Review – BTech DMR-6X2

by John ‘Miklor’  K3NXU

Several Dual Band DMR handhelds have been introduced into the market in the past few months. Having owned most of them, I would have to place this one toward the very top of the list. The DMR-6X2 is both VHF and UHF, Tier II  DMR digital as well as FM analog with most features geared strictly toward ham radio use.

Important Note:  The BTech DMR-6X2 is Not made by Baofeng. (see note below).  That being said, let’s see what’s…

In the Box
Included with the radio are the:
–  Two (2)  Li-Ion Batteries   (2100 and 3100 mAh)
–  Two (2)  Belt clips
–  Hand Strap
–  37 page User Guide – English
–  Charger base & AC adapter
–  Antenna – 6.25″ (16cm)
–  Programming Cable
–  Earphone / Microphone

General Description
–   DMR / FM
–   VHF / UHF Dual Band
–   Size:  5.1 x 2.4 x 1.5″   (129 x 61 x 39mm)
–   Weight:    9.9oz   (282g)  w/ant & 2100 mAh battery
–   Weight:   10.8oz  (306g)  w/ant & 3100 mAh battery
–   136-174   400-480 MHz
–   CTCSS/DCS  DTMF/2TONE/5TONE
–   Digital Simplex Repeater
–   <1.0w / 6.0w transmit
–   4000 channel
–   250 Zones (up to 250 channels per zone)
–   10,000 contacts
–   150,000 DMR Database Contacts
–   Part 90 compliant – 2AGND-DMR6X2
–   N0GSG Contact Manager Compatible

Basic Description  (additional features)
The heart of the 6X2 is the proven Anytone D868. Under contract with Anytone, BTech had several addition features exclusively added to the 6X2.

Some of the additional features exclusive to the 6X2 include:
–  Multiple Scan Groups
–  Priority Scan
–  Change TG via Keypad (Adhoc) with Unlimited Hold Timer
–  Display Color Options
–  Digital Simplex Repeater
–  Analog Squelch Level Adjustment
–  Start Up Code Plug Compatibility
–  Display Hold

– Multiple Scan Groups in Same Channel
The 6X2 allows multiple scan lists to be entered  per channel. You are no longer limited to one scan group entry per channel. The scan groups can include and mix of DMR or analog channels.

– Priority Scan
When developing a scan list, up to 2 channels can be assigned as priority. This allows the priority channels to be interwoven in the scan list. As an example:
–  Channel 1
–  Priority Channel 1
–  Channel 2
–  Priority Channel 1
–  Channel 3
–  Priority Channel 1

– Change Group via Keypad (“Unlimited” hold timer)
This is specially nice when using a hot spot. By setting a key function to “Dial” or “Long Press 0”, and the Group Call Hold time to “Unlimited”, you can enter a Talk Group using the number pad and it will remain permanently or until the channel is changed. No longer is the hold time set in seconds or minutes.

– Display Color Options
There are two display color options available. They are White on Black background, and Black on a Powder Blue background. (shown below). They are selectable by either software or keypad menu.

– Analog Squelch Level Adjust
The analog squelch level can now be adjusted using one of the programmable keys.

– Start up Code Plug
To assist with start up, the software was written to initially accept an Anytone D868 code plug.  I’ve had a 868 since they first came out, and this was a huge time saver. Everything transferred and I was ready to play radio in minutes.
Note: Due to the extra features in the code plug, a 6X2 CP cannot be transferred back to a D868.

– Digital Simplex Repeater
Not to be confused with a standard repeater, this feature allows the DMR-6X2 to function as a Store and Forward Simplex Repeater. The 6X2 records a transmission and stores it in memory. Immediately after the incoming signal is dropped, the transmitter keys and re-transmits the recorded audio. The re-transmission can be either on the same or different frequency (not necessarily on the same band).

This feature allows the 6X2 to be used as a relay point during events such as marathons, races, etc. where a central relay method is needed and there is no local repeater.

– Display Hold
When a signal is received, the data image (name, call, location, etc) remains on the screen until the next signal is received rather than drop back to a standby screen. There is a Call End indicator at the bottom, but the data remains.

The Technical Side of the 6X2


The
Transmitter

The frequency range of the DMR-6X2 is both VHF 136-174 and UHF 400-480 MHz. Along with DMR, the radio also supports analog FM (Wideband and Narrowband)

The power levels hold pretty close to the specifications. There are four power levels with a high of 5.0W and a Turbo mode of 6.5W. I personally run mine in 5W mode. Turbo isn’t going to Make or Break the signal, but it helps the battery.

What I do like is the low power mode is less than 1W. I run a hotspot here and if the power was only 0.3W I would be happy.

My audio reports have been excellent both through a DMR hotspot and the local repeaters. There is a five level microphone gain parameter that allows you to select the microphone gain level that best suited for your voice. I use level 3 (mid-level) for a full smooth audio response. I tried level 5 and found the audio was way too hot.

Power levels are listed below and were taken using a calibrated Bird Termaline wattmeter.

Enclosure
The DMR-6X2 case has a good solid feel and weight, and fits the hand well.  It weighs in at  9.9oz   (282g) with the standard battery attached and 10.8oz (306g) with the high capacity battery. Battery removal requires a simple push of the release slide located at the top of the battery. No battery sliding or pushing is required.

I found the keypad buttons a bit larger than most with a lighted keypad layout of three across and four down. This puts the zero (0) at the bottom of the keypad where I believe it belongs. The PTT button requires only a light pressure that doesn’t tire the finger to press.


