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Re: Yeah! No!
L2 is 6uh, which would be 25 turns (25 inches) on a T37-6 core. _._ On Wed, Dec 21, 2016 at 2:44 PM, Kent Vanderploeg kvanderploeg@... [BITX20] <BITX20@...> wrote:
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Re: Yeah! No!
Thomas Noel
开云体育Kent,? is a good source for small quantities. 25 t37-6 toroids for $5, and they sell small lengths of magnet wire. Click on “Toroids” on the home page then pick your needed toroid. Toroid page also has a calculator for cut length of wire for size of toroid and number of turns. Thomas W Noel KF7RSF
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Re: Yeah! No!
Thanks for the info.? It's definitely not something I have laying around.? Anyone point me in the direction of some place I can purchase the toroid and wire without getting killed on shipping or having to forever for shipping? Kent W9WB On Wed, Dec 21, 2016 at 3:56 PM, Joel Caulkins caulktel@... [BITX20] <BITX20@...> wrote:
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Re: Yeah! No!
开云体育Kent, L2 is a T37-6 yellow core with 45 turns of 32-34G wire. You want 6uH when you get done. Farhan would probably send you one if you don't have one. Joel? KB6QVI On Dec 21, 2016, at 1:44 PM, Kent Vanderploeg kvanderploeg@... [BITX20] <BITX20@...> wrote:
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Re: good news / Bad news
Kenyw
40 meters has been kind to me. I recently had a South African QSO. A record distance of 8380 miles on a G5RV. This was on a Flex 6300...I can't wait to try my new BITX40...I bought one just before the ordering was closed until the updated units come out.
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-----Original Message----- From: Ashhar Farhan farhanbox@... [BITX20] To: BITX20 Sent: Wed, Dec 21, 2016 11:00 am Subject: Re: [BITX20] Re: good news / Bad news
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I worked S75DX last night at 1 am on the bitx40 into a 51 foot doublet at 40 feet.
- f
On 21-Dec-2016 7:39 pm, "Kenyw kenyw@... [BITX20]" <BITX20@...> wrote:
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Re: good news / Bad news
I worked S75DX last night at 1 am on the bitx40 into a 51 foot doublet at 40 feet. - f On 21-Dec-2016 7:39 pm, "Kenyw kenyw@... [BITX20]" <BITX20@...> wrote:
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Re: good news / Bad news
Kenyw
I have a Flex SDR and recently here in Central Ohio I can count the number of signals across the whole 20 meter band on one hand.
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-----Original Message----- From: mvs_sarma@... [BITX20] To: BITX20 Sent: Tue, Dec 20, 2016 11:41 pm Subject: Re: [BITX20] Re: good news / Bad news
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May friends indicated that the propagation conditions are pretty BAD. we need to hold back before commenting on the Rx .
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Re: good news / Bad news
Baruch Atta
To the group: ?just to let you know that things are coming along. ? What I thought was a lack of sensitivity was just an out-of-band experience (out-of-body?) After I replaced my caps with NP0 caps, it seems that my range is 7.270 to 7.400 or so even with the var cap fully meshed.? So just the top top part of 40 meters.? Not good. ?but not so bad.? I could hear a station this afternoon, weak but weak also on my big rig. ? But the good thing is that the rig is solid on the frequency. ? I hooked up my oscilloscope and got a good signal from the DDS pin.? But I could not hear that on my big rig, perhaps because the wire connecting did enough to stop the oscillation.? Also, I sent out some smd caps to another user.? So my offer still holds, I will send you a few smd caps (1000pF and 150pF) if you send me a self addressed stamped envelope. But be aware and be warned: And your milage may vary. ? ?73, Joe W3TTT On Tue, Dec 13, 2016 at 2:07 AM, iam74@... [BITX20] <BITX20@...> wrote:
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DDS/VFO -Analog Device options-
Hi Guys I was checking the Analog Device website ?and there is a lot of DDS we can get for free like a sample. The AD9850 is little expensive is you have to buy hundred, but there?are others options we can get for free. Now my question: Is there someone ready, willing and able to programming ?one of these like AD9834 to do a DDS/VFO?. If you click the IC and go to the bottom of the page you will see the availability to buy or to get the?sample. To do the request, you only need a valid email address(means not a free email account), and create your own profile. I have gotten AD9833-AD9834-AD9835 and other kinds of items always for free. Qrv's 73's Jc |
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Re: Photo Permission
Jack Purdum
Thanks, Ashhar! Jack, W8TEE From: "Ashhar Farhan farhanbox@... [BITX20]" To: BITX20@... Sent: Tuesday, December 20, 2016 11:06 AM Subject: Re: [BITX20] Photo Permission
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you can use anything from the website. except for the pcb layout, nothing else is under any restrictive copyright.? - f On 20-Dec-2016 8:31 pm, "econjack@... [BITX20]" <BITX20@...> wrote:
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Re: Photo Permission
you can use anything from the website. except for the pcb layout, nothing else is under any restrictive copyright.? - f On 20-Dec-2016 8:31 pm, "econjack@... [BITX20]" <BITX20@...> wrote:
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Photo Permission
All: I'm giving a talk ("Giving Your QRP Rig a Facelift") at the Four Days In May conference that takes place on the eve of the Dayton hamfest. I would like to use some of the photos of the BITX40 that appear on the hfsigs.com web site in my talk, but I cannot find a contact link tp ask for permission. Does anyone have an contact email address for them? If you would prefer the link to be private, my QRZ.com email is fine. Thanks! Jack, W8TEE |
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Re: Bitx40 review (video)
Those who have used an Si5351 to supply both the VFO signal and the BFO signal; I am wondering where you would inject the DDS BFO signal into the BITX40 board. The existing BFO osc could be easily disabled by cutting the jumper at L5 on the PCB. If C104 were removed, could the DDS BFO signal be injected into the base of Q10 and use Q10/Q11 to amplify it? or is there a better way???
