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Re: Measuring Resonant Frequency of Traps Newbies SSTV
I don't know about you guys but when I first got a Technician license 21 years ago (after passing 5WPM CW) and I was finally allowed to use a 2 meter HT I could not purchase a 2 meter HT for anything
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Rob <roomberg@...>
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#498
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Re: Si5351 output power
Loading the clock outputs with 50 ohms (such as a 6db attenuator) will make crosstalk and phase noise much worse. Hence the discussion here of cheap 74ACT and 74LVC series buffers to drive a 50 ohm
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Jerry Gaffke
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#497
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Re: Measuring Resonant Frequency of Traps
It's a Military/Viet Nam Era thing. "F---ing New Guy" meaning the newest arrival in a unit. Also, many, many thanks for the great ideas. I think with the availability and affordability of the antenna
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k6whp
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#496
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Re: Measuring Resonant Frequency of Traps
whats the FNG mean?
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Rob <roomberg@...>
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#495
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Re: Measuring Resonant Frequency of Traps
NOTHING beats a real antenna analyzer. Just my opinion. I bought a used MFJ259 for $100 ....twenty years ago and it has been THE "go to" tool for the local radio club and has been passed around so
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Rob <roomberg@...>
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#494
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Re: Si5351 output power
Hi Yes, generally it is a good idea to make the mixer see a constant load vs frequency. So a 6 dB pad will provide a higher return loss than 3 dB will. But given that the output power from a single
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Bo, OZ2M
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#493
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Re: Measuring Resonant Frequency of Traps
A Millen Antenna Bridge will give you both the R and Xc of an antenna. But a simple Heathkit Antenna Bridge will give you only the R of the antenna. These things date WAY BACK! And they have only
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Bob Macklin
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#492
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Re: Measuring Resonant Frequency of Traps
Some newer transceivers, like the Icom IC-7300, include a graphical SWR plot function. Put a dummy load on the other end of the trap and have the radio show you the swr plot. That might help some.
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Michael Maiorana
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#491
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Re: Measuring Resonant Frequency of Traps
Did we miss the part where William explains they are FNG Baofeng techs? Eric KE6US
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Eric KE6US <eric.csuf@...>
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#490
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Re: Measuring Resonant Frequency of Traps
Or, obviously, just a transmitter with an SWR meter (perhaps Diz's tandem match). But the single number representing SWR into an assumed 50 ohm antenna system is not nearly as informative as the two
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Jerry Gaffke
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#489
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Re: Measuring Resonant Frequency of Traps
Might not be a good idea to test the traps in isolation. The remainder of the antenna system can affect resonance.
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Jerry Gaffke
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#488
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Re: Measuring Resonant Frequency of Traps
Google "nanoVNA",? $50 for a vna good from khz to ghz. Display is teensy and thumbswitch is cranky, but performance is exceptional. Newer versions are coming out. Non-trivial for the neophyte, but
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Jerry Gaffke
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#487
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Re: Measuring Resonant Frequency of Traps
Connect the parallel resonant circuit in line with their transceiver input and tune for a null or connect it across the input and tune for a peak. You could also have them reconfigure it as a series
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Eric KE6US <eric.csuf@...>
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#486
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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
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Ryan Flowers
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#485
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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,
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k6whp
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#484
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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
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Jerry Gaffke
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#483
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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:
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Don VE3IDS
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#482
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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
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Jerry Gaffke
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#481
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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
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Jerry Gaffke
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#480
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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.
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Eric KE6US <eric.csuf@...>
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#479
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