Thursday, April 21, 2022

почта from Russia: Fixing the FT-897 Display

FT-897 replacement display

As the Hudson River Radio Relay event gets ever closer, I wanted to finally get around to fixing the "zebra stripes" on my Yaesu FT-897 display so that it would be easier to use again in the field while on Bannerman's Island as N2B on June 11th.

Replacement LCD display modules and controller sourcing for this 18+ year old radio has not been easy. Luckily, there is an enterprising amateur named Aleksey in Russia who has designed a replacement and it only cost around $60 USD.

When Yaesu designed the mobile FT-857 and the multi use FT-897 radios, roughly 10 years later many users started to suffer display issues like pictured below. Now my radio was ready for a facelift! 


Not all, but many Yaesu FT-857 and FT-897
have suffered from "zebra striping" on the LCD displays


The bad news is when I finally found out about the miracle replacement display,  there were some issues starting to take shape in February 2022 in the region, which I shall not yet name.

Quickly, Aleksey rushed to the post office to hopefully get the package out of country before worse things could happen. After weeks of lead up, Russian military crossed the Ukrainian borders on February 24th. 


Display has arrived. Now what?

Amazingly, the two piece kit made it across the United States in only 3 days according to USPS after its 48 day customs event between Russia and the destination. Here is what arrived, well packed in bubble wrap. Thanks Aleksey R3ZI! 


FT-897 replacement display
The new LCD with attached ribbon cable along with the
new LCD controller on flexible PCB with connector thanks to R3ZI

After dissembling the front  of the FT-897 and separating it entirely from the radio body, all else was needed to remove the seemingly infinite number of screws holding the control board to the face.

It was rather easy to access the old LCD display and start preparing for surgery.

FT-897 replacement display
The old LCD display still set within the
white plastic holder prior to removal

FT-897 replacement display
Tilting the display up exposed the ribbon cable and the
connections which will need to be desoldered carefully 


I used a hot air SMD rework station to remove the old ribbon connections since I wanted to be careful to not lift off any of of the PCB traces on the main display board of the FT-897D.  I could have just as easily used a standard pencil iron, but when you have the means.....

Extraction was a success and a little clean up was needed to prepare for the new display controller to be attached.


FT-897 replacement display
A little more clean up was needed and what appears to be
a missing trace was intentionally blank.  Sigh of relief

I took some solder flux and solder paste and prepared the surface to receive the new flexible controller.

A quick wave of the hot air tool melted the solder into all the right places and the moment of truth in restoring display visibility was now one step closer.  

The new flexible PCB with controller is connected and now just waiting for the ribbon cable for the LCD to be attached and the radio to be reassembled. A thin bead of hot glue was put over the connections for extra security.


FT-897 replacement display

Pushing the power button

I was confident in my work and decided to just put everything back together and not try to do some sort of  "preliminary" power up test to see if everything worked the way it should.   

The moment after getting the radio fully re-assembled, applying power, connecting antenna and then taking a breath before pushing the power button was met with success as shown below. 

Thanks for reading and my goal was to NOT do some sort of step by step video or make it easy for you to find out where and from whom I sourced the display, but I promise you that this info is easy to find and is an easy project if you plan carefully.  

Hope to catch some of you from Bannerman's Island via this radio on June 11th.  Will be focusing on 17m SSB and 17m digital modes most likely as part of the N2B station.

Tuesday, April 19, 2022

UNDR Group Experiments with KG-STV

 



There is a great reason for sharing an image like that and no, those black boxes are not censorship but bad pixels when receiving a KG-STV image over amateur radio.

Why send images?

The Ulster and Northern Dutchess Readiness Group is a new organization founded in 2021 to promote ways for the casual radio amateur to learn about preparedness.  

ARES and RACES programs are excellent, but not everyone has the time to dedicate to those or the missions that sometimes prevent a higher level  of local community awareness regarding amateur radio.

Sharing photos for reasons such as training for public works damage assessment or other "grid down" information sharing reasons is an important skill to learn as part of the amateur radio hobby.

Sending photos over a repeater

To help differentiate UNDR Group, the leadership team led by Steve K2GOG has focused on practicing the use of slow scan television (SSTV) images which can be relayed through analog repeaters in the Hudson Valley.

Since October 2021, the UNDR group has found that the PD90 mode is a good trade off between resolution and time needed to send an image with excellent clarity.  A 320 x 240 pixel image sing PD90 takes about 90 seconds from start to finish.

In April 2022, the UNDR Group did an experiment simulating the need to send, receive and re-broadcast an image pretending there was a UFO sighting over the Hudson Valley.


Poughkeepsie UFO,  Highland UFO, Pine Bush UFO
Captured and then rebroadcast SSTV
PD90 image of a pretend UFO over the Hudson Valley
(Courtesy: K2GOG, W2NDG and KD2SQO)

Evolving to digital SSTV

Now that enough members of the UNDR Group have perfected the ability to send and receive images from home or the field using analog SSTV, they have just moved over to learning how to send digital versions of imagery using the KG-STV application.

With normal analog SSTV, one line of the image is sent at a time, scanning from left to right.  As the images is transmitted, those receiving it slowly start to see the image come into view. There are many modes of analog SSTV such as ROBOT36, PD90, SCOTTIE and others. 

KG-STV is different since it is sent digitally in a group of pixels at a time. The sender can choose to send these blocks of pixels in vertical or horizontal rows plus in a randomized sequence.

Sending in a randomized sequence is interesting since it prevents some types of interference or missing large pieces of an image.

Here are two examples of decoding the MARS logo which Steve K2GOG sent as part of an awareness exercise of the Military Auxiliary Radio System.  

This volunteer group managed by U.S Department of Defense via the Army and Air Force has taken a renews interest in collaborating with amateur radio operators for joint readiness exercises.


