M620 - I am Flattered - TJ2B SSB Handheld Transceiver

Well, Imitation...

 ...is the sincerest form of it.




http://youkits.com/

 

When I showed the above picture to my XYL she said "Hey!...It's your radio..."   Well, it is and isn't.  The resemblance is a little deja vu even for me too I must admit. But honestly, I am glad that someone took this to the next level for me! 

KD6VKF M620 Transceiver



To be fair, I was letting this project languish on my bench for a couple years. After building the DDS board I needed a break for my weary old eyes so I took on the Mk VII Paraset and MkIII Tinkerbox projects and never really returned to this project.

 

But lately, I had been putting the 20M version back into working state and was planning to upload some videos of the working proto on here soon.  The big speaker sounds really nice on SSB and the user interface is really easy. ( I see the TJ2B also uses the push-button switch on the frequency control knob to change the rate too!)

 

 

Check It Out.

I suppose there is some "design convergence" where a solution is pretty universal, but when I showed this picture to a few folks they pointed out that the overall design was most likely based on the M620:



TJ2B Circuit Boards

[Need M620 Circuit board pics]

The overall layout using the DDS and Radio board is very coincidental. Although the TJ2B did put the PA onto the main radio board.  I did notice that there seems to be no videos showing the overall stability of the radio in transmit. I will assume this is not a problem as the layout and other features seem well designed. Here you can watch the TJ2B in action:

http://www.youtube.com/watch?v=VIeD0CwrONg



TJ2B Board Assembly  and Wiring

M620 Board Assembly and Wiring

 



Watch the M620 in Action:

The receiver on the M620 works fairly well.  Here is an example of the above prototype on 20M SSB.  The squelch circuits in the receiver are designed for the VHF type of use...to save batteries.  Also, setting this control so only the loud ones may actually hear the M620 get through the squelch gate as the receiver can hear pretty well:

http://youtu.be/MvQegi52VHA

The transmitter is tied to a VU type meter as well.  This is a short video of the transmitter in action. The infamous and annoying "AAAAAAhh" test which shows the M620's bar graph meter's action.  The output is quite low right now on SSB but the PA can go to full 5W on CW; I think the audio level from the microphone is low.

       

 http://youtu.be/3HKJIVICWVs

100% Anyway...

 

What Now?

As my dear XYL also said; "... hey! maybe YouKits should send you a free one?"  *hint* 

Oh well, there is a significant bunch of work done here on this radio and the way I look at it; if it works, it basically gets me what I wanted all along...a hand held HF SSB Transceiver!  If I did not want copies I would never have posted this project to a blog. 

We had a new DDS/Controller board and PA board in the works. I wanted to improve the main board as well; the PTT circuits were also being looked into to simplify the T/R control and using a little more SMA technology as well with the next revision.We plan on getting the 18M version working as well. The chassis is mostly machined and ready to build the prototype with the existing PWBs.

My work will continue to complete the 18M version and get the schematics updated with all the current changes.


But in the mean time; I won't wait for my free sample to show up. It looks like KD6VKF will clear some room on the bench and get one of these TJ2B kits on order soon!



TJ2B SSB Handheld Transceiver

DDS controlled, [Miniature] LCD display with frequency 5W output Kit A TX: 5-15MHz, covering 60m, 40m, 30m, 20m band RX:3-18MHz *can extend TX to 3-18MHz by MOD. Kit B TX: 18-30MHz covering 17m,15m,12m,10m band RX:14-30MHz (Not in stock) 1Hz, 10Hz, 100Hz, 1KHz, 10KHz, 100KHz tuning rate [available]Dual VFO with 40 memories Memory transfer to VFO One tuning knob plus 4 keys to realize all functions such as Step, Mode, A/B, Memory/VFO, Memory to VFO transfer, etc. Built in speaker, mic and PTT Fully assembled, kit available Optional battery lithium pack:1600mah Enclosure size: 195mm(L) x 68mm (w) x 38mm (T)

Anyway...

 This is the radio I REALLY want:

Check it out@:

http://rigreference.com/en/rig/6001-Tokyo_Hy_Power_XT_751

I hope this little blog had something to do with this radio!  Even if not, I MUST have one... They can sign me up for the first production!

