country is also welcome to send me information that I will publish from time to time.

Note:  Click on images for larger view.

29 July 2023: 2 Meter SSB Contact in the Southern Cape

29 July 2023 01h36 VHF contact between  Mark ZS1SSM (Gouritz) and Thys ZS1TBP (Mossel Bay) on 144.300 Mhz SSB (USB)

29 July 2023: 2 Meter Q65 Contact over the Drakensberg

668Km between Derek ZS5Y (Scottburgh) and Charl ZS3K (Hopetown) right over Drakensberg on 2m Q65 17:56 CAT 29/07/2023

Wednesday, 23 August 2023, 11:04 - Ystervarkpunt Vuurtoring Naweek

 George Herald News: Radio-amateurs byeen by Ystervarkpunt-ligtoring - Ystervarkpunt-vuurtoring is so 10 km voor Albertinia naby Gouritsmond. Die vuurtoring het 92 trappe, is ’n goeie 25 tot 30m hoog, die vuurtoring werk 100% en gee nog 'n helder lig in die aande vir die skepe. Lees meer HIER

 5 September 2023 11h11  DMR Day in the Mossel Bay area

Tuesday's will be DMR Radio activity day on the GRHub Network, Mossel Bay 

Well it is now "official".   Tuesday's will be DMR Radio Activity Day on the GRHub Network and around the World.  The ZS1I DMR Bridge will be connected to the GRHub Network at 09h00 SAST (07h00 UTC) on Tuesdays.  Connecting the bridge will allow Echolink, AllStar, Repeater- and 145.550 Mhz Simplex stations access to DMR and vice versa.

More information:  Click HERE 

 

5 September 2023 06h52 Spesiale Uitnodiging: George Heritage Trust - HOTA Bedrywighede

Eden Radio Club  Nuus:

Mnr Corne Cornelius  ZS1COR

Erfenismaand word jaarliks van 1 tot 30 September gevier. Dit gee erkenning aan verskillende aspekte van Suid Afrikaanse kultuur en erfenis, beide tasbaar en nie-tasbaar. Ons vier ons unieke argitektoniese erfenis sowel as musiek, optredes, taal, die kos wat ons eet, sowel as ons herinneringe. Daar is die simboliek van saam brood breek, wat help om die gemeenskaplike menswees te deel. Ons nooi u na ‘n ontbyt - met die doel om gemeenskaplike doelwitte te identifiseer tussen die verskillende erfenis en bewaring instansies, sommige met aangrensende en oorvleuelende doelwitte.

Ons sal so 5 minute kans gee vir u om die aktiwiteite van die Eden  Radio Klub te kan bekendstel. Stuur ook asseblief vir my u telefoonnommer - ek wil graag 'n dokument saamstel met al die kontakdetails van die verskillende rolspelers.

Datum: 9 vm op Saterdag die 16e September 2023. Gratis vir 2 persone.

Venue: The Apprentice | Francois Ferreira Culinary Academy.

RSVP voor Maandag 11 September: thegeorgeheritagetrust@gmail.com

Met vriendelike groete,

Philda Benkenstein

(Namens Willie-John van Niekerk | Voorsitter George Heritage Trust)

George Heritage Trust

George Erfenistrust

GARDEN ROUTE, SOUTH AFRICA

REGISTRATION NUMBER: HM/CB/0815/35

www.georgeheritage.co.za

The George Heritage Trust, founded in 1996 as a non-profit organisation, promotes the sustainable conservation of the architectural, archaeological, cultural/living and natural heritage of George and its surrounds for the benefit of all.

 

Orania Noodgeval Herdenking langs die Oranje Rivier - Zane ZS3VO 

 

Luister na die Audio Insetsel rondom die herdenking.  Klik HIER

 

9 Nuwe Eden RAE Kandidate word geskool in Radio Prosedures:

Foto vlnr   Aiden Trahms , Leon Kapp, Henk J. Botha, Eben Hewitt en Louis Coetzee.  (Twee nie op photo:  Gerhard Bronkhorst en Henge Rautenbacht)  9 Kandidate!!  Sommer 'n lekker span voornemede radio amateurs hier in die die Suid Kaap.  Welgedaan Eden Radio Club!

Foto:  Leon Kapp

Veldstasie Video:  Eden Radio Klub

 

ZR3VDK Amateur Radio Bulletin geleentheids redakteur (Thys ZS1TBP) in Aksie

 

Thys ZS1TBP werk DX in die hok van Deon ZS1DDM

 

Jack Ass Mobile  - Nie in die Suid Kaap nie maar is 'n moontlikheid in die toekoms

Nie in die Suid Kaap nie maar wel sononiem met die area waar daar nog baie donkies is.  Miskien kan 'n radio amateur in die area met "donkie mobiel" groot pret veroorsaak. (Foto verskaf deur Curtis ZS1CMO)  

 

Woody ZS3LW take a break in Great Brak River

Welcome Woody to our area.  Enjoy your well deserved holiday.  With Woody is Marko ZS1NEU

 

UPDATED 25 September 2023: Woody ZS3WL en Thys ZS1TBP having a "ragchew" at the Sea Gypsy in Mossel Bay

"Recent Southern Cape Storm Surge" washes Snoek as far afield as Gauteng!!

