Frequency Counter advice - Page 1
Forum section: electronics / testgear

author: jim111
author_rank: Newbie
timestamp: March 02, 2021, 07:49:06 pm
content: I am looking for a good frequency counter. Budget is around $500.The primary use is for aligning 2 way radios.All suggestions are welcome.

author: jonpaul
author_rank: Super Contributor
timestamp: March 02, 2021, 08:46:54 pm
content: accuracy needed # digits, % ? Freq range min max?2 way radios can be anywhere from low band SW, FM, VHF, or UHF bands, to name a few.Jon

author: jim111
author_rank: Newbie
timestamp: March 02, 2021, 09:59:37 pm
content: Quote from: jonpaul on March 02, 2021, 08:46:54 pmFrequency range 1.8 MHz to 500 MHz,accuracy would like +/- .1 ppm, may not get that in this price range,at least 9 digits on the counter.Will be using it to align PLL/VCO's so it needs to be able to work with very low input voltages.

author: bob91343
author_rank: Super Contributor
timestamp: March 02, 2021, 10:34:41 pm
content: My venerable HP 5328A can do all that. They are available for not too much money. Try to get one with the oven oscillator 10811 I think it is. There are various options and mine will go to about 700 MHz and can resolve 0.1 Hz with 10-second count time. The VHF coverage is with one of the high frequency options.

author: xmo
author_rank: Regular Contributor
timestamp: March 02, 2021, 11:40:42 pm
content: Your frequency counter budget might be better off applied toward a service monitor or spectrum analyzer. Both of these are essential for servicing two-way radios.I have been aligning two-way radios for many years and although I have several frequency counters, I find that I never use them. I always set a radio's frequency using a service monitor (aka communications system analyzer or RF test set).For measuring low level signals, such as your VCO example, many modern spectrum analyzers have a built in frequency counting function, which - when enabled - stops the sweep at the center and actually counts the input signal frequency with the same accuracy as a frequency counter would have. (based on the respective instrument's time base accuracy) Plus, with the spectrum analyzer, you can measure the precise level of the VCO and observe it's stability and settling characteristics.With the capabilities of a modern spectrum analyzer, I find it hard to envision an application for a standalone frequency counter.

author: Electro Fan
author_rank: Super Contributor
timestamp: March 03, 2021, 02:06:11 am
content: Maybe one of these....https://www.ebay.com/itm/BG7TBL-FA-2-6GP-6G-Frequency-Counter-Power-detection-frequency-meter-11-bits-SEC/143670768349?hash=item217371f2dd:g:eYYAAOSwi8pfJSF5... taking a 10 MHz reference signal from one of these....https://www.ebay.com/itm/BG7TBL10MHz-LCD-GNSS-DISCIPLINED-OSCILLATOR-Support-GNSS-GPS-BDS-GLONASS-GALILEO/124281373714?hash=item1cefbf4412:g:ZeQAAOSw99hfJSF8... and keep ~$100 for beer

author: jim111
author_rank: Newbie
timestamp: March 03, 2021, 09:19:58 pm
content: Thanks for all your suggestions.

