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Components, 2nd round
Hans Summers
BITX'ers,
DEADLINE: 12:00 UTC THURSDAY 01-JUL-04 (TOMORROW!) Paolo, Farhan and myself are investigating the possibility of a complete kit of all parts for the project, including resistors, capacitors, variable resistors, etc along with the previous semiconductors + crystals pack. This will probably take a while to organise. In the interim, I have received a request from Charles G4VSZ for 4 component packs for himself and his club. I also have an outstanding request from Jim N6OTQ. So this week I will run another round of component sourcing. The components come mostly from Rapid Electronics because their prices are excellent. The LM386 comes from Farnell, because then I can be sure that it is the LM386N-1 variant, which is uncertain from Rapid. The 2N2219 comes from Viewcom () and incurs some postage fees which I have to add to their transistor price. The price is the price of the components, no profit for G0UPL :-( If more people order, the price will decrease slightly. Last time with 9 orders, it was ?8.19 + ?0.28 postage. At the present time with 5 orders, the prices are: ?3.29 Qty 10 of 10.000 MHz crystals, HC49 style ?0.59 Qty 25 of BC547B transistors ?0.75 2N2219A driver transistor ?1.53 IRF510 MOSFET ?0.19 Qty 15 of 1N4148 diodes ?0.07 36V Zener diode ?0.05 9.1V Zener diode ?0.05 5.6V Zener diode ?0.29 LM386N-1 Audio Amp IC (correct variety) ?1.88 Qty 5 of 2-22pF trimmer capacitor ?0.71 Miniature tuning capacitor* ?9.68 total including ?0.28 UK postage. * NOTE: The tuning capacitor is one of the miniature kind as used in portable radios. Size is 20.2 x 20.2 x 10.8mm. Control shaft is 6.6mm diameter tapped with 2.6mm thread. Panel mounting is via twwo 2.6mm tapped screws next to the control shaft. Capacitance: AM section 3.0 - 141.6pF, Oscillator section 4.0 - 59.2pF. So in parallel you'd have 200pF which is less than Farhan's design for 350pF. It might therefore be necessary to alter the VFO coil to get the required tuning range. Feel free to order extras of any item for spares, or exclude things you don't want. Any more orders? 73 Hans G0UPL |
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Re: Digital dial for BITX20 using PIC
John Fisher
开云体育This is really Cool, thanks very much
:-)
?Regards, ?John ?
=============================================
email:????? k5jhf@... photos:??? files:??????? webpage:? callsign:??? K5JHF =============================================
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Re: Inductors - RX Probs
Jim Strohm
On Jun 29, 2004, at 8:13 AM, Mark Jones wrote:
Here's what I have:That wire is large enough that it should not have fractured within its enamel coating. For L1 - 3, an ohmmeter will confirm continuity. For T1 and T3 -- this is worth asking -- did you use multi-colored wire for the trifilar winding to ensure proper connections and phasing? And did you check continuity before and after you soldered? A trifilar winding of #28 is much likelier to break without showing visible damage than the #24. The only other possible cause I can think of is that the toroids are mis-marked and are so far from providing the right inductances as to make the circuit fail. If you can trust your supplier, this should not be a problem -- to test, use the mfg. data sheet to calculate inductance, place a 1 nF cap across the inductor's leads, and hit it with a dip meter. If it's a good toroid, it'll test within 10% of predicted inductance. Jim N6OTQ |
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Inductors - RX Probs
Mark Jones
Hi all
Looking for some help here. Testing the RX today, AF amp clearly OK, the simple tests in the text work out fine i.e. Touch base Q4 static, Q3 more static, Q2 less static. Trimmers with L1,2 & 3 do little or nothing, but the trimmer in the T3 mixer has a huge effect on noise out of the speaker. At either end of the travel very loud. It looks like there is no RF coming in. I have re-wound the two mixers with no change, I'm wondering about the coils. Here's what I have: L1,2,3 22 turns 24 SWG on T-50-6 T1, T3 13 turns triffiliar 28 SWG on FT37-43 Any thoughts? Mark Jones (G0MGX) 07971 091767 |
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Re: Chip pad
Jim Strohm
On Jun 29, 2004, at 3:31 AM, g4dfv2004 wrote:
