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

by John ‘Miklor’

aprs-k2-25
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 aprs-xover-25terminated 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

Review – BTech UV-5X3 TriBand Handheld

by John ‘Miklor
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5X3 front 4UV-5X3
Although the case design is familiar, the radio inside is not.  BTech has recently introduced the new UV-5X3 to the US Ham Radio market.  This radio is a true triband transceiver with internal filters specifically configured for triband operation.The firmware in this radio has been reworked to include several new features not found in similar appearing radios.
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In the Box

Included with the radio are the:
–  1500mAh Li-Ion Battery **
–  85 page User Guide – English
–  Charger base & AC adapter
–  Hand strap
–  Belt clip
–  PTT Earpiece / Microphone
–  Antenna (1) – VHF / UHF  6  5/8″ (16.9cm)   A-V85
–  Antenna (2) –  220 MHz    6  3/4″ (17.4cm)
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** This is the identical battery that is commonly mislabeled as 1800mAh on some handhelds.
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Tri-Band – VHF  220  UHF
The UV-5X3 was specifically designed as a Tri-Band transceiver.  The internal filtering allows not only the traditional VHF and UHF frequencies, but also includes the 222-225 MHz Ham band for the US.
.   5X3 label 2Case Design
The UV-5X3 has the traditional case design, which allows me to use my high capacity  BL-5L  3800mAh battery with no alteration to the base. Accessories such as my mobile battery eliminator, Spkr/Micr, etc. are fully compatible.
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Transmitter
The frequency range is VHF 130-176 / 222-225 / UHF 400-480 MHz, supporting both Wide and Narrowband with 2.5kHz steps.The radio’s filtering scheme allows for full power on all bands. My OTA audio reports have been clean with clear with mellow audio.  Power levels are respectable using a Bird VHF/UHF Termaline.
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UV-5X3 146
MHz
224
MHz
446
MHz
High 5.2 4.2 4.6
Low 1.7 1.6 1.6
     
DTMF / IRLP Access

Something new also appearing on this model is a DTMF gain adjustment, allowing me to adjust the DTMF audio to the transmitter to a comfortable level for both repeater control and IRLP access.
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Tone Burst
If you are in a area that requires tone burst for repeater or network access, the 1000Hz, 1450Hz, 1750Hz, and 2000Hz burst are accessible by pressing the PTT along with one of the four pre-assigned keypad keys.
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Receiver
The receiver sensitivity is excellent, and the audio quality is clear, loud, and undistorted. Along with the 3 TX/RX bands, the receiver also includes the traditional commercial FM radio band. (65MHz-108MHz)
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Tone Scanning – The receiver also has the ability to identify the tone of a repeater being transmitted by a received signal.
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Scan Add / Delete
This feature gives me the ability to add / delete channels from the scanning list using the keypad. No longer a software only function. The more I can do from the keypad, the better I like it.
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Scanning
A Long Press of the [*SCN] button will start the scanning process.Channel Mode – When scanning with the Display Sync set to ON, the upper and lower display will scan together. This is explained below under Display Synchronization.Frequency Mode – When entering Scan, the image below will appear on the screen. Enter the first 3 digits set the range start, the second 3 digits sets the stop.
Example: Entering   146 : 146
Start  the scan range at  146.000
Ends the scan range at  146.999
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5X3 scan rangeAntenna
I found two antennas included with the radio. One was the standard upgraded A-V85 antenna, and a slightly longer one for the 220MHz band.
Antenna (1) – VHF / UHF  6  5/4″ (16.9cm)   A-V85
Antenna (2) –  220 MHz    6  3/4″ (17.4cm)
The separate antenna specifically tuned for 220 MHz is a great addition. The SWR shows 1.3 which is excellent. No compromise. I labeled my 220 antenna, as they are very close in appearance.
220AntLabel.
Display

