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Re: Si5351 output power
I think I would have gone for the power in the sine wave that's under those harmonics and divided the 0.8 Vpk by sqrt(2) to get the power of the fundamental. FWIW and regarding appropriate loading of
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Nick Kennedy
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#462
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Re: Si5351 output power
A couple edits are required here: < With capacitive coupling, the Si5351 is? effectively driving your?50 ohm load into 3.3/2=1.65 volts, < When a mixer says it wants 7 dBm, I believe that's defined
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Jerry Gaffke
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#461
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Re: Si5351 output power
Mike, I haven't made any such measurements, so you're ahead of me on that. I have heard in other forums that crosstalk and perhaps other forms of distortion creep in as the Si5351 output buffers get
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Jerry Gaffke
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#460
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Re: Si5351 output power
When building the DC40, Robin AC7LX recommended a 3db pad, and I implemented that. Works great. I wrote up my pad here: https://miscdotgeek.com/building-a-direct-conversion-receiver-part-4/ There's
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Ryan Flowers
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#459
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Si5351 output power
I'm just looking for a sanity check (please). Square wave output from an Si5351 is 3.2V p-p unloaded. Into a 50 ohm resistive load it drops to 1.6V p-p. Average voltage of a square wave is 1/2 p-p
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Michael Maiorana
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#458
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Re: Varactor Diode C Measurement
Hi all See a number of diode measurements here http://hanssummers.com/varicap centering around a lot of LED measurements. 73 Hans G0UPL http://qrp-labs.com
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Hans Summers
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#457
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Re: Plug and Play Receiver
Jerry, Give me a few weeks to work on this, but a simple, modular approach makes a lot of sense for the younger kids, while the joy of assembly might appeal to the older group.? Maybe a few DIP
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[email protected]
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#456
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Re: 2N2222 Transceiver ala K8IQY
I'm hardly the one to ask, am by no means an RF guru. Career was spent making QRM with digital stuff. I'm sure there are plenty of things I have never even considered that are involved in making a
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Jerry Gaffke
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#455
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Re: Varactor Diode C Measurement
I have uploaded a couple of pdfs for some diode junction capacitance comparisons that I did several years ago. They are in the K5DW directory. I used whatever I had in the junque box at the time. I
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Don K5DW
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#454
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Re: 2N2222 Transceiver ala K8IQY
Jerry, what would you think about using an AD831 for the first mixer? I have one sitting here but haven¡¯t used it yet, but the numbers quoted ( if I remember why I bought one) are a 3D order IMD of
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Scott McDonald
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#453
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Re: 2n2xx Transceiver R.I.P.
Jerry, Excellent observations. Thank you! Going with a NE5532 for audio like the SW-40+ rigs is a good idea. Should be plenty of gain. Plus, parts are available and inexpensive ($0.88 in single
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Michael Maiorana
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#452
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Re: Plug and Play Receiver
Most anything that resonates with your cap, assuming you have a bunch of wire out the window for an antenna. The coil becomes critical when there is no wire antenna, then the bigger the ferrite rod is
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Jerry Gaffke
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#451
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Re: Varactor Diode C Measurement
I used a 1N4007 in my NC-40 build. More range than the specified varactor. The PIN structure helps. 73, Gary WB6OGD
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wb6ogd
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#450
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Re: 2N2222 Transceiver ala K8IQY
Another thought:? G0UPL and KD1JV among others are using cheap BS170's in parallel for a very efficient rf power amp in class E (or there-abouts). Would be interesting to try building a class E final
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Jerry Gaffke
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#449
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Re: Plug and Play Receiver
Jerry, That looks like a really fun and quick project. I've got plenty of air variable caps. Any idea what kind of coil to build if you don't have a ferrite rod for a core? Adding this to my list of
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Michael Maiorana
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#448
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Re: 2N2222 Transceiver ala K8IQY
I'm assuming most of what people like about the 2n2xx is due to the receiver front end and IF. Anyone have thoughts about what would happen if the 2'd mixer was moved to an SA612? Jerry, KE7ER
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Jerry Gaffke
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#447
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Re: Varactor Diode C Measurement
Virtually ANY diode will work, some better than others. I have a number of projects where I used a red LED as a varactor. I usually got from low-teens pf to ~50 pf. Smaller ones tended to be better
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Eric KE6US <eric.csuf@...>
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#446
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2N2222 Transceiver ala K8IQY
Hi All, Been reading the mail on Jim's 2N2222 rigs and wanting to create PCBs (for personal use only). I'm thinking of doing one myself as I remember using one of Jims rigs (built by an FPqrp member)
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w8diz
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#445
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Re: 2n2xx Transceiver R.I.P.
I take that back. Jim's schematics on http://www.k8iqy.com/ still show a three crystal filter with an apparent last update of 2013 The Norcal thing is its own animal. Jerry, KE7ER
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Jerry Gaffke
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#444
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Re: Plug and Play Receiver
Here's an unexpected curiosity for those with way too many LM386's in the junk box. A single chip regenerative receiver. Using only an LM386:
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Jerry Gaffke
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#443
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