An easier method to make a pad for non-SMD IC's is to use 0.1"And an even easier -- yet vastly more expensive -- method is to use one of the etched adapter boards that brings out the pins from a surface-mount chip to 0.1-in spacing pads. SMD chips can be soldered to these with little difficulty and a small iron as Hans noted. Nowadays I use a lighted magnifier -- even on DIP stuff -- because it's a lot easier on me. And I have a cute little Intel Play USB microscope that has a 10X setting for the more challenging SMD stuff. Jim N6OTQ |
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Re: Block Diagram
Mark
Charles,
Where did you post it? --- In BITX20@..., "Charles" <charles@d...> wrote: HiStudents in UK. |
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Re: Digital dial for BITX20 using PIC
Hans Summers
A very nice readout. But for anyone wanting something *really* simple, have
toggle quoted message
Show quoted text
a look at my 2-chip binary readout counter . Also see my BITX20 in the G0UPL photos folder to see it installed in my front panel. My latest version is even simpler by using a 74HC390 instead of the 74HC4040, eliminating 5 diodes and 2 resistors from the circuit. The output is also easier to read: 2 columns of LED's indicating 80, 40, 20, 10 and 8, 4, 2, 1KHz. This is easier to add up than the binary 64, 32, 16, 8, 4, 2, 1, 0.5Khz of my earlier versions. The reading is 0 - 99KHz, my dial is marked 14.0, 14.1, 14.2, 14.3 and this is added to the counter reading to get the reception frequency. The 1KHz LED flickers such that it's brightness can be used to estimate the frequency inside the 1KHz resolution. Would anyone be interested if I were to offer a complete kit of parts (for ugly construction, i.e. no PCB), suitable for connection to the BITX20 VFO as in mine? The pack would include: 74HC4060, 74HC390, 5V voltage regulator + filter, 8x 3mm high-brightness red LED's, single transistor VFO buffer amplifier, all diodes resistors and capacitors. Cost ?3.37 + postage (as usual, parts cost only, no profits for poor G0UPL). If enough people were interested I could do this. 72/3 de Hans G0UPL -----Original Message-----
From: vk3bfa [mailto:ablight@...] Sent: 29 June 2004 01:56 To: BITX20@... Subject: [BITX20] Digital dial for BITX20 using PIC Hi fellow builders, posting this link for information - its a digital frequency readout using a PIC micro with user definable IF offset - might be of use to the group, and I readily admit its outside Ashan's original inexpensive transceiver concept - it would probably cost more to build than the BITx20 itself! Still, I think its an elegant solution, so let me know what you think. Its .PDF, approx 162K in size 73 de VK3BFA Andrew |
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Re: Chip pad
Hans Summers
I was wondering how to make a pad for the chip then thoughtThat's what I do too, when I need to. I use firm pressure on one of those cheap orange plastic "craft" knives. You can produce a nice thin cut with this method. The LM386 in the BITX20 I just mounted "ugly" though, with no pads. I tend to use the knife method if I need to use surface mount IC's. The pinnacle of the art came when I found I had to connect a 24-pin Analogue to Digital converter chip, in a TSSOP package. Pin spacing was a mere 0.65mm. In other words, 4 times denser than your BITX20 LM386. To do this I cut 2 columns of 6 pads on either side of the IC (24 pads total). I glued the IC to the board. The even-numbered pins (2, 4, 6 etc) were bent upwards away from the board. Odd-numbered pins (1, 3, 5 etc) were soldered direct onto the pads. The even-numbered pins were then connected to the outer columns of pads using the hair-thin individual strands of copper from ordinary lighting cable. You can find a picture of the result about 2/3 down on the left hand side of this page People who work with SMD talk of special soldering irons & bits, special solder, magnifying glass, flux, special lights etc etc. I used none of this. Just my ordinary 18W Antex CS iron with 1mm bit and ordinary 22swg solder. Just goes to show that the patient homebrewer can accomplish a lot even without specialist equipment. 72/3 de Hans G0UPL |
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Re: A tale of two tap washers...the saga goes on, an on
Arvid Evans
Sam & other BITXers