Lional ZS6DPL berig:  Lyk my die weer in die Kaap is so sleg dit het die snoek tot hier laat uit spoel. Nou moet ons maar braai!!

Terugvoer:  Spesiale Uitnodiging: George Heritage Trust - HOTA Bedrywighede

Foto:  Corne ZS1COR (Rooi sirkel)

Meer inligting rondom die byeenkoms is HIER beskikbaar.  Dankie Corne dat jy amateur radio en HOTA bevorder in die Suid Kaap.

EME Contact between Berne ZS4TX and Max SA5IKN M0SKN US6IKN

Al gewonder wat het geword van Lippe Klap elke Sondag Middag? - Thys ZS1TBP

 

Nou weet almal wat van Lekker Lippe Klap geword het.

 

Updated:  25 September 2023

 

25 September 2023 - HOTA aktivering "Ou Tolhuis" and "Montagu Pass", George - Corne ZS1COR 

 

Foto:  Corne ZS1COR

Foto: vlnr  Eben Hewitt (RAE Kandidaat) en Corne ZS1COR

TOTA  - Trains on the Air  Keith ZS6HI and Radio Operator ? on a model train.

 

Einde/End

NS:  Hartlik dank aan almal wat 'n bydrae gelewer het tov die artikel maar n besonderse dank aan diegene wat amateur radio bevorder het en ook aktiwiteit daar gestel het.  Kom ons kyk of ons in 'n toekomstige Blog plasing nog meer inligting kan plaas oor amateur radio aktiwiteite.

ZS1I GRHub (AllStar/Echolink Node) Network now linked to the ZS1I 5.8 Ghz AREDN Network in Mossel Bay (Part 1)

Why would one link the ZS1I GRHub (AllStar Node) Network to the ZS1I 5.8 Ghz AREDN Network? 

• Because I can!  This is not a reason at all.
• To brag and say I did it the first in South Africa.  Not a convincing reason at all.
• To compete with fellow Repeater Custodians.  Not my style at all.
• To show that I am an electronics expert with lots of experience.  Just the opposite is true.
  
•  Experiment to link RF Networks together.  Perhaps a better reason.
•  To assist my local community using AREDN when experiencing disasters.  Perhaps a still better reason as I have used AREDN during the Knysna Fire Disaster in 2017.

None of the above was my motivation to link the GRHub Network to the 5.8 Ghz AREDN Network. What was my reason?  Well it is quite simple.  Eskom Loadshedding that resulted in Internet failures/outages was the sole reason.  

I think many will appreciate the fact that we need to find an alternative when the Internet is down and Echolink and other services does not work.  I hear many shouting use your RF Radios (HF,VHF,UHF) when the Internet is down.  Yes, I can but that in my opinion is losing the battle and moving backwards to days gone by.  No I do not say that I will not not use RF Radios but I wanted a system/network that keeps on working and render services no matter what.  I wanted a system that incorporate radios, repeaters, links, nodes, networks etc and provide effective communications even if there is no Power / Internet / Connectivity  but most of all having to "dance" to the tune Eskom is playing in ruling and regulating our lives also in amateur radio.  I hear many saying but why not wait the 2 - 4 hours and then you can continue once power is restored and the Internet is back on line.  NOT AN OPTION AT ALL.  Be as it may I decided to find an alternative for this ruling and regulating lives by Eskom.

In 2016 I installed the ZS1I AREDN Network in the Mossel Bay Area.  Little did I know that this network would become a life saving network during the 2017 /2018  Fire Disasters in the Southern Cape Area.  It is well know that this network delivered what was asked from it during these fire disasters.  As I know the capabilities of AREDN it was not a coincidence that the AREDN Network will once again play an important roll during Power and Internet outages.  AREDN is quite capable to be used successfully with or without the Internet.  After all it was developed to work without the Internet and as a replacement platform for many Internet services in  times of disasters.  With the AREDN Network already setup I  only needed to update the nodes to the latest AREDN firmware and to ensure that all the services installed were working as they should.

