Saturday 31 October 2009
Seems I have a short somewhere, don't appear to be a duff components so must be a bridge under IC 5, 8 or the DDS chip.
Nice suggestion from N1RX (Bruce)... cut the 5V rail isolating the IC/board area and find the bridge.
Thursday 29 October 2009
More photos from build last night.
The connections and components to test the DC
The switch postion to test DC.
The IF chain, dial 602 and lm386
The DDS through a magnifying lense... bit blurred
The dds as seem naked eye. Think I did ok soldering that by eye but needed to reflow pins 13,14 and 15.
Now put into a PCB vice http://www.qrpkits.com/ and populating the board with through hole components
Top side more components.
Note I changed the kit supplied IC sockets for turned pin sockets as I suspect will remove the IC onces or twice in future
All ready for the start. 0.1uF and 0.01uF SMT first.
Small 0805 SMT components
Various stages through the population of the boards:
soldering is fine but not perfect, I worked with naked eye, 22SWG
multi core solder, temp controlled iron and 1mm bit and hand soldered,
so it is possible. I even managed the DDS chip without having to flood
and wick excess away… it is on a degree or two little wonky but fine
otherwise. I used a pinch to release type of tweezers you can see on
one of the photos to pick up components. The R and C are all 0805
which is big enough to be hand soldered but small enough to probably
cause some a few issues. Once the SMT R and C were in place and tested
the DC lines I tranfered to using a PCB vice (www.qrpkits.com)
Early in the process I added the main switch S1 and the DC supply
socket, fed with 13.8V and sensed the 6V and 5V pads around the board
feeding the IC's. My 5V is 4.996V and 6V is 6.035V. The voltage values
I get on different pins are within 5% of Bruces so I'll not reproduce
Anyway I have added photos to the hb-1a yahoo group M1KTA album for
those interested but I attached them here too.
The timestamps on the photos are accurate so you get an idea how long
it should/could take. I expect to complete this later today.
I will say that I was missing a few SMT components (R 2K2 and 47K
which I robbed from the junk box) but I was sent heaps of extra other
values and a pair of 602 and a 386… so I know what I'm building next…
another IF chain.
Maybe a 2x hb-1a homebrew build qso might be possible if anyone
interested, I am in UK and cw is qrs!
Tuesday 27 October 2009
Johnny SM7UCZ did the same and handed me a paraset!
Photos of the psu Ian (G3ROO) had built so that his rebuild of a B2set would be operational for the GQRP rally. His original transformer is being rewound as some of it has gone open circuit.
The underside of the TX side. Ian G3ROO, just as I am, has built his set to use so some accomodations will be made in this case Ian has used torroids to create the fixed values for the tuning circuit rather than 1/2" paxolin/tufnel coils as in the original. Likewise ALL the wire looms are using PVC coated modern wire.
The chokes were some I had left over from a box I shared with paraset builders.
Note the chassis was made using some double sided PCB rather than the original steel but to the original dimensions.
The tune side capacitor is not original as they are rare but the value is the same, as Ian luckly had a part T to start with the load side capacitor is original.
Some photos of the wiring loom, again accomodation using modern R and C's so that the end result is usable.
The TX side access to the small orange 4-20pF trimmer capacitor
Top view of the TX side.
The through hole components spread out.
Starting to place topside components to check fitting etc.
I just updated http://hb-1a.golonka.se/doku.php?id=component_list with some component values.
Monday 26 October 2009
Here are some images from the Homebrew Build display area before everyone arrived:
Ian (G3ROO), Dom (M1KTA) and Roy (GM4VKI), ?? (sorry!) discussing the projects over pie and peas before the doors to the area opened.
Steve (G0FUW) and George (G3RJV) had not set up the Buildathon places at this point.
Steve (G0XAR) and Hans (G0UPL) added their QRSS T and Class E >85% efficiency PA's.
After his talk Ron G4GXO added his T2 and Si570 dds to the display and John G4EDX bought his ugly Norcal 40 and an MFJ like analyser, the latter generating a lot of interest probably as it being being painted fluroescent pink!
There were a number of other projects added during the day including a Pic-A-Star by Rod G3
Thursday 22 October 2009
Wednesday 21 October 2009
The shipment had taken just over a week and, there was no customs charge, VAT or extra handling charge to pay, so the radio cost me a total of £137.82. There was a delay in arrival that was 100% due to time spent in the UK Coventry Customs arrivals point but then I expect a couple extra days ude to bottlenecks I have experienced for shipments coming from there in the past. It took 5 days real time to get to my door but an additional 4 days spent in customs!
Opening the box revealed the radio extremely well packed in expanded polystyrene, plus a photo-printed card with a picture of BG2FX in his lab - presumably the builder. There was no manual, but the eBay listing had linked to an English language manual in PDF form that I could print out.
This is a short video to show you what you get.
The PCB has the surface mount all on one side and in this video I show you the board.
I also show the components in this video.
In the video I say the case is Aluminium... the case is steel! I noted that the bag is not anti static and the PIC and semiconductors are NOT pressed into foam etc. I expect I will check those first!
