[HQRP] Fwd: New NorCal Kit: The Nor'Easter Short Wave Receiver

[Ed Manuel]

OK, all you SWL's on the list.  You been waiting for it, Ted.  Here 'tis.

Ed


>Delivered-To: directvinternet.com%edmanuel@directvinternet.com
>X-Received: 20 Aug 2002 12:41:33 GMT
>Date:   Mon, 19 Aug 2002 07:29:53 -0700
>Reply-To: ki6ds@dph.dpol.net
>Sender: owner-qrp-l@Lehigh.EDU
>From: "Doug Hendricks" <ki6ds@dph.dpol.net>
>To: "Low Power Amateur Radio Discussion" <qrp-l@Lehigh.EDU>
>Subject: New NorCal Kit: The Nor'Easter Short Wave Receiver
>X-To:   <qrp-l@lehigh.edu>
>X-Cc:   <WA6GER@aol.com>, "Steven Weber" <kd1jv@moose.ncia.net>
>X-Mailer: Microsoft Outlook Express 5.50.4133.2400
>
>NorCal is very excited to announce their latest kit, the NorCal Nor'Easter
>SW Receiver.  Bet you thought that I was just messing around in Maine this
>summer huh?  Well, we are very pleased to announce this kit designed by one
>of the Design Masters of QRP, Steve "Melt Solder" Weber, KD1JV.  If you have
>spent any time at all on this list you are familiar with his work, and he
>has done it again.  Here is what I am talking about.
>
>A 5.2 to 17 MHz Short Wave AM Receiver
>Featuring digital PLL tuning
>Custom designed for NorCal by Steven Weber KD1JV
>
>The Nor'Easter is a double conversion super heterodyne, using a 10.705 MHz
>first IF and a 455 KHz second IF. The receiver is digitally tuned, using a
>VCO and Phase Lock Loop circuit.  The kit will have a doublesided, plated
>through, silkscreened board done by our normal board house, so you know that
>the board will be first class.  This kit is a hybrid, being mostly surface
>mount (1206 parts) and a few through hole parts where practical and
>necessary.  Steve has layed out the board so that it will fit into an
>Altoids tin, in fact, mine is in just such a case.  Steve, Seab Lyon, Tony
>Fishpool, Graham Firth and I have all built one of these niftly little kits,
>and they are fun and easy to build.  The receiver does not come with a BFO
>and is not designed to be a ham band receiver, but rather a Short Wave
>receiver.  It comes with digital readout, 10 programmable memories, and just
>needs a 3 foot piece of wire for an Antenna.  I have copied several European
>Short Wave stations from California with mine.  This one will make an ideal
>traveling companion for those nights when you are away from home and want to
>listen to some short wave.
>
>What is the cost of this kit?  $50, including shipping and handling in the
>US & Canada, $55 DX.  What do you get?  The kit contains the circuit board,
>all board mounted components.  All controls and connectors are board
>mounted.  All you need is a case and you can build your own digital readout,
>memory Short Wave Receiver.  We are only going to kit 200 of these, and
>there will not be a second run.  If you want one of these, you better hurry.
>We are taking orders now.  To order send me an email to guarantee yourself a
>kit.  Address it to:
>
>ki6ds@dph.dpol.net
>
>Put Nor'Easter Kit Reservation in the subject line.
>
>I will send a reply giving you your kit order number and instructions on
>where to send your money.   The kits should ship by Pacificon, if not
>sooner.
>
>Here are some details about the kit from the manual.  If you have further
>questions, please ask Steve Weber, KD1JV, who is the designer.
>
>The audio jack is set up for stereo headphones. There is enough drive for a
>small speaker if you wish. You will need to wire it to a stereo plug, using
>the tip and ground ring. The receiver is very quiet until you are tuned to
>or near a station. Don't leave the volume turned up too high when your
>tuning around, especially with headphones on, or you might blow your ears
>off!
>
>The Nor'Easter is nominally powered with a 7.5 volt source, and draws about
>25 ma. The receiver will work with voltages between 6 and 9 volts. Power is
>inputted using a 7 mm coaxial power jack and plug.
>
>The Nor'Easter is designed to be used with a short antenna, such as a three
>foot piece of wire.
>
>When powered up for the first time, the receiver is programmed to load the
>low end of the tuning range, 5.200 MHz. The single digit LED frequency
>display will sequence out the operating frequency, MHz digit first, leading
>zero suppressed, and then go blank to conserve power. If a frequency is
>programmed into memory location [0], the receiver will power up on that
>frequency.
>
>The receiver is tuned by using the up / down tuning buttons. These are best
>activated by rocking them side to side, rather than pushing directly down on
>them.
>  The receiver tunes in 5 KHz steps, each time the button is "clicked". If
>one of the buttons is held closed for longer than one second, an auto tune
>mode is enabled, which automatically increments the frequency at fairly fast
>rate. If the auto tune mode has been enabled, 1.5 seconds after the tuning
>button is subsequently released, the frequency display will automatically be
>activated.  The delay allows you time to single step the tuning buttons to
>fine tune in a station you might have gone past, without first having to
>wait for the display to finish sequencing.
>
>The FUNCTION button controls four receiver functions.
>
>1.  Activate the frequency readout
>2.  Select preprogrammed short wave bands
>3.  Select user programmed frequencies