For 10/12 Meters this one surely is the most commercial looking portable radio I have found... I may need to get one of these as well:

Magnum 1012 Handheld SSB/AM Transceiver

'73 DE KD6VKF

~ ~ ~

M620 - Project Status March 2011

This project is on temporary hiatus...for the last year or so. My old eyes and I just ran out of enthusiasm with the low SSN during the last solar minimum. 

The concept started several years ago when I was searching to see if I could find one of the Mizuho MX SSB/CW HF  transceivers.  I started thinking about repackaging an existing QRP SSB transceiver design with a digital synthesizer. 

...and that initial idea was abandoned when I started working for a start up and it took all of my time away from projects in general.  

in 2007 I restarted the concept after a phone conversation with my dad ~ he was asking me about the cost-to-cost walkie talkies cell phones. He said "...sounds a lot like ham radio to me!"  so i began thinking of a new concept. and worked on it until 2009. I switched to build a couple of tube projects, to rest my eyes and just to have some fun!

I have begun recovering the old project files and posting them on this new blog. 


Here is the chronology of this project:

1996 - While working at RF Microsystrems on a commercial receiver design project, I discover and use a AD9854 from Analog Devices Inc DDS chip for my design - very tiny but easy to use.

1997  - I see an article in QEX  July 97, with the same series AD9850 DDS.  
1998 - Order two boards from Far Circuits for the article in QEX, get a couple chips as samples from Analog Devices  and one of the bench techs at work even solders the small chips on these for me! Thought they may be useful for ham radio someday.  Rewrite program for PIC16F84.

1999 - 2000 Order a Small Wonder Labs WM-20 20M SSB transceiver kit - (no longer available) I actully wanted just to "kit bash" for parts to test with DDS as VFO, ended up building DDS/SSB QRP radio into a 1U 19" rack enclosure ...This was actually the 1st, if not so hand hold-able prototype!

2001 - 2006  Again, work interrupts all HAM radio project development!

2007 - Revive the concept.  Come up with a form factor that looks promising.  Begin hand built several protos:


(X0) dead bug for first PCB prototype, it worked OK but did not fit in case and wrapped on both sides. 

(X1) The initial PCB did not work very well, the gains were bad and I thought layout was the problem. 

2008 -
(X2) Began full scale RF board proto that would fit in chassis, proto DDS with PIC and external DDS-60 kit. Built proto DDS board and RF PA.  Some layout issues but both work fine.  Develop the PIC software (V1.0 was hard coded to  20M band but have plans to make it configurable)Proto became too hard to modify, lots of hot melt was holding it together!

2009 -
(X3) Second PCB with all of the changes form the X2 experiments went into a second PCB, the initial results were disappointing, low gain on RX.  The root cause was the switch pattern I made for X1!  One circuit crossed in the pin out, this may have actually been the main problem in X1 as well. Spent almost a month tracking the issue and bringing up the board.  Fixed with a simple cut and jump under the switch and the PCB works as well as the protoboard. 

Transmitter testing started, got the IF and tested the PA.  The one circuit I wished I had was a test oscillator/cw generator. Built a second case.

The project was interrupted by Paraset! I got tired of FIXING all my design issues and small parts! (needed a microscope to build the synthesisers board)  Just wanted to reproduce a simple radio. (now also working on Mk-III but that is another story)


TO DO  LIST:

1. Complete RF testing on the TX side
2. RX Noise issues from CPU and LCD
3. Complete multi band firmware
4. UPDATE PCBs

Updates final proto PCBs:

•  RF PA - need better RF detectorfor meter and pre-driver layout, may add test circuits (sig gen)

•  DDS/CONTROLLER - Fix crossed LCD signals and final OP amp circuits. Add MIC and Voltage adjust to the board (makes panel layout and wiring easier) Delete external DDS connector (no longer needed) May put a better PIC, add a 2nd PIC as a RTY/CW gen/decoder/RTC/ + Serial (USB?) interface.  Better shielding/RF bypass/voltage regulators.

• IF/RF BOARD - May change to electronic switching. Simplify RF/AF path as well.  It would be a major revision.  Also may use more SMT and possibly put the DDS chip on this board. 

