QRZ! Ham Radio 4/QRZ Ham Radio Callsign Database - Volume 4.iso/files/qrp/archives/current.txt/text0032.txt

Text File | 1994-11-27 | 10.3 KB | 240 lines

Greetings to the QRP mailing list.

I just finished the assembly of my NorCal 40 Partial Kit. I did the bulk of the
soldering and inductor winding over the July 4 weekend. The only snag I ran
across was a dead transmitter section. After some signal tracing and head
scratching I found a tiny solder bridge shorting the VFO to ground near
the input of the xmit mixer. It puts out 3 watts according to my 'scope or
2.5 according to my questionable old Swan watt meter.

I did a few things different than specified, but not by choice. Since the
MVAM108 varactors have not come in I went to the local electronic
"odds-and-ends" dealer (mostly "odds" :-)).
He dug up a box labeled "varactors" and told me they
were something like 42 pF at 4.1 volts. He gave me one. In addition, Mouser
was out of stock on the 39 pF mica cap in the VFO, so I used a 33 pF mica
cap. The VFO was about 200kHz low. I took two turns off L9 for a total of
57 turns. C50 varied the VFO oouldn't matter.

I welcome anyone's comments on the use of the 33 pF cap and the unknown
varactor. The varactor looks like a glass diode with several funny bumps,
not a 2 leaded plastic transistor pack. I think the box they came from were
labeled with a part number, but I didn't write it down. If it is deemed
"acceptable" by Wayne, et. al., I might offer to send units to any takers
on this list building NC40 partial kits. I say "might" because the local
"odds-and-ends" dealer was going out of business the day I stopped in for
the varactor. It is unknown if I can still get them from him or if he can
still find them after his move. He is switching to strictly mail order, no
retail store front and moving to a smaller place that will only hold about
a third of his (then) inventory of "stuff".

Now to make that first NorCal 40 contact.....

73

--

       Jason F. Penn N9RPT |  Persoft, Inc.  |  [e-mail]
   Whenever I want to find something, it's always in the last place I look.

From [e-mail]  Thu Jul  7 13:11:34 1994
Return-Path: <[e-mail]>
    id AA22549; Thu, 7 Jul 1994 13:11:01 -0400
    id AA13111; Thu, 7 Jul 94 13:13:09 EDT
    id AA19143; Thu, 7 Jul 94 13:13:07 EDT
Message-Id: <[e-mail]>
To: [e-mail]
Subject: 40-40 questions
Date: Thu, 07 Jul 94 13:13:06 -0400
From: "John F. Woods" <[e-mail]>
Sender: [e-mail]
Precedence: bulk

So I finally put my new 40-40 into its case last night and started aligning it.
The receiver seemed to work OK, but I noticed a very strong spur at about
7,001,700Hz or so (well, the local oscillator was at 3.000700, and I think
that the NE-602 IF mixer is running at 4.001MHz, but my frequency counter
disturbs it too much to be sure).  I haven't tried aligning the transmitter
yet, since I'd like to know where that spur is coming from; does anyone else
hear it?

From [e-mail]  Thu Jul  7 18:01:13 1994
Return-Path: <[e-mail]>
Date: Thu, 07 Jul 94 01:14:27 GMT
From: [e-mail] (George Dobbs G3RJV)
Reply-To: [e-mail]
Message-Id: <[e-mail]>
To: [e-mail], [e-mail]
Subject: Re: QRP library comments
X-Mailer: PCElm 1.09
Lines: 22
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In message <[e-mail]> Daniel C Halbert writes:
> WA8MCQ writes:
> >Another good book not on Jims list:  The Joy of Electronics by
> >Horowitz and Hill.  Priced somewhere in the $70 range, and well worth
> >it--heavy, lots of pages.  I have a copy on my desk at work, provided
> >by the company,  (Also available:  student workbook; I've seen it but
> >didn't have the chance to open it; in the $25 class, I think.) ...
>
> Er, I believe it's the "Art of Electronics". It is a great book. The
> student workbook is really great, too - it goes through some designs
> and calculations step by step, includes details not in the book, and
> did a lot to increase my understanding.
>
> Dan, KB1RT
>
MY FAVOURITE BOOK ON ELECTRONICS...................................

--
---------------------------------------------------------------------------
George Dobbs G3RJV                  "It is vain to do with more,
G-QRP Club                           what can be done with less."
---------------------------------------------- William of Occam (1290-1350)

From [e-mail]  Thu Jul  7 18:01:29 1994
Return-Path: <[e-mail]>
Date: Thu, 07 Jul 94 22:44:56 GMT
From: [e-mail] (George Dobbs G3RJV)
Reply-To: [e-mail]
Message-Id: <[e-mail]>
To: [e-mail]
Subject: G QRP CLUB
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Lines: 23
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Following an enquiry, may I explain how to join the G QRP Club.

Anyone sending their FULL POSTAL ADDRESS
to [e-mail]
or to the postal address below
will receive a sample of SPRAT
with information and application form for the G QRP Club.
(If you layout your address as below, that also helps - I just cut it out
to use as an address sticker)
Typical QRPer - Anything to save energy....