73, AL - VE3RRD |
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Re: Frequency counter and huff n puff using Pic
Thomas Noel
开云体育Thanks Rob,I understood that you were emphasizing the code re-purposed for the Bitx40, but you included the link! I checked, liked what I saw, and was looking for the lazy way to an answer on buying the kit instead of joining the list and asking there.? Thanks for the update. Thomas W Noel KF7RSF
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Re: Bitx 40 board.
Thank you, Ken. Glad it helped.
You know, you can get USB and LSB through the same Cohn filter. Remember that the filter is a passband filter about 3 kHz wide with an upper and lower skirt. For proper phasing, the LSB has to reflect off the lower skirt and the USB off the upper skirt. But the filter itself is really a passive object. The trick is in adjusting the BFO frequency so that the filter thinks it is getting one or the other of the sidebands. If the incoming IF is just below the center frequency of the filter, it will pass it as LSB, and if the IF is just above the center frequency, it will pass it as USB. So, since one generates both sidebands at the BFO mixer, merely changing the BFO frequency enough is all it takes to generate one or the other. Ha! Then if one changes the VFO to reflect which sideband is coming through the filter, one can have a dual sideband rig! Say you wanted 20m and 40m. Then the 40m rig would use a VFO to generate ~7 MHz with the IF BELOW the center frequency of the filter, and a VFO to generate ~14 MHz with the IF ABOVE the center frequency. It is not so easy with analog VFO's; probably you would need two separate ones. But it is easy with a DDS. Setting the BFO frequency is a matter of loading the crystal. Remember that we have to move the frequency only a few KHz to get either sideband. That is done by diode selection of each tuning (or diode selection of 2 crystals). We are generating both sidebands all the time. The particular IF we choose just selects which to send to the passive filter. Since the IF amplifier is wideband, it can easily handle a few KHz difference in frequency. One would need to provide separate BPF's and LPF's for each band, of course -- but it is not too hard a thing to do. There are some caveats to heed. The parallel resonant frequency is not too far up the USB and reaching that can have strange effects; so one must be careful in tuning around the USB. Else, it works. Alternatively, one can choose a different IF with a different, somewhat higher (by a few KHz) frequency crystal. Also remember that the center frequency is probably NOT that marked on the crystals. It is the measured serial frequency of the filter. In the case of the BITX40, that can be anything around 12 MHz. Say your IF is 11.996600 MHz. Then the center of the filter passband is probably 1.5-2.5 KHz above that. Exactly what is a measurement. CW is also possible by allowing the BFO carrier to get through. It is less effective, however, since the passband is 2-3 KHz wide, and CW should have one about 700 Hz wide. But it can be done. One merely adds a third crystal to the BFO and allows the carrier through for the center of the passband. Some people have gotten around the wide passband problem by using varicaps to adjust the filter capacitance. But that introduces impedance problems and more extensive changing of circuits at times... 73 john AD5YE ---In BITX20@..., <chase8043@...> wrote : John You did an excellent job on explaining this subject. It's something I will be investigating more. Once in a while something comes along that I don't understand and I don't give up till I do. People like yourself are a credit to the hobby and I appreciate all your work here. 73 Ken VA3ABN |
Joel Caulkins/N6ALT