Dr. David Kirkby said: > I removed an HP 10811A OCXO from a 5370B time interval counter the other day > and put it into a HP 5352B 40 GHz frequency counter. One thing that really > struck me is that in the 5370B there was a shroud around the OCXO, which is > around 5 mm away from the sides of the OCXO. It's made of aluminium. But > there's nothing like that in the frequency counter. I think the 5370B has a fan so a shroud to keep the air currents away from the OCXO seems like a good idea. Is there a fan in the 5352B? -- These are my opinions. I hate spam.

On Fri, 1 Jul 2022 at 22:49, Hal Murray <halmurray@sonic.net> wrote: > > I think the 5370B has a fan so a shroud to keep the air currents away from > the > OCXO seems like a good idea. > > Is there a fan in the 5352B? > > Yes there is. But the 5352B runs a lot quieter and cooler than a 5370B, which would suggest that not as much air is being blown around inside the frequency counter. There’s not even a heatsink on the back of the frequency counter I see your other comment about drafts. It got me thinking that my HP GPS frequency standard is probably located in about the worst possible place for drafts - right below the air conditioning unit. I will look at moving that. Dave. -- Dr. David Kirkby, Kirkby Microwave Ltd, drkirkby@kirkbymicrowave.co.uk https://www.kirkbymicrowave.co.uk/ Telephone 01621-680100./ +44 1621 680100 Registered in England & Wales, company number 08914892. Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United Kingdom