NOTES/REFERENCES:

1. Small Wonder Labs WM-20 SSB Transceiver Kit, by Dave Benson, K1SWL:  – NLA “These are items where slow sales/high restock costs, or other factors have made it impractical to offer them at present….” http://www.smallwonderlabs.com/
2. Building a Direct Digital Synthesis VFO, by Curtis W. Preuss, WB2V QEX July 1997
3. The Mizuho MX SSB/CW HF series handhelds were actually produced from 1983 until 2002, a total of 19 years, making them probably longest on the market of any ham transceivers ever produced. The last ones produced in 2002 sold out quickly and probably will never be anymore made as many parts are simply no longer available.  http://www.mizuhoradio.com/mx.html
4. Oh yeah, I also have since changed the name from M610, it’s kind of a configuration nightmare but since this version will never be reproduced it should not be too confusing, but if you see any references to that model this is why. I'm thinking an FM –only design for 10 and 6 Meters…
5. AMQRP VFO-60 Kit  http://www.amqrp.org/kits/dds60/
6. 75 Meter Transceiver Project, by David Forsman, WA7JHZ, http://www.qrp.pops.net/Idaho.asp
7. BITX20 by Ashar Farhan VU3ICQ, http://www.phonestack.com/farhan/bitx.html
8. A Simple Dual Band SSB Transceiver  by Ashar Farhan VU3ICQ http://www.phonestack.com/farhan/xcvr1.html
9. Simple Sideband, Another Approach, by David Harrison, W6IBC QST November 2007.
10. MMR-40 Transceiver by Steven Weber, KD1JV QST Aug 2008 p33-36
11. TAK 40 Transceiver by Jim Veatch, WA2EU, QST May 2008 p33-37
12. an FM only version for 6 and 10 meters will be called the M610
13.  Low power SSB band plans: http://www.hfpack.com/air/
14. Lakeview Company, http://www.hamstick.com/
15. While researching this I found this project on the QST archive… A Transistorized Handi- Talkie, 28-Mc. Hand Carried Station for Short Range Communications,   By William J. Engle, Jr., W3KKO, QST Feb 1960 p20-22

Sources:

[A]  Microchip, Inc, PIC16F88 Datasheet.  30487c.pdf, www.microchip.com

[B]  Analog Devices, Inc., AD9851 Datasheet. www.analogdevices.com

[C]  Mouser, Inc, Parts etc., www.mouser.com

[D]  DigiKey, Inc Parts, parts, Parts  www.digikey.com

[E]  Contex Engineering, chassis  www.contexengineering.com  (also LMB Model EAS-100)

[F]  Circuit boards: www.sunstone.com

[G] Microengineering labs EPIC Programmer: www.melabs.com/products/epic.htm

[H]  Source code: Please contact author

[I]    Kits / Circuit boards: if there is enough interest I can do a PCB run, please contact author.  I may have a few prototype boards around kd6vkf@arrl.org, just ask! 

[J]    For latest updates see the M620 Website: http://tinyurl.com/4tmhqz

M620 - Progress ~ New X3 PCB

PART 3 - RF Board Construction

The whole original concept of started out based on the BITX, a 20 meter all transistor transceiver, [11] shrinking it down using SOT packages, so there are some carryover circuits from that design.  The R/T switching was based on the WA7JHZ 75 Meter Transceiver project design. [12]  (Which, by the way, is intended to provide “…several hours of quality entertainment”) The clincher to go ahead and use  integrated circuits, such as  this design used, was that a quick supplier check found a version of the venerable SA602s were still available, even in SO8 packages, just in case I need to go to smaller versions.  The interesting thing to me in that design was that it used the balanced inputs as separate single ended paths for both receive and transmit sides. It really saves on the switching, since it is all mechanical now, although the gains of each stage are cut effectively in half. The LM386 is also still available and in SO8 packages too.  The switching was done in that design by mechanically connecting several slide switches together to form a multi-pole switch.   Finally, a search turned up a fairly common 6PDT version of the E-Switch PBH series switches [P/N PBH6UEENAG1DBLK] were available and in stock and no modifications to slide switches needed.  

The original proto soon showed that the receiver’s gain was too low.  I needed more receive amplification so I based the RF front end amplifier on the W6IBC design [13] with an 8-MHZ IF [14] and also added an audio preamp. The TR switching was simplified somewhat,  based in part on that design, but still using the same mechanical switch, versus the electronic TR control. The gain distribution was corrected and it now had full speaker volume.  I have not had any audio howl as in the first design either. Sensitivity seemed OK; I heard all the usual suspects on 20 and even picked out some DX stations with my station’s vertical antenna attached to the proto.  It looks like about 90-100 dB of receiver system gain.  There is a bit more receiver noise (hiss) than I would like but the result seems OK. I used two 7mm IF can transformers for each of the two band pass filters.  This proto has a reasonable response for 14MHz and the design has been tested by simple capacitor value changes up to 30MHz can be fine tuned with the transformer adjustments and take up very little board space.  I will need to re-visit the design especially for the 50MHz version, perhaps with smaller shielded inductors and trimmer caps.  The squelch circuit was probably the only real original addition to this design, the comparator circuit uses the signal strength indication through its own audio amplifier and rectifier and chain to control the power to the audio amp. It uses the “leftover” comparator intended to delay the transmitter audio circuits, and a voltage divider formed by the squelch control pot.  