It was now just a question to link the ZS1I GRHub (AllStar Node) Network to the 5.8 Ghz AREDN Network.  Sounds quite simple but what sounds simple is not always the case.  Apart from the AllStar Nodes there was also Echolink Nodes. Thankfully AllStar Nodes work while Echolink Nodes fail if there is no Internet.  Power was not a problem as my Shack already runs on solar battery power. But what about other important Internet services.  AREDN also solves these issues.  I wanted a method to link the two networks together without to many issues.  Google here we come.  Well it turns out that there are no manuals or many examples of how to link the two networks.  Not being an IT expert I had to rely on bits and pieces to hopefully do the linking.  I wanted to be able to use both networks with or without the Internet.

I successfully managed to link both networks together and to activate the Internet for both networks.  I tested several services that worked flawlessly from and to both networks.  I was able to use clients /servers /services on both networks in both directions.  I will later if I can find the time compile a PDF Manual on a How to ....  I am very satisfied with the current setup, audio and effectiveness of the system.  I did several tests that were successful.  More on these tests in future postings.  This was the easy linking via the Internet.  In the next posting I will provide detail about linking the networks with no Internet connection.  I started working on this and is 95% there.  Now I will have to conduct latency and connectivity test to nodes, links and repeaters.  With Stage 6 and higher Eskom Loadshedding looming, I need the non Internet linking side done as soon as possible.

Updates to follow.

Images (Click on images for large view.)

Listen to the Audio quality from the ZS1I AllStar GRHub Network using a 2m Handheld to the ZS1I 5.8 Ghz AREDN Network.  Superb audio quality.  Cannot ask for better.  

What is in the Box?

Here is another "What's in the Box?"

Contents:

• 3 x 18650 Battery Holders
  
• 1 x Oled LED Screen
  
• 1 x WaveShare USB 3 to Gigabit Ethernet Converter
  

What do I have in mind for the above modules?

The 3 battery holders will be used to convert cheap LED lights.

The Oled screen will be used in a LoRa Project

The WaveShare  Converter will be used to link the AllStar GRHub Network to the ZS1I AREDN Mesh Network.

 

Follow the GRHub Network Blog for updates on these modular projects.   

Images:  Click on the images for large view.

 

Tuesday's will be DMR Radio activity day on the GRHub Network, Mossel Bay

Well it is now "official".   Tuesday's will be DMR Radio Activity Day on the GRHub Network and around the World.  The ZS1I DMR Bridge will be connected to the GRHub Network at 09h00 SAST (07h00 UTC) on Tuesdays.  Connecting the bridge will allow Echolink, AllStar, Repeater- and 145.550 Mhz Simplex stations access to DMR and vice versa.  

Scheduled times will be:

09h00 - 11h00 SAST  - Open session = Work world wide stations via DMR Talk Group 91.

14h00 - 15h00 SAST  - Open session = Work world wide stations via DMR Talk Group 91.

19h30 - 20h30 SAST - The ZS1I DMR Bridge will be linked to the South Africa DMR Talk Group 655 for the weekly ZA DMR Net.  Echolink users can connect to ZS1I-L and AllStar users to 49355.  Analog stations are wellcome to join the Net via the ZS1I DMR Bridge.

By default many Hubs, Repeaters and Links are connected to the Garden Route Hub Network. The GRHub Net is an Allstar hub node which links Allstar nodes and DMR stations around the world to form a network of nodes.

Due to the size of networks there need to be  rules to ensure orderly use of systems/networks. Amateur Radio regulations are largely self-enforced and we all need to work together and adhere to the rules listed below:  

IMPORTANT:   Sometimes stations see the call sign ZS1I on their dashboard / radio and they presume that it is yours truly calling / talking.  Please inform them that you are using the ZS1I DMR Bridge and provide them with your call sign before continuing with the QSO.  You must identify your station according to the regulations.

Please limit conversations to 5 or 8 minutes.  Other hams probably also want to use the busiest DMR Talk Group in the world.

In addition, great time and expense was put into building the Network.  In order for stations from across the world to log in from time to time, the Network/System must be free.  If you are hogging the Network, others can’t get in.

Please do not talk about politics or religion. Absolutely no obscene, indecent or profane language at any time.

Do not make comments on institutions, groups, or people.

When using the Network, you are a guest operator of its radio stations, nodes, hubs  etc.

PLEASE leave a "8 second delay" between replying to a station to allow ALL the systems to reset and connect.

Please note this is a global network and you will be transmitting on RF all over the world.

It is extremely important that you spend time ensuring your audio levels are correct before connecting and using the Network.

Correct operating procedure is a distinct characteristic of Amateur Radio.  It’s important that you convey to the public, and to new hams, the image that Amateur Radio Operators are courteous, patient, and really know what they’re doing.  A friendly style is great, but we also need to operate professionally.  

How will I know if the ZS1I DMR Bridge is active?  By listening via the Echolink ZS1I-L or on Allstar node 49355.  You can also visit the 49355 AllStar Portal HERE.  It will be listed as 46765  ZS1I DMR Bridge Network, Mossel Bay.

