Ham Radio Deluxe announces JT modes in their DM780 module

The management at HRD demoed a version of HRD containing JT65, JT9 and WSPR modes at Dayton. Not sure of what decoder they are using nor any more details of how it has been designed.
We'll see if it lives up to the hype when it finally gets released. Until then I will carry on using JT65-HB8HQX with JTAlert,

Checking the input/output of a soundcard - use with an FT-450D

On the Facebook group for Ham Radio Deluxe somebody had posted a link to a video highlighting a "bug" in soundcards that use a particular Texas Instruments audio chipset - the affected chipset is the TI PCM2900 series PCM2904 and below, pre-C revisions. See here for Reddit article.

Some radios have this chipset built into them. My Yaesu FT450-D is NOT one of them fortunately.

I had a look at the YouTube video https://www.youtube.com/watch?v=guH0NMRRTAo and the poster John Sands had a lot of useful information including how to temporarily fix it if you have the chipset. There was a link to a freeware piece of software for a Peak Level Meter darwooddesigns.co.uk/pc2/meters.html and on the Facebook page of HRD somebody linked to a Soundcard Oscilloscope zeitnitz.eu/scope_en which can be used to check the waveform of your signals.

G8YPH Soundcard Usage

The PC connected to my various radios has 4 soundcards built into it:

• The internal onboard Dell soundcard is disabled in the BIOS
• A EMU-0404 PCI high spec professional soundcard - many input/outputs, ASIO, WAVE, Full MIDI, DSP configuration possible with this card - drivers up to Windows 7 64bit are only available for this now though. So Windows 8.1 and Windows 10 might not work.
• 2 x USB cheap soundcards (costing a few quid from Amazon)

The latter soundcards are the ones that I use for the Yaesu FT-450D as they are connected to a powered USB hub close by the rigs.

The only issue I had to resolve with these sound cards are that they are not shielded. I added some domestic aluminium foil around the body and loosely connected it to the ground/earth of the USB plug. This simple modification worked very well and the dongle does not pickup any stray RF at all.
A long term modification would be to replace the aluminium with self adhesive copper foil wrapped around the case with a soldered connection to the ground. However for the time being the aluminium works well.
The sound card automatically picks up the necessary drivers from Microsoft's Windows Update site and the driver it uses is:

• USB PnP Sound Device
• Driver Provider: Microsoft
• Driver Date: 12/07/2013
• Driver Version: 6.1.7601.18208
• Digital Signer: Microsoft Windows

General Tab

Driver Tab

Driver Details

The controller information field shows up my cards as being 3-USB PnP Sound Device and 5-USB PnP Sound Device (Generic USB Audio)

If you plug the device into a different USB socket it will pickup a different number.

Naming sound cards

Recording Device Naming

Playback Device Naming

It's always a good idea to name any devices you have in Windows from the defaults ones. It aids signal tracing later on.
I have named my devices as this:
3-USB PnP Sound Device - from now on known in the blog as Soundcard #3

• Recording - RX from FT-450D
• Playback - TX to FT-450D

5-USB PnP Sound Device - from now on know in the blog as Soundcard #5

• Recording - FT-450D Headphone Socket
• Playback - NOT IN USE - I don't use this currently for anything.

The 3.5mm (1/8") plugs on the custom lead coming from the Yaesu FT-450D Data socket are plugged into the relevant sockets on the 3-USB PnP Sound Device. I also have a lead coming from the headphone socket of the rig going to the recording socket of the 5-USB PnP Sound Device.

Sound Card Levels

As the input and output levels of the FT-450D data socket are fixed then you have to resort to using the digital attenuator supplied by the driver to the sound card. Fortunately the input and output of the rig are matched (impedance and line level) to the typical computer soundcard.
On Soundcard #3 I have the following for the "Recording" settings:

General Tab
This is where you change the name of the device and
change its icon

Listen Tab

NOTE AGC on the Custom Tab is disabled

Levels Tab

Advanced Tab

For the Soundcard #3 "Playback" settings I have this

General tab
I have renamed it to something meaningful

Levels tab
63% seems to work well for me
ALC is controlled from within DM780 itself
as seen in another of my blog posts

Enhancements tab
Nothing is selected here and left at default

Advanced tab
Again nothing is changed here

On Soundcard #5 I have the following settings for the "Recording" settings :

General tab
Note I have changed the Icon to a set of headphones

Listen tab
The "Listen to this device" checkbox is ticked
see further down for details

NOTE AGC on the Custom Tab is disabled

Level Tab

Advanced Tab

I don't use the playback section of the Soundcard #5 so haven't included it.

Monitoring the rig output

I have the recording input of device 5 set to playback through the default playback device - in my case the EMU-0404
To do this:
In the Sound manager open the properties of the device

• go to the Listen tab
• check the Listen to this device box
• make sure the Default Playback Device is selected
• Click OK twice.