The second proto started by building the receiver and transmitter circuits “ugly style” on both sides of a double sided PCB scrap. Although the proto started to come to life in this form it was soon abandoned. Not only would never be able to fit in the case but would not be an accurate test bed for any of the layout’s interactions separated by the ground planes. The actual PCB layout was now almost completed so I started the third (and final) proto using the "pretty ugly" technique which used the PCB drill file as the layout template. The receiver and transmitter circuits were squeezed pretty tight to fit combined on that form fitting board.  As the circuits were built and tweaked the PCB was finalized and completely routed.  I guess I was a bit cautious by building three prototypes, I was skeptical the whole thing would even work packed so tightly on one board.   Looking back, it probably would have been OK to simply make the PCB. The major circuits changed little, and the layout worked, but the added cost of proto boards made me want to prove out the concept first before committing.   

Building this board is relatively straight forward. There are a large number of components involved so I would recommend a divide-and-conquer method of building and tuning in stages or functional blocks. It makes life easier to correct any small mistakes as you go along instead of trying to track one down when completely built.  I usually start with power circuits.  I find it a little easier to pre-tune the filters before the rest of the radio components are in place, but that depends on what test equipment is available, these are also be tuned for maximum signal after the whole radio is assembled anyway.  I usually start with the receiver circuits, from the antenna to the speaker, tuning as I go along for signal strength and finally the BFO for intelligibility. Then adding the squelch control comparator last, since it will be always on for testing without it in place. Followed by the transmit side circuits.  These are only tested for maximum signal output by first using an intermittent injected CW or speaking into the mcrophone. The final adjustments are done with the LPA in place. I then finish the transmitter circuits by adjusting the mic gain and touching up the BFO for the best signal while monitoring the output on another HF rig.  It may be a good idea to drill a small access hole in the case over it to do final adjustments with the case on.  I would guess similar holes could be made for the BPF and BFO tuning adjustments, if desired, although I have never done so.  The microphone and LED can actully be mounted on the back (or solder side) of the board.  This saves on routing as they can be lined up directly to holes on the front panel. I would recommend carfeully measuring and drilling the holes before final assembly!  I also found since the RF board will be directly under the speaker it can be tacked, with a small dab of hotmelt glue or RTV, to the back of the board just behind the speaker also makes an acceptable arrangement, without the need to make a dedicated microphone hole, the speaker cone is transparent to sound.



M620- Software Design Spec

OK here is the only thing needed to design the software. ( well, almost) The entire M620 Concept hinges on if I can come up with a workable radio display/control on a 8x2 character LCD display.  Here it is:

M620 - IF Board ~ Parts BOM

Partlist exported from C:/Program Files/EAGLE-4.16/projects/m620/M620_RF.sch at  6/28/2009 20:51:00

