tag:blogger.com,1999:blog-3676983452144254088.post9199516681322862667..comments2024-03-28T18:44:09.275+01:00Comments on PE4BAS Amateur Radio Weblog: A mind boggling USBlink VOX data interfacePE4BAS, Bashttp://www.blogger.com/profile/12958141238330445285noreply@blogger.comBlogger4125tag:blogger.com,1999:blog-3676983452144254088.post-62722775429608475882010-10-24T14:44:52.955+02:002010-10-24T14:44:52.955+02:00Update 24-Oct: After exchanging almost all compone...Update 24-Oct: After exchanging almost all components and help from Julian I still cannot get this USBlink modem to work. In my opinion my USB soundcard doesn't have enough output to trigger the VOX, although I got volume control at 100%. In the mean time I found another VOX diagram which works with only 1 transistor. I probabely going to try to build it in the future. But for now I've had it with homemade electronics ;-(<br />73, BasPE4BAS, Bashttps://www.blogger.com/profile/12958141238330445285noreply@blogger.comtag:blogger.com,1999:blog-3676983452144254088.post-57062714396947835102010-10-21T10:02:06.450+02:002010-10-21T10:02:06.450+02:00Update: Just don not get enough voltage on the bas...Update: Just don not get enough voltage on the bases of the switching transistors. I measured just before the 4K7 R but there the voltage is just 0,44V DC. Just before the diode that is connected in series between the cap and this resistor I measure 0,6V DC but exchange of this diode doesn't make it better. my knowledge of electronics is not good enough to change one of the components to get a higher voltage on the switching transistors.... 73, BasPE4BAS, Bashttps://www.blogger.com/profile/12958141238330445285noreply@blogger.comtag:blogger.com,1999:blog-3676983452144254088.post-42508547529897855112010-10-20T20:49:01.086+02:002010-10-20T20:49:01.086+02:00Hello Julian, I didn't want to e-mail you pers...Hello Julian, I didn't want to e-mail you personally as I know what your opinion is about problems with software etc. you made and described. But I appreciate your comment and advice very much. Besides that it might be interesting for others who want to build the USBlink interface.<br />Well the capacitors are connected with the right polarization. I measure 0,75 V AC with PSK31 audio on the base of the first transistor. I measure 0,42V DC on the base of both switching transistors were you measure 0,6V. I tested both switching transistors applying DC through a 10K resistor to the base and they are switching ok (LED blinking). So I thought I just replace the first transistor, this time for a 2N2222 which I know is 100 percent ok. Then I noticed that the capacitor in the original design of Skip is 10 microF, I changed that too. But still I got 0,42V DC to the switching transistors. I think that my soundcard USB stick doesn't have enough audio output to trigger the circuit. I think I'll try a variable 4K7 resistor and see when the transistors are switching...<br />More on that later. 73, BasPE4BAS, Bashttps://www.blogger.com/profile/12958141238330445285noreply@blogger.comtag:blogger.com,1999:blog-3676983452144254088.post-3170222986065593392010-10-20T00:01:13.256+02:002010-10-20T00:01:13.256+02:00It seems to me you didn't measure the voltage ...It seems to me you didn't measure the voltage on the switching transistor. I saw about 0.6V when a signal is present, which is produced by rectification of the diodes. If not you need to trace the audio through that first transistor. If you used electrolytic capacitors make sure they are the right way round or you could be losing the switching voltage through leakage. You could also check the transistor is switching by applying a voltage to the base by say a 10K from the +5V rail.<br /><br />It's a learning process building stuff, though mostly what I learn is that no matter how hard I try I still put things in the wrong way round!Anonymoushttps://www.blogger.com/profile/11984840704237681015noreply@blogger.com