kb3ouk
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« on: January 29, 2011, 03:17:53 PM » |
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i know there are a few people on here that have put one of these kits together. what capacitor did you use for C3 to center the receive range on 3.885? the only value i could find to put the voltage anywhere near 2.72 to get it centered on 3.885 is 22 pF.
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W1RKW
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« Reply #1 on: January 29, 2011, 04:51:33 PM » |
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Shelby,
I ended up paralleling 2 caps together to get my range of frequencies where I wanted them. I used a 150pf and a 22pf. I think in my situation I don't have the right number of turns on L2. I didn't use the built in voltage reference to center my receive section. I used a signal generator instead.
Bob
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Bob
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kb3ouk
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« Reply #2 on: January 29, 2011, 05:03:38 PM » |
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what range of frequencies are you using? and i might have the same problem with L2 because if i remember right i think i missed a turn
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W1RKW
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« Reply #3 on: January 29, 2011, 05:18:02 PM » |
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I'm using 3870 to 3885 on the transmit side, 4 crystals 5Kcs apart. The receive section is centered around those 4 freqs.
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Bob
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kb3ouk
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« Reply #4 on: January 29, 2011, 05:35:51 PM » |
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i found out its easier to try to allign it by using some way to listen to the LO, i use a coax jumper hooked to my icom 718 and hold it above L2 and set it for the correct LO frequency and on SSB then tune the smt variable cap till i get a zerobeat.
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kb3ouk
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« Reply #5 on: January 29, 2011, 06:26:36 PM » |
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it ends up i put a cap in unsoldered it works alrightand has a voltage very near 2.72, i solder it in and the voltage drops. what is going on?
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W1RKW
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« Reply #6 on: January 29, 2011, 07:33:04 PM » |
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I had the same experience when doing the procedure described in the assembly instructions and that is how I ended up paralleling the 150pf with the 22pf cap.
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Bob
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kb3ouk
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« Reply #7 on: January 29, 2011, 09:42:57 PM » |
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i got it at the right voltage now, ended up taking two turns off L2 leaving it with 30 turns and putting a 47 pf cap in C3. now i'm having trouble with the rest of the allignment porcedure, according to the manual, it says to touch R2 and adjust T2 for peak shortwave broadcast signal, i don't hear anything when i do this except for our electric fence, or can both T1 and T2 be peaked on a 75 meter signal?
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W1RKW
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« Reply #8 on: January 30, 2011, 06:18:32 AM » |
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yep, had the same trouble as well. I used a signal generator to peak both transformers.
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Bob
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W9RAN
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« Reply #9 on: January 30, 2011, 11:58:25 AM » |
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Good to know more Retro's are on the way. In case you're not aware, there's a Yahoo Group with nearly 300 members now: http://groups.yahoo.com/group/SWLRetro75/Search archives for helpful ideas. Designer Dave Benson K1SWL is also at your beck and call. 73, Bob W9RAN |
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kb3ouk
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« Reply #10 on: January 30, 2011, 04:36:05 PM » |
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i checked around on the yahoo group but couldn't find anything that i thought was helpful, but bob's problem with not having the right number of turns on l2 put me on the right track to fixing it myself.
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kg8lb
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« Reply #11 on: February 10, 2011, 11:51:04 AM » |
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Built three so far . All were built per instructions and all three work as stated.( Far better than I had expected !) I would suggest getting the coils "right" first . I did align a bit differently though. I used a 6.000 mHZ sig from my antenna analyzer to peak the IF , just bring the lead close to the XTAL filter bank. Next set the analyzer for 3.880 and swept the tuning pot to locate the signal. Held in as per directions assorted value caps for C3 to get the one closest to center of dial. Used the trimmer to fine tune. Go back and re-peak the IF and RF and you are in business. YRMV
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W1RKW
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« Reply #12 on: February 10, 2011, 05:21:47 PM » |
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I'd be really curious if someone could quantify receive sensitivity on the Retro. Many state their receive sections are sensitive yet mine is deaf below S9 when compared to the FT102 so I added an RF amp to the front end to liven things up a bit.
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Bob
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« Reply #13 on: February 10, 2011, 06:06:20 PM » |
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I'd be really curious if someone could quantify receive sensitivity on the Retro. Many state their receive sections are sensitive yet mine is deaf below S9 when compared to the FT102 so I added an RF amp to the front end to liven things up a bit.
Bob, It would seem something is not quite right. The Retro RX is quite sensitive . Most anything I can hear on either of my Drake R8-As is right there on the Retro as well. |
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