The radio has a tri-color display, allowing the color options of the blue, orange and purple.  The LCD can be formatted in either of three formats. Choices are Frequency, Channel number, or up to 6 Alpha Characters.
Display Synchronization
The UV-5X3 supports display syncing, which gives ability to track both the upper and lower LCD. I keep mine set to display the channel name in display A, and the frequency in display B. When you change the channel, both the upper and lower displays move together.5X3 sync.
Programming
Manual programming is pretty straight forward once you enter a few channels. A programming guide can be found at Manual Programming with a Menu Definition summary available at Menu Definitions.
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Software  
The software support for the UV-5X3 can be found in the Latest Daily Build of CHIRP. There are a few new options that will be added to the 5X3 in the near future. One is the ability to Stun, Kill, Revive. This gives you the ability to disable your radio remotely.
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3rd Generation Chipset
The new chipset (RDA1846S and RDA5802N) provides reduced AGC switching noise and a low-IF digital audio processor for improved sound quality.
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Programming Cable
The programming cable requires a traditional two pin Baofeng / Kenwood style. There are several cable available. The generic cables may require special drivers, due to the use of cloned chips. For Plug and Play, a cable using an FTDI chip is recommended.cableK2 Conclusion
The UV-5X3 firmware has obviously been reworked to include:
–  Tri-Band Support: VHF/1.25M/UHF
–  D-ANI  (Display incoming DTMF Tones)
–  Synchronized Displays
–  DTMF audio gain level adjustment
–  Add / Remove Channels from Scanning list via keypad (LCD Dot Indication)
–  On the Fly scanning by Frequency Range
–  4 Tone Burst options
–  Remote Stun, Kill, Revive
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It appears that BTech has once again managed to stay one step ahead of the curve. With the 220 MHz ham band operation back on the rise in the US, this radio hit the market at the right time.  Even if 220 isn’t popular in your area, the additional new features still give it an edge over the traditional dual band series.
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More Information:   Miklor.com,  BaofengTech,  CHIRP
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Review – BTech UV-50X3 (Tri-Band)

by John ‘Miklor’

50X3combo-SFour years after its initial design, the VGC 6600PRO has evolved into the BTech UV-50X3, a full featured Tri-Band mobile that delivers a full 50W on VHF and UHF, with addition of a 220 MHz module that delivers 5W output.  The 220 MHz module was specifically designed and filtered for 222-225MHz US ham band operation.  I mention this as there are currently radios being advertised as Tri-Band operating in the range of 240-260MHz that are not adaptable to frequencies below 240MHz due to their internal filtering.

 
What’s in the Box

Included with the radio are:
–  Remote control head
–  Control Head Suction Cup Mount
–  18′ Separation Cable
–  Microphone with a 20 button keypad
–  Chrome metal microphone hanger
–  Metal mounting bracket with screws
–  Cooling Fan with Thermostat
–  Heavy Duty DC Power Cable (HD Auto Fuses)
–  Full 33 page English User Manual

50X3  Weight:  Main Chassis  2.1kg (4.6 lbs)
Chassis Size: 5.5″ x 1.8″ x 6.0″  (140 x 46 x 150mm)
Control Head: 6.3″ x 2.6″ x 6.0″  (157 x 66 x 33.5mm)

Specifications

The 50X3 is FCC Part 90 certified for commercial use in the US.
Full specifications can be found HERE
 
Enclosure and Mount


The main chassis i
s a solid 4 lb heat sink with an added cooling fan. The chassis and cooling fan can be mounted either under the dash, or trunk mounted using the included 18′ control cable.  The radio is terminated with a standard SO-239 connector.

 50X3case-S  50X3mount

Control Head

The suction mount is about the best I’ve ever used. It requires a smooth metal or glass surface, but the silicon rubber cup will not let loose. My control head has been mounted atop my computer for over a month, and it is going nowhere.
 

The control head has two tuning knobs as well as two volume controls allowing the transceiver to essentially function as two separate radios in one package. The left can be scanning in the Channel mode while the right can be monitoring in the VFO.

The button functions are displayed on the LCD screen for easy function identification. The PTT button on the upper right is for Momentary or Toggle PTT. One press turns the TX on, next press turns it off. Setting to Toggle is convenient if running a net or using a mobile headset.

50X3head-S

Cooling

The radio chassis is one large block of heat sink that when testing takes forever to heat up. When it does, the 70 x 70 x 15mm cooling fan turns on. It’s very quiet and because of it’s size it’s very effective.
  
Transmitter

 
One of my main interests was the included 220MHz US ham band, as I have several Ham repeaters within 35 miles from my house. The power on 220MHz is rated at 5W, which I found was more than enough to reliably get into my local repeaters.  The signal and audio reports have been excellent.

I used my 13.8VDC power supply to emulate a standard auto battery. Running the radio at high power (50W) into a Bird Watt meter for 3 minutes showed no decrease in power or excess heat.

The 220 ham band transmit range is limited to 222-225MHz. The receiver is capable of being programmed above and below those frequencies, but may be outside of the performance range due to the ham band specific filtering.