The clam shell steel case (palm paddle magnet will attach to it) is pre drilled well-painted in a black crackle finish. The white lettering is adequate although I do not think it may last too long.weight.
I posted to the list too but just in case put it on the blog too.
Please if anyone thinking of bringing something along, and there are no categories at all this year it is completely open so you could almost bring anything, please contact me off list (UNTIL 10am FRIDAYwhen travelling up to Rishworth) or on the day at Rishworth. If you can though please bring a A4 sheet showing the circuit or description and your callsign and what you call it. I am sure those looking at the builds might want to ask the builder the odd question too.
I will I have my nth build of a 6V6 valve rig I finally got working thanks to many donors of bits and used on 80m in GQRP valve day this July.
George's comment to me this morning was "We think it will be in theBuildathon area .......still got to work out space and oversight. I suspect we will put things in the room early then allow the public inonly when the Buildathon begins [12.30]". This means the display area should not be left unattended.
Following the list kit thread I thought I'll bring somebuilds/projects to display. PFR-3, ATS-3B, an ATS-3 Unbuilt, QBSA,NorCal-20, BITX20A, KD1JV MARS (#140 SPRAT rig), KD1JV ADC-40 andKD1JV PSK and K1SWL PSK-20, my own pcb versions of VK3XU (DrewDiamond) TCF 40 Manhatten/Paddy Board RX and TX boards, Norcal FCC-1/FCC-2 frequency counter/DDS, qrpkits BLT, qrpkits long wire tuner, K1SWL SW20+ and anything else suitable that will fit in the box. I may have the HB-1A SMT kit BD4RG just sent me from China...
Anyone able to bring along a K2, K1, KX1, Howes, Tentec or Walford kit, with the cover off?
I'll put up photos and links for the projects that turn up.
Tuesday 13 October 2009
After Simon Brown's SDR talk at RSGB Convention this year I have been looking at ways of using a SR with a 'normal rig' and I found this circuit. The eLAD device he mentioned was not available and I couldn't read the circuit diagram. There are probably a zillion ways to do this... and I claim absolutely no originality for the idea/design. This circuit is from a Ten Tec Argosy, and handles that rig's 50 watts with ease and I found it was fine for my use, cw only right now.
The circuit appears broadband enough for HF use, not sure about use up to 6m though. The notes are that this requires 20 to 40 mA of total diode current.The paralleled 330 ohm resistors. 330 ohms, 1/4 watt may be ommitted if there are no breakthough problems from local AM stations.
The IRF510 MOSFET is used as a switch and I think most qrp homebrewers have at least one spare of these. If not try GQRP sales, I also tried it with a IRF630, either way if this doesn't switch very fast then the capacitor (.47 uF a 100V box capacitor from the junk box) that holds the switch closed on TX would need to be larger, I think you can modify the qsk delay at this point. There are probably smaller MOSFETs available for such low-current switching and I think a 2N7000 might even be used? 1N4007's are 1 kV rectifier diodes that I happen to have in the junk box, I also have some MPN3404 and MPN3700 from W8DIZ but the 1N4007 seemed to do fine and I didn't need the PIN diodes. They appear to operate fine. I used 1N4148 instead of the 1N914's and at 5 watts, I have also had satisfactory results with them.
The chokes are small molded ones bit like fat 1/2 resistors.
Monday 12 October 2009
That said as the keyer PIC is separate from the main control PIC and the button S3 (CQ/SET) is used for the CW CQ message I suspect another option might be to roll your own keyer. I wonder if there is enough PCB 'space' to use a small daughter board and say SMD PIC16F628 if so then a lot of the 16F628 keyers out there (code and pin number dependant obviously) might be possible.
Maybe other possible keyer chips might be used?
A Softrock V9.0 RX with isolated antenna input and sound card outputs (using 600 ohm isolation transformers). There is no BPF fitted in this image. The BPF that goes with this build I include a couple of close up images of it, I placed it on a £20 note so you can get an idea about the scale involved. This particular electronically switched BPF is made up for 80m-10m and 6m. The final one Simon has now is for 160m to 10m.
Q:How did you mount the isolation transformers to the box? It looks like there two lines of tape involved, any comments?
Q:The diecast Hammond box, which part number did you use?
Q: On the temperature controlled soldering iron, what temperature setting were you using or would you recommend?
Q:What parts did you use for your antenna connection?
Q: What parts did you use for your I and Q audio connections? (I realize they were gold plated)
Q:What parts did you use for your chassis isolation standoffs?
Q:What is the switch for?
Thursday 8 October 2009
The values are: S Points, Voltage into 50 ohms, dBm into 50 ohms
These values are valid on HF. on VHF, values are 20dB lower e.g. S9 is 5uV or -93dBm. I do not think many commercial transceivers adhere all that closely to this scale.
Wednesday 7 October 2009
Although I am expecting the HB-1A kit to use SMD components here are some images been sent to me and appear to be the same from a Chinese manual for the HB-1A kit. It is for a build using through hole components. See above the SMD one is on the right, it still has some through hole components. Note the little trimmer capacitors with the through PCB adjustments.