author: Electro Fan
author_rank: Super Contributor
timestamp: March 04, 2021, 04:35:14 am
content: Quote from: jim111 on March 02, 2021, 09:59:37 pmBG7TBL FA-2 spec’d to work down to -20bBm up to ~5GHz, and down to -50dBm up to 550MHz—-CH1 Frequency Accuracy:0.1s Gate Time: 0.001Hz@10M1s Gate Time: 0.0001Hz@10M10s Gate Time: 0.00001Hz@10MCH1 Test Speed: 11 bits/second@10MHzCH1 Power Test Range: -50dBm~+20dBm, 1M~550M@50 ohmCH1 Power Test Accuracy: 0.5dB@10MHzCH1 Connector Type: BNCIntroduction of CH2:CH2 Frequency: 30MHz-6GHzCH2 Input Impedance: 50 ohmCH2 Power Accuracy: 1dB@2.45GHzCH2 Frequency Accuracy:0.1s Gate Time: 1Hz@1GHz1s Gate Time: 0.01Hz@1GHz10s Gate Time: 0.001Hz@1GHzCH2 Input Power: -20dBm~+13dBm@0.5~5GCH2 Connector Type: SMACH1 Frequency Accuracy:0.1s Gate Time: 0.001Hz@10M1s Gate Time: 0.0001Hz@10M10s Gate Time: 0.00001Hz@10MCH1 Test Speed: 11 bits/second@10MHzCH1 Power Test Range: -50dBm~+20dBm, 1M~550M@50 ohmCH1 Power Test Accuracy: 0.5dB@10MHzCH1 Connector Type: BNCIntroduction of CH2:CH2 Frequency: 30MHz-6GHzCH2 Input Impedance: 50 ohmCH2 Power Accuracy: 1dB@2.45GHzCH2 Frequency Accuracy:0.1s Gate Time: 1Hz@1GHz1s Gate Time: 0.01Hz@1GHz10s Gate Time: 0.001Hz@1GHzCH2 Input Power: -20dBm~+13dBm@0.5~5GCH2 Connector Type: SMA

author: fourfathom
author_rank: Super Contributor
timestamp: March 04, 2021, 06:00:05 am
content: Quote from: Electro Fan on March 04, 2021, 04:35:14 amTo get that accuracy you need an external 10 MHz reference with zero frequency error. Otherwise that's just resolution.Fortunately, a GPSDO can be pretty inexpensive. I use the Bodnar Mini GPS Reference (http://www.leobodnar.com/shop/index.php?main_page=product_info&cPath=107&products_id=301). Since it uses a VTCXO it doesn't have as good holdover as a GPSDO with an OCXO, but as long as you have a stable GPS signal it does the trick.

author: Electro Fan
author_rank: Super Contributor
timestamp: March 04, 2021, 09:10:38 pm
content: Quote from: fourfathom on March 04, 2021, 06:00:05 amThat's why I suggested both....---https://www.eevblog.com/forum/testgear/frequency-counter-advice/msg3493400/#msg3493400Maybe one of these....https://www.ebay.com/itm/BG7TBL-FA-2-6GP-6G-Frequency-Counter-Power-detection-frequency-meter-11-bits-SEC/143670768349?hash=item217371f2dd:g:eYYAAOSwi8pfJSF5... taking a 10 MHz reference signal from one of these....https://www.ebay.com/itm/BG7TBL10MHz-LCD-GNSS-DISCIPLINED-OSCILLATOR-Support-GNSS-GPS-BDS-GLONASS-GALILEO/124281373714?hash=item1cefbf4412:g:ZeQAAOSw99hfJSF8... and keep ~$100 for beer---I think the BG7TBL GPSDO uses an OXCO rather than a VTCXO.BG7TBL makes a variety of products. This one might be a cost-effective solution for a 10 MHz reference signal to drive a counter (if the counter has a 10 MHz ref input). But it might or might not work for the OP as it has a 13 dBm spec - although this would drive the counter, and the counter would be used with the radio gear, so it might be ok.https://www.ebay.com/itm/By-BG7TBL-10MHz-OCXO-Frequency-Standard-Sine-Wave-Output/174517025907?hash=item28a2067c73:g:3ZUAAOSwrXhfrmRy

author: jim111
author_rank: Newbie
timestamp: March 05, 2021, 12:56:48 am
content: How about the B&K Precision 1823A Universal Frequency Counterwith a Leo Bodnar Precision GPS Reference Clock?

author: Electro Fan
author_rank: Super Contributor
timestamp: March 05, 2021, 02:10:16 am
content: Quote from: jim111 on March 05, 2021, 12:56:48 amfrom the 1823A manual...INT/EXT TIME BASE SELECTOR:Selects the source of the time base. EXT.STD. IN sets up BNC as a nominal 600 Ω input impedance path for an external 10 MHz time base signal. INT. STD. OUT sets up BNC to monitor the internal time base signal.INT/EXT TIME BASE BNC:Provides a connector through which the internal time base signal can be monitored or through which an external time base signal can be applied (see item above). The external signal should have a voltage range of 1.5 V~5 V rms.