Is it a mag loop? Lets find out!

Here is a preliminary review of a recent antenna toy acquisition thanks to some spare Amazon points.

If this antenna proves to be a good option for MF waves instead of EF waves, this is likely going to become a popular product pretty quick. Let's dig in here, shall we?

MF, EF - What is it? A round antenna duck?

Here the antenna is on Amazon and it comes in BNC, SMA and SMA-J variants so it will pretty much work with most radios if you buy the right one.  

The vendor on Amazon does not call this a magnetic loop and I have not taken this antenna apart to see if a hidden capacitor is in that black bubble at the top of the loop but I suspect there is.

For me, I chose the BNC connector antenna version since using it with an adapter like the ones shown in the "Portable RF Connector Emergency Kit" are always on hand.

Where to find this?   Look on Amazon

How does this compare to the original factory antenna?

The radios tested with the HYS antenna pictured include the Alinco DJ-MD5XTG, the Kenwood TH-D74 and the Lanch HG-UV98 all using the original factory antennae.

A second round of testing was done with all three same radios but with the same aftermarket Diamond SRH320A tri-band antenna.

The test scenario was to communicate via a 2m repeater 30 miles away with all three different antenna options and at all available power levels for each radio. 

The results were from an audible report from different users on the repeater without telling them what I was doing over the span of a few hours on different days.

Results of Test: Non- Scientific you say?

The reason why I chose to use different radios is that different antennas will work differently based on the radio mass offered as the reflective or counterpoise part of the antenna system. What?   Here, look into counterpoise or "Tiger Tail" if you must learn more...

This test allows us to see more uniform tests in a real world environment instead of lab style results.

For each transmission, the radio was held the same way and at the same height.

Signal reports in green were all positive and as good as one could expect to come from an HT 30 miles from a repeater. Yellow reports included comments of fading or weak signal but still audible.  The red reports were scratchy or not very pleasant sounding.

At first pass, we can say that the HYS "Loop" antenna and stock antenna are all pretty much about the same results.  As expected, the longer and higher "gain" Diamond antenna worked the best.

Now with some baseline curiosity under control, lets do something more scientific in terms of radiation patterns and reception tests.

Is this an EM or RF antenna?

To test if the HYS functions in the "electro-magnetic" wave or the "electric" wave function,  I used a field strength meter to check radiation patterns of all three antennae at three distances outside in my backyard away from anything before it snowed this morning.

Based on the test data as expected, stronger signals from the stock and Diamond antenna were strongest when they were vertically oriented which matched the polarity of the sense antenna used with the field strength meter.   

When transmitting with the radio held horizontally, the field strength meter dropped to more than 70% less than what was shown in the vertical test.

Here is the interesting thing with the HYS antenna though. No matter which orientation (horizontal or vertical) the same signal strength was recorded at the field strength meter.

MATH TIME  (1005/146.500 MHz = 6.8 * 12 = 82.3 inches)

Rotating the HYS antenna to have the edge of the hoop or broadside of the hoop aimed in phase with the sense antenna did not show any major differences unless I moved to the furthest test location which was five full wavelengths  away from the sense antenna.  

At the one and three wavelength distance, there was no major difference with all three radios transmitting at highest power levels.

What does that mean?

I think it is safe to say that the polarization of the HYS antenna does not conform to the normal EF wave portions and this seems to function like a true magnetic loop when used for transmitting since its polarity and field strength are very different.

For reception, there is a very sharp null off the edge, but it is very sharp.  Testing this with an attenuator built in to the Kenwood TH-D74 while tuned to the local repeater or NOAA Weather station which are known locations was the only way I could tell there is a sharp null.

Magnetic waves work differently compared to electric waves.  When a true EM or MF antenna is used, signals received may be lower, but with less noise.  This means that the "signal to noise" radio is higher and better for reception usually.   This is what makes a true MF antenna interesting.

This  becomes important especially for HF frequencies where there is more man made noise than ever.  Even still, today more man made noise also happens in the VHF spectrum and this small loop might come in handy. 

If you want to learn about EM antenna, especially for HF, use your Google subscription to discover more about that. Many options exist, including overpriced commercial products and many DIY projects that are fun to look at if you are interested in this for HF spectrum communications.

Further Testing Needed

There are not many people local to me involved in casual non-contest 2m SSB or FT-8 activity to see how well this will work as a portable antenna for SOTA with the Icom IC-705, so that will have to wait.  

Some testing on APRS however has been interesting but will need to drive around with the antenna on the roof for more testing too.

Overall, I think this antenna is worth a purchase if you have some Amazon points or other disposable funds anxious to leave your ownership. 