Your measurements explain my results then. Instead of tap/faucet washers I used 1/4 inch slices cut from "1/2 inch" PVC pipe (the schedule-40 or medium-thick-wall type). These measure about 13/16" OD and 5/8" ID. In my BITX20 I followed Farhan's instructions regarding the nunber of turns and my coils came out nearly perfect for inductance value. I just wound a second set of coils using the PVC material and facilitated the winding process by cutting a slot in the plastic former. This means I did not have to thread the wire through the core 150 times. These new coils check out on the dip meter as also being on-the-money for inductance. It is interesting that these "air-core" toroids exhibit some of the same characteristics as ferrite cored units. My dip meter does not get a strong coupling to the coil itself unless I add a coupling loop through the core. I thought that phenomena was due to ferrite channeling the magnetic field, but maybe the shape of the coil has more influence than I thought. Arv _._ --- In BITX20@..., Sam Caldwell <samc@x> wrote: Hans Summers wrote :investigate differencesthe nature of the infamous tap washers, and in particular the 1/2 inchbetween ordinary and "delta" washers. (12.7mm). As close as I can measure with my ruler:As I understand it, the " half -inch' refers to the bore of the water |
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Digital dial for BITX20 using PIC
vk3bfa
Hi fellow builders,
posting this link for information - its a digital frequency readout using a PIC micro with user definable IF offset - might be of use to the group, and I readily admit its outside Ashan's original inexpensive transceiver concept - it would probably cost more to build than the BITx20 itself! Still, I think its an elegant solution, so let me know what you think. Its .PDF, approx 162K in size 73 de VK3BFA Andrew |
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Re: A tale of two tap washers
Sam Caldwell
Hans Summers wrote :
As I understand it, the " half -inch' refers to the bore of the water pipe with which they are associated - and includes three-quarter and one-inch as part of the series. A typical "half-inch" tap washer in the past would measure perhaps three-quarters of an inch dia., but in more recent times the proliferation of fancy bathroom ware has given rise to a variety of custom taps (faucets) with their own washers. My own houshold taps ( I'm told ) have ceramic washers which ( I'm told ) never wear out and ( I know ) are drip-free. Regards, Sam C. ZL1TOI |
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Re: Chip pad
vk3bfa
Hi Charles,
what you describe has been used in VK for a while now, described (and used) by Drew Diamond VK3XU - he is a master of this style of homebrewing and has published many articles over the years (and 2 books) - some construction articles are available in .PDF format from the website go to AR mag page and have a look around. Well worth the effort for inspiration! 73 de VK3BFA Andrew -- In BITX20@..., "Charles" <charles@d...> wrote: Hiholder. pad.
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Re: Chip pad
John Fisher
开云体育Very nice pads, applicable to many projects.
I use an 8 pin Motorola microcontroller in my Morse Code training device, and
this will be great for those projects too. Info on the MCD is on my webpage
below.
?Regards, ?John ?
=============================================
email:????? k5jhf@... photos:??? files:??????? webpage:? callsign:??? K5JHF =============================================
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non-ferrite balun cores
Arvid Evans
BITXers
Since the tap washers, faucet washers here in the US, are mylon or similar plastic type material, it would seem that they do not contribute much to the functionality, other that to hold the wire coils in a circular shape. Also, since there is no magnetic field contribution by the nylon or plastic dore former it would seem that one could cut a small slot in the material to facilitate winding the coil without having to thread each turn through the center hole. After the coil was wound one could use hot-melt glue (or anything sticky that hardens well) to close the slot and to mount the coil to the chassis material. Has anybody tried this yet? Thanks, Arv-K7HKL _._ |
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Chip pad
Hi
I was wondering how to make a pad for the chip then thought use a piece of PCB with a cut through the copper in the centre and then additional cross cuts of the copper to make the lands for the holder. By bending out the legs of the holder they can be soldered to the pad. Chip Pad Photo added to my album. Charles G4VSZ |
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Re: Off topic - i am blocked out
Mark Jones
开云体育Farhan
?
