Sometimes Hacking is done with a Soldering Iron

This is my second post in a series about building and hacking a BITX40 radio. The series starts here.

Some BITX40 radios -- including mine -- built as designed exhibit tuning clicks. That is as the DDS frequency changes there is an audible click in the speaker or headphone output. There is some debate as to the cause. Some believe it is the result of how the DDS circuit is handled in software and that it can be fixed in software. Pavel Costa has written a library that has a number of benefits, including eliminating the tuning clicks. That link has some interesting reading, and the first thing I did was to compile and install his software and his modification of the BITX40 sketch. I still had tuning clicks, so not entirely a software problem.

The other solution proposed on the internet was that the Raduino voltage regulator was insufficiently decoupled from the 12VDC supply. Heavy computing and circuit use surrounding a change in frequency would cause an increase in current draw, which was bleeding back across the regulator to the main power circuits and appearing in the amplified audio. There are a number of ugly and somewhat dubious solutions adding components to the back of the Raduino board. None of these appealed to me so I took a different route.

If the problem is decoupling of the voltage regulator I could de-solder the regulator from the board, replace it with a header, then I could experiment with the required circuit. So that's what I did.

Raduino with regulator replaced by header.

While the iron was hot I also soldered in a 5 pin header in the area used for other hacks to make things easier in the future.

With the header in place I could put the regulator on a prototyping board and build up the required circuit. I found a 66 ohm resistor in series with the input 12VDC line and a 333uF capacitor between the 12VDC line and ground eliminated the tuning clicks.

Prototype decoupling circuit.

Here are some YouTube videos of the radio tuning without and with the added decoupling circuit:

• without decoupling 
• with decoupling

All that remained was to transfer the working circuit to a permanent board and install it in the radio.

Final decoupling circuit.

As an added benefit this board now has the main 12VDC, Raduino 5VDC and ground so it is perfect for other hacks and experiments.

73s
Richard
VE3YSH

Building a BITX40 40M SSB Radio

This is the first in a series of posts about the BITX40 radio, the next post is here.

The radio kits from HF Signals are quite popular because they are:

1. inexpensive;
2. hackable in both hardware and software;
3. well supported;
4. work well considering they are inexpensive and hackable.

The kit doesn't come complete, which makes it easier and less expensive to ship. But that does mean you will need to come up with a power supply, a case (or at least some way to mount the boards and controls), complete or find a microphone assembly and some others things. Some may see this as a drawback, but I see it as an advantage if your goal is to experiment with the radio rather than simply use it as you would any other appliance. You have the option of only building that which you need for you experiments.

My radio kit arrived in September but I did not really have time to put the radio together, and had not decided on a case. I finally settled on a case from Amateur Radio Kits World-Wide, the colour is very nostalgic of my days as a signalman.

Universal Case Siemens Grey II & Accessories

It comes with some useful parts not included with the BITX40

The case, like the BITX40 ships from India, but the only shipping options is by Post. Never the less it arrived at my mailbox in Canada less than three weeks after I ordered it right in the middle of the holidays. Perfect timing to put it together.

The first thing I did was test fit the boards and parts into the case. Doing this while reading the wire up instructions gives you a better idea of how the wires traverse the case and a chance to consider various options. I learned three things while doing this.

First, the BIT40 diagram is a bit confusing because it shows the Raduino board from the side facing the front of the case, rather than the side you would be looking at while running the wires. The text instructions are better, but again from a point of view I would not have chosen. But this is not a huge problem.

Second, I had to ream out some of the mounting hols to get them large enough to mount the parts. Again not a huge problem, nor unexpected since the case is powder coated, but one you should be prepared to deal with.

Third, the voltage regulator on the Raduino protrudes past the left side of this style of case. Again easily dealt with by carefully folding the regulator the other way.

Voltage regulator folded back between the Raduino and the LCD display.

The rest of the installation was quite easy as described on the BITX40 web pages.

Left side of the radio.

Right side of the radio.