Your mother told you NOT to stare, right?  Here are some of the things used during the test
(Source:  Steve Bossert K2GOG)

K2GOG EOY 2021 Loose Ends #2: Battery Upgrade

 

With a few less days in 2021 remaining, I was hoping to upgrade the batteries in a pair of  "vintage" Yaesu VX-1R over the holiday break, but still find myself waiting on the replacement 14650 cells to arrive. 

So for now, this project is on hold while my batteries which were ordered on December 17th should have shipped today, but have not yet status updated! 

Memory Lane: The Yaesu VX-1R

All the back in 1997, this micro-miniature amateur radio came to market with its 500mW of RF output in the 2m and 70cm spectrum bands when using the internal battery. And, plugging the radio into an external DV 6 V source provides up to 1W of RF output.

With wide analog reception from 76 to 999 MHz with few gaps, this was an interesting radio, along with some experimental AM broadcast band coverage too.

This was also my third ever amateur radio handheld, so I have always had a fond memory of it and was glad to find two at reasonable price while at the NEARFEST in Deerfield, NH this past October.

Even today when compared side by side with a modern radio like the Alinco DJ-MD5XTG, its amazing how advanced the Yaesu VX-1R was almost 25 years ago for an analog only transceiver for its size.

Spending upwards of $30 USD today for a replacement battery in 2021 is a tough sell for an older radio like this which sells for about $50 to $75 used almost 25 years after its release.

The optional FBA-20 AA battery holder accessory has become harder to find, so the cheapest way to bring new life to these great little radios is by rebuilding the original battery.

The original Yaesu FNB-52LI battery is rated at 3.6v at 700 mAh and the inside of each battery has a charge controller and lithium 14650 cell. 

Versions of the 14650 are available today in 1100 mAh capacity, although some vendors boast of some with 1600 mAh which is not very believable.

After putting four old cells in the freezer for a few hours, I was able to use a hobby knife to slice down the side of each battery and reveal the insides.

A curious thing was that all four batteries on the outside appear identical, but one of them uses a slightly different charge controller as shown below.  

Functionally, they are probably all the same and the date codes all seem around the same manufacturer period but this was interesting to see.

So when the new 14650 batteries arrive, it will be a pretty easy replacement process by swapping the old cells for the new and reattaching the charge controller before stuffing it all back inside the original casings. Will probably print some nice new labels including date codes too while I am at it.

Other battery projects

I think once I finish up the Yaesu VX-1R battery rebuilds, I will try and tackle the same idea for some other vintage radios from the late 1990's too, but those will require some more thinking as they all originally used NiCd or NiMH chemistry and I rather make everything run on lithium cells instead. 

Do you have any similar projects in mind?   Drop come comments below if you do.

APRS with your Alinco DJ-MD5XTG or Anytone AT-D878UVII

How do you send analog APRS with your Alinco or Anytone radio?   This video explains how to configure your radio. 

Please note that while this video focused on the Alinco DJ-MD5XTG, the basics will apply to the Anytone AT-D878UVII as well.  Sweet! 

There are earlier versions of both radios that could not support this feature as noted in the Alinco DJ-MD5XTG teardown as well as on Jason's fantastic page about these radios down in VK land. 

It is worth noting that the latest Anytone AT-D878UVIII supports analog AX.25 APRS reception via an additional circuit board. 

Alinco does not offer this on its latest XTG model, but having packet transmission capability is still great to have. 

How do I get my DMR recordings?

 

Kraken is coming and we all need to prepare for its arrival.  On Tuesday October 19th 2021, Steve K2GOG was invited to the North Star Digital Net to give a quick chat about what does it do and why its important for the future within the broader topic of "software defined radio".

A few people who could not attend the live discussion had asked Jim WA2UMP and Steve K2GOG to see if they could record the audio presentation.   This is a fun problem that needed to be solved first to start this article, so read onward!

How do you record DMR audio?

Steve K2GOG planned to use his Alinco DJ-MD5XTG to talk via his hotspot which reaches the Brandmeister 31630 (STEM) talk group.  A nice feature with this radio, as well as the popular Anytone AT-878 series of radio, is that it can record transmit and receive audio with timestamps and by who was speaking.

Its easy to scroll through recorded audio files one by one or play all your recordings on a loop to play them all in order. This could be helpful if you thought you may have missed some important scheduled discussion or activity on your favorite talk group.

One annoyance is that the recordings save to internal memory on the radio instead of a micro SD card, like on radios such as the D-Star focused Kenwood TH-D74 or the Fusion based Yaesu FT-5DR. 

