<P ALIGN="CENTER"> <FONT SIZE="5">This <I>really</I> needs frames.</FONT><BR> (It has one iframe which is crucial.) </P>

HDSDR 2.61 Documentation
(the AB1JX version)

I begin at the main user interface: what your screen looks like. Individual dialog boxes are discussed below.

The image below is an image map. Move your mouse over it and you should see your cursor change to what you normally see when you hover over a link. In some browsers you'll also see something similar to tooltip help with a brief description of the link. Below the image is an inline frame (medium blue background), which I use to show a long list of entries keyed to the links above. When you click on something in the image, the text in the iframe should scroll to that. The image is 1024x768 pixels, the size of my laptop screen. This is full screen mode: notice there are no window borders. I apologize for having a big image but as time goes on and screens get higher resolution, this won't be so bad. :)

The Waterfall and Spectrum are swapped from the default here, just because that's what I'm used to (SDR#). The swapping is under Options -> Visualization, covered below.

Pay attention to the number before the colon in the tooltip in case you don't end up in exactly the right place below when you click.

If you can't find something you're looking for, use the Find option in your web browser (usually Ctrl-F).

01: db scale 02: Spectrum Area 03: Signals 04: Move Down 05: Frequency Scale 06: Timestamps 07: RF Waterfall 02: Spectrum Area 03: Singals 05: Frequency Scale 07: RF Waterfall 08: Move Up 10: S Meter, Click scale to set Squelch level 11: AM Button 12: ECSS button 13: FM Button 14: LSB Button 15: USB Button 16: CW Button 17: DRM Button 18: Local Oscillator A 19: Frequency Manager Button 20: ExtIo Properties 21: Volume Slider 22: AGC Threshold 23: Soundcard Options 24: Bandwidth Settings 25: Options Button 26: Keystroke Help, Check for Updates 27: Full Screen Mode 28: Stop Playing, but leave open 29: Minimize, but keep playing 30: Exit Completely 31: Record 32: Play 33: Pause 34: Stop (Record/Play) 35: Rewind Wave File 36: Loop Playback 40: Noise Reduction 41: RF Noise Blanker 42: IF Noise Blanker 43: RF +0 Button 44: Reusable Slider 45: Mute Button 46: AGC Off 47: Notch 48: CW Zap 49: CW AFC 50: CW Peak 51: CW Despread 52: CW Full BW 53: Date and Time (system clock) 54: CPU Load from HDSDR 55: CPU Load Total 56: Tune Frequency 57: Set RF Waterfall Brightness 58: Set RF Spectrum Scaling 59: Set RF Waterfall Contrast 60: Set RF Display Minimum Level 62: Set RF Display Resolution Bandwidth 61: Set RF Display Zoom 64: Number of Averaged FFT Lines (RF) 65: RF Display Speed 66: Audio db Scale 67: Audio Spectrum 68: Drag Line to Adjust 69: Audio Frequency Scale 70: Audio Frequency Waterfall 71: AF Waterfall Brightness 72: AF Set AF Spectrum Scaling 73: AF Waterfall Contrast 74: AF Spectrum Minimum Level 75: AF Display Resolution Bandwidth 76: AF Display Zoom 77: AF Display # of Averaged Lines 78: AF Display Speed What you clicked on above should appear here:

HDSDR can be found at http://www.hdsdr.de but there isn't a lot of documentation so I wrote my own version. The program has tooltips of its own, but a few of them only display for a fraction of a second on my computer.

There's also a howto at http://www.hdsdr.de/howto, and an FAQ at http://www.hdsdr.de/faq.html. And g4zfq's https://sites.google.com/site/g4zfqradio/installing-and-using-hdsdr   There's a list of supported hardware at http://www.hdsdr.de/hardware.html

This is made for fancy SDR hardware that can transmit, but I've just got a $20 NooElec RTL2832 dongle and it works fine with that, once I got the right ExtIo file installed. I already had Zadig installed from using SDR# and RTL1090. The frequency I'm tuned to here is one of the NOAA weather broadcast frequencies, which make handy beacons in much of the US. On a good antenna I get 6 or 7, on a bad antenna I only get one that's line of sight 20 miles away.

Dialog boxes

Soundcard (F5) Bandwidth (F6)
soundcard bandwidth

With a serious SDR setup having multiple sound cards there'd be more in here. This is a laptop and I don't have a USB or PCMCIA sound card. Normally you'd use this to choose which sound card was used for what.

The Sampling Rate dialog on the right has 96000 selected as an audio sampling rate, for use with broadcast FM. The 2400000 at the bottom is the RF sample rate selected in the ExtIo dialog. The Input column is unused with my lack of hardware.

