Can't find an old thread: Inexpensive E & H near-field probes? - Page 1
Forum section: electronics / testgear

author: cvanc
author_rank: Frequent Contributor
timestamp: March 07, 2018, 04:56:48 am
content: I know there was a good discussion on EEVBlog about this but my search mojo is weak tonight. Can anyone point the way? Thanks.

author: tautech
author_rank: Super Contributor
timestamp: March 07, 2018, 05:02:10 am
content: Quote from: cvanc on March 07, 2018, 04:56:48 amI sometimes struggle on that same one too !But just remember it was started by memberFraserso check his profile and look in his Topics to find it.

author: hendorog
author_rank: Super Contributor
timestamp: March 07, 2018, 05:34:02 am
content: This one came to my mind due to loxodes being one of the open VNA chaps.https://www.eevblog.com/forum/rf-microwave/open-hardware-near-field-probes/https://github.com/loxodes/emc_tools

author: Brumby
author_rank: Unknown
timestamp: March 07, 2018, 05:43:41 am
content: Is this it?https://www.eevblog.com/forum/testgear/new-affordable-emc-probe-set-at-a-bargain-price-from-ariel-rocholl's-lab/

author: Kean
author_rank: Unknown
timestamp: March 07, 2018, 08:33:36 am
content: I think the cheapest ones are the RF Explorer near field probes from Seeed (unless you make them yourself)https://www.seeedstudio.com/RF-Explorer-Near-Field-Antenna-Kit-p-2784.htmlThere are also a nice set from Tekboxhttps://emcsupplies.com/collections/near-field-probes/products/tekbox-emc-near-field-probe-set-tbps01I have both sets. The RF explorer ones are quite a bit smaller/shorter, but the Tekbox ones have good handles to help keep your hands away from the PCB you're measuring.Tekbox also have some nice wideband RF amplifiers, which you will possibly need to make the most of these probes.

author: Gandalf_Sr
author_rank: Super Contributor
timestamp: March 07, 2018, 10:30:23 am
content: I have a set ofthese beehive ones. The ones linked to from Fraser's post onseeed studiolook nice for $98.Can anyone tell us how these 2 sets of probes compare?

author: Kean
author_rank: Unknown
timestamp: March 07, 2018, 05:02:20 pm
content: Quote from: Gandalf_Sr on March 07, 2018, 10:30:23 amI almost bought the Beehive ones, but then Tekbox brought out theirs at a lower price. I think Beehive may have dropped their price a bit since then.Ken Wyatt has done a bit of a comparison here of the Beehive vs Tekbox vs R&S:https://www.edn.com/electronics-blogs/the-emc-blog/4440825/Review--Tekbox-Near-Field-Probes

author: EE-digger
author_rank: Frequent Contributor
timestamp: March 08, 2018, 01:49:59 am
content: The Beehives are good. The owner of the company is former HP/Agilent who was involved in their near field probe designs. He is very helpful if you need information or application help.You can also make your own and they can be quite good. Just the right size and with good E-field rejection if you're careful, with semi-rigid coax.The E-field probes are simply an exposed length (like 6mm for instance) of coax center with insulation.By simply looping 0.085 center conductor back to the shield (i.e. loop diameter 0.040 - ish) I've mapped H field emissions off the top of an FPGA very precisely, fixed with self adhesive absorber.I apologize ... did not answer the original question

author: EE-digger
author_rank: Frequent Contributor
timestamp: March 08, 2018, 02:01:43 am
content: A quick look at Ken Wyatt's review led me to examine the datasheet for the 100C probe I have from Beehive, a bit upset that perhaps my probe sucked.The 100C has a 3dB point at 50MHz for its diameter. What Ken saw as "lack of sensitivity" is actually the first resonant point of the probe in the 300 to 600 MHz range (Beehive says 500MHz).You need to use a probe over its specified range or understand the limitations imposed by exceeding that.Otherwise, I love Ken Wyatt's articles