LCD Frequency Counter Module - #205 Is this LCD version better than the LED kit version from video #21 in 2020? Link to previous video here: • Frequency Counter and ...
Very good review. For home built equipment such as shortwave amateur radio receivers/transceivers - such a cheap module is a great addition. It can also be easily added to old communication receivers with the addition of a high impedance buffer amplifier. I have a couple that I plan to use for this purpose. It is certainly better than the digital display kit that could be built into the old FRG-7 receiver!!!!
Looks as if the input circuit has a pair of protection diodes, and a connection to the first gate of a BF998 cascode MOSFET. That's a VHF/UHF gain stage in front of the PMB2313 prescaler. The second gate has a fixed bias voltage. I can't quite follow where the drain is going - it's pulled up to the power supply with an RC network, but I can't quite follow the signal path topside. Does the documentation say what the trimmer next to the prescaler is for? £13 is amazingly cheap for what it does! (But that board layout is still appalling.)
I have ordered two of these modules, as well as two LED 7-segments, 8 digits modules. I intend to use one of these as a frequency indicator in my grid-dip-meter. The range of the GDM is 150kHz-150MHz, so it will cover the RF from LW up to USW. The schematic is an adaptation of an old schematic that I built in the late 80s. The specs for this LCD module says that it can measure from 1MHz up to 500MHz. As I saw, it have not a great accuracy at the ends of the range. What is the minimum frequency it actually can measure? It have a way to calibrate, is there a calibration mode or it is needed to tweak the software? You have mentioned something about it having a menu. Also, what is the minimum voltage that the signal have for the module to correctly run? I saw that the input diodes are connected as a level limiter, I guess to 0.7V (1N4148?) so I can assume that the input voltage can be around min 0.5v? The 8-digit LED module range is 100kHz-1GHz and is the same price. When it arrives, I will see how well it performs compared to this LCD module.
What I want is schematic and programming details to allow installing the K3NG software to customize, add a CW keyer, audio frequency announce, beacons, memories to QRP radio projects.
Yeah, that's what it looks to be. And the board layout around it is sort of awful. For a prescaler that fast, I'd use stripline and a board-mounted BNC or SMA for the RF connection, and probably add a MMIC front end. (And have it better isolated from all the digital crud going on around it - with its own ground bonded to the digital ground at a single point.) One of these years, I'm going to spin a board for my own counter design, unless I can find a cheap kit that I can actually stand.
Very good review. For home built equipment such as shortwave amateur radio receivers/transceivers - such a cheap module is a great addition. It can also be easily added to old communication receivers with the addition of a high impedance buffer amplifier. I have a couple that I plan to use for this purpose. It is certainly better than the digital display kit that could be built into the old FRG-7 receiver!!!!
Awesome thanks !
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Looks as if the input circuit has a pair of protection diodes, and a connection to the first gate of a BF998 cascode MOSFET. That's a VHF/UHF gain stage in front of the PMB2313 prescaler. The second gate has a fixed bias voltage. I can't quite follow where the drain is going - it's pulled up to the power supply with an RC network, but I can't quite follow the signal path topside. Does the documentation say what the trimmer next to the prescaler is for?
£13 is amazingly cheap for what it does! (But that board layout is still appalling.)
Is there provision for IF offset on this meter (10.7MHz / 455 kHz) to use as a frequency display in a receiver?
I have ordered two of these modules, as well as two LED 7-segments, 8 digits modules. I intend to use one of these as a frequency indicator in my grid-dip-meter. The range of the GDM is 150kHz-150MHz, so it will cover the RF from LW up to USW. The schematic is an adaptation of an old schematic that I built in the late 80s.
The specs for this LCD module says that it can measure from 1MHz up to 500MHz. As I saw, it have not a great accuracy at the ends of the range. What is the minimum frequency it actually can measure? It have a way to calibrate, is there a calibration mode or it is needed to tweak the software? You have mentioned something about it having a menu. Also, what is the minimum voltage that the signal have for the module to correctly run? I saw that the input diodes are connected as a level limiter, I guess to 0.7V (1N4148?) so I can assume that the input voltage can be around min 0.5v?
The 8-digit LED module range is 100kHz-1GHz and is the same price. When it arrives, I will see how well it performs compared to this LCD module.
What I want is schematic and programming details to allow installing the K3NG software to customize, add a CW keyer, audio frequency announce, beacons, memories to QRP radio projects.
The little chip is a PMB 2313T prescaller probably, have fun dude
Bill is not a ‘dude’ - he is British (he sounds like it at least). and we don’t have them over here. 😂
I think the translation for "dude" is "bloke;" either-way, the extra information is appreciated. 😂
Yeah, that's what it looks to be. And the board layout around it is sort of awful. For a prescaler that fast, I'd use stripline and a board-mounted BNC or SMA for the RF connection, and probably add a MMIC front end. (And have it better isolated from all the digital crud going on around it - with its own ground bonded to the digital ground at a single point.)
One of these years, I'm going to spin a board for my own counter design, unless I can find a cheap kit that I can actually stand.