 


The image above decoded by Tom N2FZC shows only slight pixilation and the image below from Lou KD2TVS shows a bit more given he is much further away from the repeater compared to Tom which relayed the signal 




For a first time test of KG-STV, this was still a great start as it took on average of 6 times using analog for UNDR Group members to get near perfect copy. 

The reason to experiment with KG-STV is that the application can also send text communications which makes it a valuable tool for when audio communications may not be appropriate. 

When does UNDR Group meet?

Every Monday evening at 8:00 PM Eastern Time is the UNDR Net via the WA2MJM 146.805 analog repeater.  The UNDR Net typically shared a list of announcements including upcoming events at the start and the follows a short thematic discussion. 

At around 8:30 PM, the focus shifts to a form of digital communications which can be shared via the analog repeater.  Different forms of SSTV are the current focus, so please check it out as no other organizations are doing anything else like this in the Hudson Valley and possibly in a larger part of the New York Metro area.

More information about UNDR Group can be found at www.undr-group.com 

Thursday, March 17, 2022

FEB 2017 REBOOT: 2022 APRS on the cheap!

 


Time to finally start going back in the time machine to see how things have changed since the early HVDN days.


Feb 7th 2017:  The first HVDN article

Fellow Hudson Valley amateur radio related organization known as the Overlook Mountain Amateur Radio Club (OMARC) used to have a message board that I used to post content to.

Some of those articles were then mirrored to start HVDN, such as the "Mobilinkd TNC2: Bluetooth APRS on the cheap!"  one but the photo links are now broken since they closed down that message board last year and is where those original images were hosted.  Is that you McFly?

Since the time of that article, Rob WX9O has released his TNC3, which basically does the same thing as the earlier TNC2, but the main improvements for $124.95 include:


    • Bluetooth 4.2 support (dual-mode EDR/LE) iOS Compatible
    • 1200 and 9600 baud capability!!
    • USB serial port
    • DCD and TX indicator LEDs
    • More powerful DSP and modem
    • Higher dynamic range ADCs and DACs
    • Buffered inputs and outputs
    • Input amplifier for improved input level matching across a wider range of radios
    • Optimized for packet radio
    • 900mAh rechargeable battery lasts for 2 full days

Now supposing you already have a smartphone,  VHF/UHF radio and the TNC3 plus cable to hook this all together, you have a pretty portable and capable APRS system.  But is there a cheaper way in 2022?  Lets find out!

Its not about being cheap: 2022 APRS on the cheap!

The TNC3 is actually really great, but without a smartphone and its built in GPS and whatever APRS smartphone/tablet application you want to use, you have a few limitations.

The Appalachian Trail Golden Packet (ATGP) is fast approaching on July 16th 2022 and a specialized APRS Appliance is being developed by an amazing team using off the shelf parts and open software to fill a gap left by manufacturers of ready to use APRS equipment.

It would be easy to just use the TNC3 with an appropriate VHF/UHF radio, but that may not be best for some events such as the historic Appalachian Trail Golden Packet event.

Here is a general block diagram of what the APRS Appliance contains:



Direwolf software is run on a Raspberry Pi computing device which provides a software emulated TNC. 

The DINAH interface provides a safe and stable way to connect the Raspberry Pi to a VHF/UHF capable radio which can handle FSK 9600 baud or AFSK 1200 baud data. 

For a fixed location station, this is all that is needed in addition to the appropriate power sources for the Raspberry Pi and VHF/UHF radio plus an antenna for the radio.

If there was a need for this to be taken mobile, including a USB GPS with external antenna would be needed for continual location updates.  

The additional USB Wi-Fi device shown provides a secondary connection to either debug or provide connection to a smart phone or tablet to view or control the device.

A bill of materials for the basics as above, excluding the VHF/UHF radio, power supply system and antenna would cost about $200 or less.

You said cheap APRS!!

Portable APRS that is full featured is actually a hard thing to do still, even almost after 20+ years and this should not be the case.

With the mobile Kenwood TM-D710 radio being hard to purchase new and the hand held radios they also made being discontinued like the TH-D72 and TH-D74, the only off the shelf options for a full self contained APRS device are the less feature rich Anytone AT-D878UVII+Lanch HG-UV98 and a few Yaesu radios such as the FT-5DR, FTM-300DR  and FTM-400.


Trusted on the International Space Station, the Kenwood TM-D710
is considered by many to be the best mobile APRS radio ever made



Needless to say, to do what the APRS Appliance offers is actually not a bad deal, plus the parts may be on hand or you can repurpose them for other projects.

Surplus commercial radios like the Motorola CDM750 or CDM1250 are great for higher power mobile APRS installations when used in conjunction with the APRS appliance.

Stop being cheap!!!

An option to use a $20 interface cable, old smartphone and almost any inexpensive $50 VHF/UHF handheld radio will not be close to the same data capability as what the Mobilinkd TNC3 or an APRS Appliance can offer for true versatility with an appropriate radio, like an Alinco DR-135 or surplus commercial gear by Motorola, Vertex, Kenwood, etc.

The primary reason is that a lower cost radio does not have the same quality of RF switching and front end needed for a reliable APRS system in mission critical or dense signal environments.

A second reason is that using "voice activation" or "VOX" functions found in some radios would not offer the faster switching and turn around time needed to process higher volume packets.  Dropping packets or partial decoding means failure.

Summer 2022:  More planning than just buying sun screen

For the ATGP event on July 16th 2022 and maybe even the Hudson River Radio Relay event on June 11th 2022, it is critical for all participants to use the same or nearly the same equipment for reliable communications.

Now is a great time to start thinking about your capability and to test it in advance with local friends and not during the actual event.