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How to post schematics, images, etc.???
k7hkl_arv
Help please...
I'm new to this forum thing, so I have to ask "How does one go about posting a schematic or picture of BITX related info"? I sent an attached file with one of my posts and now my email post is there but the attached .gif file is referenced as "Not Saved". )-8 Thanks, Arv - K7HKL _._ |
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Re: Atachments
Ashhar Farhan
yahoo groups doesnt not retain attachments. if you can forward the
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pictures to me, i canupload them on the folder. i am new ot yahoo groups. i don't know if you can directly upload the pictures without being a moderator. - farhan On Sat, 26 Jun 2004, Sam Caldwell wrote:
G'day Troops, |
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Re: BFO Clarification?
Ashhar Farhan
Mark,
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USB requires setting the carrier to the lower edge of the filter's passband and LSB requires setting the carrier to the upper edge. given that we are sourcing crystals from varied places, it probable that you will have to pull the crysal frequency down for USB and pull it up for LSB. adding a small series capacitance to the crystal pulls the frequency up (good for LSB). to pull the frequency down you need inductive capacitance in series with the crystal. it is often difficult to estimate just how much (capactiance/inductance) will be required to position the bfo correctly. in case of LSB, a 22pf trimmer in series with the crystal can be tweaked to get the proper results. in case of USB, i have found about 5uH to be ideal for the crystals that i have used (3 builds so far). this may not work for you. so you can either play with the number of turns on L3, or use the inductor with a capactiance in series to vary the net reactance to set the frequency properly. - farhan On Fri, 25 Jun 2004, Mark wrote:
All |
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Re: Components
Jon Harris
<AOL> Thanks Hans, all arrived safe and sound
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Jon H. ----- Original Message -----
From: "William Ford" <ford1@...> To: <BITX20@...> Sent: Friday, June 25, 2004 10:18 AM Subject: Re: [BITX20] Components Component parcel received today.many thanks Jack ----- Original Message ----- From: Hans Summers To: 'BITX20@...' Sent: Thursday, June 24, 2004 4:57 PM Subject: [BITX20] Components Hello Just to let you know that all the components arrived this morning, from three different suppliers. The LM386 was from Farnell because I wasn't sure that the Rapid Electronics version was the correct LM386N-1 version. All components have been counted out and shipped, UK orders by first class post (should arrive tomorrow morning) and international orders via airmail. When I'd finished there were 14 BC547 transistors left over. This could be because they are so cheap that counting them precisely costs Rapid more than giving a few extra. Or it could be that I messed up my own counting, as the whole process was rather tedious and I have been having a very stressful day. If anyone is missing any then let me know, or needs some extra spares. I owe quite a few of you emails and also have a couple of other things to say, but am too busy to do it today so pls QRX 72/3 de Hans G0UPL Yahoo! Groups Sponsor ADVERTISEMENT ----------------------------------------------------------------- ------------- Yahoo! Groups Links a.. To visit your group on the web, go to: b.. To unsubscribe from this group, send an email to: BITX20-unsubscribe@... c.. Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service. |
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BFO Clarification?
Mark
All
I'm happy soldering here, but have a question: In the text for the BITX20 it says "If you are using this for 14MHz and above, the BFO will need a coil in series with the crystal". This is what I have done - seems to work OK (see G0MGX folder in pictures on reflector). I just saw the alternative coil data that has been posted on the reflector and that says "L3 was used in series between the crystal and the 22pf trimmer cap plus I added 7pf Mica fixed cap across the trimmer. Needed for USB" I am therefore confused! Can anyone shed any light on this? Mark. G0MGX |
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Re: The PC as a lab instrument
Hans Summers
I thought this forum was focused on the BITX20.Hey it wasn't *that* far off topic! Have a look back in the archives... It stems from Farhan's questions about PC use which also relates to his telling us previously about him using his computer for some audio and AGC processing. Several people have asked for possible AGC circuits for the BITX20. I'll see what I can find over the weekend. 73 Hans G0UPL |
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Fw: RE: The PC as a lab instrument
I thought this forum was focused on the BITX20. Have I gotten into the wrong forum by accident?