Qty Value         Device          Parts
1                 22R103C         L1
1                 78LXX           VR1
2                 DIODE-D-5       D4,D5
1                 DUOLED5MM       D8
1   0             R-US_0204/2V    R38
11  0.01          C-US050-025X075 C8,C11,C22,C24,C25,C29,C36,C39,C43,C44,C46                      
14  0.1           C-US050-025X075 C4,C17,C26,C27,C28,C37,C38,C40,C41,C42,C45,C48,C49,C50       
3   0.047         C-US050-025X075 C1,C3,C19                                                               
4   1.0           CPOL-USE5-5     C10,C15,C23,C47                                                        
1   1.2k          R-US_0207/2V    R40
6   1K            R-US_0207/2V    R14,R18,R20,R21,R31,R37                                              
1   1M            R-US_0207/2V    R36
1   1N4004        1N4004          D1
1   2.4k          R-US_0207/2V    R41
1   2N3386        2N3440          Q3
3   2N3904        2N3904          Q4,Q5,Q7                                                                
1   2N3906        2N3906          Q8
1   4.7           CPOL-USE5-6     C9
3   4.7K          R-US_0207/2V    R17,R22,R39                                                             
2   4.7p          C-US050-025X075 C30,C33                                                                  
5   8MHZ          CRYSTALHC49S    X1,X2,X3,X4,X5                                                        
1   9MM           CPOL-USE5-8.5   MIC1 
2   10            C-US050-025X075 C2,C21                                                                   
2   10            CPOL-USE5-6     C51,C52                                                                  
3   10            R-US_0207/2V    R4,R11,R30                                                              
9   10K           R-US_0207/2V    R3,R19,R25,R29,R32,R34,R35,R42,R43                                
1   10K           R-US_0207/10    R10
1   10K           TRIM_US-CA6V    R2
2   10UF          CPOL-USE5-6     C16,C20                                                                  
1   12K           R-US_0207/10    R1
4   15p           C-US050-025X075 C31,C32,C34,C35                                                        
3   22            C-US050-025X075 C5,C6,C7                                                                
2   22K           R-US_0207/2V    R28,R33                                                                  
1   22K           R-US_0207/10    R9
1   27            R-US_0204/7     R15
4   42IF223       71S5-24153      T1,T2,T3,T4                                                            
1   47K           R-US_0207/2V    R23
1   47P           C-US050-025X075 C13
1   51            R-US_0207/2V    R8
1   82            R-US_0207/2V    R13
1   100           R-US_0207/2V    R27
1   100           R-US_0207/10    R12
1   100K          R-US_0207/2V    R5
1   100K          R-US_0207/7     R7
1   150K          R-US_0207/7     R24
1   220           R-US_0207/2V    R16
1   220P          C-US050-025X075 C12
1   220UF         CPOL-USE5-8.5   C18
1   222           L-US0207/10     L3
1   470           R-US_0207/2V    R26
1   AGC           PINHD-1X1       JP3
1   AUDIO         PINHD-1X2       JP2
1   CKG20015      CKG20015        C14
4   FB-085        FB-085          L2,L4,L5,L7                                                            
2   FET           VN10KM          Q2,Q6
1   FT-23-43-BIFV FT-23-43-BIFV   TR1
1   LM386N        LM386N          U1
1   LM393N        LM393N          U4
1   LO            PINHD-1X1       JP1
1   NE5532N       NE5532N         U5
1   PBH-6U        PBH-6U          SW1
1   PN5179        PN5179          Q1
1   PWR           PINHD-1X1       JP14 
1   RFD           PINHD-1X1       JP8
1   RX            PINHD-1X1       JP5
2   SA612AN       SA612AN         U2,U3
1   SQL           PINHD-1X2       JP6
1   TEST          PINHD-1X2       JP11 
1   TX            PINHD-1X1       JP4
3   U.FL          U.FL            J4,J5,J6                                                                
1   VR            PINHD-1X1       JP12 
1   VT            PINHD-1X1       JP13 

M620 - X2 Board Redlines for X3

M620- Software Revision Plan

Firmware Version 1  DDS W/8x2 LCD, S-BARGRAPH, VOLTS
 OLD-> NEW
1     20G  -> 1A  EXISTING VERSION-G: DDS60 w/30 MHZ Clock, 20M
2 H  -> 1B  Vin Volt Scale (Vin/4)
3 I ->  1C  DDS w/66.666MHZ Clock, 20M (14.3MHZ)
4 J  -> 1D  CAL MENU
5 K ->  1E  BANDS 20, 17, 15, 12, and 10 (Select @ compile)
6 L  -> 1F  FREQ DISP RE-FORMAT
DO NOT USE: 1G
7 M ->  1H  RX / TX RE-SCALE w/ PTT + BARGRAPH REFORMAT
8 N  -> 1I  MEMORIES
O = NOT USED
9 P  -> 1J  SETUP MENU
10 Q  -> 1K  TBD - 12/10 MTRS?
11 R  -> 1L  TBD - 6MTRS? 
12 S  -> 1M  TBD - SCANNING?
13 T  -> 1N  TBD - LAST FREQ MEMO?
DO NOT USE: 1O
14 U  -> 1P  TBD - DUAL VFO?
15 U  -> 1Q  TBD - ?
16 W  -> 1R 
17 X  -> 1S 
18 Y  -> 1T 
19 Z  -> 1U
20       1V
21       1W
22       1X
23       1Y
24       1Z