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QRS kit quesion from Newby kitter
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"Newton White"
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Hi All,
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I am building?the 30M QRSS and one of the interim checks is to see if
the circuit is oscillating at 10.140 MHz.
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I am using my FT-450 to check for oscillation, cw mode, and I do not detect
any noise there or anywhere +/- 200 Hz.
I decided to check voltages with my meter - one side of the crystal shows
voltage and the other side shows zero. Is the zero V reading?normal on one
pin of a crystal if there is a voltage on the other side? If not, then may I
assume the crystal is probably something I need to replace?
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72,
Newt
k0nwt
or
K0NeWby T |
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"Charlie , W5COV"
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Newt ,
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The oscillator signal may not be strong enough for
you to hear it . Take an old test lead ( or just a piece of wire ) with a banana
plug and put it in the center of your antenna connector and then bring the end
of that lead near your crystal . You should be able to hear it then
.
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Crystals "normally" , unless they have been
dropped or treated roughly are not a component to suspect first .
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Charlie , W5COV |
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"Newton White"
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I figured it out with some helpful advice from several of my mates.?I
now understand why no DC is shown on my meter, as it shouldn't be there! AC is
what belongs there, and so it is. The crystal is indeed working and I originally
saw it up 4 KHz on USB instead of CW. I added the rest of the parts and now it
is oscillating closer to 10.140.00.
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I should have a working beacon with a resonant dipole a few feet in the air
later this week.
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72,
Newt
k0nwt
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"Newton White"
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Well, I had it working for awhile. I listened on my radio at the beacon
working 12 words a minute. Then I think I went too far counter clockwise on R8
whilst adjusting the power out. I added the jumper to slow the dits to 6
seconds. Now when I power up, the call is sent once and at 12 words per minute,
then a pause, then the carrier is keyed up and hangs. Did I fry a component when
I went too far on the R8 adjust?
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72,
Newt
k0nwt
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"Charlie , W5COV"
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Newt , not being familiar with building the kit , I wonder
if you were using a dummy load or the same load doing all of the tests ?
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If it is not something in the way the ID is configured ,
it could be some RF getting back into the transmitter , especially if you
switched from a dummy load to an antenna .
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If you are still showing RF output , you probably haven't
hurt anything in the final . It is running pretty easy at the 5-6 volts shown
.
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Charlie , W5COV |
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Ed - K9EW
Hi Newt,
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You say the carrier is keyed up after your call is sent at 12wpm, but then just hangs.? Here are some things to check: 1)? If you listen to the carrier on your receiver, do you hear a very slight shift in frequency occasionally (it should change frequency by a few *cycles* whenever the voltage on pin 3 of IC1 changes)?? If you can hear that frequency shift, it's working. 2)? If you don't hear that, measure the voltage on pin 3 of IC1 with a DVM (black lead to ground).? It should be toggling occasionally from 0 to 5V.? (You *are* using a 5-6V supply, right?) 3)? Make sure the twisted wires on C3 aren't shorted together.? (If they were shorted, you would see the signal voltage on pin 3 of IC1 on L1.) 4)? Check all your solder connections while you're at it; it only takes one bad connection to ruin your day. 5)? Check the voltage on the "Q3 side" of R6.? It should be between 0 and supply voltage. 6)? Check the voltage on the "Q3 side" of L2.? It should be a little bit lower than the supply voltage. 7)? Do you have an oscilloscope? Report back to us what you've found. 73, ed - k9ew On Sun, Jun 6, 2010 at 11:08 PM, Newton White <k0nwt@...> wrote:
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"Newton White"
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Hi Ed,
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I am finally getting back to this as life, work, etc. has a habit of
interfering with other fun at times. I went back and did a better job of
matching the rf out to a good 50 ohm load. After that I decided to listen again
through my receiver. I do have a decent bench top power supply that I recently
acquired. I set it to 6.0 V and limited the current to 0.20 A. I heard my call
again at 12 wpm, and then listened carefully for about 20-25 seconds and heard
the very slight freq. shift for about 12 seconds after which it shifted again. I
am positive it is working correctly now.
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The next step is to start the Argo grabber and figure out the kits
operating frequency and also the shift. I did acquire an Oscilloscope this past
weekend at the Atlanta Hamfest from Mr. Garcia, but I now need a crash course in
it's proper operation before I can make good use of it. It's an older 100 MHz
made by Kikusui - I was able to see a sine wave at around 10 MHz when probing
the kit - I just need to see how to get an exact reading.
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I will put the kit in a plastic box with 4 D-cells and attach to a tuned 30
M wire dipole hopefully by the weekend - I will post the operating freq. on
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Thanks for the suggestions!
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k0nwt
Newt
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Ed - K9EW
Hi Newt,
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Sounds like you've got it nailed.? Congratulations. A 'scope is a real handy thing to have around; I'm sure you'll get a lot of use out of it. 73, ed - k9ew
On Wed, Jun 9, 2010 at 7:59 PM, Newton White <k0nwt@...> wrote:
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