I spent a bunch of time trying to do WEFAX with both Fldigi and Wx2img, with less than satisfactory results. I moved this output sample rate up and down, and the sample rates in the other programs. The conclusion I came to was that it doesn't matter what you set these to (at least under Windows). The rates don't have to match. I didn't get any very good pictures, because both of these other programs are quite sensitve to CPU load, especially variations in it. The CPU load imposed by HDSDR varies in jumps all the time. If a big spike in CPU load comes along, it causes the imaging program to miss a few samples, which causes the image to have a step sideways at that point. I think they could do better buffering. I saw the stepping problem first under OpenBSD and asked the program author about it. It was due to a screensaver, Xearth, that rotated its view of the Earth every minute, and that caused the steps. I have gotten perfect pictures with EasyPal because it's more robust.

Options (F7) -> Select Input Options (F7) -> Visualization
input visualizations

This is the main Options (F7) dialog at the left. I cover each of the right-pointing pop-out arrows so you can see what the choices are. This is the "Select Input" one. Whatever ExtIo files you've got in place will show up to replace the Realtek I've got here. This is normally what you should select. You can also open a wav file that's not just sound but the entire saved spectrum, or a sound card if you've got a downconverter converting an IF to the sound card's range. Only 16 bit drivers show up here on XP Pro, so that's possibly all there are. The Input Mixer is the standard Windows mixer, input devices panel.

On the right are the choices under visualization. The top 3 have more details below. The rest are simple options for the display and not hard to figure out. Notice I have "Swap Spectrum/Waterfall Position" turned on here. I'd like to be able to turn off the audio spectrum and waterfall, but unchecking "Show Lower Display" turns off more than that. Mainly the slider for zooming the RF spectrum, which is hard to live without.

FFT Windowing Color Palette Waterfall Timestamp
FFT Windowing Color palettes timestamp options

Left to right: FFT Windowing You can play with this, but unless you're into higher math the names probably won't mean much to you. FFT is Fast Fourier Transform or the way time domain signals get transformed into frequency domain spectra like at the top. Some people may have strong preferences here, I don't see a lot of difference.

Color Palette Different signal strengths get mapped to different colors, and the palette controls what level gets mapped to what color. You can live with any of them, so play around. It's mostly just an aesthetic choice.

Waterfall Timestamp I'd never seen these before and didn't particularly like them, so I turned them off. Since they're at irregular intervals anyway I found them distracting. There's no control over the interval, but if you could set it to maybe 5 or 10 seconds that would be good. I found myself trying to figure out why they're spaced the way they are. As I said, a distraction. You can put them on the left or right sides of the waterfalls.

Input Channel Mode for RX Output Channel Mode for RX Input Channel Calibration for RX
channel mode for RX Output channel mode for RX input channel calibration for RX

Input Channel mode for RX If you're using a sound card for input you should think about this box. I'm using a dongle that puts out I/Q signals so there's only one choice that really applies.

If you have a sound card, it's possible when using mono (not stereo) to have the two channels doing unrelated things. In transmitting for instance it's common to have one channel feeding audio to the transmitter and the other carrying a tone that keys the transmitter.

Output Channel mode for RX Similar to above, this controls what the channels are doing on the output (HDSDR output) side. It might be possible to have HDSDR sending raw audio out the left channel, and Dream listening on that channel and sending converted audio out the right channel.

You get into a need for a patch panel if things are very complicated, and adding Virtual Audio Cable may or may not help.

Input Channel Calibration for RX Read the text in the box. I did it by tuning to my upconverter's oscillator frequency (125 MHz) then tuning to mimimize the image signal at 124.980 while the LO was set to 124.990. I think it helped. I don't know about the adjustments across the top of the box.

Swap I and Q Channel for RX Input. Another one to not touch unless you know what you're doing. There's no dialog box to show, a check mark appears next to it when they're swapped, I didn't leave it that way long, but it was a little like being in the wrong sideband. I could hear everything but couldn't quite tune anything in so it was understandable.

Options(F7) -> Misc Options
Misc. Options

Misc Options: A list of things, most of which don't have their own dialog boxes to show here.

If this is turned on, HDSDR will automatically start when opened, without clicking the start button. I don't know if it's necessary to turn this on when doing scheduled recordings or not, but it probably wouldn't hurt.

For some reason when I use autostart it doesn't start at the same frequency it was on before, but that probably depends on how it was shut down.
set LO <-> Tune Offset
Offset When you do Quicktune, etc. by typing a frequency out of the blue then clicking the MHz button, this is how far offset the LO is from the frequency you typed in. I wondered where this number came from.
Tune Fixed to 'LO <;-> Tune Offset'
This effectively binds the LO frequency and the tune frequency together, with the offset above between them. When you change one the other changes too. It sounds like a good thing but it can be a little slow waiting for the PLL to lock each time. You usually don't need to move the LO. Turn it on if you're letting a newbie play around rather than explaining.
S-Meter calibration
s-meter It seems a little dangerous to have the S-meter calibration in the same place as setting the squelch level, but notice that this item has a check mark on it. I think it only affects readings while the check mark is on, with no permanent effect. I don't have a calibrated RF source so I didn't try it.