If you look closely you will notice that I have not completed the hook up. I have not:

• provided for MIC or headphone jacks,
• installed a PTT switch or any way to get the radio to transmit,
• trimmed the shaft of the tuning pot.

This is because I intend to do a number of modifications. The first step in this process will be to decide on which firmware to run. But these are discussions for a later post. I will leave you with pictures of the front and back panels and an anecdote of my first test.

Front panel.

Back panel.

The only antenna I have at home is a 2m ground plane whip in my attic which works well for me on 70cm as well. Once the radio was completed and knowing there was no way I could accidentally transmit and perhaps damage the rig I hooked up this antenna and started tuning around the band. I quickly game across a stations calling "CQ contest" likely for this RAC event. I was able to make out some VA3 call signs. Some more tuning and I came across a station from Long Island NY calling "CQ DX" and listened to him for a while. Not a bad days work as a HAM if I do say so myself.

73s
Richard
VE3YSH

VE3RLR Gets New Fusion Repeater

Over the months of December and January the Rideau Lakes Amateur Radio club was pleased to introduce a new technology to our repeater complex. We purchased a Yaesu Fusion repeater system and a number of mobile and handheld Fusion radios to equip our membership. We would like to thank Radio World for their superb support in fulfilling this order and are looking forward to welcoming them to our Flea Market this year.

Update. This fall we upgraded our VHF repeater to DR-2X Fusion II and moved our DR-1X equipment to UHF providing automatic mode (digital or analog)  support on both repeater frequencies.

The Fusion repeater has finished tests and familiarization for our club members and is now installed as our VHF repeater:

VE3RLR 147.210 + PL 151.4Hz AMS IN/OUT
VE3RLR 442.750 + PL 151.4Hz AMS IN/OUT

The AMS IN/OUT means that the repeater will automatically adapt to the mode used on the input frequency. If you call the repeater using FM it will transmit using FM. If you call the repeater using C4MF (The Fusion digital mode) it will transmit using C4FM.

Richard
VE3YSH

FTM-100D Firmware Update

Introduction

This is a work in progress.

This post is to help club members upgrade their FTM-100D radios. As I go through the update procedure I will add information here. At the moment there is a link to the Yaesu website update description PDF document. And a link to where I have extracted the USA update files from the bulk update file with all three versions.This file is one third the size available from Yaesu.

Files

• Update description (PDF)
• Yaesu Update Download Link (42MB ZIP File)
• FTM-100D USA Update 1024 (14 MB ZIP File)

Smiths Falls Flea Market 2017

We had another very successful flea market again this year despite the record setting rain and floods in various areas around us. Luckily Smiths Falls, even though it is on the banks of the Rideau is also relatively resistant to flooding.

We would like to thank all our vendors whether private or commercial, but we especially thank the commercial vendors who provide a great service by bringing so many products our that we can look at, ask questions about and buy if we are so inclined.

Finally a huge thank you to Peppers Radio and Radio World who both provided the door prises even though Radio World wasn't able to attend this year.

Peppers Radio

Durham Radio

Maple Leaf Communications

MacFarlane Electronics

FTM-100D Dual Receive Function

Many amateur radios that have multiple "Bands" such as Band A and Band B have multiple receivers built in. This allows each band to receive a different frequency and share a single transmitter. This makes dual mode operations such as APRS on Band A and half duplex voice operation on Band B quite easy to do. Some, such as the Kenwood TH-D7 have two transmitters allowing them to do full duplex. It appears (I have to admit I'm not fully familiar with the radio yet) that Yaesu built the FTM-100D with only one receiver. At first this seems like a limitation, but modern digital receivers can switch frequency very quickly simulating more than one receiver. In this post I will talk about using this capability to operate APRS and work the repeater at the same time. The procedure could be used to do something simpler as well, such as work one repeater and monitor another.

If you are going to use this procedure to work APRS you should have APRS configured on your radio before you proceed. You can use this post to get started.

