20 Meter Ham Band Direct Conversion Receiver
BOM from BOB
Qty / Price / Value / Part / WWV2 / 0.50 / 36 pf C0G / C4.C6
3 / 0.75 / 0.01 (103) / C1,C5,C15
1 / 0.25 / 15 pf C0G / C3
1 / 0.25 / 27 pf C0G / C2
1 / 10 uf / C12 / Y
1 / 0.12 / .022 uf (223) / C11 2x.01?
1 / 220 uf / C8 / Y
1 / 100 uf / C14
4 / 0.1 (104) / C9,C10,C13,C7 / ~Y
2 / 42IF123 / L1,L2 with capacitors removed / Y
1 / 0.10 / 1N4002 / D1 varactor substitute
1 / 1N914 / D2 / Y
1 / SA612 / U1 mixer / Y
1 / LM386 / U2 amplifier / Y
1 / 0.29 / 78L05/6/8 / U3 regulator / Y
2 / 10K ¼ w / R5,R6 / ~Y
1 / 100K ¼ w / R3
1 / 0.04 / 10 ohm ¼ w / R4 / Y
1 / 1.11 / 10K ½ w pot / R2 linear
1 / 0.75 / 10K ½ w pot / R1 Jameco 254204
1 / Phone jack / J1 / Y
1 / 6.95 / PCB / Jameco 616673 $6.95 or 617649 $13.95 or 262511 $12.95
Adafruit Perma-Proto 3-pack $19.95 Raspberry pi $40
1 / 5.95 / Case / Jameco 675500 5.6x3.3x1.5” or 18914($3.95)
