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PostPosted: Mon Jul 15, 2013 1:21 pm 
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Joined: Mon Jul 15, 2013 12:23 pm
Posts: 74
Hi, I just received my Barebones 5 watt driver kit and will be using it as a final amp for one of my QRP projects, and was wanting to know when the new assembly instructions for the Rev B board with the PTT relay might be available. Also, can you tell me what model number that relay is, I thought the ones I had in stock would work but they are too big to fit on the board. What PNP transistor should be used for the driver to the relay, any switching transistor? If I install D201, (a 5.1V Zener), there would be no need for 5V at the power plug would there? Sorry for all the questions, but I'm having a hard time understanding the documentation.

Joel
KB6QVI


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PostPosted: Mon Jul 15, 2013 8:20 pm 
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Joined: Mon Jul 23, 2012 6:25 am
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Hi Joel,

With getting the new amp instructions ready and the report for the FCC, I've been neglecting the driver. There are several relays that come in the 10 pin dip case. The NEC EA2-12NU available from Newark 25M9064 is $2.28, the Tyco D3002 is $2.48 at Mouser.

The PNP transistor is just a switch a 2N2907 or 2N3906 will work just fine. Make R209 4.7K, R208 1K. D201 should be a 5.1V zener and yes it eliminates the need for an external 5V.

Otherwise the instructions here: https://sites.google.com/site/hardrock5 ... driver-pcb are pretty much the same for T201 and mounting Q201.

There are alternate winding instructions for T201 if you would like 10W rather than 5W. If you want to use the 3 cap/2 inductor filter you'll need to remove C210 and C211 and figure out the values for C213, C214, C215 and L202/L203 depending on which band(s) you want to run. You could use the 40/30M, 20/17M, 15/12/10M or 6M filter values from the Hardrock-50 schematic if you want other pairs 30/20M, 17/15M should be possible but I don't have a design handy. I can crank one out if needed. I'll find one for 80 as well because the HR50 uses a single coil filter on 160 and 80M.

I'll try to get more solid instructions posted.

73's
Jim WA2EUJ


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PostPosted: Mon Jul 15, 2013 11:21 pm 
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Joined: Mon Jul 15, 2013 12:23 pm
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Thanks Jim,

That was the info I was searching for, don't rush the documentation for me. I do want the 10 watt option so will be winding the autotransformer, I may need some additional info on that, but will cross that bridge when I get to it. Thanks again.

Joel
KB6QVI


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PostPosted: Fri Aug 02, 2013 1:44 pm 
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Joined: Mon Jul 15, 2013 12:23 pm
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Hi Jim,

A few more questions,

What are the values for the optional resistors R205,R206?
Should I install R207, (what value), or install a jumper? I will be driving it with about a watt, but sometimes 330mw.
I have installed a 5.1V zener in D201, so am I to assume that I should connect 12V to the power connection marked 5V and the one marked 12V?

Thanks
Joel KB6QVI

Edit: Sorry, I just found this page, Driver Input Attenuator, so I'm clear on this now.


Last edited by caulktel on Fri Aug 02, 2013 9:14 pm, edited 2 times in total.

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PostPosted: Fri Aug 02, 2013 3:38 pm 
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Joined: Mon Jul 15, 2013 12:23 pm
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One more,

I will be using my driver as a final on a QRP transceiver, so what will be the values for the 5 element LPF?

Joel KB6QVI

Edit: I looked at my MST400 schematic which is 40 meters also, I can copy those values for the LPF, they are: 1.1Mh for the inductors and 470PF for the outside caps and a 1000PF for the middle cap. Does that sound good? I appreciate the help.

Joel


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PostPosted: Fri Aug 02, 2013 6:10 pm 
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Joined: Mon Jul 15, 2013 12:23 pm
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As far as the 1:3 transformer goes, does this look right?
[img][IMG]http://i222.photobucket.com/albums/dd4/caulktel/photo_zps7fa68003.jpg[/img][/img]


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PostPosted: Mon Aug 05, 2013 6:49 am 
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Joined: Mon Jul 23, 2012 6:25 am
Posts: 1143
Hi Joel,

I was away for the weekend but I'm back now. The photo of T201 looks correct as far as I can see, the 3:1 should have a 1 turn winding from 12V to the Drain and a 2 turn winding from the drain to the output, it's an auto transformer so the 1 turn winding is used twice to make 3:1.

If you put a 5.1V zener in D201 and a 1K resistor at R208, populated Q7 with a 2N3906 and R209 with a 1K-5K, the bias supply should come on then you ground the PTT line.

Although now that I look at it there maybe another issue. The coil on RLY201 actually has a built in diode. The good news is that you won;t need D202, the bad news is that it's hooked up backwards. Pin1 should get +12 and Pin10 should be grounded. It should be easy enough to correct, cut the thermal relief 'spokes' connecting pin 1 to the groundplane, cut the trace feeding pin10, jumper pin to to the anode of the now unpopulated D202 site and jumper the cut trace that used to feed pin 10 over to pin 1.

As for LPFs for 40M just about any 50 ohm in/out filter will work. I ran the values you gave below through Eagleware and they look good, see the posted jpg. The HR50 uses T50-2 (red) cores with 12 turns of #22 wire 560pf's on the outsides and a 1000pf in the middle. That filter is for 40M and 30M.

For 40M only try T37-2 with 16 turns of #24 wire with 1000pF on the outsides and 1500pF in the middle.

Kepp us posted on your results.

73's
Jim WA2EUJ


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PostPosted: Mon Aug 05, 2013 8:48 am 
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So, if I understand correctly, the diode is unneeded because of the internal diode in the relay. The relay IS or isn't mounted correctly? but the traces going to it are swapped? Is this because of the relay I used? Should I have used a different one? Thanks for the LPF info, I figured it was pretty close. Is the updated documentation going to be ready soon?

Joel
KB6QVI


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PostPosted: Mon Aug 05, 2013 11:09 am 
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Joined: Mon Jul 23, 2012 6:25 am
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Yes the diode isn't needed. You used the correct relay, I messed-up the schematic/layout. Since the relay is already installed you can see if it works, but I think that pins 1 and 10 need to be swapped which you should be able to do without removing the relay.

See diagrams ...


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PostPosted: Tue Aug 06, 2013 5:59 pm 
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Joined: Mon Jul 15, 2013 12:23 pm
Posts: 74
The board is all finished except for the final Mosfet, waiting for the heat sink to get here. All mods have been done on top and bottom of the board.

Something I'm still not clear on is, when I power up the board do I apply +12V to both the power pins, the 12V and the 5V?
Also. I need to know how to set the bias current for the final, ( I found some reference to it in the Hard Rock 50 alignment procedures, but not sure if it applies to this board or not).

[img][IMG]http://i222.photobucket.com/albums/dd4/caulktel/photo1_zps1b11659e.jpg[/img][/img]

[img][IMG]http://i222.photobucket.com/albums/dd4/caulktel/photo2_zps2229c422.jpg[/img][/img]

Joel
KB6QVI


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