Freq Low Mid High
146 8 20 50
222 5 5 5
446 10 24  55


HP 6580 analyser images

Microphone

The radio comes with a full function keypad style microphone. On the right side are two slide switches that control the Lock and Lamp feature, and on top of the microphone are two frequency Up and Down buttons.  Along with a 16 button DTMF style keypad are 4 programmable function keys. Choices are Squelch Off, TX Power, Rptr Shift, Reverse, and Tone Call.

There are two microphone input jacks. One on the control head, the other on the main unit. There is also a built in microphone element inside the control head. Although the audio quality is excellent, the sensitivity is that of a standard microphone. The OTA reports were excellent with plenty of audio, so there’s no reason to shout.

A nice feature in the audio section is an adjustable microphone gain control. There are 5 settings available. Min, Low, Normal, High, and Max. Normal is great for speaking in a normal volume an inch from the microphone. Running a net with VOX and a headset, you can bring it up a bit. Driving in an off road vehicle, you just might need to set it back.

50X3mike-S

Receiver

The UV-50X3 has two Double Conversion Super Heterodyne receivers, each with 500 channels, for a total of 1000 memories.

Along with the standard VHF / 220 / UHF frequencies, the receiver covers:

0.5-1.7 MHz   (AM Radio)
76-108 MHz   (FM Radio)
108-136 MHz  (AM Air Band)
137-250 MHz  (Ham & TV Band)
300-520 MHz  (Ham & General)
with a scan rate of 4 channels per second.

The control head has built in speakers, as well as one in the main module. An external speaker jack in the rear also allows for a larger speaker if desired. The jack provides for either mono or stereo output. (each receiver can have it’s own speaker). I found a menu setting to adjust the tone of the speaker as well. Although there is more than ample audio output, when the volume control is all the way down, the radio is silent, as it should be.

Cross Band Repeat

The radio takes full advantage of the independent receiver by including a Cross Band Repeat function.  I entered the VHF and UHF frequencies, power level and tones, selected the Cross Band mode, and was ready to go. The audio levels are preset and the audio quality reports were excellent.

Cross band repeating using a 220MHz frequency was not possible. This is more than likely a precaution due to the minimal frequency separation.

Display

The control head has a large 5″ LCD with your choice of background colors. Options include White-Blue, Sky-Blue, Marine-Blue, Green, Yellow-Green, Orange, Amber, and White. The brightness and contrast are also menu selectable.


Programming

 

When you first attempt to program the radio manually, it may take a few tries to understand the flow of the menus.  After that, everything falls right into place. I’ve put together a programming flow to help assist with understanding the process.  All functions including the entry of 6 character Alpha labels can all be entered manually.

50X3menu

Unless you are only entering a few channels, I would recommend the optional PC05  programming cable. The UV-50X3 uses the CHIRP programming software.
 
Up to six Alpha Numeric characters (upper and lower case) can be displayed to identify each channel.

Scanning in the VFO mode allowed me to scan either the VHF, 220MHz, or UHF band.  In the Channel mode, the scan would select any channel in the list regardless of band.

Power Cable

The power cable supplied with the 50X3 is properly fused and will easily handle the current draw of the radio. This cable was meant to be connected directly to the battery or fuse panel.

There are radios that draw less power whose power cables use thinner wire, lower value fuses, and  can be plugged into accessory plugs. Do NOT use these cables, even though they may be plug compatible. The 50X3 draws twice the current, and will blow the fuses and possibly overheat the wire.

The cable on the 50X3 appears to match that of the hi-power Yaesu, Icom, Kenwood series.  ONLY use the proper cable for the radio.

Base Station Operation

The 50X3 draws upwards of 11-12A on high power transmit. A power supply capable of 15-20A continuous (not just surge) is recommended. Here are a few power supply Examples.

For mobile drive testing, I teamed this radio with a Nagoya Tri-Band  TB320A  and SB-35 NMO mag mount and the results were excellent.

Conclusion

The 50X3 has the power, functions and quality you would expect in an upper end tri-band transceiver.  It is based on a proven design, and I have found no issues with the radio over the past month. A bit more power on 220 would have been a plus, but it still gets me into the local repeaters fine.

Some of the added advantages to the US market are the FCC Part 90 certification, local US support, and exclusive program support using CHIRP software. The radio can also be shipped worldwide by contacting BTech directly.

This is definitely one of the nicest mobile transceivers I’ve used; and yes, I’ve owned the “big 3”.

