APRS Cables for Baofeng UV-5R: Two options

August

2021

управление, aprs, схемы

3 August 2021 0:56

How to make a cable for APRS.

APRS was intended for use in autonomous conditions - for example, when cellular communication does not work or absent.
The APRS standard is also quite open, and does not change for many years - APSK modulation without encryption, which allows you to "read" messages even without special software, simply observing the reception window of the decorator of the amateur radio standard Packet at the Mixw or Hamradiodeeluxe, or even SoundModem by Uz7ho.

To transmit information, this or that computing platform is needed - a smartphone, PC or laptop (netbook). For Android there is a good program -APRSDROD, for Windows PC - UI -View, APRSISE/32, for Linux - Program XASTIR.

My understanding of APRS prospects. Advantages and disadvantages

The conditions for the development of technology are good, but in recent years, the interest of radio amateurs in APRS began to fade away. Why? Ready-made D-STAR radio stations, the site and forum www.dstar.su was launched in June 2012. D-STAR radio stations were two standards (numbers and analogue), also knew how to transfer APRS packages, the need for TNC controllers and KISS modems disappeared.

The lack of solutions based on D -STAR - they are compatible with digital modulation only with themselves, with their standard. Accordingly, the amateur radio amateurs were forced to play with an expensive toy, to “throw it” on the market while the transceiver can still be sold.

Then a cheaper option followed - DMR, but in it the APRS processing of packages occurs at the level of the "nucleus" of the BrandMeister network, and not at the level of the local node, as in APRS. On numerous requests of users to include APRS decoding in the DMR/D-STAR assembly, from the developers it follows that they do not even have this. DMR users are deprived of choice: their packages go to the APRS network only through the main DMR network BrandMeister. The technology came out not autonomous, not adapted to work in conditions, for example, the complete absence of the Internet. Also, various radio stations “speak different languages” when transmitting GPS coordinates, and for translating packages to the APRS standard, there are servers processing incoming traffic abroad. Thus, the DMR is the most attached to the Internet Radio amateur technology.

What is the reason for increasing interest in APRS

Observing foreign sites, and only there, I noted a surge in interest in the classic APRS , for the following reasons:

Previously, APRS controllers (Kiss/TNC modems) were similar to old modems - large and iron. Recently, private firms have established the production of Plug and Play TNC/KISS controllers the size of a slightly larger matchbox, which, using adapters on the headset connector, turn any cheap analog radio station into an APRS knot. The connection with the smartphone on which the APRSDROID program is launched, radio amateurs are often installed without wires - using Bluetooth, which is convenient. The price of the kit without taking into account a smartphone is more than democratic - from 100 to 135 dollars. The controller can be transferred along with the radio station - take on hiking or trips, transferring its coordinates at the generally accepted frequency. There is good support for such devices on YouTube, which shows their configuration and use.
The distribution of inexpensive, available radio stations of the Baofeng UV-5R type, as if specially created for APRS-based solutions. They have built -in VOX.
Resumption of programs from the International Space Station (ISS) - APRS packages at a frequency of 145.825 MHz.
1. Abroad, great interest in a healthy lifestyle (which is also noticeably rising in our country): simple, but exotic hobbies for us, such as Trekking ("Scandinavian walking") on a pre -well -known route, hiking (amateur walking tourism for low mountains), CICLING (highway, family or group cycling) and TRILIL Riding (Extreme Cycling Race in Crossed Army). Where portable radio stations are often used, radio amateurs can try to include APRS to inform your comrades about their route movement. The concentration of radio amateurs, for example, in any national park, can lead to a "transition of quantity to quality" - the emergence of moving tags on the map APRS.Fi.
Change of generations - the arrival of a new wave of people aged 16-25, who will be interesting to radio, APRS and the same ISS.

In our country, Russia, for a number of reasons (certain difficulties with the order of equipment from abroad are the same language barrier, the impact on the price of fluctuations in currency courses, problems with logistics), the option with the purchase of a modern controller for APRS cannot become mass.
Self-assembly of controllers of such KPC-3 on PIC controllers is available to the elect craftsmen with "golden" hands.

There is a prospect of using portable radio stations with various cables and adapters for connecting to a smartphone. Many of which can be bought at Ozon, AliExpress, or in computer stores. Below are photos of dwuh working options for APRS cables, which are tested for reception and transmission. The formation of the AFSK sound on the date is a smartphone (which displays the sound to the nest of headphones / headset), and directly by the transmission - the radio station with the VOX (Voice Activated Transmission) function. Reception APRS traffic from the air: the sound of the APRSDroid program adopted by the radio station (sound in the sound from the same 4-pin headphones / headset). The level of sound recording should be set by the volume control - a handle on the radio station and fixed the regulator in the highest position with an elastic band for banknotes purchased in the office of stationery.

To configure the system, it is advisable to have two radio stations to control the presence of sound / modulation when transmitting APRS packages.

The first version of the cable for a smartphone using adapters "Jack 4pin" is 2 pcs. "Jack 3 PIN"

The output of the sound of the radio station is supplied to the microphone input of the smartphone, and the sound of the radio station is the sound of the radio station - output sound of the smartphone. The adapter was used from the Baofeng/Kenwood radio station for the iPhone headset.