The Dual Receive Function utilises the Band Home memory and any other frequency either from memory or using the VFO. So the first step is to program the repeater into the Home memory for the Band you are going to use, I will use Band A but you can use either A or B. Setting the Home memory frequency is covered on page 54 of the manual but the steps are:

1. Switch to VFO mode and Band A.
2. Tune in the frequency you want, and set up any other operating settings you want (PL tones, etc).
3. Press and hold V/M MW for over one second. The Memory Write screen appears.
4. Rotate the dial to select Home.
5. Press DISP Setup. The overwrite confirmation screen appears.
6. Rotate the dial to select OK, and press DISP Setup.

Now you should tune in the APRS channel. If you have programmed it into a memory location for Band A you can enter Memory Mode rotate the dial to select that memory, if not you can enter VFO Mode and enter the frequency manually. Now press the A/B DM button for more than one second. The band display will change from MA if you are using a memory location or just A if you are using the VFO to DA indicating you are in Dual Receive mode. Periodically (every 5 seconds by default) the receiver will quickly switch to the Home frequency to see if there is any activity. Dual Receive mode is covered starting on page 70 of the manual, including how to change the 5 seconds.

One thing to be aware of. When using this for APRS beacons will be transmitted when it is time as determined by the APRS software and the receiver doesn't detect activity regardless of what frequency the unit is actually tuned to. If you get involved in a QSO you may end up transmitting a beacon on the repeater frequency. Not the end of the world, but also maybe something that you don't want to do. An easy way to prevent this is to have the Home frequency stored in a memory location in the other Band (Band B) and have that Band set up to work the repeater. Then by switching to Band B for the QSO the APRS and Dual Receive operations will be suspended until you switch back to Band A.

Another is that if you use APRS Muting from page 59 of the radio APRS manual you won't be able to hear the activity on the home frequency. This is because this is APRS operating band mute and all activity on that Band A or B will be muted. I think we are better off using the voice alert procedure from www.aprs.org anyway.

This may seem a little complicated, but I've used this to operate APRS and have had QSOs with a couple of people and it is easy to do once you have practised a bit. So if you want to operate APRS without dedicating the radio to that, or just want to monitor one repeater while you work another give this a try.

This YouTube video may also help although this video shows setting the "APRS" frequency as the Home station, but I don't think that is the base way to do it.

Richard
VE3YSH

FTM-100D Using APRS

This is the first is a series of posts describing what I have leaned about using the FTM-100D dual band C4FM/FM transceiver from Yaesu with a Fusion repeater. The first thing you need to do is download the APRS manual for the radio from the Yaesu web site.

I found setting up APRS by following the manual was quite simple. The radio defaults and the settings the manual guides you through will get you up and running on APRS quite quickly. In fact by the time you get to page 12 you should be beaconing. You can then go through the balance of the manual to set the radio up just the way you like it.

Here are a number of recommendations I have:

1. You can use the built in GPS for position, or set the position manually. The GPS works very well, even in my home office surrounded by computers so I recommend using it. If you are in a building where the GPS signal is poor you may have to set it manually.
2. Our digipeater, like most, is 1200 baud.
3. Don't use the APRS Mute setting, more on this later in the series. APRS.Org recommends using CTCSS tone of 100.0Hz. This keeps the digital traffic quiet but allows the APRS frequency to be used as an alternate calling frequency when you see someone you want to talk to has wandered into simplex range. This is easily configured on the FTM-100D. Using Setup go into APRS then option 25 VOICE ALERT. Set VOICE ALERT to RX-TSQL and TONE SQL to 100.0 Hz. See page 78 of the APRS manual.

I have found the radio performs APRS beaconing very well. The receiver and demodulator seem to be quite good at picking up weak signals and transmitting on low power allows me to reach digipeaters that are quite farm from my home. It is also very nice to have everything you need to start working simple APRS in one rig without managing several devices and the associated cabling. So go get your FTM-100D on the air beaconing and enjoy.

Richard
VE3YSH