Antenna
The included dual band antenna is 6.25″ which is a fairly common size for a handheld. I found that there was a slight improvement of about 2db by using an NA-771.  The 771 is 10″ longer, so a difference would be expected, but I’ll probably stay with the stock antenna.



Receiver and Audio
The receiver sensitivity is very good on both digital and analog. I found the receive audio is amazing with wide and smooth frequency range.

The volume control range is adjustable with the software. Level 1 sets the full range of the volume control to a soft level, even at full volume. Level 8 sets the volume range to very loud at the top end. My preference is level 3 to 5 which is plenty loud, even for mobile operation.

Display
The radio has a two multi-color display options. The high contrast White on Black, and the softer is a Powder Blue with multi-color icons. The color is selectable via software or as a keypad menu option. The screen size is 1.1″ x 1.4″ with excellent resolution .

There are multiple sites where the current DMR User Database can be downloaded. There are various formats available allowing you to view name, call, location, user ID, license class, etc.

.
Software
Along with entering data in the conventional manner, the software allows you to import and export data to ‘csv’ files. Loading in a contact (TG) list, channel list, database, etc. is relatively simple.

I found being able to export to a ‘csv’ file has several advantages. I like having my channel list in sequence. With most software, you can only add new channels to the bottom of the list. Now I can sequence the list so it’s easy to view then load it back into the code plug.

Adding a new repeater can be done in minutes. I just cut and paste a copy of an existing repeater, change the frequencies, and load it back.

Note: The BTECH 6X2 can import a code plug (.rdt) from an Anytone D868UV directly. This is a great way to get your 6X2 on the air. Once loaded, however, due to the expanded parameters, the D868 is not capable of reading a 6X2 code plug.


CSV transfer Caution
Adding large amounts of data, updating and re-sequencing via CSV files is a major plus, but should always be done with Caution. For instance, Talk Group data must always be loaded before or at the same time as the Channel data. If not, improper data attachment may not occur.

Always backup your current code plug before modification.

Firmware
As additional features and future enhancements are developed, the radio can be updated to latest model. A firmware upgrades can be done with a Windows computer in about 5 minutes.

Note: The DMR-6X2 firmware is specific to this radio. It cannot be uploaded to a different model in hopes of adding new features.

Programming Cable
The DMR-6X2 comes with the necessary programming cable. The UART chip inside the radio, so the cable itself is straight through. There is no circuitry inside the cable itself. The driver will load automatically when the cable is attached.

For reference, although the cable appears to be the same as some that have the chip in the cable, those cables are not compatible.

 

The charger base requires a standard 12vdc wall wart (included). The LED on the front of the charger base is Red when charging, and Green when either fully charged or no radio in the cradle. The battery easily charges to full capacity with an overnight charge.

Battery and Charger
There are two batteries included with the 6X2, a 2100mAh and a high capacity 3100mAh. With battery save on, I can get 2 to 3 days out of the 3100mAh battery before needing a charge.

There are also USB charging cables available with output of 12V. These can also be used in place of the included Wall Wart.

Conclusion
If you think the BTECH DMR-6X2 very closely resembles a D868UV, you are correct, but as shown above, it is definitely not simply a rebadged Anytone. There are features and enhancements that set these two radios apart. I think BTECH was wise to wait for the bugs to be ironed out before introducing the 6X2 to the market.

If you’re waiting for this radio to drop in price, don’t hold your breath. Its features and performance make it well worth the price.

The obvious pros are the following:

–  True Tier II DMR
–  Same Band and Cross Band digital simplex repeater
–  Dual Band VHF/UHF operation
–  Multiple Scan Groups per Channel
–  Priority Scan
–  On the Fly Talk Group Entry
–  Built-in Voice Recorder
–  2TONE and  5TONE decoding
–  150K user database capacity
–  FCC Part 90 certified for commercial use
–  N0GSG Contact Manager Compatible

There are plenty of options geared more for hams than commercial use. It performs well and makes a nice addition to the ham shack.

Available from:    and    Amazon


For Clarification
BTech (BaofengTech) is not a division of Baofeng. They are an ODM that partners with OEM manufacturers to spec and build to their own requirements, whether from scratch (UV-5X3) or from an existing product. This 6X2 is an Anytone at heart with additional unique features found only in that model.

 

 

 

Here’s a comparison chart showing the major differences.
Click to enlarge.

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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.

Tubular Bells and VLF interference

Tubular BellsRemember that album from Mike Oldfield? A user on YouTube found out that this album contains a hidden and unintentional CW message.

This was caused by a powerful VLF station located next to the recording studio, which interfered with the recording equipment. Because the signal is very weak nobody ever noticed it — until now.

The video below shows you how to receive VLF signals with nothing else than an antenna plugged into the microphone input of your sound card and SDRSharp to make it visible and audible.

The decoding of the the Tubular Bells signal is shown at 9:54.

(via Reddit)

Just canceled an order for a Samsung Smart TV

… after reading online reports regarding their Privacy Policy regarding the use of their Smart TV’s.

“Samsung may collect and your device may capture voice commands and associated texts so that we can provide you with Voice Recognition features and evaluate and improve the features. Please be aware that if your spoken words include personal or other sensitive information, that information will be among the data captured and transmitted to a third party through your use of Voice Recognition.”

I’ll buy a dumb TV. Much cheaper, and its lack of any intelligence will be more in line with the quality of the programs.

Speaking of which: I remember that I forgot to mail FOX. Around New Year they aired SHREK, and I thought that would be a nice program for my little granddaughter to watch while I did some shopping.

shrekBig mistake. After I returned she asked me questions about some ads about vaginal infections and Durex pleasure gel. FOX must be desperate for money, and determined to ruin a little girl’s innocence. Idiots.