![interface rtty interface rtty](https://www.aa5au.com/wp-content/uploads/2018/07/n6tv-interface.jpg)
I did not observe poor decoding with other programs I tried. Most digital mode programs use a sample rate of 11,025Hz or can select the native sample rate of the sound card. I am not sure of the reason for this but it may have to do with the sample rate used. When playing back recordings I made of weak EME (earth-moon-earth) signals the faint morse code could not be heard at all.
INTERFACE RTTY SOFTWARE
I must point out that in tests I made a few months ago I found this particular type of dongle to give poor results with some sound card software such as the AGW Packet Engine. These sound devices are better quality and more reliable than the cheapest thumb-sized "dongles" and have controls for speaker volume and muting the mic input and speaker output. Purchased from a supplier in the UK they are a bit more expensive. At the time of writing these devices can be purchased from China on eBay for a couple of pounds if you are willing to wait a couple of weeks for delivery. The USB sound card I used is shown on the right. The USBlink comprises an inexpensive USB sound card together with a simple audio VOX circuit, housed in a small case.
INTERFACE RTTY PORTABLE
It also lets you make the interface very small, which is a bonus for portable operation. But omitting these components allows a big cost saving to be made, as long as you are one of the people who, like me, does not need to isolate the radio from the computer. The one time I used a commercial interface with isolation - to connect an Asus Eee PC to my FT-817 - I experienced bad 50Hz hum and had to solder a link between the grounds on the radio and PC sides because the netbook had no grounding through its power supply and so it was floating.īecause my USBlink doesn't provide many of these functions of the TigerTronics SignaLink it can't fairly be called a SignaLink clone. It's enough to make me wonder what I'm missing because in all the time I have been using sound card digital modes since the late 1990s I have never used an interface that had isolation and never found it to be necessary. Every commercial sound card interface and just about every published sound card interface design includes transformer isolation of the audio circuits and opto-isolation of the PTT line. My USBlink also does not provide isolation. I don't know of any digital modes where you would want a slow acting VOX. My USBlink requires you to use the computer mixer slider controls to set the audio levels, just as you would when using a regular sound card, and the VOX delay is fixed and fast acting.
INTERFACE RTTY FULL
It also provides full isolation between the radio and the computer.
![interface rtty interface rtty](https://slideplayer.com/slide/12562272/75/images/2/RTTY+Contesting%2C+A+to+Z+Introduction+Part+1%3A+Operating.jpg)
The TigerTronics SignalLink has three front panel rotary controls that let you set transmit and receive audio levels plus VOX delay.
INTERFACE RTTY SERIAL
This avoids the need for a serial interface using a second USB port just to control the transceiver PTT, which is the bane of interfaces like the RigBlaster, and it works with just about any digital mode software. The SignaLink USB Interface is a USB powered device that contains a sound card and VOX circuitry that keys the radio PTT whenever the digital mode software goes into transmit and produces audio. So how would you like to build your own USB sound card interface for a fraction of the cost of a SignaLink? I did, and I called it the USBlink. It's a fine piece of kit and I've heard nothing but good reports of it but it is quite expensive.
![interface rtty interface rtty](http://www.m0pzt.com/datamodes_simple.jpg)
![interface rtty interface rtty](http://www.iw5edi.com/wp-content/uploads/2019/09/civ.gif)
Many solve the problem by buying a SignaLink USB Interface. However what with YouTube ham radio videos, podcasts and other hobby-related multimedia most hams want to have sound from their computer and are unwilling to give this up to work digital modes. Digital modes using sound card software have become increasingly popular over the last few years.