DSDPlus

[br0adband]

Two questions:

- what OS are you using
- what laptop are you using (actual brand/model number)

It's possible - I'm saying it might be possible that you have a laptop where the "mic" input can do double duty as a true line-level input. My Dell Latitude E6400 allows for that behavior (helped someone earlier in the thread figure theirs out but it was different from mine, which uses what's called an IDT sound chip).

The basic gist of the signal pathway is this:

For DSD+ to typically work, with defaults, it will "attach" itself to whatever device is considered to be the Recording device in your system, that could be the mic input, it could be the Stereo Mix aka "What You Hear" or something else. The input for DSD+ is the audio coming from that default Recording device (should be baseband audio aka from a discriminator tap or data stream as some scanners can provide now), decodes it for potential content, and if there's audio/voice traffic it'll then output that audio/voice content to whatever the default Playback device is in your system.

I know it sounds easy (no pun intended), and it is when you look at it from the signal pathway perspective. A lot of people get hung up on the mixers in Windows (Playback and Recording) which each have a variety of devices they can attach to at any given time (which is where most problems come from). That's why DSD+ rocks so much in the respect that if you have some oddball audio setup that doesn't work automagically just by running DSD+ and letting it work, you can "force" particular inputs and outputs so DSD+ itself pulls and pushes the audio from where and to where you want it to go so that it actually does its job correctly.

And as Mike stated, as far as the receiver/scanner is concerned, especially an AOR device, it's only going to tune one frequency at a time basically (unless it's a high end model with dual VFOs or something), so once you're "tapped" there's zero reason to keep the audio volume up on that - you get sick of control channel or digital modes really fast when you listen to them too much.

 

[highmaster2]

Win7 Pro 64 bit

Clevo W150HRM

It has the Realtek HD Audio, but I don't know what chip...

OK. I think I'm getting closer. Finally dawned on me that the Mic input I was using was probably the internal. DOH! Switched to rear panel Mic input and I started getting this in DSD+:

C:\DSDPlus>dsd.exe -fr -i3M

DSDPlus Rev 1.023
Decoding only DMR/MotoTRBO
Appending synthesized audio to file 'DSDPlus.wav'

audio input device #1 = 'Microphone (Realtek High Defini'
audio input device #2 = 'Stereo Mix (Realtek High Defini'
audio input device #3 = 'Mic in at rear panel (black) (R'

audio output device #1 = 'Speakers (Realtek High Definiti'
audio output device #2 = 'Realtek Digital Output (Realtek'

audio input device #3 (Mic in at rear panel (black) (R) initialized
audio output device #1 (Speakers (Realtek High Definiti) initialized