Fine
on all of this, I have friends in your country who have reported the same before
now.
?
Hope
you get access soon,
?
Mark
G0MGX
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TV Balun
g4dfv2004
Hello, I have uploaded a photo of a two-hole "binocular" ferrite
core (see G4DFV album). Ashtar, please can you tell me if this is anything like the TV balun that you have used? My core measures 13mm x 7mm x 6mm, the holes are 3mm diameter and the centres are spaced 6mm. Duncan G4DFV |
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Re: Off topic - i am blocked out
Hans Summers
Farhan
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Show quoted text
Sorry to hear of your problems. I'm sure you are right to fight for the free exchange of information. One possible solution is to use an anonymisation service such as . In this case the URL to the BITX20 group would become . I work for a US company. One might expect freedom of information to be assured. But they insist nevertheless on blocking any website which meets some criteria of being pornographic, related to betting and gambling, or any terrorist activity. I don't know if they thought that perhaps we would sit here in the office in full view of our colleages watching porno movies or something. Anyway be careful I'm getting on my soapbox here... To cut a long story short, I had a big battle and I lost, they still refuse to change it. The battle arrived when I tried to look at the website of Thomas OZ2CPU, whose excellent web page I have visited many times in the past. Only to find that it was blocked, with a message something like "if you feel this web page has been wrongly blocked, please contact the IT helpdesk". You can contact them as much as you like, and if they don't feel it is related to your business requirement they won't unblock it, even if it IS wrongly blocked. A colleague wanted to buy something from a camping store. Couldn't access it. So had no option but to take a long lunchbreak of 2 hours, on company time, to visit the store. Even if it's non-business, it can assist business by making the employee's life easier. All of which led me to write my own internet browser application, which enclosed an Internet Explorer component. On coming across the hated IT helpdesk message, it redirects its enquiry to anonymization.net which (nearly always) gets the page Ok. This is all done in an invisible way, the actual real address at anonymization.net is hidden from the user. So I was able to give the application to my friends in the company to assist them in streamlining their non-business related activities, in the knowledge that if the information finds its way back to the IT dept, at least it won't be instantly evident how it works, though I don't doubt that they would be able to trace it eventually, having access to everything. Sorry to have got on my soapbox even though I tried to stay off it - this issue touches a raw nerve. Good luck with battle which is much more serious than my little problem here. 73 Hans G0UPL -----Original Message-----
From: Ashhar Farhan [mailto:farhan@...] Sent: 28 June 2004 12:59 To: BITX20@... Subject: [BITX20] Off topic - i am blocked out for the last 48 hours, groups.yahoo.com has been blocked out by the two major bandwidth providers to india. most of my internet accounts belong to isps that in turn take their bandwidth from either of these two (i have several). this has been done as the indian govt. asked the isps to block certain a fanatic group (read 'hate') from being accessed from india. some of us are fighting this with the govt. and i hope that the access will be restored soon. until such a time, i cannot see the pictures that are being uploaded although access the emails (the emails are to and from my server located in boston). i cannot wait to see all the lovely efforts being made by everybody and it feels like being left out of the party. though a number of users have suggested using proxies to gain access to the site, i want to regain my right to free exchange of ideas and information as much as i believe the fringe hate group should. the issue has become significant to a number of us in india. - farhan Yahoo! Groups Links |
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Re: BITX20 component list
ik1zyw
--- In BITX20@..., "ik1zyw" <pcravero@a...> wrote:
It's me again. Has anyone attempted to list all BITX20 components? I haven't foundI have uploaded in the Files section a TXT file with a component list for BITX20. It DOES include driver/PA section but it DOES NOT include inductors. The list is meant to be a list you give to the shop attendant and then return home with everything you need to build a BITX20. Tap washers can be purchased at a hardware store, which usually doesn't sell electronic components. Coils wire can be salvaged from old transformers. Please someone cross-check my work! 73, Paolo IK1ZYW |
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