Review – BTech AMP-25 series for Analog & DMR

by John ‘Miklor’
K3NXU

The  AMP-25  series  VHF / UHF Amplifiers

The recently announced BTech Digital and Analog amplifier series puts a whole new spin on mobile operation. It performs more like a mobile than it does a power amp. The D series are true TDMA Tier2 DMR amplifiers.

Note: This review was done using an Anytone D868UV on both DMR and analog.

In the Box
Included with the 40W Mobile Amp are:
–  Mounting Bracket
–  3′  Interface Control Cable (Kenwood K1 connectors)
–  3′  RF connect cable (SMA-M to SMA-F)
–  Microphone and Hanger
–  All necessary mounting hardware
–  User Guide

General Description
–  UHF or VHF Power Amplifier
–  2-6W  >  20-40W  Output

                         Modes of operation include:

V25  U25	V25D   U25D
Analog (FM) C4FM (Fusion) P25  (Phase 1) NXDN IDAS dPMR MPT1327	>  DMR Tier II (TDMA)  >  P25  (Phase 2) Analog (FM) C4FM (Fusion) P25  (Phase 1) NXDN IDAS dPMR MPT1327

A Different type of Mobile Amplifier

I found these to be much more than a typical power amplifier. Although they can function as a simple ‘In and Out’ power amp, this is about as close to a full mobile as you can get. Although the driving force was my DMR handheld sitting in my cup holder, the transmit audio was that of the included hand microphone and the receiver audio out was coming through the built in speaker driven by a four watt audio amplifier.

Transmit Power

I tested the power on two different models. The VHF V25 (non TDMA) and the U25D for UHF DMR.  The power was tested using the analog side of both into a calibrated Bird Termaline wattmeter. The maximum current drain from my 13.6V 30A power supply was just under 6A. This is low enough for the amp to be powered by the 10A accessory jack in your vehicle.

Enclosure

The basic frame measures 4.6″W x 1.3″H x 5.5″D (excluding the SO-239) and weighs in at 26oz.  I was curious to see the internal layout of the amp and to no surprise, there was a 5/8″ finned heat sink spanning the entire length and width of the case along with air vent along the back of the enclosure.

Operating Modes

These are single band amplifiers.
V25(D) = VHF 136-174MHz
U25(D) = UHF 400-480MHz.

Note: The V25D and U25D were designed to include DMR Tier II (TDMA) and P25 Phase 2 along with all other modes. Their operation varies slightly.

V25  /  U25
To operate VHF through the UHF (U25) amplifier, or UHF through the VHF (V25) amplifier, simply power off the amplifier. This will allow you to run straight through directly to the antenna without power amplification on that band.

V25D / U25D
These amplifiers will only operate within their specified VHF or UHF range. This is due to the circuit switching design of DMR Tier II and P25 Phase 2.

Hook Up

The simplest configuration is using the included RF cable to attach the radio to the amp. You could add a Spkr/Micr to the handheld, but you would still be bypassing some of the best features.

I use the two included cables. The 3′ RF cable to attach the radio to the amp, and the control cable. This allows me to use the full size hand microphone as well as connecting the four watt audio amp powering the speaker. The power included power cable is compatible with handhelds using the standard two pin Kenwood style connector, such as an MD380, D868, GD77, UV5R, F8HP, UV82, etc.

I use an Anytone D868 on DMR as well as analog with the hookup diagrammed below. Depending on your radios antenna jack, you may need to pickup an SMA-M to SMA-M adapter.

 

Convenience

All channel selection and volume adjustments are done using the handheld. No duplicate programming or code plugs are necessary. Whatever is in my handheld is what I operate in the mobile

Operating my handheld in the low power position, I still get 22W out on UHF and my handheld’s battery life remains excellent, but high power gives me a solid 39W.

Conclusion

I was glad to see someone finally develop what is a full featured mobile amplifier capable of  DMR as well as all other modes including C4FM and D-Star that is small enough to mount in the car, boat, and on top of your computer. This amplifier is Part 90 certified and definitely worth considering.

Available from Amazon:    V25     V25D     U25     U25D
and     

VHF /UHF
Digital / Analog
Mobile Power Amplifiers

 

Review – BTech APRS-K2 Cable (TRRS/APRS)

by John ‘Miklor’

APRS-K2
It’s long overdue, but there’s finally a TRRS/APRS cable available for radios using a standard Kenwood style K2 connector.

I’ve been wanting to get involved with APRS for a while now, and this made it extremely easy.

APRS-K2 interface cable
The APRS-K2 cable allows you to interface your handheld transceiver with your existing mobile device, including. iPhone, iPad, and Android.

One end of the cable uses the Kenwood style K2 connector, while the opposite end is terminated with a TRRS connector. Also included with the APRS-K2 is a Reverse Adapter to insure compatibility with all devices. This adapter allows cable to connect to earlier 3.5MM TRRS standards, such as Nokia.