Mono audio decoding initiated; press Esc to exit...
Sync:+DMR
+DMR slot1 BS DATA ERR3 CC=3 VOICE Header
Sync:+DMR
+DMR slot1 BS DATA ERR2 CC=1 Idle
Sync:+DMR
+DMR CACH ERR slot1 BS DATA CC=1 Idle
Sync:+DMR
+DMR slot2 BS DATA ERR3 CC=11 Idle
+DMR CACH ERR slot1 BS DATA ERR3 CC=1 Idle
Sync:+DMR
+DMR CACH ERR slot1 BS DATA ERR3 CC=7 Idle
+DMR slot2 BS DATA ERR2 CC=1 Idle
Sync:+DMR
+DMR CACH ERR slot1 BS DATA ERR2 CC=1 Idle
Sync:+DMR
+DMR CACH ERR slot1 BS DATA ERR2 CC=1 Idle
Sync:+DMR
+DMR CACH ERR slot1 BS DATA ERR3 CC=1 MBC
+DMR CACH ERR slot2 BS DATA ERR3 CC=1 Idle
Sync:+DMR
+DMR CACH ERR slot1 BS DATA ERR3 CC=9 Unknown TypeF
+DMR slot1 BS DATA ERR3 CC=0 Unknown TypeB
Sync:+DMR
+DMR CACH ERR slot1 BS DATA ERR2 CC=1 Idle
Sync:+DMR
+DMR CACH ERR slot1 BS DATA ERR1 CC=1 Idle
+DMR CACH ERR slot2 BS DATA ERR3 CC=8 PI Header
+DMR CACH ERR slot1 BS DATA ERR3 CC=5 Rate 3/4 Data
+DMR CACH ERR slot2 BS DATA ERR3 CC=1 Idle
+DMR CACH ERR slot1 BS DATA ERR1 CC=1 Idle
+DMR CACH ERR slot2 BS DATA ERR3 CC=12 PI Header
+DMR slot2 BS DATA ERR3 CC=2 PI Header
+DMR CACH ERR slot1 BS DATA ERR2 CC=1 Idle
+DMR CACH ERR slot2 BS DATA ERR3 CC=1 Idle
Sync:+DMR
+DMR slot2 BS DATA ERR3 CC=0 PI Header
+DMR slot1 BS DATA ERR1 CC=1 Idle
+DMR CACH ERR slot2 BS DATA ERR3 CC=1 Idle
+DMR CACH ERR slot1 BS DATA ERR3 CC=9 Idle
+DMR CACH ERR slot2 BS DATA ERR3 CC=9 Rate 3/4 Data
+DMR CACH ERR slot1 BS DATA ERR2 CC=1 Idle
+DMR CACH ERR slot2 BS DATA ERR1 CC=1 Idle
+DMR CACH ERR slot1 BS DATA ERR3 CC=1 Idle
+DMR CACH ERR slot2 BS DATA ERR3 CC=1 Idle
Sync:+DMR
+DMR slot2 BS DATA ERR3 CC=1 Idle
+DMR CACH ERR slot1 BS DATA ERR2 CC=1 Idle
+DMR CACH ERR slot2 BS DATA ERR3 CC=6 TLC
Sync:+DMR
+DMR CACH ERR slot1 BS DATA ERR1 CC=1 Idle
Sync:+DMR
+DMR CACH ERR slot1 BS DATA ERR3 CC=6 Idle
+DMR CACH ERR slot2 BS DATA ERR3 CC=5 TLC
+DMR CACH ERR slot1 BS DATA ERR3 CC=1 Idle
+DMR CACH ERR slot2 BS DATA ERR3 CC=8 Rate 3/4 Data
+DMR CACH ERR slot1 BS DATA ERR3 CC=1 Idle
Sync:+DMR
+DMR CACH ERR slot1 BS DATA ERR3 CC=14 Idle
+DMR CACH ERR slot2 BS DATA ERR3 CC=13 TLC
Sync:+DMR
+DMR slot2 BS DATA ERR3 CC=9 CSBK
Sync:+DMR
+DMR CACH ERR slot1 BS DATA ERR3 CC=1 Idle
Sync:+DMR
+DMR CACH ERR slot1 BS DATA ERR1 CC=1 Idle
+DMR slot1 BS DATA ERR3 CC=0 Rate 1 Data
+DMR CACH ERR slot2 BS DATA CC=1 Idle
Sync:+DMR
+DMR slot2 BS DATA ERR3 CC=5 PI Header
Sync:+DMR
+DMR CACH ERR slot1 BS DATA ERR2 CC=1 Idle
Sync:+DMR
+DMR CACH ERR slot1 BS DATA ERR2 CC=4 Rate 3/4 Data
+DMR slot1 BS DATA ERR3 CC=5 VOICE Header
+DMR slot2 BS DATA ERR2 CC=1 Idle
Sync:+DMR
+DMR slot2 BS DATA ERR2 CC=5 Unknown TypeD
+DMR CACH ERR slot1 BS DATA ERR2 CC=1 Idle
Sync:+DMR
+DMR CACH ERR slot1 BS DATA ERR3 CC=5 Unknown TypeD
Sync:+DMR
+DMR CACH ERR slot1 BS DATA ERR2 CC=1 Idle
+DMR slot2 BS DATA ERR2 CC=1 Idle
Sync:+DMR
+DMR CACH ERR slot1 BS DATA ERR3 CC=4 Unknown TypeD
Sync:+DMR
+DMR slot2 BS DATA ERR2 CC=1 Idle
Sync:+DMR
+DMR slot1 BS DATA ERR3 CC=1 Idle
+DMR slot2 BS DATA ERR3 CC=8 Rate 3/4 Data
Sync:+DMR
+DMR CACH ERR slot1 BS DATA ERR3 CC=8 Rate 1 Data
Sync:+DMR
Sync:+DMR
+DMR slot1 BS DATA ERR3 CC=1 Idle
Sync:+DMR
+DMR slot2 BS DATA ERR3 CC=1 PI Header
Sync:+DMR
+DMR CACH ERR slot1 BS DATA ERR3 CC=1 Idle
+DMR CACH ERR slot2 BS DATA ERR3 CC=1 PI Header
Sync:+DMR
+DMR CACH ERR slot1 BS DATA ERR3 CC=1 PI Header
+DMR slot2 BS DATA ERR3 CC=0 VOICE Header
+DMR CACH ERR slot1 BS DATA ERR3 CC=13 Unknown TypeE
Sync:+DMR
+DMR CACH ERR slot1 BS DATA ERR3 CC=1 Idle
Sync: no sync

It goes on and on, but so far no voice. Speakers are active - I can hear the Ding when I change volume.