It effectively turns HDSDR into a field strength meter. In theory you could use this for comparing antennas, preamps, coax runs, etc.
Lock Volume
I can see why you'd want to lock the volume but with my computer and dongle this doesn't seem to do anything other than a visual cue. You might well want to lock the volume if you're feeding audio into another program.
Show Time in UTC
This does what you'd expect, and does put a "UTC" on the screen after the date and time to remind you.
Normal Process Priority (default)
High Process Priority
Something else not to mess with. I can't quite imagine what would be important enough to do this for, unless maybe if you've got marginal CPU power and you're decoding something to play over a PA system in a stadium and you're worried about getting skips in it. Windows can get downright sluggish and unresponsive running something at a high process priority. Usually patience is a better alternative.
Show Status
Statue I suppose it's worth knowing what's normal here for your system then looking here if it acts up. Nothing you can change here anyway except locking your downsampler ratio.
Reset to Factory Settings
The panic button. In any piece of software this complex there are bound to be times where something gets messed up and you maybe lose control. You just want to reset. But resets often reset more than you want, so just to get a feel for what it does try it early on before you get a lot customized. I've never used it here, but I know the one in Fldigi takes a few minutes of going through settings afterward.
These are options for wheel mice. I don't like wheel mice: I consider them to be a Microsft invention so I don't trust them, and they seem like they would cause repetitive strain disorder if you use them very much. I'd much rather have a real 3-button mouse. But mostly I only run Windows on a laptop which doesn't have a wheel mouse anyway.

Each little step in the rotation moves the frequency by the amount in "step" here. For fine tuning, Ctrl-up/down arrow does the same thing. Ctrl-left/right arrow does a "quick tune", moving both the tune and LO frequencies.

In a crowded band I hold down the right Ctrl key with my right index finger, then hold down the up or down arrows with the other fingers on my right hand. This is my contrived equivalent of turning a tuning knob.
Mouse Wheel
Wheel mouse
CAT to Radio (Omni-Rig) CAT to HDSDR DDE Client
cat to radio cat to hdsdr DDE

CAT to Radio (Omni-Rig) I'd never heard of Omni-Rig before HDSDR, but it seems less fully developed than Hamlib. There is an ExtIO_HamLib.dll available on the HDSDR site. It seems to let HDSDR control an external radio, but since my radio isn't SDR it doesn't do me much good. It looks like it might work well with Softrocks, and there are some Flexradio and other SDR hardware known to Hamlib.

I don't have either Omni-Rig or DDE configured, so I didn't try these.

CAT to HDSDR These are the settings for using Omni-Rig to control HDSDR and your sdr hardware. To Omni-Rig your computer would look like an another radio.

Having the same capability for having Hamlib control HDSDR could be quite interesting, given the variety of SDR hardware that HDSDR can control. Hamlib has no real user interface, but it can be driven by Fldigi and Gpredict among others. There are also beginnings of control over a TCP/IP connection in both Hamlib and Fldigi.

DDE Client Since DDE is another Microsoft invention, I'd prefer to not know much about it. It doesn't talk to Fldigi, Wx2img, or Gpredict but some of this looks useful if you use these programs.

Old but true: "The nice thing about standards is that there are so many to choose from." This won't control any software I use, and I'm not going to switch to suit it.

RF Front-End + Calibration
RF Front end

RF Front-End + Calibration
A very useful looking box, but I don't have experience with most of it because of my SDR hardware. I have an upconverter for my dongle, so I use "SDR hardware on Down/Up-Converter LO Frequency of Down/Up-Converter". There's a 125 MHz oscillator, so I plug 125000000 in here.

I tried to use the LO frequency calibration on the right, but ended up doing it this way: Tune to 15 or 20 MHz WWV, zoom up the size of the peak then bring up the ExtIo dialog and adjust the ppm value while watching where the peak is relative to the calibration mark. I wish I could get a WWV at 1 GHz. :)

Recording Settings/Scheduler

Recording Settings/Scheduler
This box makes all kinds of things possible. You can schedule recording satellite passes, nets, anything you might otherwise miss. If the recording mode is set to RF, a giant wav file will contain everything within the covered RF spectrum range, which you can decode later. Most of us will check the AF box and be satisfied. Watch your hard drive space.

I only tried this once and a question just occurred to me: Does HDSDR even need to be open, or are these events queued up for Windows Scheduled Tasks to handle by calling HDSDR? I assume it won't boot up the computer to run them, but such things are possible.

Not covered:
Both occurences of the words waterfall and spectrum do something when you click on them, it's not clear to me just what.

In the spectrum display there are 2 vertical lines shown. The left is the tune frequency. The right one, with the frequency and db value attached, moves with your mouse. If you click the tune frequency moves there.

It has been a pleasure to write this. It's been a long voyage of discovery and appreciation. As a modest programmer myself I can appreciate the hundreds of hours that went into writing it and ideas for features that possibly have come from dozens of people using and testing it.

It is, in a word, majestic. It's the Total Commander of SDR programs. Fine German programming again.

My main wish is that I didn't have to spend time in Windows to use it. I might also wish it were open source like Fldigi which has been developed concurrently under multiple operating systems.

ab1jx / toys