 

50X3combo-S

More Information:   Miklor.com

Inverted High Frequency Loss with LMR-450G

By John ‘Miklor’ K3NXU

PERFORMANCE  TESTS  –  LMR-450G
The recently announced LMR-450G cable has aroused much curiosity since its characteristics have not been collectively available by any one source.  By multiple inquiries to several manufactures (only three at this time) and numerous lab tests, we hope to put many of the existing questions to rest.

DESCRIPTION
The physical make up of this cable varies slightly from most conventional RF cables.  The center conductor is a semi-stranded copper alloy surrounded by Telfon, which will absorb and distribute cable ‘hot spots’ caused by excessive standing wave.  The double silver braid and foil outer coating which provides a 98.6% shield is what the inverted high frequency loss characteristics are attributed.  The loss is substantially less as the frequency increases, making this cable especially attractive for UHF, cellular, PCS and microwave applications.

Measuring cable loss under lab conditions

Measuring cable loss under lab conditions

LOSS PER 100′
30 MHz     2.4 db
50 MHz     2.1 db
150 MHz    1.6 db
450 MHz    1.1 db
800 MHz    .51 db
1200 MHz  .37 db
1950 MHz  .31 db

The cable’s most unique property is attributed to the outer jacket material Neo-glow, an RF sensitive composite plastic which will visibly indicate RF ‘hot spots’ in the cable.  Adjusting the cable length to the antenna system for the ‘perfect’ impedance match is crucial at high frequency, thus the importance of a low SWR for peak performance.

LMR-450G

From 100 Watts and up this cable will brighten up your world.

PROPER  INSTALLATION
The low level emission of light from LMR-450G cable can be enhanced by wearing lightly tinted sunglasses with UV protection, which enhances the light radiation from the cable.  Select an approximate length of cable needed for the installation which must be multiples of a 1/4 wavelength for the desired frequency.  The exact length can be determined by using the formula 467 / Freq (MHz) plus approximately 18 inches.

The initial tests should be run with a 50 ohm dummy load at one end of the cable.  With a minimum of 7 watts from the transmitter, you will see a faint glow from the cable indicating the ‘hot spots’ to be eliminated.  These are the points along the cable where the RF is at its maximum.  It is at these points where the RF connectors should be mounted.  Trimming the excess cable may be required at both ends of the cable to produce the most effective match.  Use caution not to trim too much cable as the loss characteristics improve with longer cable lengths.

SUMMARY
This could be the beginning of the long awaited high frequency “SUPER” cables.  Only available in limited quantities at this time; contact your local cable supplier for more details.

‘USA 1776’ DMR Talk Group

DMR-logoOne of the nice things of D-Star and DMR is the ability to talk all over the world without the need of an HF rig and a bunch of big antennas. While this largely reduces a radio to a simple Internet-driven communication tool – just like Skype or other VoIP apps – it’s definitely nice to use.

There are a few problems surrounding DMR, one of which is the lack of more than two time slots. For example, if hams are using the Dutch Hytera network and occupying talk group 204 on slot 1, World Wide (which uses the same time slot) will be unavailable. Because 204-1 is a busy place, world wide QSOs are often impossible. It’s one of the reasons I thought of dumping DMR all together — I can talk to the same Dutch guys on analog while enjoying a much better quality audio.

There are reasons to keep DMR too. DMR is maturing; there are more than enough possibilities to put less pressure on the nation-wide network by going local. Now if only hams would do that…. but most don’t. Another reason to keep DMR for now is the gateway we recently added, which connects D-Star to our DMR network.

Not available on the Motorola network, sorry — some people responsible for that network appear to be so scared of such innovations that they will ban a repeater from the network if such a gateway is detected.

Talk group ‘USA 1776’ could add to the appeal of DMR. It’s unclear on which network this talk group will reside, but my best guess is that it will be the Motorola network.  MITCON writes:

The “USA 1776″ (English preferred) Talk Group will be distributed worldwide to DMR networks upon request.  The spirit of “1776” is to continue the Amateur Radio tradition of international friendship and to push the boundaries of technology in the new frontier of digital communications.

USA 1776USA 1776 is intended to be a flexible, politically neutral, unrestricted Talk Group that can be used as Push-To-Talk (PTT) or Full-Time (FT) to meet the operating requirements of a DMR Network.  DMR subscribers are welcome to use 1776 as a universal meeting place to “Rag Chew” or as a jumping off point and QSY to an alternative Talk Group if desired.  To add USA 1776 to your DMR Network please contact us to schedule a time for configuration & testing.