 

[highmaster2]

Also getting this from DMR Decoder:

2:43:18 PM Bad Short LC !
2:43:18 PM DMR Embedded Frame - Error !
CACH : TACT Ch 1 First fragment of LC
2:43:18 PM DMR Data Frame - Error !
CACH : TACT AT=1 Ch 2 Continuation fragment of LC
2:43:18 PM DMR Embedded Frame - Error !
CACH : TACT Ch 1 Continuation fragment of LC
2:43:18 PM DMR Data Frame - Error !
CACH : TACT AT=1 Ch 2 Last fragment of LC
2:43:18 PM Bad Short LC !
2:43:18 PM DMR Voice Frame with Embedded Signalling
CACH : TACT Ch 1 First fragment of LC
EMB : Colour Code 1 : Continuation fragment of LC
2:43:18 PM DMR Data Frame - Error !
CACH : TACT AT=1 Ch 2 Continuation fragment of LC
2:43:18 PM DMR Embedded Frame - Error !
2:43:18 PM DMR Data Frame - Error !
CACH : TACT AT=1 Ch 2 Last fragment of LC
2:43:18 PM DMR Embedded Frame - Error !
CACH : TACT Ch 1 First fragment of LC
2:43:18 PM DMR Data Frame - Error !
CACH : TACT AT=1 Ch 2 Continuation fragment of LC

Not sure what it means, but it doesn't look good - lots of errors...

 

[highmaster2]

Now hearing just bits of voice - not even whole words - every now and then

 

[highmaster2]

Changed Invert setting - now getting this from DSDDecoder:

2:57:09 PM DMR Voice Frame (BS)
CACH : TACT AT=1 Ch 1 First fragment of LC
2:57:09 PM DMR Voice Frame (BS)
CACH : TACT AT=1 Ch 2 Last fragment of LC
2:57:09 PM DMR Voice Frame (BS)
CACH : TACT AT=1 Ch 1 First fragment of CSBK
2:57:09 PM DMR Voice Frame (BS)
CACH : TACT AT=1 Ch 2 First fragment of CSBK
2:57:09 PM DMR Voice Frame (BS)
CACH : TACT AT=1 Ch 1 First fragment of LC
2:57:09 PM DMR Voice Frame (BS)
CACH : TACT AT=1 Ch 2 Last fragment of LC
2:57:09 PM DMR Voice Frame (BS)
CACH : TACT AT=1 Ch 1 First fragment of CSBK
2:57:09 PM DMR Voice Frame (BS)
CACH : TACT AT=1 Ch 2 First fragment of CSBK
2:57:09 PM DMR Voice Frame (BS)
CACH : TACT AT=1 Ch 1 First fragment of LC
2:57:09 PM DMR Embedded Frame - Error !
2:57:14 PM DMR Voice Frame - Error !
2:57:14 PM DMR Embedded Frame - Error !
2:57:14 PM DMR Voice Frame (BS)
CACH : TACT AT=1 Ch 1 First fragment of LC
2:57:14 PM DMR Voice Frame (BS)
CACH : TACT AT=1 Ch 2 Last fragment of LC
2:57:14 PM DMR Embedded Frame - Error !
CACH : TACT AT=1 Ch 1 First fragment of CSBK
2:57:14 PM DMR Voice Frame (BS)
CACH : TACT AT=1 Ch 2 First fragment of CSBK
2:57:14 PM DMR Voice Frame (BS)
CACH : TACT AT=1 Ch 1 First fragment of LC
2:57:14 PM DMR Voice Frame (BS)
CACH : TACT AT=1 Ch 2 Last fragment of LC
2:57:14 PM DMR Voice Frame (BS)
CACH : TACT Ch 1 First fragment of CSBK

Still just bits of voice.

 

[br0adband]

Well it's working, now you need to adjust the mic input levels so they're not distorting to Hell and back again before they get to DSD+ - if it gets distortion, it's just going to get nothing but errors. A good place to start, because mic inputs are incredibly sensitive to levels, unlike line-level which is obviously a solid static signal (in terms of voltage), is around 20% on the slider, then do some decoding tests, etc.

