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aliexpress freq counters views
¿ªÔÆÌåÓýI have one - they are not outstandingly accurate (mine read 30 Hz low at 10 MHz. Replacing the crystal oscillator with a 0.5ppm TCXO made a big
difference.? Being able to setup the IF to be I only tested it up to 100MHz as I have nothing to generate anything higher. You can vary the LED brightness via the buttons, I have the Green one. I 3d printed a box for it . Dave
On 28/11/2024 10:21, paul larner via
groups.io wrote:
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On Thursday 28 November 2024 07:50:27 am David Slipper via groups.io wrote:
I have one - they are not outstandingly accurate (mine read 30 Hz low atAnd yet they give you eight digits? And claim to be usable up to 1200MHz? I think I'll pass... Replacing the crystal oscillator with a 0.5ppm TCXO made a big -- Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, ?a critter that can be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters" - Information is more dangerous than cannon to a society ruled by lies. --James M Dakin |
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On Thursday 28 November 2024 08:57:10 am Andy via groups.io wrote:
It's noteworthy that it is more than 2 months waiting for delivery of one of these.Which is one of the reasons why I won't order from them. I have ordered some stuff from Banggood, and one of the last things was a Baofeng radio, where the web page specifically stated that the AC adapter for charging would have a plug suitable for the country you were in. What they send me uses a Euro style plug. (One of these days I need to see if such an outlet is available anywhere.) Email to customer service has gone unanswered. Nope, I'll pass on those chinese suppliers, and get stuff like that from ebay US sellers or similar. Though Ebay is its own irritation, charging sales tax on stuff that should be charged. -- Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, ?a critter that can be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters" - Information is more dangerous than cannon to a society ruled by lies. --James M Dakin |
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On Thu, Nov 28, 2024 at 11:03 AM, Roy J. Tellason, Sr. wrote:
And yet they give you eight digits? And claim to be usable up to 1200MHz? I think I'll pass... Sometimes having lots of digits can be helpful, even when it does not mean precision accuracy.? Then it is up to the user of the instrument to interpret it correctly.
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For example, when making comparative frequency measurements.? The more digits, the better.
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1200 MHz might be do-able, but most likely sensitivity suffers at that end.
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Andy
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On Saturday 30 November 2024 04:42:30 pm paul larner via groups.io wrote:
well i orderd one along with some esp32 blue pill boards to make a coil winder with,will see when they get here,aliexpress say delivery should be on dec 5th.Oh, that ESP32 is a fun one. LOTS of capabilities there. Check out the youtube videos by Ralph S. Bacon (who unfortunately hasn't uploaded anything recently, I hope he's okay). He does a number of them that deal with that part... -- Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, ?a critter that can be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters" - Information is more dangerous than cannon to a society ruled by lies. --James M Dakin |
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Has anyone tried cutting tracks to separate the high and low inputs?
This shows a conventional preamplifier for each channel paralleled at the input, each channel using a
dual gate MOSFET as a preamplifier followed by a buffer stage (CH L) or divider/buffer (CH H). The
buffer transistors in each channel are used to obtain a TTL level. This somewhat "agricultural"
approach suggests that the low channel is likely to be excessively loading the higher channel, and that
is precisely what we see in the French sensitivity results
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wn4isx
I've stayed out of this thread because I post too much.
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Anyway I tried several of these modules and found them to be useless for any thing resembling precision.
I had 3, one in each color, and all drifted...drifted really bad. I tried a insulated case with a clear lexan window, tightly regulated power supply.
Before spending too much effort, get a known frequency reference, 100MHz is gooed, connect it and monitor the displayed frequency for an hour or so.
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I used a local FM station on 98.1 MHz as my reference.
I used a dipole, a narrow pass RF filter, two ganged FM boosters, with another narrow pass filter between them and a home made high gain amp, with another narrow pass RF filter between the output of the last booster and final amp. I had ~1 V 98.1 MHz signal, a spectrum analyzer showed the FM stations nearby in frequency were way down.
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Another option might be a 10 MHz disciplined oscillator, extract the 10th harmonic with a filter and amp.
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I ended up going with a Jackson Harbor pre-scaler kit
And a Tektronix CF250 100 MHz frequency counter a friend gave me.
My combo counts to 1500 MHz with the expected last digit bobble.
It is a lot larger but extremely accurate after replacing the 3.58MHz reference with a reference derived from a GPS disciplined oscillator.
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I ended up junking all three counters and only saved the brass hardware. An expensive lesson.
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Another poster suggested replacing the stock oscillator on the frequency counter module with a precision unit. That would probably work.
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¿ªÔÆÌåÓýSome of these are supposed to have tcxo mine had an unmarked
Plain xo. Replacing it with a cheap aliexpress 0.5ppm tcxo made an enormous difference
And checked against my gpsdo is rock solid at 10mhz and 100mhz and within 0.5ppm. Its not particularly sensitive but good enough for my needs.
Dave
Get
On 6 Dec 2024, at 21:45, "wn4isx via " <hotmail.com@groups.io target=_blank>[email protected]> wrote:
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