Search found 75 matches

by davidhooau
Sat Jan 11, 2014 2:31 pm
Forum: Yahoo groups backup
Topic: Expanded log detector and 10.11MHz filter
Replies: 9
Views: 1663

Re: Expanded log detector and 10.11MHz filter

Hi Lin,
I'd love to know what GPIB test software you use. I've collected some nice equipment over the last couple of years and have it all hooked up via GPIB, but can't afford the HP or NI packages to develop test programs. Any advice?
Cheers,
david
by davidhooau
Mon Aug 26, 2013 8:34 pm
Forum: Yahoo groups backup
Topic: Question on the MSA input impedance
Replies: 7
Views: 1464

Re: Question on the MSA input impedance

<r>Hi Len,<br/> <br/> <br/> <br/> I think you should read the link Scotty provided. The input of your MSA is now around 25R (50R || 50R) unless I'm reading your post incorrectly.<br/> <br/> <br/> <br/> If you find a supplier of low cost RF test equipment at good prices, please share! Buying old HP e...
by davidhooau
Mon Oct 22, 2012 7:56 pm
Forum: Yahoo groups backup
Topic: Spare PLO PCB
Replies: 0
Views: 2090

Spare PLO PCB

<t>Hi All,<br/> <br/> <br/> <br/> Does anyone have a spare PLO PCB I could beg, borrow, buy or steal?<br/> <br/> <br/> <br/> I've found some Bliley 100MHz VCXOs which I'll lock to my GPSDO 10MHz reference, and it'll be easier to start with a PCB.<br/> <br/> <br/> <br/> Thanks!<br/> <br/> <br/> <br/>...
by davidhooau
Thu Jul 12, 2012 10:06 am
Forum: Yahoo groups backup
Topic: USB Quick Start Guide
Replies: 3
Views: 420

Re: USB Quick Start Guide

<r>Jim,<br/> <br/> <br/> <br/> I've just added a 56 pin Cypress, and would like to add a couple of additions to your fine guide.<br/> <br/> <br/> <br/> My Cypress board enumerated as a completely different device to any in Dave's driver package, so I removed the EEPROM jumper, allowing it to enumera...
by davidhooau
Tue Jun 12, 2012 7:58 pm
Forum: Yahoo groups backup
Topic: Reflection Mode Question
Replies: 13
Views: 1118

Re: Reflection Mode Question

<r>Howdy Sam,<br/> <br/> <br/> <br/> That was an interesting learning exercise!<br/> <br/> <br/> <br/> Phase_detector_fix_how_to.pdf is in the group's file section. Rev C of the PDM schematics includes C24, and I note that there's also a C25: I'll check if I'm being affected by this being absent, th...
by davidhooau
Tue Jun 12, 2012 10:39 am
Forum: Yahoo groups backup
Topic: Reflection Mode Question
Replies: 13
Views: 1118

Re: Reflection Mode Question

<r>Sam,<br/> <br/> <br/> <br/> Yes, it was a 50 ohm termination: sorry, I should have made that clear. BTW, the parallel line bridge is working quite beautifully once I get the sample rate high enough. After a calibration, and before the usual drift, a 50 or 100 ohm load measures within 0.05 ohm fro...
by davidhooau
Mon Jun 11, 2012 12:30 am
Forum: Yahoo groups backup
Topic: Reflection Mode Question
Replies: 13
Views: 1118

Re: Reflection Mode Question

<r>Hi Sam,<br/> <br/> <br/> <br/> I've refined my test method somewhat, and found it simpler to use a linear scan from 0.8-1GHz, and using less steps/sweep to cause the issue to arise.<br/> <br/> <br/> <br/> I've posted 3 images. One is the result of a through cal, one is the bridge with no cal, and...
by davidhooau
Sun Jun 10, 2012 1:33 pm
Forum: Yahoo groups backup
Topic: Reflection Mode Question
Replies: 13
Views: 1118

Re: Reflection Mode Question

<r>Hi Sam,<br/> <br/> <br/> <br/> Sorry for the delay. The transmission scan you suggested looks perfect. <br/> <br/> <br/> <br/> A scan, transmission or reflection, calibrated or otherwise, looks perfect from 100MHz to 1GHz. Changing the steps/sweep from 400 to 200 causes the problem to occur, at a...
by davidhooau
Tue May 08, 2012 9:53 am
Forum: Yahoo groups backup
Topic: Reflection Mode Question
Replies: 13
Views: 1118

Re: Reflection Mode Question

<r>Sam,<br/> <br/> <br/> <br/> A quick update, and 2 new scans uploaded. Let me know if the PNG files are easier to read please.<br/> <br/> <br/> <br/> One scan is 2 decades after OSL cal, with garbage clearly visible. Second is with no physical changes, just "clear band cal" and then restart. Garba...
by davidhooau
Mon May 07, 2012 7:26 pm
Forum: Yahoo groups backup
Topic: Reflection Mode Question
Replies: 13
Views: 1118

Re: Reflection Mode Question

<r>Hi Sam,<br/> <br/> <br/> <br/> Thanks for the advise about the image formats. And yes, it was a 100R test load.<br/> <br/> <br/> <br/> I reproduced and resolved the "jumpiness" at least 10 times by merely changing the scan parameters, but I'll swap all cables and try again after w**k (sorry Scott...