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Re: NP0 Capacitors for QRP homebrew
Heh yeah, they are just listing then numerically rather than by capacitance. Kind of silly, but there's a good variance in the capacitors themselves. Ryan Flowers
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Ryan Flowers
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#337
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Re: NP0 Capacitors for QRP homebrew
I got an email from Amazon a couple days ago offering a capacitor assortment from 0.1 uF to 100 nF. Could we expand that range a little? 73- Nick, WA5BDU [email protected]> wrote:
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Nick Kennedy
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#336
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Re: NP0 Capacitors for QRP homebrew
Thanks everyone for the awesome replies. I decided to go halfway with this. I ordered the cheap kit, knowing that NP0 isn't needed for anything that RF circuits. I usually use QRP Labs kits for those
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Ryan Flowers
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#335
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Re: NP0 Capacitors for QRP homebrew
http://vakits.com/ceramic-capacitor-kit-50-values
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John KJ4IFO
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#334
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Re: "A Binaural IQ Receiver" QST Mar 1999 Campbell KK7B
The Si5344 apparently does not support programmable phase shifts. Jerry
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Jerry Gaffke
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#333
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Re: "A Binaural IQ Receiver" QST Mar 1999 Campbell KK7B
Hans, So the VCO in the Si5351 seems to work from roughly 200 mhz to 1200 mhz. The max is 6 times the min, absolutely amazing! I had assumed the VCO was a straight up analog oscillator using a
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Jerry Gaffke
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#332
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Re: "A Binaural IQ Receiver" QST Mar 1999 Campbell KK7B
Hi Jerry external clock into a crystal oscillator pin but phase noise got quite bad. somewhere up around 25-27 MHz. That was on the QRP Labs forum. Or at least, we DID have that on the QRP Labs forum,
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Hans Summers
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#331
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Re: Replacing SBL-1 with hand built mixer?
The NE602 also clips at a much lower input level; you¡¯ll have better performance with a passive mixer. -- Bob Clarke M: 978.337.2720
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Bob N1RC
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#330
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Re: "A Binaural IQ Receiver" QST Mar 1999 Campbell KK7B
I wrote:? "I wonder if that VCO/4 step size is by design or just a happy coincidence." I'm betting happy coincidence, perhaps a result of the tricks they play to get low jitter fractional divides.
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Jerry Gaffke
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#329
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Re: "A Binaural IQ Receiver" QST Mar 1999 Campbell KK7B
Hans, Good stuff! Table 5 of the datasheet says crystal reference oscillator on the Si5351 can be 25 to 27 MHz, but that the Si5351-C in the QFN20 with the separate CLKIN pin can take a reference
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Jerry Gaffke
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#328
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Re: Norcal 40a (testing 4.9MHz xtals)
It's good that you've found the problem. The issue with the counter affecting the source reminded me of what I saw in a counter I got from eBay. From my notes: "Hey, I noticed this after connecting it
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Nick Kennedy
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#327
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Re: "A Binaural IQ Receiver" QST Mar 1999 Campbell KK7B
Hi Jerry lowest two divider. The reason the reference oscillator frequency is involved, is that it determines the minimum possible VCO frequency specified by the configuration registers. The minimum
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Hans Summers
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#326
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Re: Norcal 40a (testing 4.9MHz xtals)
Turned out that the berg connector that the counter vendor supplied had a faulty connector. A friend of mine had the same counter and with that counter the oscillator worked just fine. Another
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Ramakrishnan Muthukrishnan
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#325
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Re: "A Binaural IQ Receiver" QST Mar 1999 Campbell KK7B
This section from Hans' FDIM writeup is key: "The MultiSynth division ratio has a minimum of 4 (for output frequencies over 150MHz). The phase offset register has a maximum value of 127. Since we are
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Jerry Gaffke
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#324
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Re: "A Binaural IQ Receiver" QST Mar 1999 Campbell KK7B
Thanks Jerry, that's what it was. The FDIM paper you linked to ended up on QRP Quarterly - just like his 2019 presentation about the design challenges of the QSX also got published in the current
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Karl Heinz Kremer - K5KHK
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#323
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Re: "A Binaural IQ Receiver" QST Mar 1999 Campbell KK7B
Hans is selling a complete Si5351 VFO with uC and display that gives quadrature clocks for $33: http://qrp-labs.com/vfo Given all the features, that's a very good deal. Not sure, but I don't think
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Jerry Gaffke
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#322
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Re: "A Binaural IQ Receiver" QST Mar 1999 Campbell KK7B
Karl is right and it¡¯s almost embarrassingly simple compared to what folks had to go thru in the old days. I built a Mini R2 a couple years ago using the phase shift feature in the QRP Labs VFO and
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Scott McDonald
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#321
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Re: Replacing SBL-1 with hand built mixer?
I tried homebrew mixers using BAT54S and BN43-2402 cores, they work just fine. For use with Si5351A? I prefer KISS mixer built on FSA3157 or SN74LVC1G3157 parts. Look for Chris N7ZWY articles about
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vbifyz
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#320
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Re: Replacing SBL-1 with hand built mixer?
Cory and the group: As mentioned, the NE602 (SA612, NE6xx, etc -- they're all the same chip) is a handy device indeed, but it's not a replacement for an SBL-1 diode-ring mixer. The biggest factor in
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Kirk Kleinschmidt, NT0Z
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#319
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Re: "A Binaural IQ Receiver" QST Mar 1999 Campbell KK7B
With the Si5351 you can actually create quadrature clock signals directly -?al least for frequencies starting in the 80m band if I remember correctly. See Hans'?writeup in a recent QRP Quarterly
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Karl Heinz Kremer - K5KHK
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#318
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