App Driven
The APRS-K2 cable uses a virtual TNC found in several apps, such as APRSDroid, APRS.fi, and Pocket Packet. Plug in the cable, turn on the VOX, and you’re pretty much set to go.

Product Description
BTECH APRS-K2 TRRS / APRS Cable A simple way to start using APRS by using devices you already own. The BTECH APRS-K2 Cable will quickly connect your radio to APRS by using virtual TNC (app driven) on your tablet or device. The APRS-K2 cable is built with a custom circuit board that will automatically adjust the audio for clear packet transmissions with minimal adjustment; along with protecting your devices from strong over modulated signals.

Along with allowing APRS functionality the APRS-K2 cable can provide a simple interface gateway to allow several features to your radio!

Easily record radio conversations:
By connecting the APRS-K2 cable between your radio and any recording (line-in) device.

Use the APRS-K2 cable as a Mic In Connector:
Set up VOX on your radio to accept any form of incoming audio – such as a Push-to-talk application on a Phone – or a Line-out application from your computer.

Use the APRS-K2 cable to push transmissions over a speaker system:
Easily play audio over a intercom or speaker system from your handheld.

With a backup radio and your own ingenuity, the APRS-K2 cable can serve as an interface for a variety of applications for any amateur. Compatible with Kenwood K2 Accessory Slot Radios (such as BaoFeng, BTECH, Wouxun, TYT) Compatible with all phones, tablets, and computers with 3.5MM Audio In/Out Ports

Includes:
APRS-K2 Cable
Reverse Connector Adapter
Quick Start Guide

Conclusion:
The cable comes with a simple one page instruction sheet which should have you up and running in about 10 minutes after the appropriate app is loaded.
–  Plug in the cable
–  Set your handhelds volume control
–  Turn on the VOX
–  Set your handheld to 144.390 (US)
–  Activate the app

That’s all it takes. If you’ve been considering building an APRS cable, you might find this an easy Plus and Play alternative.

The APRS-K2 can be ordered from   Amazon, or if outside the US, you can go to their website and contact them directly.   Baofeng Tech

Too many toys, too little time.
John ‘Miklor’   K3NXU
http://www.miklor.com

Build your Own Programming Cable

by John ‘Miklor’ K3NXU

Frustrated with that generic programming cable?
This $2 solution might just be your ticket to sanity.

Let’s See…

You purchased a radio and programming cable, loaded the software, and that’s as far as you’ve gotten. You’re fighting with error messages:
– Radio did not respond
– Could not open COM port
– Run Time Error
and Windows (TM) 10 keeps changing your drivers.

Now you do what many owners do. Put the radio in the drawer to be worked on later. This is like buying a roll-away treadmill and putting it in the closet until the next time you want to exercise. (NOT going to happen)

But wait, yours has the company name and logo right on the cable.
– It doesn’t matter. Keep reading.

There are a few options available, such as an FTDI cable. It’s truly Plug ‘n Play, and costs about $20.

But here’s a project that just might solve the issue for around $2. All you need is a small flat blade screwdriver, a soldering pencil, and a CP2102 board.

CP2102

The CP2102 is a USB to TTL UART chip. What?
Long story short… It’s the same thing that’s in your current cable now, except these work.

CP2102 boards can be found on eBay for around $2 and on Amazon.

Here’s How

Let’s start with that original cable.

Take a small screw driver and pry the open the case from the back where the cable enters.

It should only be snapped together.
Unsolder the 3 wires connected to the board.  GND is Black, TX is Red, RX is White.
Solder the 3 wires to the corresponding terminals on the new board.

Note 1: Some boards may have the TxD and RxD reversed. If it doesn’t work the first time, reverse the two wires. No damage has been done.

Note 2: Some boards have pins on the back requiring small connectors. You can either remove the pins, solder to them, or use the connectors. (Whatever floats your boat.)

Driver

When you insert the new board into the USB port, give Windows a chance to find and load the new driver. Should take about 30 seconds. When it says Driver Found, you’re done.

If the driver is labeled CH340 instead of CP210x in Device Manager, that’s not a problem. Both chips are designed to do the same thing.

But I don’t have a Cable

If you don’t have a generic cable, you can use 2.5 and 3.5mm stereo jacks. Here are the pin outs, and what Jim’s (KC9HI) cable looks like.

 

Cosmetics

If you are adventurous, try retrofitting the new board inside the original plastic housing. This will require a Dremel tool, X-Acto knife, Glue, and some patience, but it can be done.

If the board only has 5 terminals instead of 6, it’s not an issue. You only need GND, TX and RX.

Some come protected with a piece of clear heat shrink over the board so you can see the cool blinking lights.