You can then listen to the output of the the FT450D through the shack speakers and control the level using the AF Gain control on the rig (or control that with HRD Rig Control)

Monitoring sound card output

The Digital Level Meter software from darkwooddesigns.co.uk can be configured to monitor the input level of any of your sound cards.
I set mine to monitor Soundcard#3 microphone socket - this is connected to the rig data output socket. I tuned to a typical busy position of the 20m band which has a lot of activity - 14.070 MHz USB the PSK portion.
As the level of the digital attenuator is set to 49%  I get peaks of around -3.8dB and an average of -8dB which is just less that the software overload position.

A good peak level

I turned the attenuator up to 100% (so it wasn't doing anything) and immediately went into the red peaking at 0db - and flashing OVERLOAD - which I would have expected. This was also verified in the DM780 module too as everything was saying OVERLOAD

Bad peak level

As there was no way of turning down what is coming from the rig the only alternative is to activate the digital attenuator on the soundcard. This is not an ideal but the only thing I have.
I turned the attenuator back to 49% and all was well.

Using a digital oscilloscope to check the waveform for clipping.

The Soundcard Oscilloscope software can be used to check any permutation of soundcard within a PC. I had a look at the waveform of the signal on the Soundcard#3 microphone socket.

When set at 49% the signal was pure and smooth. When increased to 70% the peak level meter was just peaking into Overload also confirmed with DM780. The waveform on the Oscilloscope was also starting to clip.
I increased the level to 100% and the waveforms were continually clipping.

So I decreased the level back to 49% again and all returned to normality.

I think that level works well for me although I don't currently operate any of the JT65 or JT65-HF weak signal modes. These modes need your sound card set for optimum levels and the two pieces of software I highlighted can help in setting your station up to operate these modes.

Monitoring Sound Card Input,

It's always nice to see the signal that your PC is generating is at a good level and isn't introducing distortion into the start of the signal chain.
The Software Oscilloscope can be used to monitor the signal both coming from the computer and into the soundcard feeding the rig.

In my case I chose Loopback: TX to FT-450D
(aren;t you glad you named the soundcards earlier on!)

You can compare the waveform and make the necessary level adjustments.

A fairly smooth waveform being fed into the sound card

Conclusion

It is easy to monitor the levels and waveforms of digimode audio both going in and coming out of your rig using a few simple freeware programs. You can then make sure you are making the most of your computer by obtaining the cleanest possible audio signal.

Tuning out QRM on datamodes using the Yaesu FT-450D with DM-780 and Ham Radio Deluxe

The standard way of operating a datamode such as PSK-31 is to leave the filter width as wide as you can and tune to the operating frequency. The software, in my case Ham Radio Deluxe running the DM780 module, then uses software filters to narrow reception down to whatever audio frequency you have selected in the waterfall. This works well 99% of the time but you do get occasions in the middle of a QSO when a very strong station starts transmitting in an adjacent audio frequency. That station probably can't hear your contact so doesn't know that it is generating QRM.
This can sometimes result in swamping the signal coming from your contact.

The two useful filters on the FT-450D highlighted in yellow

The radio then comes to the rescue. From very early days it has been possible to engage IF filters, notch filters and such like on communications equipment. When somebody is tuning up close to your listening frequency engage your tunable notch filter. If somebody is transmitting on SSB a few KHz up then engage your IF Shift. The ways of getting rid of QRM are very wide ranging and easy to do.

PSK-63 working higher up the audio frequency waterfall

I noticed that when working on the 15m PSK frequency (21.070 MHz) trying to make a contact with a contest station on PSK-63 my station could not be heard. The waterfall showed this station at around 2300 Hz.
After checking out my ALC levels it was noticed that the ALC meter reading was considerably down at the low end despite the audio drive level being high. I went into the Transmit section of DM780 (the  Ham Radio Deluxe module dedicated to audio/digital modes) and turned up the volume.
My station still could not contact the caller.

So I changed the radio frequency to 21.07150 MHz and tuned up again. This time the caller was at around 1KHz on the waterfall so was right in the sweet spot of my rigs audio range. The Transmit drive was reduced back to 30% and I sent out a reply to his CQ.

Rig retuned lowering the apparent waterfall frequency
to around 1000 Hz

BANG - got him straight away with the ALC two points less than the FT-450 colon symbol.

The moral? - Try to work stations at around 750 to 1500 Hz on the waterfall, re-tuning the rig if necessary, and you will put out a better PSK signal especially on higher bandwidth digimodes.

Monitoring transmissions using a SDR receiver

When using digimodes you have to rely upon another amateur who can tell you if you signal is being over-modulated. Or, as per my previous blog entry, look at the ALC meter on the rig.
Another way of doing it is by using another computer in the shack (everybody has an old one!) and logging onto a Web SDR receiver somewhere on the internet.

There are many now and a quick search on Google reveals where they are.

Install Ham Radio Deluxe onto the old PC and set it in demo mode so you are only controlling a demo radio.
I found a piece of shareware software called Virtual Audio Cable that runs in demo mode.
Download it from here

Install it and launch the Audio Repeater part of it.
Set this to take the output of your audio card and feed it to the Virtual Audio Cable 1 as per this picture