I am doing the work now to put the VNA board into an enclosure, and am in the process of deciding how to provide the +5V for the signal sources. How do most...
Hi Dudley, I recommend a switching regulator, as in my Part 2, to reduce heat generation inside the enclosure - particularly if you're going to use 13.8V...
... (First of all, apologies for posting this, and then disappearing for several days. Back at the weekend.) I didn't feel comfortable about a switching...
Heat being the overriding concern, I'm curious about something else. A few of the example kits show the VNA in a ventilated box with a fan, while others have...
Dudley, I think your logic is correct. I experimented with fans/heatsinks/nothing watching the DC offset drift, and found that the best option is a small...
I installed the DDS and other chips without heat sinks. I'm not sure what such a creature would look like or how to attach it - and I think I can't do it now...
Hi Dudley, ... That is similar to what several people have done and it should work fine. Maybe some of the users of VNAs with fans will comment on how that has...
Anyone have recommendations as to a model of heat sink and how to secure it to the master oscillator and DDS on the original VNA board? Ivan references copper...
Anyone tried using a power supply out of a PC? They have a +5 & +12 volt output. Probably a bit over kill on the wattage, but it's free because I have one...
Ivan, Have you posted any photos of your assembled unit? On your website you show some suggested connector layouts with the Hammond case, but I'd lke to see ...
Steve, as you said, they are not there.. I definitely remember seeing the pics with where the copper fingers were shown attached to the enclosure. Could be ...
Steve, as you said, they are not there.. I definitely remember seeing the pics with where the copper fingers were shown attached to the enclosure. Could be ...
Walter, I hope I answered in my previous post. Best regards, Ivan ... From: "ve7wrs" <ve7wrs@...> To: <N2PK-VNA@yahoogroups.com> Sent: Tuesday, April...
Thanks Harold. I have not seen the pictures at http://homepage.ntlworld.com/john.brister/G6AKwebpages72.htm. They provide food for thought :) Steve K8JQ...
Stan, The +12 V power supply for a computer is used to power motors on drives et-cetera. It might not be regulated well enough and have low enough ripple to be...
Robert Hagenbach
rc_hagenbach@...
Apr 4, 2007 4:30 am
2486
I like to use the National Semiconductor "webench" to work out 5V and 3.3V power supplies. I take their starting point for "simple switcher" with all the...
I checked out the board and it didn't look like there was adequate filtering. I'll check it out on the scope. I can always add some filtering. The +12v output...
Stan, Be aware that many PC switching power supplies require a minimum load on the 5 volt output. They may not properly regulate any of the outputs without...
Don has made a valid point. The AT power supplies are the worst, ATM ones are better. The AT one I have would not even start without 0.5A on 5V channel. One...
This is a ATX type (current type) power supply. I am reading 5v & 12v with no load on the supply. There are a couple of leads that you have to jumper in order...
Stan, yes it is ATX type , not ATM as I said. I think Paul has the PS specs quantified in his documentation including the ripple - I think you could simply...
... filtering. I'll check it out on the scope. I can always add some filtering. ... pretty well regulated since the motors in the harddrives have to be ...
... and 3.3V power supplies. I take their starting point for "simple switcher" with all the appropriate SMD capacitors/resistors. Then I look at the...
What I do is look at their list of substitutes and pick from those. They do cost a small bit more but it is better to buy one from mouser than 10+ fm DK....
I powered my VNA off the 5v on the USB port on my laptop. I have posted details of how I did on my website at http://myweb.tiscali.co.uk/gm8bjf/vna_usb.html I...
All, I am giving up on the VNA project. Soldering is too risky. I have a N2PK Dual Dectector Rev 4.1 for sale. This includes two detector boards. The price is...
Hi Dan, Sorry to hear you feel the soldering would be too risky for you. Ivan's V4.1 PCB with its solder mask makes it easier. ... Do you mean two bridge...
All, I kitted 14 VNAs for folks mostly in the RTP area. If folks look at the photo of my VNA on N2PK's web site at: http://www.n2pk.com/VNA/AG4AY_VNA.JPG they...
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