DSD+ has a ton of potential in terms of tuning for a given system's particular idiosyncrasies and it's very capable but but but... you should focus on getting a good clean undistorted signal to it before you even start mucking around with the tuning features and dsdtune (another great program that helps some people considerably). It's also entirely possibly you're in a bad area and getting horrid reception as well so, there's a lot to try and cover.

With respect to DSD+, what you see on the screen scrolling by is not as important or relevant as the audio you're getting and by that I mean sure, the data is relevant to some degree but even with a lot of errors at any given time DSD+ has proven itself - purely with the defaults - to be quite capable of still decoding even low quality and error-prone signals so, again, make sure you're getting a good signal to it first. That means making sure the receiver is getting a good signal by signal strength, that you're dead-on with the frequency, and then probably most importantly that you get the mic input level correct.

I wouldn't bother running all sorts of funky command line switches with DSD+ to get started, I'd say just run DSD+ itself (like dsd.exe or dsdplus.exe or whatever you're got the executable named) and see how well it works with the defaults. Do all the necessary checks and one more time check the audio input level with the mic input (do a recording of it if necessary and play it back, if it's distorting or crazy high on the meters - like over 80% - it's probably distorting like mad and DSD+ is having fits with it.

Once it's solid and working better, then there's the other tuning you can do but I wouldn't suggest getting into that side of things just yet.

As Mike noted above, DMR/MOTOTRBO monitoring is usually a great idea alongside DMRDecode so you can see more info about what's going on, the groups, color codes (which DSD+ tells you as well).

Basically after everything I've said in this post and others, here's the best advice I can give you at this moment:

Don't allow yourself to get "drowned out" by all the data as represented visually in the command prompt window as it scrolls on by, nor the data that DMRDecode can and does provide - what matters most is being able to listen to it and as long as that's possible you're already ahead of the game.

Also: DMRDecode is just a data decoder, not an audio one but I think you get that by now. DSD+ provides the decoded audio so, get that working first or at least focus on getting that working, then fuss with DMRDecode if needed.

Last tip: Look for other DMR/MOTOTRBO activity in your area if you can find it. That's one thing that makes SDR so damned appealing right now - you can SEE what's going on and learn to spot what's what in the blink of an eye and not just sit there scanning randomly around the dial, so to speak, hoping to hit on something useful or actually useful.

 

[W4UVV]

Here's my Win 7 desktop excellent DSD Plus Configuration

Now hearing just bits of voice - not even whole words - every now and then

DSD PLUS installed in the C Root Directory (MS DOS).. Made a directory (folder) called "DSD PLUS". Changed to "DSD PLUS" and copied all DSD Plus related software to this directory. Although DSD "dsd.exe" is in a separate directory so as not to confuse with my "DSD PLUS" software I renamed DSD PLUS "dsd.exe" to "dsdplus.exe". Strong signal inputs are provided to my ICOM R7000. My modified ICOM R7000 with a 15,000 ohm in line audio out cable inputted to LINE INPUT (Although MIC can be used it is not recommended), Mono input AUDIO GAIN levels set to 7%. I FOUND THE INPUT AUDIO LEVELS SETTINGS TO BE EXTREMELY IMPORTANT IN ACHIEVING OPTIMUM DMR AUDIO DECODING. I can hear DMR signals with different level settings but 7% input gain setting is optimum for MOTOTRBO, NXDN and P25 Phase 1). Output audio inputted to audio amp with adjustable audio controls including tremble/bass.

I also have modified my XP desktops and XP laptops to work but because of the slower sound card sampling rate the audio is inferior to the Windows 7 HD audio which samples at 48,000 cps.

Hope this helps.

John
W4UVV

 

[br0adband]

The reason the audio levels are so important is because people are using - and sometimes they don't have any choice in the matter, like most laptop owners - the mic input for the discriminator taps and it causes issues. Here's why:

Line-level inputs use a constant voltage level hence the name, "line level" - it's a solid relatively unchanging voltage level and makes things a bit more standardized in terms of audio interconnects. It's been around for a long time, and some old timers might remember it being referred to as "RCA inputs" because those type of connectors were traditionally used to connect something to either a line-in or line-out.

Now, the basic reason for why the levels matter so much with mic inputs is because line-level is typically 1V solid, with almost no variation across the hundreds if not thousands of thousands of devices with such inputs and outputs. Mic level, on the other hand, typically has a voltage in the microvolt range, thousands of times less. When you attach a mic, the mic itself will produce an incredibly small amount of voltage itself, and a mic input is expecting that very small amount of voltage.