Both of those radios and even the Icom IC-705, all require the user to remove the SD card from the radio to access recorded audio but that makes it really easy to access those files  on your computer and send them to someone to share interesting transmissions like during a satellite contact. 

In the case with the Alinco and Anytone, you need to connect up a cable to your computer to access the recordings but you can not pull those files off which is super annoying. The manufacturers software seems to lock this function out but would otherwise clearly support this as pictured below.

If you click any of the files listed in photo above, the recording simply plays through the radio speaker but we are no closer to sharing the recordings.

The Alinco DJ-MD5 series of radio uses a simple USB micro cable to program the radio but does not output audio.  The way to solve this problem is to use the headphone port on the Alinco which uses the standard 3.5mm plug found on most all consumer headphones.

Using a 3.5mm stereo to stereo cable, the other end plugs right into the microphone jack on your computer sound card.  If you have a modern laptop which uses a TRRS (Tip, Ring1, Ring2, Sleeve) style connector, you may instead need to use a USB sound card as mentioned in Steve's explanation video below.

Now that we have that problem solved, you can use a program like Audacity with the sound activated record function enabled to "re-record" the audio from the radio to your computer.  While this takes a little while to do, it lets you easily stitch together the audio segments you want with no gaps. 

If you are over a certain age where you may remember double cassette recorders, this activity may bring back memories of less technological days when you had to get creative to make a mix tape from "borrowed" cassettes or maybe songs off the local broadcast station.

Hopefully this modern solution may give you some ideas on getting more from your DMR radio.

Getting back to Kraken

After all that, now we can finally get to the recording you might have missed! 

Here is an MP3 recording mostly of the segment from Steve K2GOG.  

It sounds like he missed a few parts but is otherwise complete. It looks like a time intensive operation to click on all recordings in order, so bear that in mind if you wish to do something like this yourself.

The recorder function works on any "over the air" DMR signal, so using it also to record simplex activity like what took place during the NEARFEST on US national DMR simplex of  446.075 MHz on time slot 1, color code 1 and talk group 99 is another idea.   

But, if you plan to record audio from Brandmeister you can also just use the "Hoseline" function and route that audio from a talk group into Audacity just as easily using virtual audio cables. 

And with that, I hope you are looking forward as much as Steve is to getting the new Kraken once its starts shipping in March 2022.

Teardown: Alinco DJ-MD5XTG (2nd Generation DMR)

What can I cay, I have always liked Alinco products going back to my first ever HT, the credit card sized Alinco DJ-C1T.  

Much has happened in  the world of amateur radio since and Alinco continues to do interesting things via its latest DMR handheld offering, the DJ-MD5XTG. 

This article details from the inside out, what makes this model different than its predecessor. 

Alinco had different DJ-MD5 radios?

Let me first start out and dispel a rumor I created that the latest Alinco DJ-MD5XTG would support the 220 MHz band. It does not or at least officially, which makes the band coverage on par with the popular Anytone AT-D878UV, available from vendors such as Bridgecom.

At the time of this article, the second generation Alinco DMR DJ-MD5XTG is available in the United States by DX Engineering.

When purchasing an Alinco DJ-MD5 series radio, there are now three versions that have been created and the most basic DJ-MD5T is discontinued. The major difference between it and the Alinco DJ-MD5TGP is the inclusion of GPS functionality.

 If you are looking to sell your original DJ-MD5 series radio to offset the cost in buying the new radio or are looking for a deal, please think about some of the following based on the teardown of the new DJ-MD5XTG.

The major differences

I did the hard work so you do not have to by doing a basic tear down of the DJ-MD5XTG and comparing it to the DJ-MD5TGP, which I also tore down back in November 2018. The below non-RF major component  table will help guide us along. 

Both versions main PCB interestingly both show that they are both considered revision 2.0, but with different date of manufacture codes.

1st Point: You get a faster MCU with more memory

Really the only major difference is that the Alinco DJ-MD5XTG upgrades to a 1024k flash and 96k SRAM memory configuration which is identical to that of the Anytone AT-D878UV.  

The older Alinco DJ-MD5TGP and DJ-MD5T (Without GPS) has the 512K flash and 64K SRAM memory configuration. The GD32F3030 (VGT6) is what is found inside the latest Alinco DMR radio.

The extra memory, like in the competing Anytone radio, allows for Alinco to support a few new features in the software which we will talk about later such as roaming and analog transmission of AX.25 based APRS. There is also a GPS/Baidou toggle, weather alert and few other changes.

If you have really good eyesight, you may notice what appears to be sloppy soldering on the MCU, but this is intentional. 

