General Digital Questions

Discussion in 'Working Different Modes' started by W7EMI, Mar 19, 2012.

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  1. W7EMI

    W7EMI Ham Member QRZ Page

    I recently got an Alinco DX-SR8 (HF only transciever [USB, LSB, CWU, CWL, AM, FM] with an 8-pin mic), and I was wondering how I'd be abl to send digital (PSK, RTTY, Packet) with it, as it doesn't have a radio to computer cable. Is there any possible way to feed signals from my sound card into the 8-pin mic jack? If so, how would I build a cable for this? Which program should I use?

  2. N6OIL

    N6OIL Premium Subscriber QRZ Page

    Make you life easy and get a Tigertronics SignaLink USB device with the right cable. DXEngineering has good prices on them.
  3. N6OIL

    N6OIL Premium Subscriber QRZ Page

    The cable you will need is the SLUSB8R
  4. G0GQK

    G0GQK Ham Member QRZ Page

    Or if you have an ACC1 socket on the rear of the rig, a DIN plug and cable can be connected to an optocoupler and then to your computer. May I suggest you do some googling and reading about PSK, I'll see if I can find some sites for you to go to
  5. G0GQK

    G0GQK Ham Member QRZ Page

  6. K7MEM

    K7MEM Ham Member QRZ Page

    Just about any transceiver capable of SSB can be used for PSK and RTTY. I use the DM780 portion of Ham Radio Deluxe with my Icom IC-735 and my Radio Shack HTX-100. I use the rear panel connector for the IC-735 and the front panel microphone jack with the HTX-100. There are many commercial interfaces that can help you out, or you can build your own. I chose to build my own.

    Except for the PTT keying, my interface is only made from wires. I wire the audio from the transceiver to the audio in of the PC and then the audio out of the PC to the audio in of the transceiver. Some users have grounding issues and use isolation transformers. So far I have not had a problem. The PTT is handled with a simple interface from the PCs serial port. If your PC does not have a serial port, you can buy a USB to Serial port converter. Then just add a small circuit to key the PTT. My circuit is built into the DB-9 serial port cable header and consists of one resistor, two diodes, and a transistor.

    With my HTX-100, all the signals I need (audio out, audio in, PTT) come out the mike connector. In your case you could use the external speaker output. Also, on the HTX-100, I only use the 5 Watt mode for PSK-31. Running that into a tri-band yagi will get you almost anywhere. With the IC-735 I usually use about 20-25 watts maximum. That is more than enough power.

    As I said earlier, I use the DM780 portion of HRD. But there is other software that works just as good and uses the same interfacing. It just a matter of taste. Beyond DM780, I have tried Digipan, Airlink Express, and FLdigi, They all work find and are available as free downloads. There are a couple, like EhoCW and MRP4064, that mainly target CW operations. For those software, I use the PTT output to key the CW Key input of my transmitters. All of the software usually comes with a description of the interface required or there are lots of web sites that detail the interfaces they made. I am sure some will respond to your request.
  7. W5LDA

    W5LDA Ham Member QRZ Page

    Just get a Rigblaster plusII. Runs from the mic connector and can still use the mic for its intended use.
  8. W7EMI

    W7EMI Ham Member QRZ Page

    Thanks for all the information! Those interface units look neat, but they're a little pricey I'm just looking for a simple way to key the mic and send PSK over SSB via my soundcard. Is that possible, or do you have to have an interface?
  9. K0RGR

    K0RGR Premium Subscriber QRZ Page

    Your radio does not have an accessory jack with a constant level audio output. This means that for receiving, you need to use the external speaker jack. This has a few drawbacks for digital use. First, with something plugged in, you can't hear the speaker in the radio. Second, the volume control will change the audio level from this jack, making it more difficult to go back and forth between digital and other modes. Third, there is no isolation between the speaker output jack of the radio and the computer.

    For transmitting, you will need to key PTT line and feed audio into the mic connector. Page 46 of the Alinco manual shows the details on this connection.

    You can certainly build your own interface. For receiving, this will be pretty easy. At minimum a straight cable from the speaker out to the computer mic or line input should work. However, I would add some isolation between them, in the form of an audio isolation transformer. Radio Shack sells small 1:1 audio isolation transformers, and Mouser sells the 42LX016-RC for under $2.00.

    A very simple interface is one designed by KH6TY. He isn't selling the kits anymore, but he gives you the circuit and the Mouser part numbers for all the parts, if you want to order them. This interface uses the audio out from the computer to key the PTT line. You will have to make your own interface cable to connect to the mic jack and the speaker out jack. I'd suggest coming up with an outboard speaker - perhaps an amplified one with it's own volume control - and leaving the main audio level control at the same setting all the time, but use the volume control on the external speaker, instead. That way, you can change the audio to whatever you want - even 'off' - while still feeding audio to your computer from the radio.

    If you use this, be sure you turn off all the normal sounds that Windows makes. You don't want to be transmitting 'You've got mail' on the 20 meter PSK frequency. ​
  10. WD4OOZ

    WD4OOZ Ham Member QRZ Page

    After being a ham for over 30 years last year I started digital modes...psk31....This is what I have found from my experience with digital modes. Download your program that you are going to use...I used Ham Radio Deluxe, every program has its own good points and bad. Next you can connect up your audio from you rig to you computer ...external speaker or headphone output or line out audio from you rig to the mic input or line in on the computer. Once you have audio to your computer you can start to recieve the digital modes on the waterfall. You don't have the ability to transmitt yet. Spend some time listening and getting familiar with the program and set up. If you are good at building your own interface there are many available and cheap that work very well. BUT....I will recomend that you purchase an interface unit. One of the major problems that you are going to have is RF getting into you audio or your computer. The commercial interface units are very well rf shielded and have all of the cables with rf beads to help with this problem. These interface units cost in the range of $50 to $100 or more. They also can be picked up used either here at QRZ or Ebay for less. You will find the commercial unit will be worth the money even if you pay full price for it. Look at the MFJ 1273 ...$60 with no mic... to the MFJ 1275...$110 with mic connector....this is one brand name as an example ...there are more out there....I found my sound interface unit at a hamfest for less than 1/2 price of the new one and I have seen them cheaper than that. You will also need a handfull of the clip on rf suppression beads or chokes. I have had fun with the digital modes and occasionally still go on cw and work a few stations with the Ham Radio Deluxe decoding and comparing the software decode to my (in my head) download, i found many operators using computer generated cw and it was near 100 per cent accurate but the old fists didn't copy well. I hope this helps. keep reading and asking questions.... See you on the waterfall soon...good dx

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