When you feed a mic input something as "intense" (I just can't think of another word, duh) as a discriminator tap, it's like someone asking for a sip of water and you point a fire hose at their mouth and open the valve - it's just too much input hence needing to adjust the mic level input down very very low or else (as I mentioned in a post above) the signal distorts like crazy as the mic input is trying to cope with having such a high level signal jammed down its throat, figuratively speaking.

If you have the option to use a line-level input for a discriminator tap, do it and don't think twice about it. Also as noted above, some laptops will have an audio chip onboard that - when you install the full drivers and software - will allow you to alter the functionality of the "mic" input jack so it can accommodate a line-level input. Sometimes it'll do so automagically, other times you have to go into the sound options and manually change the mic input to line input. I don't know if that's possible with highmaster2's laptop, I'll check on that aspect here in a bit, but it might and if it does that will make a huge difference in things with DSD+.

Regardless, once you feed a discriminator tap signal into a mic input, make sure you start with the mic levels on the Recording mixer at a very very low setting, say no more than 20% to get started and adjust as required.

 

[W4UVV]

You are correct. Matching audio input levels to laptops are a different matter. At first I had a issue with the Win 7 desktop audio line input level. 10,000 ohms audio matching was recommended but it did not work for me. Going to 15,000 made the difference between working and not working. Finding the right match for laptops usually is an exercise in frustration.

John

 

[br0adband]

For those saddled with mic inputs and discriminator taps, here's a solution...

Well, folks, I have the solution that will make a rather dramatic difference for you IF - yes that's a big IF there, on purpose - you are one of those unfortunate souls forced to use a mic input for your discriminator taps. We SDR folk are beyond such problems nowadays, thankfully, but there's a pro and a con in that respect: the pro is we can do quite a bit of things with SDR that regular scanners and even communications receivers dedicated to such tasks can't do, and the con is you end up having to have a whole computer just to make use of it.

Anyway, here's the solution:

6.5-Ft. Attenuating Dubbing Cord with 1/8 Phone Plugs : Dubbing Cords | RadioShack.com

Please make sure you understand that is NOT just a regular old 1/8" mono to 1/8" mono patch or dubbing cord - might seem like it at first glance but there's much more to it. Being mono is fine since we're just working with the discriminator tap signal which just has two leads anyway, signal high and ground.

I just remembered those as I used one many many years ago (too many years, I think) when all I had access to was a cassette recorder from the good old days of audio recording and it was only capable of mic input. Feeding it a line input signal of course destroyed and distorted what I was actually trying to record in the first place because of the horribly mismatched signal levels/voltages as explained in my post(s) above.

This cable, or a similar one I suppose from another seller (shouldn't matter as long as it's an attenuating audio cable, it should work the same), allows you to use mic level inputs aka what so many of you are stuck with sans a line input with "high" level signals like line level or even headphone/speaker outputs such as those that we also deal with using scanners and receivers.

tl;dr version: this cable takes the "very loud high voltage" line output or discriminator tap signal from one end of the cable and reduces it so that by the time it gets to the other end it's hundreds of times lower in strength - basically it makes high voltage level signals into low voltage ones so the mic input can be used with far FAR more success in terms of our purposes with discriminator taps.

I promise if you get one and you're stuck with a mic input, this will pretty much be like a whole new world in terms of being able to make full use of that discriminator tap, seriously.

They're $.97 - that's ninety seven cents for Pete's sake, so grab a few so you're covered on all fronts... for a laptop computer owner slash scanner enthusiast hoping/wishing to make use of discriminator taps, this is simply a must have item.

Note: you may need to get yourself an inline 1/8" jack - splicing this cable is not recommended because you can't be 100% sure which end or plug the actual attenuator circuitry (basically just a resistor inline, iirc) is incorporated into. It's barely a buck in cost for the cable, and yes I suppose it's entirely possible to find a schematic and make a homebrew version too but, it's a buck, come on, don't be such a cheapskate.

 

[Boatanchor]

^^^^^ This ^^^^^^ - Good suggestion

 

[cobraDIHO]

How strong is the particular DMR signal you're trying to decode, highmaster?

 

[mancow]

Can you ohm out the cable and tell us what the resistance is please?

 

[br0adband]

Can you ohm out the cable and tell us what the resistance is please?

Unfortunately I don't have a multimeter, never really saw the need for one - I'm just a casual electronics geek for the most part.