George Dobbs  G3RJV
St. Aidan's Vicarage
498 Manchester Road
Rochdale
Lancs
OL11 3HE
England
--
---------------------------------------------------------------------------
George Dobbs G3RJV                  "It is vain to do with more,
G-QRP Club                           what can be done with less."
---------------------------------------------- William of Occam (1290-1350)

From [e-mail]  Fri Jul  8 11:23:34 1994
Return-Path: <[e-mail]>
    id m0qMHlR-0000AaC; Fri, 8 Jul 94 10:22 CDT
Message-Id: <[e-mail]>
From: [e-mail] (Jason Penn)
Subject: Revised Tale of My NorCal 40
To: [e-mail]
Date: Fri, 8 Jul 94 10:22:56 CDT
X-Mailer: ELM [version 2.3 PL11]
Sender: [e-mail]
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(This is a revised version of my posting from yesterday. As many of on list
probably knew before I did, I was wrong about some rather important aspects
regarding my NorCal 40's alignment. I am reminded of the quote, "I thought
I was wrong once, but I was mistaken".

Greetings to the QRP mailing list.

I just finished the assembly of my NorCal 40 Partial Kit. I did the bulk of the
soldering and inductor winding over the July 4 weekend. The only snag I ran
across was a dead transmitter section. After some signal tracing and head
scratching I found a tiny solder bridge shorting the VFO to ground near
the input of the xmit mixer. It puts out 3 watts according to my 'scope or
2.5 according to my questionable old Swan watt meter.

I did a few things different than specified, but not by choice. Since the
MVAM108 varactors have not come in I went to the local electronic
"odds-and-ends" dealer (mostly "odds" :-)).
He dug up a box labeled "varactors" and told me they
were something like 42 pF at 4.1 volts. He gave me one. In addition, Mouser
was out of stock on the 39 pF mica cap in the VFO, so I used a 33 pF mica
cap. The VFO was about 200kHz low. I took two turns off L9 for a total of
57 turns. C50 varied the VFO over a range of 260 kHz (wow! the manual says
it should vary about 75 kHz) and the tuning pot covers a range of 68 kHz
(which would seem about right). I set it up to tune from 7.082 Mhz to 7.150
Mhz. Oh yeah, I used 4.9152 MHz crystals because that's what I found cheap
at Dayton. I figured a 200 Hz change in the IF wouldn't matter.

It turns out that the above tuning ranges are hogwash. I (initially) used
my HF rig to "listen" for the tx/rx signals. I accidentally fell upon
what must have been the third harmonic of the VFO. The third harmonic
explains the ridiculously large apparent tuning range. A quick rewind of
L9 with 62 turns got it down to 7.108 MHz with a high end of 7.131 for a
range of 23 kHz. I verified these frequencies with the big HF rig *and*
a frequency counter. By the way, an oscilloscope probe makes a nice
frequency counter probe. Just be careful that the signals you connect to
the counter won't fry it. My counter isn't very sensitive and will take
up to a few volts. Your mileage may definitely vary.

I welcome anyone's comments on the use of the 33 pF cap and the unknown
varactor. The varactor looks like a glass diode with several funny bumps,
not a 2 leaded plastic transistor pack. I think the box they came from were
labeled with a part number, but I didn't write it down. If it is deemed
"acceptable" by Wayne, et. al., I might offer to send units to any takers
on this list building NC40 partial kits. I say "might" because the local
"odds-and-ends" dealer was going out of business the day I stopped in for
the varactor. It is unknown if I can still get them from him or if he can
still find them after his move. He is switching to strictly mail order, no
retail store front and moving to a smaller place that will only hold about
a third of his (then) inventory of "stuff". The MVAM108 is the hot setup,
but substituting another varactor can get you started until the real thing
arrives.

Now to (still) make that first NorCal 40 contact.....

73

--

       Jason F. Penn N9RPT |  Persoft, Inc.  |  [e-mail]
   Whenever I want to find something, it's always in the last place I look.

From [e-mail]  Fri Jul  8 12:10:25 1994
Return-Path: <[e-mail]>
    id AA25293; Fri, 8 Jul 94 11:08:54 -0500
          via Charon-4.0A-VROOM with IPX id 100.940708110809.320;
          08 Jul 94 11:08:24 +0500
Message-Id: <[e-mail]>
From: "Evert Halbach" <[e-mail]>
Organization:  Nicholls State University
To: [e-mail]
Date:          Fri, 8 Jul 1994 11:07:58 CST
Subject:       20 mtrs "Shrinking"
Priority: normal
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Sender: [e-mail]
Precedence: bulk

What is the garbage I hear around 14.050 and above.  Sounds like
WEFAX or something.  It seems as though they keep gaining on the cw
portion of the band.  It looks like they have "slid" down an
additional 10 kc (Khz) since I started listening to cw again a couple
of months ago.  Am I wrong or is it that we are being "invaded"???

            73 de WA5OJI Evert



        Evert R. Halbach   WA5OJI
Internet - [e-mail]
Phone    - [phone]
Snail    - P.O. Box 2168   Thibodaux, La. 70310