Cheap Frequency Counter from eBay
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- เผยแพร่เมื่อ 29 มิ.ย. 2024
- A subscriber sent me this cheap frequency counter he got from eBay. It is advertised to work up to 2.4GHz so let’s test it.
Manual PDF: www.zl2pd.com/files/PLJ-8LED_...
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I had a look at the manual and there is a test graph showing that the input sensitivity falls with frequency quite rapidly. The input to the prescaler is in parallel with the low frequency input, rather than switched in series. There is a suggestion to split this on the board into two separate inputs. There is also an argument for adding an external prescaler for SHF work. This is what I have done for my RACAL counter. I also note that you can adjust compensation for the TXCO with a trimmer, when measuring against a known frequency standard. All in all an interesting little module and worth putting some extra work in to improve it. Thanks for the review and I’ve just ordered one.
I know that Laver might not be looking at this after four years but please if you are - can you nominate any freq divider chips ie prescalers that will take say 4 Ghz down to 1 Ghz to put in within range of this counter ? I don't believe the Txco is really temperature compensated. I think it 's just a standard miniature canned oscillator. I got my manual off the website of the US Reseller who might be in Georgia. Appreciate any insights. Tim F
Thank you for your thoughts and efforts.
Amazing little guy for the price. In for one.
I want to thank you for a real test
Woosh! Love it, no idea why I'd use it tho. Oh, hang on, what frequency is my new R9M actually outputting, then I can fine tune my r9mm rx antenna? But the rx might not be calibrated to recieve that frequency, how to check that?
EBay gadgets leave you wanting more.. Great age to live in if you love electronics 📆
mine was unstable w/a 12 volt smps so i used a 9 volt supply instead. rock steady and accurate too.
i paid a little more to get the clear case.
Need to disconnect the h/l inputs which are in parrellel. Tiny dtsp swith or 2 seperate input connectors on cabinet
copy you manual ,, thank you for post.
Basic specs for this type of device are
PLJ-6LED is a cost-effective microprocessor based, six-digit digital frequency display/counter. It can be used for conventional frequency measurement or as a transceiver band displ;ay.
Features: small size and reliable performance.
Settings are automatically saved
Features:
Processor: Microchip PIC16F648A
Power: 8V ~ 15VDC (with reverse polarity protection )
Operating current:
So ..Sir are you going to do a video on modified antennae for smartphones?
Can you make a video for a long range 5.8ghz cantenna ? I can't find any good online calculators. I want the gain to be as great as possible without a too narrow beamwidth.
Intresting
Hi all, hoping to get some advice/help. My fiance lives in the mountains in the philippines. She has a smart phone and I got her a globe pocket wifi. At her house signal is very spotty most times, signal gets better about 2am to 5am. I was wondering if there is a way to boost the signal to her pocket wifi so that we can communicate better when she is home. Any help would be greatly appreciated. I am sure Andrew is very busy. Best Regards
whats the maximum allowed vdc to be at point the rf is to be measured ?
This is my dreams channel
I have one of these and really like it for HF but I haven't used it above that. This would really benefit from a color lens in front of the LED. The color depending on the color of the LEDs in your unit. Even a piece of cellophane might work. Does anyone know where to purchase tinted plastic like that?
Just Google "colored transparent plastic." You can get sheets or tape. 🤠
Thanks I just ordered one thought it would be good enough we’re doing electronics 101 class homework projects. Just HP 3312A function generator working for $39 and HP 5345A universal frequency counter with option zero 20 and zero 60for $59 eBay working. I can tell you the nearly 40-year-old Heward Packard frequency generator put out a much cleaner and stronger signal then the brand new Chinese made $80 frequency generator.
Great deals, recently saw a HP 3314A go for ~$177 on shopgoodwill.com!
I've been looking into the HP 3325 based on this suggestion though have the 8640B OPT 323, Wavetek 142HF, Protek B801, Tektronix FG503 and most recently the Wavetek/PMI NS201's:
www.quora.com/What-your-favorite-make-and-model-Signal-Generator
The Victor 3165 seems to be working fine for now as a counter investment... though I do want to buy a HP counter most likely eventually.
