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152
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eHam Forums / Digital / RE: Digipan Waterfall Width
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on: June 22, 2010, 06:29:17 PM
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The only way to adjust the width that I'm aware of is to change the sound card sample rate, which you can do by going to Configure-->Sound Card. If you lower the sample rate, your 2.5 to 3 kHz of passband will be spread out over a larger display width. Try sample rates of 12000 and 7000 and you'll see what I mean.
Two things to be aware of:
- If you sample at too low a rate, anything leaking through your receiver that's above half the sample rate will alias back into the passband. For example, if you sample at 7000 Hz and your receiver is passing frequencies above 3500 Hz (not likely, if your IF filters are decent), those higher frequencies will be appear somewhere in the passband.
- Some sample rates are problematic for some PCs. For example, some Windows-based PCs will produce an offset between rx sample rate and tx sample rate when the sample rate is set to 11025 Hz; this results in a slight but significant offset between tx and rx frequencies. For me, a sample rate of 8000 Hz works well, and produces a reasonably wide waterfall display.
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155
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eHam Forums / Licensing / RE: Why I Couldnt Upgrade to General
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on: May 29, 2010, 12:22:14 PM
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As a VE, I hate hearing about people having problems with test sessions, and I'm sorry for the trouble you encountered.
There are any number of reasons for what you experienced, ranging from a web site glitch (the ARRL recently redid its site, and some folks have encountered problems with incorrect contact information on the exams page) to a last-minute emergency on the part of one of the VEs (I know of one session that had to be canceled because the VE group leader had a death in the family, and forgot to transfer the test materials to the other VEs). And yes, I agree: you should have had a way to find out.
The bottom line, though, is that all of these sessions are run by standard-issue human beings who are fallible. All of the VEs I know personally are completely committed to doing a good job, and yet from time to time all of us have made errors.
I hope you give the General test another try. I wouldn't give up on anything I cared about because someone else goofed up.
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156
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eHam Forums / Elmers / RE: Amateur Radio is Hard
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on: May 17, 2010, 08:26:47 AM
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We can give you all kinds of advice, but none of it will be anywhere near as helpful as you finding a local ham who can help out. Every newcomer to ham radio can benefit from finding someone--a neighbor, a member of a local ham club, whoever--who has confronted the very same problems you're encountering now, and has learned from his or her experience.
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158
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eHam Forums / Digital / RE: SignaLink USB
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on: March 30, 2010, 08:59:11 PM
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The SignaLink USB has its own VOX; if the computer sends audio of sufficient amplitude to the SignaLink's internal sound card, the transmitter will be keyed. So some program that your computer is running--maybe WSJT, maybe something else--is generating that sound.
By the way, I'm not at all sure what you mean by "sequencer," so I don't fully understand your setup.
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159
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eHam Forums / Digital / RE: Frequency creep
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on: March 29, 2010, 05:26:05 PM
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One possible problem is sound card calibration. If your sound card transmit and receive sample rates differ, the result is a slight offset in transmit and receive frequencies. I had this problem with my SignaLink USB at a sample rate of 11025 Hz, but cured it by switching to 8kHz. You can find out more here: http://www.eham.net/forums/Digital/5212
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162
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eHam Forums / Digital / RE: Upper case characters in PSK31
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on: February 18, 2010, 02:16:42 PM
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The PSK31 software you're transmitting with doesn't know what your font looks like, or what lower-case characters look like relative to upper-case. All it knows is that you asked it to transmit, say, a lower-case "a". It then sends the appropriate sequence of binary digits for a lower-case "a".
By the way, it's true: upper-case characters take longer to transmit in PSK31. So anyone typing in upper case is not only shouting, they're shouting slowly.
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164
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eHam Forums / Digital / RE: Opinions needed for PSK31 newbie
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on: February 14, 2010, 01:34:07 PM
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If you're going to use your sound card solely with the FT-102 or similar ~3kHz passband rig, then I don't see any advantage to getting an Audigy SE over, say, whatever generic 16-bit sound card you might otherwise use.
But if you ever plan to experiment with a receiver that outputs wide I/Q baseband, an Audigy SE can be pretty nifty. I attached a SoftRock 40 SDR to a computer that has an Audigy SE, with spectacular results. Using (free) Rocky software and running the Audigy SE at 96kHz, you can see all the way from 7.010 MHz to around 7.1 MHz at once. It's all that much more impressive when you realize you're doing this with an $18 kit attached to a $32 sound card. (Admittedly, the computer cost something, too, but I already had it.)
This probably isn't the info you were looking for when you asked the question, but I thought I'd mention it.
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