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Dbory den.
Do you know of any interface for digital mods that does not use transformers to separate the audio path, but optocells??
I've been trying to find something all day, but somehow I'm looking bad again.
Marek,
interfaces between radio and PC mostly use NF transformers to separate the NF path (digital modes via the sound card in the PC) and optocells are used to separate knocking on the market (PTT) and serial port on the PC. The use of an NF transformer and optocouplers has the advantage that the radio is galvanically isolated from the PC, not only does it not hum, but it protects the inputs / TRX outputs, resp. PC.
I use this interface with my TS-850 and it works like clockwork, I added one branch with an optoclen to it and I can also broadcast CW:
http://www.qsl.net/k0bx/soundcard.htmUnless you explicitly want to use NF transformers, try to divide the voltage from the two resistors (their dividing ratio depends on the output level on the sound card and the maximum input level on the radio)
Good luck, Rado 2zz
Look at RZ 4/98
I must have expressed myself wrongly.
I know how it is done and why (for OM2ZZ)
In Radiozurnaly, the connection from the NF transformer is described, if I remember correctly, and the separation of the control signals is solved there.(for Hlavac)Because I don't have one at home and I can get it from a store, I only have one and he won't send it to me because the order is under 500,- SKK. I changed my mind to solve the NF department by optopath. Unfortunately, no radio amateur did it. But luckily, people are into audio engineering. And I've already found two solutions, I'll just try it and hope that it won't cause me a big distortion (Ktore dost vadi Furierovym Transformaciam)
Hi,
if you have the chance to watch FUNKamateur, number 4/2007 str. 400 and the sequel 5/2007 str. 512.
There it is solved by optocouplers, but simpler and also cheaper are the NF hits. If you want, call me.
73 ! JosephIf audio transformers are the problem , so I took apart a Panasonic phone . switchboard , at least they were there 40 ks . If only this is the problem – I donate . OM3WCD amorvay@zoznam.sk
Thank you for the offer.
I'm currently a PN, so I have time to try the optocoupler connections, if it doesn't work, I'll get back to you.I am now building an interface with optocouplers. I'll try to send you the documentation somehow. I emailed it.
73 OK1UMB.I'm going to break some ideas a little. It's a fact, that using galvanic isolation can help in some cases, i.e. if the PC and TRX have a different ground. But I don't like this state very much, i don't know. But it's not true, that it protects something. A transformer is no obstacle for HF, the capacitance between the turns is considerable. It's probably a little better with the optocouplers, but not by much.
I personally do not separate at all and have no problems. I note, that PC, modem and TRX have a common ground.
We did it in the club and it works fine on Echolinks. It is a scheme for separating PC and hifi connections (quite elegant). An amplifier and power supply had to be made from each side. Input – output calibrated one to one by instrument. We tried a large number of transformers (control was already simple opto) but there was always an unacceptable distortion (ak islo o voice). We have recordings archived somewhere. Modem-Signal didn't care, the voice was more demanding. Of course it was absolutely necessary, even if it had a PC, TRX atd. common ground. Antena will definitely never have her together, and there will be a potential difference. The only solution was not to ground the pole with the antenna, well, that was not the happiest solution. It didn't matter when moving the Echolink up to 70 cm, small works and smaller ones were enough, low antennas. With a simplex line on 2m, but we used X510 on a 15m pole. It must have been grounded. Link's councils were not dealt with in the same way. The procedure was different for Kenwood, Icom, Yaesu, etc.
karel: well, it is done mainly because of the ground loop. for me, it is generated by an 8 m long extension cord and a computer. (Zosik is on the same double socket, but without an extension cord, and the extension is exactly according to standards and goodness) So my fears about the department are fueled by my own experience.
OM3KVT: I don't think so. can you send the link to the recordings with those distortions? Personally, I remember from school about the distortion we had in the case of bad impedance matching. (PC sound systems are quite prone to that)
Try this link, there are about three samples and a comparison without a hit (wave alebo MP3 files). Address http://www.sidvedgroup.co.uk/om3kwt/download/
thanks i'll look. but then it amazes me why even in 'pro” devices for digital operation are transformers.
Common optocouplers are designed for digital operation, ON/OFF mode, so they are two-state. They are not linearized and when applied in linear mode the result is highly unsatisfactory. Linear optocouplers are also produced, but their price is several dozen times higher, like ordinary optocouplers and are relatively unavailable. I prefer to mention the complexity and possible additional linearization by circuit solution only in passing. Therefore, the most economical solution still appears to be a conventional isolating transformer, although it also has its flaws (possible induction of interfering signals, near strong mag. fields, dimensions etc.). The price of such hits (3 second, according to the transfer) with in “S.O.S electronics” is around a hundred Sk including VAT. That there is interest in their production, it also proves that, that they are still on the market. In extreme cases, it is possible to use small 1W mains transformers 230/24 In to the circuit board (transfer approx 10:1).
Note: Even if these are digital types of traffic, modulation is a harmonic signal.As for the difficulty, in our case, the price of the interface was around 1500 SKK, I don't think it was more, saving power, amplifiers, connectors etc. The quality was tremendous, 20-20K (Hz) or 15-15K (Hz) I don't know exactly. It was originally designed to separate the HiFi connection from the PC, I strongly feel for it, that the whole HiFi thing will remain. I think we ordered optocells from Czechia, I would have to scroll backwards, or ask. In any case, the interface works absolutely reliably for at least the fourth year. We used it approx 3 years with Echolink for OM0OET operator. If we lost the digital record of the operation, without devices, it was impossible to distinguish what is a record and what is a nominal operation. In the case of using commercially produced rig blasters, it was probably immediate – see the situation in central England, where approx 200 FM stations have the same (equally distorted) modulation in situations such as internet gateway.