Arv - K7HKL -----Forwarded Message----- From: Hans Summers <Hans.Summers@...> Sent: Jun 25, 2004 7:34 AM To: "'BITX20@...'" <BITX20@...> Subject: RE: [BITX20] The PC as a lab instrument <html><body> <tt> <BR> does anybody have more stories about using PCs in the <BR><BR> Farhan, I don't have a PC at home at all, except an old laptop my XYL uses<BR> for internet access. I prefer to do everything without a PC. I even built my<BR> crazy 30m QRSS beacon project with no PC or microcontroller, see<BR> <a href="></a> and<BR> <a href="></a> . I sit in front of a<BR> computer here in the office every day and somehow prefer that when I am at<BR> home I don't have to be attached to one.<BR> <BR> There's also the problem of the "homebrew only" law which rules my station.<BR> So far the only exception to it is my old 5MHz oscilloscope and my DVM. Some<BR> day I will get my Z80 computers up and running, and will be able to write<BR> some homebrew software for QRSS and PSK31 etc. <BR> <BR> 73 Hans G0UPL<BR> <a href="></a><BR> </tt> <br> <!-- |**|begin egp html banner|**| --> <table border=0 cellspacing=0 cellpadding=2> <tr bgcolor=#FFFFCC> <td align=center><font size="-1" color=#003399><b>Yahoo! Groups Sponsor</b></font></td> </tr> <tr bgcolor=#FFFFFF> <td align=center width=470><table border=0 cellpadding=0 cellspacing=0> <tr> <td align=center><font face=arial size=-2>ADVERTISEMENT</font><br><a href=" alt=""><img src=" alt="click here" width="300" height="250" border="0"></a></td></tr></table> </td> </tr> <tr><td><img alt="" width=1 height=1 src="></td></tr> </table> <!-- |**|end egp html banner|**| --> <!-- |**|begin egp html banner|**| --> <br> <tt><hr width="500"> <b>Yahoo! Groups Links</b><br> <ul> <li>To visit your group on the web, go to:<br><a href="></a><br> <li>To unsubscribe from this group, send an email to:<br><a href="mailto:BITX20-unsubscribe@...?subject=Unsubscribe">BITX20-unsubscribe@...</a><br> <li>Your use of Yahoo! Groups is subject to the <a href=">Yahoo! Terms of Service</a>. </ul> </tt> </br> <!-- |**|end egp html banner|**| --> </body></html> |
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BITX20 & BITX40
Hello to the BITX20 group (this is my first posting on this forum).
Farhan and myself have exchanged a couple of off-forum emails regarding mods to his excellent design. One interesting possibility is replacement of the LM-386 with a discrete component AF Amplifier. He said that he had not had the time to work up a schematic...so I have provided one (see attached .gif file). This can allow those without access to an LM-386 to build the unit. Also, my layout for the BITX20 uses 10.7 MHZ IF transformers salvaged from dead AM/FM radios ( I dislike winding toroids! ). My construction is a BITX40 (40 Meters) and requires 55 pf across the 10.7 IFs to resonate on 7.2 MHZ. These 10.7 IF transformers might be made to resonate on 20M if the internal capacitors were removed ( break them with a screwdriver point ) and a small variable ( 5-25pf ) used to bring them to resonance. 73's Arv - K7HKL |
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Re: More components
Hans Summers
开云体育Thanks
for the offer Bruce. Let's keep it in mind and see how it goes. Over half the
orders I had were from the UK, other than that US, Singapore and New Zealand. I
don't know if that's because I announced the list on the GQRP mailing list and
therefore more UK members joined, or if people were more inclined to buy locally
to keep postage costs down. Though at ?1.31 for postage for the packs to the US
and worldwide, it wasn't too bad.
?
Is
anyone a member of the US QRP-L list? I was but I couldn't handle the huge
volume of email so I unsubscribed. Perhaps someone who's a member might like to
announce the existence of this group, I'm sure the BITX20 would be of interest
to many on that list too.
?
73
Hans G0UPL
?
