Top IMO. ?Bottom actually degraded things on MY board. ?Probably need a few more people to test tis before a cull consensus can be reached.
Jim
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On Oct 12, 2018, at 4:34 PM, David Posthuma <
davep@...> wrote:
Jim:
?
I have built everything in my shack including an Elecraft K2 (I was a beta tester for the 100-watt linear amp), auto-tuner, and other smaller projects. So, I am fairly comfortable, but putting them in is far easier than getting them out¡a lesson learned from too much previous experience.
?
What is the consensus, solder the relays on top or on bottom of the board?
?
David A Posthuma, WD8PUO
1 (616) 283-7703
?
?
? will get you the relays at the cheapest price in the USA that I know of ?They even have free overnight shipping. ?
NO absolutely do NOT use a PC oven. ?You must use a solder sucker or solder braid from the underside of the board and unsolder each pin very carefully. In this case, using an oven would apply too much heat in all the wrong places with potentially disastrous results.
Not knowing your electronics background/expertise, my suggestion to you if you aren't comfortable with de-soldering the relays one pin at a time, ?you might try to find someone with de-soldering experience to help you so you don't accidentally destroy your uBITX PC board.
------ Original Message ------
Sent: 10/12/2018 11:58:40 AM
Subject: Re: [BITX20] Harmonics and Relay Replacement
Jim:
?
What are the actual part numbers of the Axion relays and where are you ordering them from? Did you need to use a PCB oven to remove the relays? What was your technique? I¡¯m sorry if these topics were already addressed and I missed it.
?
David A Posthuma, WD8PUO
1 (616) 283-7703
?
?
I have another V4 board that I'm going to build up, but I'm waiting on a special 3.2" Color TFT touch screen display (NOT a Nextion) for use with the Trimuvirate Skonk Worx "BITeensio" controller board. ?We have 2.8 and 5" displays running nicely with released software and instructions for them. ?The 5" draws too much current so the next is a compromise down to the 3.2" and that will probably be our last display iteration unless something really innovative comes out that's larger and keeps the current draw under 200 mA so we don't have to add heavy duty 3.3V regulators on the BITeensio.
I've already replaced the relays on the 3rd board with Axions (mounted on top) and I have one more set of the Axion relays on hand. ?I may just make up a test bed using a V3 board I have left over and keep it open frame with DIP sockets for the relays to make it easier to change them if something better than the Axion comes along. ?
One thing the Axions seemed to help with was reduce radiated pickup of digital noise from the controller card & wiring. ?It may be because I replace all 5 relays, or may be because I got better solder joints (non lead-free solder) when I replaced the relays.
------ Original Message ------
Sent: 10/12/2018 9:45:08 AM
Subject: Re: [BITX20] Harmonics and Relay Replacement
Good Morning Jim,
Thanks for entertaining the idea.? Your shared data maybe useful as you have shown same board and relay with different measured results.
For that particular board and the measurement data you gathered, I would say the results ARE encouraging from this viewpoint:
You have 4.5 dBc more margin to FCC spec on your worst case data point (40m 3rd harmonic) with the supplied data set.
<image001.png>
Comments:
I have no measurement error / uncertainty reference or relevant personal judgement / experience to truly offer.
But, I would think it more difficult to accurately measure the case of more suppression, and so the uncertainty here would be higher.
Note that the 2nd and 3rd harmonics are swapping (80m Top and 17m Bot)
Regards,
Gary
AG5TX
Jim Sheldon