Alinco has bridged the shown pins on purpose, just like as found in the earlier Alinco DJ-MD5 radio as well as the Anytone AT-D878UV and the earlier AT-868UV. 

I just want to point this out that there is no bad workmanship inside this radio, especially since many find it easy to question construction capabilities of radios made today to save costs because of frugal or entry level customers.

The Alinco DJ-MD5TGP is indeed a high quality product and assembled/manufactured in Japan and not China like most, not all Alinco communications equipment.

However, the absolutely useless instruction manual which is little more than an instruction guide on how to attach the belt clip, connect the battery, screw in the antenna and turn on the radio along with some basic operation instructions is indeed printed in China, so take that for whatever value you want to place on that.

For what the manual is, it is rather well made and laid out, but just lacks any major value.

2nd Point:  Newer versions of other major components

Beyond the MCU (Micro Controller Unit), the baseband vocoder which helps your radio become a DMR radio, has a new production code and but is identical to the 2018 version of the SCT3258TD. 

Everything else is the same too and the only other differences which have not yet been thoroughly  tested  on the the main PCB are some slight changes in the RF front end and filtering compared to the older radio.  The below photo shows the main PCB along with the two RF shields removed on the DJ-MD5XTG.

3rd Point: What does the FCC have to say?

The Alinco DJ-MD5XTG does carry the FCCID of  PH3DJ-MD5, which is the same as its predecessor, so we may see an update on the FCC website in the coming months, but it does not seem like it may mean much from an RF perspective. Here is the Alinco DJ-MD5XTG fully disassembled.

Hardware:  DJ-MD5XTG instead of the Anytone AT-D878UV?

What attracted me to the Alinco DJ-MD5TGP back in 2018 are the same reasons as the DJ-MD5XTG.

Starting with how to program the Alinco with the Computer Programming Software (CPS) is that you use a common USB micro cable used with smart phones instead of a dedicated cable like that of the Anytone and other radios like the TYT, Radioddity, Lanch HG-UV98, Baofeng and Ailunce radios that have been covered across past HVDN articles plus the much higher end Kenwood TH-D74.

This may be a benefit to some people if you have a habit of misplacing things and need an instant replacement. It is also worth noting that while the Kenwood D74 can be programmed wirelessly via Bluetooth, it can also use a standard USB micro cable as well.

Another reason I like the Alinco over the Anytone is that it is a perfect radio for taking hiking. The speaker/microphone connection uses a 3.5mm jack for the speaker/headphone function and the smaller 2.5mm jack for the microphone. 

While this is now considered opposite of what used to the standard, this lets me use a regular pair of wired 3.5mm stereo headphones or earbuds with the Alinco should I wish to listen to communications or music privately.  While its common to have Bluetooth earbuds these days, sometimes a wired version is helpful to have since they do not require rechargeable batteries!

One thing I did learn with the original Alinco MD-5TGP is that using a speaker microphone seems like a burden, even with the nicely made Alinco EMS-76.  

Alinco and its resellers caution every user to only use this microphone with this new DMR radio, but if you have an older microphone wired the same as the EMS-76, it will work just fine. 

Just avoid trying any of the speaker microphones meant for other radios as they will damage your radio due to incompatible wiring.

I say a speaker mic might be a waste since the microphone is nearly the same size as the radio itself. Instead, while hiking as an example, I just clip the radio upside down on my pack strap such as pictured below while visiting Red Hill Tower last September as part of the Catskill Fire Tower Five Challenge.

The Anytone AT-D878UV still offers Bluetooth capability for remote PTT and for pairing to external audio devices.  It would be nice to see bluetooth added in the future to the Alinco DJ-MD5 series, but battery life may then become an issue.

My personal opinion is that I do not see this as any shortcoming. Please also be aware that the SMA-J style antenna connector is used on the DJ-MD5XTG like its predecessors, so this is NOT the same as what is used on the Kenwood D74 for comparison.

Software:  This needs another article or three, maybe four?

There are some new features found in the Alinco DJ-MD5XTG which will really make it appeal to those that enjoy an active converged lifestyle and some future articles will cover:

• What is roaming and do you really need it?

• Analog APRS:  This is the original, not the new APRS or D-APRS

• GPS: How do you set it up and actually use it

• Proof is in the programming:  Basic US Alinco DJ-MD5XTG code plug

• Talking about the band options in the Alinco DJ-MD5XTG

Keep an eye on the HVDN Notebook for future articles all December long about the Alinco DJ-MD5XTG or bookmark this handy link. https://hvdnnotebook.blogspot.com/search/label/Alinco%20DJ-MD5XTG