>4.  Store a frequency into memory.
>
>The various functions are selected by holding down the function button for
>various lengths of time. A momentary click of the function button will
>activate the frequency readout. Holding the function button closed for a
>longer than one second will start to sequence through the remaining options,
>in one (1) second intervals. The current function is indicated on the
>display and that function is activated by releasing the function button
>while that option is being displayed.  Scrolling past the last function will
>exit the function select mode.
>
>Functions are indicated by the following letters on the display:
>
>"b" Band selection
>"r" recall a memory
>"S" store into a memory
>
>Once a function is selected by releasing the button, the selected function
>indication will remain on the display until the Tune Up or Tune Down buttons
>are used, or the function mode can be escaped with no action taken by
>pushing the function button again.
>
>Six preprogrammed short wave frequencies are available for quickly getting
>to various locations in the tuning range of the receiver.  These are:
>
>  (0) - 6.000 MHz, (1) - 7.500 MHz (2)- 9.5000 MHz (3) -11.500 MHz (4)-13.500
>MHz (5)- 15.500 MHz
>
>Locations 6-9 are not used and pushing the function button while one of
>these locations are selected will return the receiver back to the frequency
>where it was tuned. If one the 0-5 locations is selected when the Function
>button is pushed, the receiver will tune to that frequency and the frequency
>display will automatically activate.  Up to ten of your favorite short wave
>stations may be stored into memory. If a frequency is stored into memory
>location "0", this is used as the default power on frequency of the
>receiver. Operation of the Memory recall function works just like the band
>selection mode. Use the Tune up or Tune Down button to select one of the ten
>locations, 0-9, then use the function button to activate. The display will
>automatically readout the new frequency. If the location is blank, an "E"
>for empty will be displayed for one second.
>
>The antenna input circuit is comprised of L1 (10uHy) and C1 (22pFd) and is
>then coupled to the input of a SA612 mixer/oscillator, U1. L1 and C1 form a
>low pass filter, which helps keep local FM broadcast stations out of the
>mixer. Strong VHF signals can mix with harmonics of the VCO and cause
>problems. L1 also helps to base load the short wire used as an antenna.
>The oscillator section of U1 is used as the first Local Oscillator. The tank
>circuit is comprised of the two coils, L3 and L4, and the varactor tuning
>diodes, D2, D3. MOSFET Q4 is used to short out L4, in order to increase the
>range of the oscillator. In order to work, a DC voltage needs to be applied
>to the Q4's drain and is supplied by R22, a 4.7K W resistor. The VCO signal
>is picked off the junction of the two oscillator feed back capacitors, C4
>and C5. Q1 is used to isolate and amplify the VCO signal in order to drive
>the input of the PLL chip, U3. Q1 receives it's operating voltage from the
>U1, through resistor R1.
>U3, a MC145170 PLL chip, contains the logic for controlling the VCO
>frequency. The chip is serially loaded with data from the mP controller,
>giving it the proper set-up information, divide ratio for the reference
>frequency and input frequency division ratio. The reference frequency is set
>to 5 KHz, which is derived from the 10.240 MHz crystal also used as the
>second LO. This sets the minimum tuning step of the receiver. The input
>divider (/N counter)  is set to divided down the VCO to match the reference
>frequency. A Phase detector determines if the two frequencies match or not.
>Differential outputs of the phase detector drive the inputs of the loop
>filter, with a CMOS rail-to-rail output op amp as the active part of the
>filter. The phase detector drives the inputs to the op amp in such a way so
>that the output of the op amp produces the proper tuning voltage for the
>desired VCO frequency.
>The output of the first mixer goes through a 10.7 MHz ceramic filter and
>then into the input of the second mixer, U2. Since a 10.240 MHz crystal is
>used to convert the 1st IF to the 2nd IF of 455 KHz, the actual 1st IF is
>10.705 MHz.  After being converted to 455 KHz by the 2nd mixer, the signal
>passes through a 455 KHz ceramic filter, which provides most of the
>receivers selectivity. The signal is then amplified by a high gain cascode
>amplifier, consisting of Q2 and Q3. "Back-to-back" 455 KHz IF transformer
>are used on the output of the amplifier, providing some additional
>selectivity. Since T2 is lightly loaded on it's output, it provides some
>additional passive gain. R5, a 1 megaohm resistor, is used to supply some
>forward bias to diode D1, which does the AM signal detection. The addition
>of the forward bias greatly increases the sensitivity of the receiver. The
>recovered audio then goes into the volume control and then into a LM386
>audio amplifier.
>
>72, Doug


---
Send e-mail to 'listar@stevens.com' with subject:

  'unsubscribe hqrp YourEmailAddress'  to unsubscribe from this list
  'subscribe hqrp YourEmailAddress'    to subscribe from this list
  'help'              for more information

Send e-mail to 'dave@stevens.com' to contact a list administrator