Feel free to add information to the wiki or make edits as needed. Please respect the work of others by adding your own content rather than editing or removing someone else's content unless doing things like updating URL's etc.?
|
Re: Measuring Resonant Frequency of Traps
Although it may qualify as "fancy" equipment for the "desert island" scenario, an antenna analyzer can easily show you the SWR of a filter at a given frequency, and you can manually plot a curve if
By
Ryan Flowers
·
#485
·
|
|
Measuring Resonant Frequency of Traps
Thought I'd throw this out for the group. I got trapped [sorry!] into schooling some "Baofeng Techs" (FNGs) who are interested in getting into HF about building trap antennas. Of course, being new,
By
k6whp
·
#484
·
|
|
Re: Si5351 output power
If the load is of high enough impedance, you might get by without the push-pull pair. So I might try first without Q72,Q73, drive your tube rig over a twisted wire pair (or coax) from the junction
By
Jerry Gaffke
·
#483
·
|
|
Re: Si5351 output power
Jerry I like the idea of the ubitx audio stage. I should have all the parts on hand to give that a try. Thanks! 73 Don ve3ids [email protected]> wrote:
By
Don VE3IDS
·
#482
·
|
|
Re: Si5351 output power
I like the notion of two 74ACT04 gates in push pull. But wonder what kind of trouble you could get into using that to drive a transformer. Whenever I see a full description of the design process for a
By
Jerry Gaffke
·
#481
·
|
|
Re: Si5351 output power
It is sobering to think how they got by with such simple gear in say, the late 1920's. Amazing that a single tube regenerative receiver works at all, let alone well enough to use on the ham bands. A
By
Jerry Gaffke
·
#480
·
|
|
Re: Si5351 output power
It would work fine. I used my K2 as a VFO for a Drake 2NT until I could get something built for it. We might overthink things in the digital age. They used to be a lot simpler, and the still could be.
By
Eric KE6US <eric.csuf@...>
·
#479
·
|
|
Re: Si5351 output power
Something to keep in mind in circuits that use multiple power supplies is power sequencing: It is important that the 5V comes on before the 3.3V and turns off after the 3.3V when the 3.3V turns off.
By
Steven Dick, K1RF
·
#478
·
|
|
Re: Si5351 output power
Hi all Loading an Si5351A output at 50-ohms also affects phase noise. I did a study of Si5351A phase noise, particularly in relation to the QCX CW transceiver http://qrp-labs.com/qcx . One of the
By
Hans Summers
·
#477
·
|
|
Re: Si5351 output power
If you read the datasheet, the Si5351 claims to have a 50 ohm output. But yes, it is primarily designed to replace cheap 4 pin crystal oscillators. Jerry
By
Jerry Gaffke
·
#476
·
|
|
Re: What level math is in the RF design books?
Good news: Algebra for designing and biasing bipolar circuits. Not so good news: Partial differential equations for biasing FET circuits, though I¡¯d probably just copy an oscillator circuit rather
By
Bob N1RC
·
#475
·
|
|
Re: Si5351 output power
It¡¯s a clock generator and was designed to drive a logical load, that is, a CMOS or TTL input, and definitely not a 50 ohm resistance. The first rule in a situation like this is to *read* the data
By
Bob N1RC
·
#474
·
|
|
Re: 7 MHz Oscillator Ideas
I¡¯d grab a 40 meter tank circuit from one of the older handbooks for a cheap and cheerful solution. Or a DDS circuit like this
By
Bob N1RC
·
#473
·
|
|
Re: 7 MHz Oscillator Ideas
Thanks for all the ideas gents, I need to get some parts from Diz and Rex and start experimenting. Hopefully after Christmas.
By
JT Croteau <jt.tobit@...>
·
#472
·
|
|
Re: Si5351 output power
That ebay amp can drive 50 ohms with a whopping 10dBm, or 10 milliwatts. That works out to about 0.707 volts RMS on the output, less than your Si5351. It's meant for use in front of a receiver, or
By
Jerry Gaffke
·
#471
·
|
|
Re: What it is this?
It has a 14mhz crystal, a transistor, a few passive components, a transformer, and then a two inductor output filter. So I'm going with Eric that it plugs into a larger assembly, and say that this
By
Jerry Gaffke
·
#470
·
|
|
Re: What it is this?
No idea, but given the stacking header and part designations all in the 20's, it looks to be part of an assembly. A daughterboard of some sort. Maybe that'll jog your memory. Eric KE6US
By
Eric KE6US <eric.csuf@...>
·
#469
·
|
|
Re: Si5351 output power
Jerry Thanks for the info. I need about 10 volts. What are your thoughts on this? https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F162854440017 73 Don ve3ids
By
Don VE3IDS
·
#468
·
|
|
What it is this?
Hi all, I have gotten back into radio after about a decade. ?Finding my goodies I didn¡¯t complete. ?One kit I found doesn¡¯t have any documentation or any info on the board. ?The crystal is
By
Kurt Loken <kurt.loken@...>
·
#467
·
|
|
Re: Si5351 output power
Maybe this 74ACT04N, $0.50 plus $10 shipping: https://www.mouser.com/ProductDetail/Texas-Instruments/SN74ACT04N?qs=sGAEpiMZZMtYFXwiBRPs03JnqncIqXT7 Ground pin 7 with a very short wire (or just bend
By
Jerry Gaffke
·
#466
·
|