Note 3: If you are trying to retrofit the board inside an existing shell, the red board below is a bit shorter and easier to fit.          Amazon       eBay

For about a dollar or so more, you can find the same boards in a metal case.

What’s the Advantage

– First and Foremost, it works. Take the radio out of the drawer, program it and have some fun.

– Next, it only cost around $2 to save the generic cable from the trash.

– Very Important – Bragging Rights. Now, when you go to a club meeting and someone says they can’t get their cable to work, tell them they can build their own, just as you did.

I hope you had fun with this project. It’s super simple and very rewarding. I’ve made several and never had a failure. Say goodbye to driver issues.

My thanks to Jim KC9HI for his input on this project

More Information: Miklor.com

Review – Pofung (Baofeng) UV-82HP

by John ‘Miklor’ K3NXU

Not just a Power Upgrade
The new UV-82HP is not just a power upgrade, but a combination of all major features of both the UV82 and UV5R series in one package.

What’s in the Box
– The UV82HP
– Newer upgraded A-V85 Antenna
– 7.4V 1800mAh Li-Ion Battery
– Upright Charger and wall-wart
– Manual written in English
– Belt Clip
– Hand Strap

The radio sports all traditional features of the UV82 design, with the larger keypad buttons and the zero at the bottom of the number pad where it belongs, etc.  It also is built using the latest generation chipset.

– The frequency range is the full  136-174.99 MHz, 400-520.99 MHz range.
– VHF output on the test unit clocks in at 7.3W with UHF at 6.0W
– The Dual PTT button is now an option that can be turned off. Previously only available with the commercial version (UV82C)
– Live On-the-Air audio reports are excellent.
– Alpha tags can be added with the required software below.
– The receiver sensitivity is still excellent.

So, What makes this version an upgrade?
– The original UV82 took a traditional UV5R, and added design features such as an upgraded case and Dual PTT switch. (comparison)
– Next came the UV82C which included options to synchronize the Dual PTT function to emulate a Single PTT, and the ability to lock out the VFO to prevent accidental field programming.
– Next came the 8W F8HP, the first of the high power Baofengs.
– An expanded feature added is R-Tone, a repeater tone for those requiring a 1000, 1450, 1750 or 2000Hz audible tone for access. This is not to be confused with CTCSS or DCS. Prior models provided Burst for 1750Hz only.

The UV-82HP now includes all of the above features in one package. The PTT synchronizing, VFO lockout, High Power, R-Tone, and newest generation chipset.

It has kept the traditional UV82 case design to ensure compatibility between all existing options, including Dual PTT Spkr/Micr, battery cases, holsters, battery eliminators, etc.

Feature	UV82HP	UV82	UV82C	F8HP	UV5R
High Power  7-8W	Yes	–	–	Yes	–
Dual PTT	Yes	Yes	Yes	–	–
Single PTT Sync Option	Yes	–	Yes	–	–
VFO Mode Disable	Yes	–	Yes	–	–
Repeater Access Tones     1000, 1450, 1750, 2100Hz	Yes	1750Hz	1750Hz	1750Hz	1750Hz

As mentioned above, with software, the UV-82HP can lockout the VFO mode to prevent accidental changes.

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The Factory Software has been added to the Miklor.com  Software section.  The radio has also now included in the Latest Daily Build of CHIRP.

Note: A programming cable is required to run the software. Acquiring a quality cable is highly recommended. You will spend more time using the radio and less time trying to load special backdated drivers to your PC. A generic cable is less expensive, but a cable with an FTDI chip is Plug ‘n Play.

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The UV82HP allows locking the PTT Button to simulate a Single PTT and override the Dual PTT feature.

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Software Note
As you may have expected, running the UV82HP software will not activate or create new features on an older UV-82/82C.

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Compatibility
All of my accessories for the standard UV82 are compatible, including the Dual PTT speaker/micr. With the exception of the battery and charger, all UV5R accessories work as well.

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Conclusion
You can always run this radio in low/mid power to conserve battery, but when you need the extra power, it’s there.It’s nice to see a true upgrade of features to the UV82 series, and not just a fancy case or the addition of extra letters and numbers to the UV82 label.

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A Feature Comparison published between the standard UV82 and its predecessor can be found at UV82_vs_UV5R

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A full in-depth Technical Review of the Original UV-82 was done by Hans last year.

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More Information:  CHIRP,  Miklor.com, Review, BaofengTech

Video: Baofeng UV-82 charger repair

My review of the Baofeng UV-82 seems ages ago. At first I thought that the erratic / defective chargers were just bad luck, but six months later complaints are still rolling in. The fix (link) was easy — no technical knowledge required.

John Reinhart made a video of the process and posted it on Facebook, which I %$@&#* couldn’t watch without having an account. John immediately sent me the original, which I then posted on Youtube. Have fun.