I figure rescue the Made in the USA high quality systems if you have the room. They're easier to work on to repairs seems also.
I tested this on fm digital radio and it shows exact.. it seems that your frequency generator is off and need calibration... guaranteed your freq meter is off showing minus 4% to minus 7% lower then it should.. recalibrate freq generator.. 87.00mhz - 108.00mhz exact guaranteed
I"ve made a mini stepper motor spindle run by PWM. to measure to speed I plan to get PWM frequency and calculate it. Is It suitable to measure speed this way and will it handle the voltage output of pwm driver?
PWM does not adjust the frequency, it adjust the duty cycle.
Any tips on interfacing this module with a receiver or transmitter? I have not been able to get the module to read anything except my signal generator...
Set if offset to above or below local oscillator. Receiving 10 MHz, with radio that has a 455 kc if, the local osc will usually be on 10455 kc. The 2 freqs combine and give 455 out to if amp. So read osc, via small cap or a few turns of insulatrd wire around pdc tube/ transisr, etc. Set if offset per manual and cointer shows 10 mc recv freq. Plj-8led-c manual on net search will get you close.
would this work for cb radio ?.
Thooms (e.i. Thooms; British equivalent for Thumb. Pronounced as "loom." As in a cotton loom. - American influence/non- "King's English") Up. (Hehehehe- Ya gotta love that English Accent. Tickles ya).
I cant seem to find in the manual what wattage this will take when transmitting into it. Any Idea? Had one of thease for years and never used it and now wish to use it to align some CB's I was given to restore.
No watts at all. It is not dummy load! A foot of wire near cb ant gives all you need. No more yhan 0.01watts.
What cellphone single boosters work? I really need one that works. Because where I live, I don't have a good cellphone connection. I also need the internet too work also
Please let me know. And thank you
Get one from your cellular service provider.
Don't those cheap rtl-sdrs have better accuracy?
minecrafter9099 Yeah... don't go to 2,4Ghz either though.. (at least the basic ones)
How do you connect it to a radio
Wire near local oscillator. Set if offset to match radio. To rcv 1 mhz station, osc is at 1.455 mc typically. Set if at upper 455 kc/ KHz. Counter displays 1,000,000
Why is the cheap counter's frequency display SO unstable? That's hopeless for any accurate work! My 2 same modules are extremely stable up to the last 1 or 2 digits - even at 2GHz+.
Accurate work costs more than 8 euros
@@johnrussell6620 This true but I was talking about stability of the reading - NOT accuracy! With a GPS disciplined oscillator and a frequency multiplier you can gauge the accuracy - but not if the display is jumping around! 😀 As I said my 2 examples (admittedly working off a battery supply) show stable, but not absolutely accurate, readings even at 2GHz+
@@hectorpascal This one actually is pretty stable with an increased amplitude signal as shown later in the video. I think he could have turned it up a bit more, but he did not. He was describing his increases in 1 and 2 and 3dB increments. I lost track of where he stopped. I just want one to see if any frequency is happening at all and if it is anywhere close when in the field without any bench equipment. Anyway, don't buy or build one if it won't make you happy in the end. ..... p.s. This thread is 4+ years old and the author probably doesn't care about either of our comments.
@@johnrussell6620 Yes FWIW, when I tested mine I seem to remember they were particularly "unhappy" at low input levels when powered with an SMPS supply - but I almost expected that and never explored it further. Switching to a battery supply the display was much better behaved.
I really don't get how a frequency counter that's out by 7MHz at 200MHz is useful for anything, I am missing something here?
I don't think he did a calibration on the FC. He never mentioned it was even possible, though he went on for 5 minutes about his main equipment needing to warm up for 45 minutes. There is a trimmer cap on the back to make the fine adjustment to the TCXO. Just watch a few of the other videos to see how to do it.
@@johnrussell6620All good if you can cal it and it remains stable. I'm still gobsmacked that this guy says "it's pretty acceptable". He looking at it being a good 7 or more MHz out and says that's acceptable. Wow.....
is there a video doesn't start with the word "so" ?
I think SO
Hee, you cant grumble ;)
So, so what?
Not acceptable !!
can you send me link for pdf manual? thanks master
link in description
@@andrewmcneil Thanks