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Re: cheap aliexpress LC100a = $13 paperweight?
Hi Doug,
The problem is you don't know what your test capacitor's value really is. You say the cap is 5%, so that could make it 313.5 to 346.5 pF,? and both meters read? the cap within that 5%.
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Steve Ratzlaff
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#9423
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Re: cheap aliexpress LC100a = $13 paperweight?
Try this
https://ludens.cl/Electron/LC100A/LC100A.html
It is very interesting and I think you are a perfect candidate for his process.? Please let me know how you get along.
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Doug Hendricks
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#9422
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cheap aliexpress LC100a = $13 paperweight?
I bought a no name LC100a on aliexpress figuring it was worth the risk as they offered free returns.? Unless I am really missing something, it looks like I will be taking them up on the free
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Doug W
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#9421
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Re: LT Spice Alternatives
I must have missed your initial post. I don¡¯t want to dismiss your feelings about LTSpice, but in my experience it is one of the easier Spice flavors. I may have to put this into perspective, my
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Karl Heinz Kremer - K5KHK
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#9420
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Re: L/C Meter Test
I am getting a PeakAtlas LCR45 meter tomorrow because between that and the DE-5000, it was less costly.. I will have to get some +/- 1% caps and measure though.
--
Ramakrishnan VU2JXN
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Ramakrishnan Muthukrishnan
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#9419
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Re: SolderSmoke DC Receiver Challenge
Dave - I gotta say, getting a "neat-looking build" compliment from you made my day.? Thanks!? :)? ?The variable caps came from a stash of Tektronix parts that I accidently acquired when I bought
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bill K7WXW
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#9418
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Re: Building a PTO VFO
IF you want a more interesting mechanism see
https://qrpbuilder.com/pto_mechanism
Its a kit of board that duplicates a lipstick mechanism.
That eliminates the screw moving in and out of the
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ajparent1/kb1gmx
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#9417
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Re: Source for 88 millihenry inductors?
Rewind old inductors! Over the years, before being displaced by LEDs, I had been collecting defunct CFLs. One immortal component is their EE-core choke (ballast) in series with the tube. At least in
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Daniel Ricardo Perez
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#9416
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Re: Active Mixer
other actie mixers used for DCRX over the last 50 years include:
Dual gate mosfets (BF998)
Simulated dual gate mosfet using a pair of cascade wired J310s
SIngle ended mixer using J310
Single ended
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ajparent1/kb1gmx
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#9415
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Re: Active Mixer
Examples of passive mixers are diodes and sometimes mosfet.
Most common examples of active mixer are Gilbert Cell which is in the common ne602/sa612 which use an array of transistors or dual gate
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Curt
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#9414
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Active Mixer
Hello,
I remember some message on this group where someone said a DCR that was designed by Chuck Adams had an active mixer in it instead of a passive double balanced diode mixer as you would normally
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Daniel KK4MRN
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#9413
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Re: Source for 88 millihenry inductors?
Sorry for the off-topic. Consider using Sallen-Key active filters.
A couple of examples using BJTs rather than opamps are below.
Simply cascading 3 identical
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vbifyz
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#9412
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Re: f_t checker circuit
It's a clever circuit alright, and I guess I'll have to give it a shot too.
Some years back I was discussing how to measure Ft with Glen Weinweber. I
think he got a little further along than I did.
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Nick Kennedy
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#9411
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Re: LT Spice Alternatives
Not a direct answer to your question, but ... yes, LTspice can be tough but
probably no more than any other true SPICE package. I've presenting
an introductory talk on the subject at FDIM. I'm not a
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Nick Kennedy
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#9410
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Re: Source for 88 millihenry inductors?
I've been winding my own 88mH inductors on pot cores from Amidon using their PC-2213-77 cores.? For 88mH I think it took
about 100 turns.? The wire is wound on a bobbin, so it's not like putting
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Gerald Wolczanski
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#9409
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Re: f_t checker circuit
Yep, it's a 5 ohm resistor in parallel.? The circuit on the web has two 10 ohm
resistors in parallel.
I'm thinking of going with a RF voltmeter instead of the scope.? I get some
'jitter' on the max
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chuck adams
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#9408
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Re: SolderSmoke DC Receiver Challenge
That's a neat-looking build Bill. I like the yellow trimmer capacitors in the BPF. I have a number of those that I got from Dan's Small Parts and Kits. They are 65pF, and Dan sells them for a dollar
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Dave AA7EE
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#9407
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Re: f_t checker circuit
i have a peak transistor tester, which gives me f_t but that little tester looks like a fun project and i have roughly a zillion 2N3904s, 2N2222s, etc that i could run through it, so build it i
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bill K7WXW
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#9406
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Re: f_t checker circuit
Hi Chuck,
That's an interesting circuit. It's hard to tell from your picture, but do
you have two 51 ohm resistors in parallel to ground on the "CAL" pin? Or is
that a 5 ohm resistor in parallel with
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Michael Maiorana
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#9405
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Re: SolderSmoke DC Receiver Challenge
Hi everyone,
I think you have convinced me to build it.
So, I have a few more parts to get.? No biggie.? But I have everything else.?? I have an audio transformer for a crystal radio - just not
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Daniel KK4MRN
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#9404
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