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Re: The PC as a lab instrument
Hans Summers
There's also the problem of the "homebrew only" law which We should not look askance at ALL "store-bought" technology.Don't get me wrong, I don't look askance at store-bought technology at all, nor have anything against it or any other aspect of amateur radio. Some people are committed QRP enthusiasts. I am mostly QRP but sometimes if condx are bad and I want to get through to a friend I turn the 80m CW TX up to its maximum 10W and I don't feel bad about it. There are so many aspects to amateur radio, each ham has his own areas of interest. Some hate CW, others operate it exclusively. To each his own! But my own passion is to homebrew everything. For really extreme homebrew, I hope one day to build a valve transmitter and matching receiver using components which are all constructed from household items or things that can be purchased from the hardware store. Every component: valves from baby food jars, capacitors from kitchen foil, etc etc. See for the capacitor I built, the only part so far. But that's just me - people who operate QRQ QRO black box contest stations don't bother me either. Unless it's a time such as once happened when I was in QSO with an SM6 on 80m, 2-way QRP CW and both about 339 or something rather marginal, and midnight GMT comes around and suddenly the whole place explodes with contest traffic and the SM6 and myself, well we both got practically vapourised by the volume of the audio in our receivers. Had to curse them a bit then ;-) 73 Hans G0UPL |
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Re: Components
Hans Summers
Mine arrived today too, many thanks Hans.No problem Mark. Sorry list members, Jack's earlier message on this subject and my reply got copied to the whole list when in fact it was intended to be offlist. Note that this list is configured such that the default reply address is the list itself rather than the original message sender. This means that by default replies go back to the list and if you want to reply only to the sender you have to copy and paste their address in. I prefer it this way, it generates more list traffic but I feel that often what is of interest to the original sender will usually be of interest to others, since we are in general all discussing the same rig. If there is any significant feeling about this and you want it set the other way, that can be done. 73 Hans G0UPL |
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Re: The PC as a lab instrument
Jim Strohm
On Jun 25, 2004, at 8:34 AM, Hans Summers wrote:
There's also the problem of the "homebrew only" law which rules my station.We should not look askance at ALL "store-bought" technology. Sometimes, recycled gear is nearly as satisfying as homebrewed, especially if it's recycled from the dust bin. A few months back, I was challenged to write a book describing how to build a transmitter and receiver starting from ZERO technology. So far, I've outlined sections on how to knap flint, how to make fire with sticks, and how to develop the most rudimentary tools for metallurgy. It appears that the shortest route to homebrewing a radio station essentially from dirt is to use gold for the wiring ... so far, I've found much more gold in the dust bin than lying about on the ground. Jim N6OTQ |
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Re: Components
Mark
Mine arrived today too, many thanks Hans.
--- In BITX20@..., Hans Summers <Hans.Summers@t...> wrote: morning. My very best wishes to your wife, and good luck with the project whenyou have time. Nearly 60 years of marriage is wonderful. I am 33, marriedfor 8 years so some catching up to do! We have a 15 month old daughter whotakes most of my time.from three different suppliers. The LM386 was from Farnell because Iwasn't sure that the Rapid Electronics version was the correct LM386N-1version. All components have been counted out and shipped, UK orders by firstclass post (should arrive tomorrow morning) and international orders viaairmail. could be because they are so cheap that counting them precisely costs Rapidmore than giving a few extra. Or it could be that I messed up my owncounting, as the whole process was rather tedious and I have been having a verystressful day. If anyone is missing any then let me know, or needs someextra spares. things to say, but am too busy to do it today so pls QRX< 76/D=gr oups/S=1705063108:HM/EXP=1088241546/A=2128215/R=0/SIG=10se96mf6/*http ://comp anion.yahoo.com> click hereM=295196.4901138.6071305.3001176/D=groups/S= :HM/A=2128215/rand=941782905>Service <> . |
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Re: The PC as a lab instrument
Hans Summers
does anybody have more stories about using PCs in theFarhan, I don't have a PC at home at all, except an old laptop my XYL uses for internet access. I prefer to do everything without a PC. I even built my crazy 30m QRSS beacon project with no PC or microcontroller, see and . I sit in front of a computer here in the office every day and somehow prefer that when I am at home I don't have to be attached to one. There's also the problem of the "homebrew only" law which rules my station. So far the only exception to it is my old 5MHz oscilloscope and my DVM. Some day I will get my Z80 computers up and running, and will be able to write some homebrew software for QRSS and PSK31 etc. 73 Hans G0UPL |
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Re: Components
Hans Summers
开云体育?
No
problems Jack, thanks for the cheque which was received this morning. My very
best wishes to your wife, and good luck with the project when you have time.
Nearly 60 years of marriage is wonderful. I am 33, married for 8 years so some
catching up to do! We have a 15 month old daughter who takes most of my
time.
?