Baofeng/Kenwood cable manufacturer RETEVIS, cable model TCK01, price about 500-550 rubles with AliExpress. - 1 pc.
Остальные составные части кабеля куплены в ближайшем компьютерном магазине:
2.Adapter 4 -pin mini jack 3.5 mm (m) - 2 x mini jack 3.5 mm (f) - 2 шт.
3.Audio Dudino cable Jack 3.5 (M) - Jack 3.5 (M) - 2 шт.



 ** [Mark] Supplement from 03/2024 [/Mark] ** The problem of filing the transmission in my opinion is related to the absence of "land". TRRS adapter on 3-Pin shifts average contact, the Earth appears and the radio station with VOX (level 1) ends the transmission in the absence of a signal. For indicating the error - thanks RM1M!
See the picture below.
 ![TRRS](trrs.png "trrs") 
 ** Enough adapter of the 4-pin connector TRRS 4PIN on 3pin ** 
You can buy it [On Yandex](https://market.yandex.ru/product--adapter-perekhodnik-dlia-mikrofona-s-razema-mini-jack-3-5-mm-trs-na-trrs-c-3-pin-na-4-pin-chernyi/54194422).
 ![Adapter adapter for a microphone from the mini jack 3.5 mm TRS on TRRS (C 3 PIN on 4 PIN)](izol.webp?cropresize=525,700&lightbox=1200&classes=img-zoomable "Адаптер переходник для микрофона с разъёма mini jack 3,5 мм TRS на TRRS (c 3 pin на 4 pin)")

The filing of the transmission has stopped.

!! The sound level on a smartphone and a home -made cable should be reduced by two single presses to avoid overloading the entrance of the radio station. Also, the volume at the radio station itself is set by 20-30%, because There is no divider here.

516.11 rub. 18%discount | RETEVIS TKK01 for Kenwood 2pin Up to 3.5 mm Women's phone Audio High -Tax Transfer Cable for Retevis RT22 RT22 RT27 H777 C9061A
 [https://a.aliexpress.com/_akkp42](https://a.aliexpress.com/_AKKp42) 

#### The second option is a finished cable with AliExpress (the price of the issue is about 2000 rubles)

Brand cable ** APRS-K1 **. Does not require comments.

I will add, the level of signal for transmission with the APRS-K1 cable is slightly lower (it does not have to be reduced by the smartphone volume by adjusting the volume), because The manufacturer inside the "boxes" impleched the attenuator for several dB to eliminate the overload of the entrance of the radio station. The same divider is implemented on the reception (setting maximum volume on the radio station corresponds to the optimal level for recording sound or decoding on a smartphone).
 ![2nd](2nd.webp?cropresize=525,700&lightbox=1200&classes=img-zoomable "2nd") 

1 655.92 rub. 45%discount | APRS-K1 Audio interface cable for Baofeng UV5R UV-82 5RA 5RB 'D XUN TYT (APRSPRO, APRSDROID, compatible-Android, iOS
 [https://a.aliexpress.com/_wlub4](https://a.aliexpress.com/_AWlUB4) 

 ** [Mark] Addition from 03/2024 [/Mark]: ** 

##### APRS-K1 device
Photo:
 ![APR-K1-BOTTOM](apr-k1-bottom.webp?cropresize=525,700&lightbox=1200&classes=img-zoomable "apr-k1-bottom") 
(The manufacturer painted the nominal for elements with a permanent marker).
The flip side of the board-one element is installed: the resistor red-red-red-gold = 2.2 kOhm.
 ![APR-K1-Top](apr-k1-top.webp?cropresize=525,700&lightbox=1200&classes=img-zoomable "apr-k1-top") 
На This photo is visible the names of the elements: R6 C3 R5 R4 C4 / C1 R2 R2 C2. The last element P1 is not installed.
 ![APRS-K1](aprs-k1.webp?cropresize=525,700&lightbox=1200&classes=img-zoomable  "aprs-k1") 

##### APRS-K1 adapter connection diagram to the Baofeng radio station and smartphone
 ![Sheme-APRS-K1](sheme-aprs-k1.png?cropresize=525,700&lightbox=1200&classes=img-zoomable "sheme-aprs-k1") 
If the radio station on the left is the colors of the wires from top to bottom:
* Mic - Red
* Gnd - blue
* sp - black
Smartphone on the right:
* sp - blue
* Gnd - red
* Mic - orange (golden)

### Work check and conclusions

The cable verification was carried out by a stationary "APRS" RA1AHQ-1 APRS radio station (on which Direwolf and Xastir were launched), while the Baofeng UV-5R portable station had SSID -5 (in APRSDroid). The minimum capacity of 100 MW was installed on the transfer at the portable station in order to not reach the packages on the APRS Gate. Frequency - 144.800 MHz.

Initially, decoding at the control radio station did not go, with a good level of volume, the air of the packages transmitted to the air.

The reason turned out to be banal: it is necessary to increase the duration of the “preamble” so that, before transferring the main part of the package, VOX radio stations have time to work: the duration of the preamble 200 ms small (there is no decoding), and 1000 ms is large, it can be reduced.

!!!! Both cable options work.

! ЗAmethyl is not quite the correct setting of APRSDroid by default - Wide1-1 path. In the APRSDroid “more” - “parameters” - “APRS path” menu, it is necessary to change the path value to Wide2-2 - a shorter distribution of APRS packages, within the framework of one city or district.

 **Conclusion:** 

Such an APRS tracker has the right to life.

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