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: QRP TX LPF illustration
Hi Goody,
For my example I used an existing LPF and simply used each inductor to calculate what resonating cap worked at the 2nd and 3rd harmonics and picked the closest standard value cap to use.
By
Steve Ratzlaff
·
#9507
·
|
|
Re: 1W and 5W build guides
Thanks Chuck!
I may celebrate and build my Organic 5W CW Transceiver Kit for 40m finally...
I have an extra PCB and keyer chip in case I screw up.?? But just so others know - the keyer chip and
By
Daniel KK4MRN
·
#9506
·
|
|
Re: QRP TX LPF illustration
I have a homebrew 80m CW rig I built 20 years ago that was out of spec and
I'm re-doing the final PA and LPF. Did you use an online calculator to
determine the values? I'd like to try this harmonic
By
Anthony Good
·
#9505
·
|
|
QRP TX LPF illustration
We're all aware of the current FCC regs for harmonics and spurious outputs from a transmitter needing to be -43 dBc or greater below the fundamental output. Here's a 40 M LPF with the original
By
Steve Ratzlaff
·
#9504
·
|
|
Re: Final PA Transistor
I run my 40 and 17x 5watters all the time. Awesome little radios!
I need to rig up an attenuator knob for the 17 because the filter is so tight/narrow that it rings horribly on strong signals.
I
By
Tim Tyler II
·
#9503
·
|
|
1W and 5W build guides
Forgot.? Old links at kitsandparts.com are for the old call.? Here are
the new links.
<https://www.aa7fo.com/5w.pdf>
<https://www.aa7fo.com/1w-108.pdf>
<https://www.aa7fo.com/onewatter.html>
and I
By
chuck adams
·
#9502
·
|
|
Final PA Transistor
Here is one used in the 1W and 5W xcvr of KitsAndParts designed by Diz, W8DIZ<sk>.
I bought a 100 and tried them in a 20m 5W and a 12m 1W and got the exact same
output as non-fake parts.? Go look at
By
chuck adams
·
#9501
·
|
|
Re: 60 Meter homebrew rig IF frequencies
*Hallas Rule ( https://soldersmoke.blogspot.com/2015/05/sideband-inversion.html ) :? Sideband inversion only occurs when you are subtracting the signal with modulation FROM the signal without
By
hwstar
·
#9500
·
|
|
Re: RF Power Transistors
On another side note (this one very much a side note), in addition to some of the now seemingly substandard 2SC2078's I bought from Dan, I also bought some metal can Jan 2N2222A's. I was thinking that
By
Dave AA7EE
·
#9499
·
|
|
Re: Benchtop DMM Recommendation
Hi Jerry,
I bought the Owon from Amazon but I haven't used it yet so I can't add much
but I did make my decision after spending a lot of time reading the many
positive reviews and looking at other
By
Jim WB4ILP
·
#9498
·
|
|
Benchtop DMM Recommendation
Yesterday I managed to blow out the front end of my Sigalent SDM3045X benchtop DMM. Sending it in for repair will cost almost as much as a new one and the schematic is proprietary so repairing it
By
W0PWE
·
#9497
·
|
|
Re: RF Power Transistors
As a side note, looking at Dan's site just now, I notice he lists manufacturers such as Motorola for some of his RF transistors, and doesn't list anything for others, such as the 2SC2078. Knowing what
By
Steve Ratzlaff
·
#9496
·
|
|
Re: RF Power Transistors
Steve,
Since you publoshed the circuit I will build it and test them out.
73 Mike N2MS
By
Mike N2MS
·
#9495
·
|
|
Re: RF Power Transistors
Hi Mike,
No, I have not tried any of Dan's other RF power transistors, just the 2SC2078. If you wanted to send me one of your other ones I'd be happy to check it out and return it to you.
73,
Steve
By
Steve Ratzlaff
·
#9494
·
|
|
Re: 60 Meter homebrew rig IF frequencies
I believe that the correct description of sideband inversion is as follows:
1.? Occurs when LO = RF+IF
2.? Does not occur when LO = absolute value of (RF-IF)
Mike N4MWP
By
Mike Dinolfo
·
#9493
·
|
|
Re: 60 Meter homebrew rig IF frequencies
High side injection looks a lot better...
12288 kHz IF high side injection
A. For an IF of 12288 kHz:
2x the LO will be 34976-35376 kHz
3x the LO will be 52464-53064 kHz. [6 meter ham band]
4x the
By
hwstar
·
#9492
·
|
|
Re: RF Power Transistors
Steve,
Thanks for the update. Sorry to hear about Dan's Small Parts. Maybe his suppliers are drying up. Did you ever evaluate is RCA4013 transistors? I have a handful of them.
73 Mike N2MS
By
Mike N2MS
·
#9491
·
|
|
Re: 60 Meter homebrew rig IF frequencies
I just realized the 60M is USB only not LSB. So you may have hit on something. It has to be high side injection.
Steve
WA6ZFT
By
hwstar
·
#9490
·
|
|
Re: 60 Meter homebrew rig IF frequencies
For 11059 kHz, the band is almost 2X the IF frequency.
Frequencies in kHz:
11059-5200 = 5859
11059-5400= 5659
The LO would tune 5859 to 5659 MHz.? Too close to the 5200-5400? for comfort.? Too
By
hwstar
·
#9489
·
|
|
Re: 60 Meter homebrew rig IF frequencies
If only it were so easy (it isn't) Sideband inversion: When the LO is above the IF the sideband gets inverted. The Crystal filter favors the LSB with the steepest roll of on the high side of the
By
hwstar
·
#9488
·
|