24 / 17.06 / Totals
Supporting Items for Meeting
1. 3 Copies of this document
2. DDS VFO document
3. Scope, power & test cables
4. Alligator clips
5. UL30A
6. XG3 & cable
7. Headphones
8. Antenna wire
9. BPF on perfboard
10. 20M receiver
11. TT1056: SA612, LM358 dual op amp, TDA2611 amp
12. Glasses, flashlight, magnifying glass
Lecture
1. Welcome fellow ham hackers; we are here to ham it up
2. Treasury report
3. Request donations of $1 per meeting
4. Progress reports from builders
5. Define: coulomb(Q), ampere(Q/sec), volt, capacitance(Q/V)
6. Micro(-6), nano(-9), pico(12)
7. ufd, uufd, nf, pf, 104, 390
8. Physical C=Ak/D
9. Tolerance J=5, K=10, G=20
10. Temperature C0G & NP0
11. Schematic errata
12. 20M DC block diagram
13. Superhet 4-module block diagram
14. LO with T50-2 specified with DL5SWB calculator
15. DDS VFO
16. BPF with 42IF123's on Radio Shack board
17. Wee Willy, Beach 40, MST400, DL7LP DSB transceivers
18. Youtube video demos of above 40/80 radios
19. Demos: scope XG3, scope audio, scope LO, DDS VFO, TT 1056
20. DTC or Elsie for modular BPF with IF cans or toroids
21. Layout tips: spacing and ground transformers
22. Test with MFJ 971 random wire tuner
23. sites.google.com/site/farsbarc and barcfars.blogspot.com
24. Yahoo Groups: BARC, BitX, Minimalist, Regen
25. Mouser BOMTool
- PBS Silicon Valley 2/5
27. WTWW@5950 & WWV@5MHz?
28. WWV review
29. 42IF123 datasheet
30. Resonance equation equates Xc=Xl: f=159/SQRT(LC); LC=(159/f)**2
31. Elsie & DTC for RF filter and RFSim99 for LO
32. BPF & DTC (test with GQRP table) next meeting
Superhet Specs
1. DTC RF filter module
2. 5 MHz LO from NC40A, Demaw, Farhan, ZL2BMI
3. SW-20 9 MHz IF or SST
4. NE5534 amp
Theory of Operation
ARRL QRP Classics Neophyte for 40/80M converted to 20M
Direct conversion means RF to AF in one step; RF+/-LO = AF(1KHz) so LO~=RF
RF filter – mini Ring Core Calculator or RFSim99 or DTC
Toroids self-shielding, low tech and cheap
Local Oscillator – RFSim99
Mixer datasheet
Amplifier datasheet
Circuit photo
Circuit diagram
Assembly Steps
1. Builders: BobV, KeithA, DonR, JeffS, NickC, JohnW, Rob, Ed KD6KCA, Elise observed
2. Tools needed
3. Parts needed
4. Insert 3 IC's
5. Amplifier and test with 1KHz from scope
6. Regulator and test
7. RF filter
8. Shorten leads in LO and move caps away from inductors
9. Ground inductor cans
Experiments
1. Demo scope 1KHz to LM386 input with&without gain cap
2. Demo scope on LO
3. Demo XG3 to scope
4. Demo scope to LM386 output with and without XG3 input
5. Demo Spectrogram for audio
6. Replace C2 with 60 pf varicap and tune with scope and XG3
7. XG3 as CW to calibrate LO
8. DTC with 56pf and 10 MHz crystal for WWV
9. Varicap in LO or filter
10. R3=100K
11. DTC or Elsie for BPF with toroids
12. PA2OHH spectrum analyzer
13. Anchor inductor for BPF
14. SST LM386 & AGC with an LED
15. Swap SA612 1&2 and LM386 2&3
16. Beach40 LM386 filtered amplifier
17. Build all VK3YE.com circuits
18. Cheap audio filter: 82R, 2x104
19. Build a 14-15 MHz LO to receive WWV: stripped down Farhan VFO
20. WWV antenna filter converted to 20M with 27 pf caps
21. Layout critical
22. 78L06 with bypass cap
23. LO shielded
24. SigGenNorCal.jpg
25. Diode mixer
Tools, Tutorials and Inspiration
CircuitLab.com
RFCoolTools.com
Opencircuits.com
RF Toolbox for Linux
mini Ring Core Calculator from http://www.dl5swb.de/html/mini_ring_core_calculator.htm
RFSim99 from http://www.eyou.com.au/product/rfsim99/
HR20.pdf from RamseyElectronics.com
Search for SA602 at frrl.wordpress.com; also read Ian Purdie's NE602 description
Comtekk Tone Generator $50 at http://www.comtekk.us/products.htm
Read 80M DC Receiver by PA2RF and http://www.ke3ij.com/DC-80.htm
Indiana Kits CSRX01 20 Meter Receiver
edaboard.com
Youtube radiofun232
555 timer oscillator (sentex.ca Timer Tutorial: CPO and CW Monitor)
DXZONE QRP projects
SW-AM converter with SA612
www.qsl.net/f8voa
http://www.qrp.pops.net/
http://www.lulu.com/spotlight/radioam232
http://www.seekic.com/circuit_diagram/Electrical_Equipment_Circuit/20_METER__DIRECT_CONVERSION.html
http://www.qsl.net/v/vu2upx/Projects/dc_rx.htm
http://www.vanyi.net/homemade/homebrew-hf-ssb-transceivers/#80m-3.5Mhz-transceivers
http://www.rason.org/Projects/rose80/rose80.htm
http://n8wq.blogspot.com/2012/05/improved-neophyte-receiver-part-3-at.html
http://kubi.selfip.com/electronics/html/dc_mixer_with_ne612.html
http://ozqrp.com/index.html MST400
http://home.alphalink.com.au/~parkerp/vk3ye.htm Beach 40 etc.
http://sa555.blogspot.com/2009/03/n7zvy-chris-traskgnat-20.html
http://www.4sqrp.com/HamCan.php
http://www.qrp.pops.net/willy.asp
ke7hr.com/caveradio/DSB75.pdf
http://home4.swipnet.se/~w-41522/qrproot.html
http://wps.prenhall.com/chet_paynter_introduct_6/0,5779,426330-,00.html
http://www.falstad.com/circuit/e-colpitts.html
http://www.qsl.net/7n3wvm/supervxo.html
http://www.wa0itp.com/crystalsetsssb.html
http://www.icrobotics.co.uk/wiki/index.php/Turning_the_Raspberry_Pi_Into_an_FM_Transmitter
http://qrp-projects.blogspot.com/2011_03_01_archive.html
http://www.expandedspectrumsystems.com/
http://www.vk2zay.net/ Alan Yates' Lab
http://pa0rcl.com/PA0RCL/MKARS80.html 80M LSB XCVR
http://fhs-consulting.com/aa1tj/reggie.html Reggie 80M CW QRP XCVR
http://f6bcu.monsite-orange.fr/ French Bingo – translate with Google
http://lowfer.us/k0lr/proto/LFproto.htm
http://www.youtube.com/watch?v=ZuRcaxpbYCw HDSDR
http://www.qrp.pops.net/VFO-2011.asp VFO
http://members.ozemail.com.au/~jgprice/80M-DSB.html
http://www.techlib.com/electronics/audioamps.html
http://home.kpn.nl/pg1n/hambrew/hb_20m.htm
www.tradeofic.com/Circuit 794 pages of circuits
http://search.yahoo.com/search?fr=mcafee&p=mjlorton+youtube+tutorial MJLorton Youtube tutorials