How do I connect to the ZS1I DMR Bridge to use the system / network?

• Echolink - Connect to ZS1I-L.  ZS1I-L is connected to the 49355 AllStar Hub that host the ZS1I DMR Bridge Network.
• AllStar - Connect to node 49355 ZS1I via AllStar.
• VHF Simplex - 145.550 Mhz Simplex in the Mossel Bay Area.  Remember the 88.5 khz CTCSS Tone.
• Any other Echolink, AllStar, Repeater or Linked station that is connected to the ZS1I-L or 49355 at the time you are connected.

Finally:

If you need any assistance in connecting or using the system/network  please feel free to contact the GRHub Adminstrator by clicking HERE

Transmit - let radio amateurs know you are there.  Start or answer a CQ call on DMR or on Analog and make new friends.

Never fear that you are "tying up the network system"  - It is there to be used. 

Enjoy using the ZS1I GRHub Network and the ZS1I DMR Bridge Network !!

DIY Soundcard Interface for the Baofeng Handheld Radio. (Part 1)

I was recently looking at a cheap USB Sound Card Radio Interface to use with:

• Baofeng Handheld Radio
  
• APRS Digipeater and Igate 
• Winlink via FM Vhf using ARDOP
  
• Testing different digital modes on VHF/UHF
• Work the ISS using APRS Packet Digipeater

Prerequisites:

• Simplicity (using of modules)
• Use of a external USB Soundcard Dongle (SYBA)
• Needed adjustable speaker audio level to match the mic input
• FT232 compatible to convert to USB plug and play.
• Reliable switching between TX and RX (5v Relay Module)
• Transmit audio level circuit needed good audio isolation (1:1 Audio Transformer)
• Needed fast PTT switching for ARDOP
• Reduced audio sensitivity to ensure reliable reception of data via the Baofeng
• Weight and size was compromised due to using modules.  With my bad eyesight it was fairly easy to join all the modules together without to much effort. 

Components:

• R1 = 1K 1/4 watt
  
• R2 = 1K Pot
• R3 = 82K 1/4 watt
  
• TRF = 1:1
• C1 = 0.1uF Electrolytic 
• 2 x 3.5 mm Stereo Jack Plugs
• 2m Audio Cable
• 1 x Speaker/Mic cable
• 1 x Veroboard
• 1 x FT232 Module (Red)
• 1 x 5v Relay Module
• 1 x USB Cable for FT232 Module
• 1  x Sound Card Dongle

Building/Construction:

I am not going to go into detail as the images underneath provide more than enough information to successfully construct this interface.

Setup / Working:

The 1:1 audio isolation transformer isolate the Baofeng 3.5 mm sleeve from ground to enable the PTT circuit to work. Resistors R1 and R2 are used to attenuate the transmit audio level so that the deviation of the transmitted signal is ~ 3 kHz for a 1200 baud packet signal at maximum speaker gain on the soundcard. Careful initial tuning of the deviation by setting R2 is required in order for your signals to be reliably copied by others.

When the serial port RTS line goes high, the relay turns on shorting the sleeve of the 3.5 mm Baofeng connector to ground and asserting PTT on the radio.  Simple as that.....but do not short the outputs and the Input as you will experience the well know smell and observe smoke escaping.  This can also damage your radio!!!!

The receive audio circuit includes capacitor C1 to block any DC voltage from the soundcard. Resistor R4 is chosen to attenuate the audio signal from the Baofeng speaker (2.5 mm connector) to a level compatible with the soundcard microphone input. Assuming a typical soundcard microphone input impedance of 15 k Ohms, a value of 82 k Ohms attenuates the voltage by a factor of a approximately 6.5 (or 16.25 dB). Using this value of R4, together with a soundcard mic gain setting of between 7 and 10 on the computer.  Reliable reception with the Baofeng audio knob set anywhere between the 6 and 9 o’clock positions.

The soundcard interface works well with the 1200 baud packet radio and ARDOP protocols. For the TNC, I use Sound Modem and ardopc by G8BPQ for ARDOP. I also tested the interface with MMSSTV and it works great.  This interface could also be used with a hardware packet TNC.

Finally:  Please note that this unit is specifically built for the Baofeng Radios.  I have not tested it on any other cheap or more expensive handhelds.  I have build many Sound Card Interfaces in the past and using my experience to build this interface.  If we talk sound card interfaces then there is not only one or two designs available out there.  I would however like to thank Dave K0RX and Charlie ZL2CTM as I used both their posts to create this Baofeng Sound Card.

In Part 2 I will provide more info on the practical working and images of the final installation of the modules in a cabinet.

Images:  Click on images for larger view.