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KD8IIS
11-13-2008, 05:31 PM
Does anyone have any plans for a homebrew interface. I only run the sound from my earphone jack to my PC soundcard. So it only needs to be for CW sound alone. I do not use rtty or PSK.

K3WRV
11-13-2008, 07:24 PM
First tell us about your radio. On my rigs (tentec and Collins) I've never used one (except back in the HamCom days). I just run from the xcvr "goes outta" on th rig into the sound card "goesinta" on the sound card and vice versa. And I just use VOX to handle the switching.

Depending on your rig, you may need a keying transistor if you want to transmit. A google for "HamCom interface" should give you an idea (it you're still using RS-232 ports and what your softeware wants for an input. These days, most of us just use the soundcard and the mixer settings. HamCom interfaces are pretty obsolete (except they still work pretty well)

cAN YOU GIVE US MORE SPECIFICS (sri - capslok) on what you need to do? Some interfaces handle switching, most try to get RF out of your transmitted signal. A simple audio cable should work well for receive (Thst's what I have here). With modern programs, mixer levels can be an issue. Hope this helps, but probably not. But what's wrong with what you have? Over driving the sound card creates lots of problems.

de Bob

K7MH
11-13-2008, 07:54 PM
Does anyone have any plans for a homebrew interface. I only run the sound from my earphone jack to my PC soundcard. So it only needs to be for CW sound alone. I do not use rtty or PSK.

The interface isn't going to be "mode specific" or easier to make for one mode than 20 modes. That would be a software issue.
You should be able to Google up a lot of articles.
Using software for copying CW is only going to yield fair at best copy.

KI4NGN
11-13-2008, 09:06 PM
cAN YOU GIVE US MORE SPECIFICS (sri - capslok) on what you need to do?

Laughing! Couldn't you have just backspaced??

Mike

PD7MAA
11-13-2008, 09:13 PM
Does anyone have any plans for a homebrew interface. I only run the sound from my earphone jack to my PC soundcard. So it only needs to be for CW sound alone. I do not use rtty or PSK.

This will work.

Transformer is 800-1200 Ohms 1:1

2 taperecorder or casettplayer heads mounted face to face will work also HI.


73s John

KE7VUX
11-13-2008, 09:22 PM
First tell us about your radio. On my rigs (tentec and Collins) I've never used one (except back in the HamCom days). I just use VOX to handle the switching.


Since I also have a TT rig..

I currently have an audio cable from the back of the 586 over to the input on my sound card, and that works fine for receive (and as someone else mentions, the CW copy is marginal - I thought I had the wrong mode or something until my elmer stopped by and copied some code for a bit and we checked it against the computer and found it was copying 1/2 to 2/3 of the code most of the time)

Anyhow.. I just wanted to confirm, that you're just running the PC audio-out to the VOX input on the back of the rig, and running VOX mode - no need to implement a PTT device? That seems so simple and easy.. no wonder I didn't think of it before.

That's good news, if so.

(Now if I could find the source of the "clicking" when I use the RS232 CV-I)

K3WRV
11-13-2008, 10:57 PM
I jusr run the aux audio out (on the back of the rig) to the input on the sound card, and the line or spkr out from the sound card to the aux audio in (or phone patch in) on the back of the rig. I have the rig set for VOX, so the sound card audio will key it, and have my mike set to PTT (which disables the MIC element unless I key the mic). Cables are cheap audio shielded cables from CellFo Shak - 12 foot long cut in half with 1/8 inch mini phone plugs soldered on the cut ends.

In other words, the PTT handles the mic audio, and everything else is done with the VOX (meaning the computer audio and the mic audio once I push the PTT).

I get no RF in the audio, but if you do, try PD7MAA's approach - CellFo Shak sells 1:1 transformers for aboutr $2.00 each.

I use this for PSK, RTTY snd SSTV up to about 600 W output w/o problems. But a lot of guys feel much better spending $100 on a RigBlaster or something. But my setup may or may not work for you, and if you have problems it's time to try "Plan B". I don't have speakers connected to the Computer - they can introduce RF into the sound card. For PSK/RTTY, you don't need the mic, but we use voice on SSTV sometimes.

de Bob

KD8IIS
11-13-2008, 11:30 PM
my Yaesu FT-450 only has a speaker out in the back and an earphone jack in front. I use a nine pin For any software controlled apps. The sound does not go through the nine pin. I have a little monitor on the CW Skimmer i use to look at the cw in a big visual picture. Not only reads but it's easy to zero beat, and read weak signals by looking at it when i can't hear it very well. But it clips coming from the radio, and I want to make sure it doesn't cause any damage.

KD8IIS
11-13-2008, 11:49 PM
I'm going to try the transformer.

G4ILO
11-14-2008, 11:30 PM
Why the need for a transformer? I have been working data modes since the late 1990s and have never use other than a straight cable between the rig and the soundcard, with a resistive attenuator on the TX audio if necessary.

The one time I used a "proper" commercial interface that was fully isolated with transformers on the audio and an opto isolator on the PTT I had hum lines on the waterfall. The reason: The computer was an Eee PC laptop that was not grounded through its power supply so the shield on the computer side of the interface box was floating. The problem, after I figured out the cause of it, was soon cured by taking the thing to bits and defeating the isolation by soldering a wire linking the shields on both sides of the interface. Annoying, since the only reason I bought an interface in the first place was because I didn't want to spend the time making one...

KA1MDA
11-15-2008, 01:30 AM
"Why the need for a transformer"

You need a transformer (in most cases) to isolate ground loops. I have built a number of home-made interfaces, described at:

http://www.ka1mda.org/ham/homebrew/sound/index.htm

I have built both isolated and non-isolated interfaces, and, depending on what type of computer is used, there could be a ground loop issue. When I build interfaces now, I use isolation transformers for both TX and RX audio. I also include a ground-lift switch, which is used to make or break the common ground between the computer and radio. I have found using non-isolated interfaces with desktop computers results in hum. The situation appears to reverse itself for some laptops- using an isolated interface with my laptops results in hum, hence the need for the grounding switch.

I use opto isolators to key the radio from the computer to maintain isolation. If a simple switching transistor is used, the keying line common connection negates the isolation provided by the transformers.

Tom, KA1MDA
www.ka1mda.org

KQ6XA
11-06-2010, 01:34 AM
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CLICK HERE for INFORMATION about Homebrew Computer Radio Interface RS-232 C-IV Icom data modes:
Homebrew Computer Radio Interface RS-232 C-IV Icom Kenwood Yaesu and other transceivers soundcard data modes (http://hflink.com/interface)


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