Leads For a Frequency Counter? - UK Vintage Radio Repair and Restoration Discussion Forum

OldTechFan96 · 27th Jan 2021, 8:28 pm

I recently bought a Thandar TF200 frequency counter, it should be with me soon.

I am wondering what cables members recommend I use with it as I'm not too sure myself.

Input A is has an impedance 1Mohm and is in parallel with 25pF.

Input B has an impedance of 50 ohms.

Something that terminates in crocodile clips would be handy. I probably would need BNC to BNC leads and a splitter to connect multiple things together.

All help appreciated!

Radio Wrangler · 27th Jan 2021, 8:48 pm

Input A use a scope probe

Input B any 50 Ohm cable should be reasonable.... a bit of RG58 with a BNC on each end. make a BNC female to croc clips to go on the end if you must. You don't normally go probing around with 50 Ohm stuff. A 1k resistor in the end of another BNC femle can be useful

David

mickm3for · 27th Jan 2021, 9:08 pm

Hi i second the scope probe as i use a x10 switched probe with mine great portable counter Mick

OldTechFan96 · 28th Jan 2021, 6:58 pm

Thanks for the tips, they have been useful. The counter came today and I have had some time to play around.

An oscilloscope probe has been working well for input A. For input B I have used a BNC to phono adapter and a composite video lead. Things seem to be working well.

27th Jan 2021, 8:28 pm	#1
OldTechFan96 Octode Join Date: Jul 2017 Location: Newcastle Upon Tyne, Tyne & Wear, UK. Posts: 1,186	Leads For a Frequency Counter? I recently bought a Thandar TF200 frequency counter, it should be with me soon. I am wondering what cables members recommend I use with it as I'm not too sure myself. Input A is has an impedance 1Mohm and is in parallel with 25pF. Input B has an impedance of 50 ohms. Something that terminates in crocodile clips would be handy. I probably would need BNC to BNC leads and a splitter to connect multiple things together. All help appreciated!

27th Jan 2021, 8:48 pm	#2
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,902	Re: Leads For a Frequency Counter? Input A use a scope probe Input B any 50 Ohm cable should be reasonable.... a bit of RG58 with a BNC on each end. make a BNC female to croc clips to go on the end if you must. You don't normally go probing around with 50 Ohm stuff. A 1k resistor in the end of another BNC femle can be useful David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

27th Jan 2021, 9:08 pm	#3
mickm3for Heptode Join Date: May 2015 Location: Chatham, Kent, UK. Posts: 965	Re: Leads For a Frequency Counter? Hi i second the scope probe as i use a x10 switched probe with mine great portable counter Mick

28th Jan 2021, 6:58 pm	#4
OldTechFan96 Octode Join Date: Jul 2017 Location: Newcastle Upon Tyne, Tyne & Wear, UK. Posts: 1,186	Re: Leads For a Frequency Counter? Thanks for the tips, they have been useful. The counter came today and I have had some time to play around. An oscilloscope probe has been working well for input A. For input B I have used a BNC to phono adapter and a composite video lead. Things seem to be working well.