Having said that, I did find a homebrew schematic that is probably the same thing for the most part and should be able to function the same way:

http://wa8lmf.net/miscinfo/Universal-Sound-Card-Cable.pdf

Pretty simple thing to construct I suppose, hope that helps.

 

[mancow]

I assumed it was a single resistor, thanks for the link.

 

[mtindor]

Changed Invert setting - now getting this from DSDDecoder:

2:57:09 PM DMR Voice Frame (BS)
CACH : TACT AT=1 Ch 1 First fragment of LC
2:57:09 PM DMR Voice Frame (BS)
CACH : TACT AT=1 Ch 2 Last fragment of LC
2:57:09 PM DMR Voice Frame (BS)
CACH : TACT AT=1 Ch 1 First fragment of CSBK
2:57:09 PM DMR Voice Frame (BS)
CACH : TACT AT=1 Ch 2 First fragment of CSBK
2:57:09 PM DMR Voice Frame (BS)
CACH : TACT AT=1 Ch 1 First fragment of LC
2:57:09 PM DMR Voice Frame (BS)
CACH : TACT AT=1 Ch 2 Last fragment of LC
2:57:09 PM DMR Voice Frame (BS)
CACH : TACT AT=1 Ch 1 First fragment of CSBK
2:57:09 PM DMR Voice Frame (BS)
CACH : TACT AT=1 Ch 2 First fragment of CSBK
2:57:09 PM DMR Voice Frame (BS)
CACH : TACT AT=1 Ch 1 First fragment of LC
2:57:09 PM DMR Embedded Frame - Error !
2:57:14 PM DMR Voice Frame - Error !
2:57:14 PM DMR Embedded Frame - Error !
2:57:14 PM DMR Voice Frame (BS)
CACH : TACT AT=1 Ch 1 First fragment of LC
2:57:14 PM DMR Voice Frame (BS)
CACH : TACT AT=1 Ch 2 Last fragment of LC
2:57:14 PM DMR Embedded Frame - Error !
CACH : TACT AT=1 Ch 1 First fragment of CSBK
2:57:14 PM DMR Voice Frame (BS)
CACH : TACT AT=1 Ch 2 First fragment of CSBK
2:57:14 PM DMR Voice Frame (BS)
CACH : TACT AT=1 Ch 1 First fragment of LC
2:57:14 PM DMR Voice Frame (BS)
CACH : TACT AT=1 Ch 2 Last fragment of LC
2:57:14 PM DMR Voice Frame (BS)
CACH : TACT Ch 1 First fragment of CSBK

Still just bits of voice.

Whatever inversion setting you had for this one, switch back to the previous. All voice frames in DMRDecode is usually an indication that you need to switch invertedness. Sure, there could be a lot of voice on it, but when you try to decode voice and voice frames are all you see, you need to invert [or revert your previous invert heh].

Of course, that doesn't have anything to do with audio in DSD+. Others have instructed you pretty well with regard to ensuring that the audio level is suitable.

Mike

 

[SCPD]

While you're playing around with different cables - it is nice to actually see the waveform. Run an oscilloscope program.

Soundcard Scope

If you happen to have Unitrunker installed, you've already got a 'scope program.

Audio Recording Level Adjustment

 

[highmaster2]

How strong is the particular DMR signal you're trying to decode, highmaster?

They are using the same freq/site they used on analog. On analog they were 5/9. With the DMR they are showing full scale on the meter on the AR8200.

 

[highmaster2]

More on Attenuating Cable

Had already wondered about that.... I actually have one somewhere - probably quicker to get another on from the Shack than to try and find it. I am currently using 15k ohms of attenuation. Probably really need at least 100k. Also, in the reviews on the Shack website is the following schematic for a stereo version.

 

[Boatanchor]

Had already wondered about that.... I actually have one somewhere - probably quicker to get another on from the Shack than to try and find it. I am currently using 15k ohms of attenuation. Probably really need at least 100k. Also, in the reviews on the Shack website is the following schematic for a stereo version.

One thing to be aware of if using that cable..

One end (stereo plug) will have a 100Ohm path to ground, the other end will show a 100kohm path to ground.

If you have a 10kohm resistor fitted to your disc tap, it may not make any difference which way around you plug the lead in, but you may find that the 100 Ohm end loads the scanner's disc circuit down somewhat. It's probably best to use the 100 kohm (high impedance) end for the scanner.
Trouble is unless you have a multimeter, you wont know which end is which