73 de
Hans G0UPL
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Re: Components
William Ford
开云体育Component parcel received today.many thanks
Jack
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Components
Hans Summers
Hello
Just to let you know that all the components arrived this morning, from three different suppliers. The LM386 was from Farnell because I wasn't sure that the Rapid Electronics version was the correct LM386N-1 version. All components have been counted out and shipped, UK orders by first class post (should arrive tomorrow morning) and international orders via airmail. When I'd finished there were 14 BC547 transistors left over. This could be because they are so cheap that counting them precisely costs Rapid more than giving a few extra. Or it could be that I messed up my own counting, as the whole process was rather tedious and I have been having a very stressful day. If anyone is missing any then let me know, or needs some extra spares. I owe quite a few of you emails and also have a couple of other things to say, but am too busy to do it today so pls QRX 72/3 de Hans G0UPL |
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Re: The PC as a lab instrument
Jim Strohm
On Jun 24, 2004, at 5:37 AM, Ashhar Farhan wrote:
the PC is a powerful a DSP as you can hope to own. the problem is in"Back in the day" ... A decade or more ago, it was trivial to get ISA-bus prototype boards to wire up new gadgets like A/D converters. With the limited bandwidth of ISA and the low frequency of consumer-affordable A/D chips, board layout was not an issue. In fact, some of us were building MIDI interfaces/audio digitizers for Macintosh out of a single A/D chip and a couple of connectors. And it's trivial to use the PC printer port (LPTx) as a data interface. A PCI breadboard is a lot harder to come by nowadays, and it's not even something that an enterprising hobbyist could etch up himself. However, PCI has the bandwidth and the newest consumer-grade A/D chips have sampling rates that were almost unheard of just 5 years ago. But it would be (relatively) simple to design and build a PCI A/D board. The biggest challenge would be to equalize the signal traces from the A/D chip to the PCI connector. Assuming one could etch a PCI connector, this could be done at home. An easier interface would be USB 2.0 or FireWire (IEEE 1394). Most PCs built since 1999 have USB 1.0 or higher; some PCs since 2002 have FireWire (Macs introduced since 1998 or so all have FireWire). The significant advantage to USB is that most consumer OSes besides Mac OS X have drivers for most USB devices built in, so there's a good chance that for any given USB interface chip, the OS will recognize its data stream and be able to provide it _somewhere_. This isn't as easy to implement as an LPTx scheme under DOS, but there are a number of simple programming environments for Windows such as Visual BASIC (yecch) or National Instruments' LabView (hurrah!) that make data acquisition and manipulation easy to set up. And Linux has at least as many drivers, plus the ability to drop to a command-line interface, which makes accessing machine-level functions a whole lot easier than under an MS OS, now that DOS has been effectively buried under Wind0ze. Theoretically, all you need for data capture is -- suitable conditioning and buffering circuitry to deliver your analog signal to your A/D converter, a buffer/interface to your bus, and a suitable bus connector. In the case of USB and FireWire, which are serial interfaces, you need as part of the bus buffer/interface from the A/D -- a data serializer. This would be any scheme that would take the parallel-bus output from the A/D and convert it to a serial stream compatible with USB or FireWire. Some newer A/Ds now have serial outputs, so the interface would be as simple as doing level conditioning and perhaps some timing adjustment. The stuff's out there -- try TI or National Semiconductor. Both companies have reasonable sample policies if you know how to ask. It's harder to design the board than it is to get free parts. (N.B. -- Some parts are US export-restricted, even though they're made or assembled outside the US.) And -- if you have lots of money to throw at the problem, National Instruments has already solved it. Reverse-engineering their hardware at lower performance levels should be within the scope of most savvy home builders -- their catalog offers ample design solutions that show you what CAN be done. After that, it's just a matter of software. Or, if your signal of interest is 20 kHz or narrower, you merely need to convert it to baseband and feed it to your sound card. There's a lot of amateur DSP software available. And again, if you have a lot of money to throw at the problem, there's also MatLab for developing your own DSP software. And -- the modulation characteristics and core DSP source routines to match those characteristics are freely available on the Internet if you are a diligent searcher. Programming in C is an advantage here. If you choose to explore this avenue, you'll soon find that having a stereo input sound card opens up a huge new world of capabilities. Most of them beyond the scope of HF SSB, CW, or PSK31. Jim N6OTQ |
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The PC as a lab instrument
Ashhar Farhan
i have been quitely following hans' travails on rec.radio.amateur.homebrew
with his digital counter experiments. i dug out a counter from my junk box. it consists of just a 74HC4020. the output of the fed to the sound card of my PC. on the PC i wrote an application to count the zero crossings and multiply the result by 1024. it gave a rough indication of where my VFOs were. the counting took a second. but it is a rough and ready instrument. like most amateur intrumentation. but that brings us to an often overlooked piece of equipment that is present in almost every shack. the PC. i know that a number of us cannot live without spice. i haven't figured out how to use it. but for many of us, designs do start with spice. "can i spice it?" is a regular refrain on the net. a number of excellent design tools written by hams are useful around the home lab. i use a large number of small code snippets to calculate inductances and capacitances from a test oscillator's frequency readout. another useful application of the PC is as spectrum analyser workng at audio frequencies. while this may not seem much at first glance, if you feed the output of direct conversion receiver to the PC's sound card and run a DSP software on it, it turns into a fairly useful measurement. for instance, you can evaluate the crystal filters, tune the front-ends etc. a half unfinished project at my shack is a spectrum analyser that uses this principle. the PC is a powerful a DSP as you can hope to own. the problem is in getting signals in and out of it. the only available means of doing it is via audio (baseband). i have used a PC based scope too. but that is a costly option. costlier than the PC itself. but it might be interesting to see how useful can the ordinary PC become by strapping some home made circutis around it. does anybody have more stories about using PCs in the home lab? - farhan |
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