[DSP-10] DSP-10 C203-C219?Feed-through capacitors

[ve3ytz at sympatico.ca]

Thank-you Courtney

Your comments are very interesting and useful. Clearly, I was way off track linking the ferrite beads (FB) to the feed-through capacitors (C203-C219). Now it is pretty obvious to me. 

With your observations in mind, I looked at Figure 11 in the QST article once again and I see illustrated the 2 FB per connector. I also notice that the drawing representing P205 illustrates the FB in a different manner than that shown for J211-J213 & J206. Any ideas regarding the significance for the different representation of the FB in J205?

Thanks again for your help & 73

BTW, I found your web-site very useful. Thank you for that as well.

Greg/VE3YTZ

> 
> From: Courtney Duncan <cbduncan at earthlink.net>
> Date: 2005/05/17 Tue PM 11:21:37 EDT> To: Discussion of DSP-10 2-meter transceiver <dsp-10 at mailman.qth.net>
> Subject: Re: [DSP-10] DSP-10 C203-C219?Feed-through capacitors
> 
> The way I read Figure 11., the ferrite beads went on the wiring on the 
> inside of external connectors J205, J206, and J211-J213, two each.  I 
> did not put any on the feedthroughs to the DSP box, C203 - C219, either 
> on the inside or on the outside.
> 
> I have a couple of not-very-good pictures of this on my website> 
> http://home.earthlink.net/%7Ejccool3/dsp10.html
> 
> Scroll down to the two pictures between February 24 and February 26, 
> 2005 text entries.  These are reduced in size in the web page 
> representation, but in my browser I can right click on the image, select 
> "View Image", then when the image is the whole view, the cursor becomes 
> a "+" which will magnify it so much that it doesn't entirely fit on my 
> screen.  In this huge view, I can see one of the ferrites on one of the 
> yellow coaxes in the middle and around the power inputs at the upper 
> left on the top picture.  In the bottom picture you can see a bead 
> around each of the coaxes, one on the BNC and one on the "TX Out" (red) 
> phono jack.
> 
> This was the only way to put the beads that I had around the coaxes that 
> I had.  I wound each power lead through each ferrite twice because I 
> could and this would lead to more isolation.  I think it is best to have 
> these ferrites as near the wall / connector as possible.  I think mine 
> ended up being trapped there by the wiring arrangement in the final 
> assembly and if I had thought there would be a problem with them staying 
> put, I would have tacked them with a little RTV, but I don't think I 
> thought or did this.
> 
> By the way, the rat's nest of internal interconnects pictured is not 
> well made up.  Most of the DSP-10s built on this list (I bet) have well 
> bundled and routed harnesses, such as those pictured in QST, which is 
> generally a better approach, and which I would recommend.
> 
> ve3ytz at sympatico.ca wrote:
> 
> > Greetings to the group
> > 
> > I am in the process of constructing the PC-board box and looking down the line I see I have to mount some feed-through capacitors. There are some ferrite beads that also come into play. In the Oct 1999 QST article describing the DSP-10 project, Bob wrote:
> > 
> > In some cases,there are bypasses right where a connector
> > is mounted and ferrite beads are placed over the connecting wires. These beads are shown in Figure 11, the interconnection
> > schematic. It is best to err on the side of extra shielding and filtering than having to add parts later on.
> > 
> > I must admit it is not very clear to me how these beads should be mounted: are they just loose and and hang between the PC box and the connecting wire, or are they soldered /glued? The fit is very snug, but they will pop off. Are the beads on the outside of the PC-box or inside or are they both side (inside and out)? 
> > 
> > I have searched through the discussion forum (found nothing) and looked closely at a number of pictures (including the said QST article) and it isn't clear to me how this is done.
> > 
> > As always, I appreciate the help.
> > 
> > 73
> > 
> > Greg/VE3YTZ> > 
> > _______________________________________________
> > DSP-10 mailing list
> > DSP-10 at mailman.qth.net
> > http://mailman.qth.net/mailman/listinfo/dsp-10
> > 
> _______________________________________________
> DSP-10 mailing list
> DSP-10 at mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/dsp-10
>