For your information, here is an e-mail that I sent to GMC some days ago, and the reply, from GMC Germany I assume, and forwarded by GMC France.
My E-mail:
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De : ..................................................
Envoyé : mercredi 24 mai 2017 22:33
À : GMC-I Service GmbH; FR, Info
Objet : Metrahit Ultra M248B issue
Dear Madam, dear Sir,
I was close to buy one of the model mentioned in the subject, and, when looking at some reviews on the web, I found this:
...
No need to say that I have postponed my purchase.
According the author of these videos, he wrote a letter to your company, but did not receive yet any reply.
I doubt that this is an isolated issue affecting only that unit.
Before I take any decision, I would like to know:
1) If this is an isolated problem.
2) What are the models in your products list which are affected by these issues.
3) Do you intend to solve these issues ?
Regards.
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GMC Germany reply, forwarded by GMC France:
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Bonjour monsieur ..........,
Au nom de l’équipe GMC Instruments, je vous remercie pour l’attention que vous portez à nos produits.
Vous trouverez ci-dessous la réponse que le responsable de l’activité multimètres a donné à vos questions. J’espère qu’elles répondront à vos attentes. Si tel n’est pas le cas, n’hésitez pas à nous demander toute précision que vous jugerez nécessaires.
Bien cordialement,
Bruno COMBY
Managing Director
GMC Instruments France SAS
No need to say that I have postponed my purchase.
We regret that you postpone your purchase, because METRAHIT ULTRA is a robust precision multimeter despite the behavior reported by Smith in the EEVBLOG.
According the author of these videos, he wrote a letter to your company, but did not receive yet any reply.
Yes, Joe Smith wrote a letter to the subsidiary in the USA. He targeted to receive a description of the interface protocol in order to calibrate the device by himself, which the subsidiary refused to release. This leaded to contrary positions and a not answering to his letter.
I doubt that this is an isolated issue affecting only that unit.
Before I take any decision, I would like to know:
1) If this is an isolated problem.
It is true, we recognized a sensitivity of the METRAHIT ULTRA to electromagnetic interferences (susceptibility) too. This can be recognized for strong electric fields. Joe Smith tested with 10V/m, a relatively high field strength leading to the observations he made. We usually test with 3V/m which does not affect the METRAHIT ULTRA. Please observe that the device is nevertheless compliant to all relevant ISO standards. Furthermore this can be observed only in the lowest DC measuring range, the 300 mV range we has to be selected manually, i.e. not in AUTO range mode.
Nevertheless we started in our R&D a process to improve the immunity of the METRAHIT ULTRA against electrical fields.
We cannot reproduce the observed emission problem at 1.2 GHz. The peak reported in the video is approx.. -90dBm equal to 1pW. We could not find this peak. I might be a resonance problem due to the size of Joe’s cake box. A low level emission below the sensitivity of our test instruments could become larger because of resonance effects in the cake box.
2) What are the models in your products list which are affected by these issues.
The other multimeters in our portfolio do not show the same sensitivity as the METRAHIT ULTRA. The problem is solely a subject of METRAHIT ULTRA.
3) Do you intend to solve these issues ?
Yes, we already started activities to improve the EMC of the METRAHIT ULTRA.