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Re: DDS VFO!
"NC-40 filter is too narrow for SSB (though I have listened to ? The NC40 uses crystal filters so, referencing the schematic, it would be a simple matter of changing C9-C13 to alter the bandwidth of the filter.? There were a few people on the BITX series radios who replaced the fixed capacitors in the crystal filter with varactor diodes to make the bandwidth variable. ? ? |
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Re: DDS VFO!
On Tue, Nov 5, 2019 at 08:07 AM, Bob Macklin wrote:
NorCal40 As the NorCal 40 uses the SA602/612 GC mixer, the 49er DDS should work just fine.? That said, the SA602/612, unlike many of the mini-circuit mixers (SBL-1 types), is not a 7dBm device, which again, is why the AD9850 DDS from the 49er (W8TEE) works well with that device.? The W8TEE DDS used in the 49er project, has an output level adjustment for tweaking. If using a si5351 DDS, which has more than double the output level of the AD9850, it would be a good idea to pad (attenuator) down the output level down to something more palatable to the SA602/612.? Additionally, and this is just personal experience, putting some level of pad between the DDS and the mixer input lets both devices see a solid 50 ohm impedance which, is a good thing. Robin - AC7LX |
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Re: Arduino Connectors?
开云体育Bob,Besides Samtec you might look for/at the Molex KK series.? Those are .1" excuse me 2.54mm spaced male and female headers.? If you search ebay and Amazon they are often called JST connectors as JST style are used a lot.? The pins are .025" square or round pins and the male headers are usually breakaway style.? I recently bought some of the 20 pin female headers that Rob linked on ebay.? They are not breakaway though.? You do have to cut them and unlike the Molex style you have to sacrifice a pin so if I want a 20 pin female header or 2 of them from the 40 pin strip it ainta gonna happen!? If you try to cut it between pin 20 and 21 you will end up with 2 headers of 19 pins so save yourself some grief and just cut it right over pin 21! In searching I see that Arduino makes or lists those female headers under their brand name.? I just bought a bunch of the 6, 8, and 10 pin stackable female headers from nooelec.com on their ebay store.? I just tried to find them at their non ebay site but do not see them.? Nooelec.com also sells many of the SDR dongles and appears to be their claim to fame. I was just looking and Jameco shows these: I did not look at Adafruit but am sure they also have them. The thing about these "stackable" headers is that they employ long male pins which makes them very convenient for Arduinos because you mount the female header on top of the Arduino and the LONG male pins stick through to also give you the male header to plug in to the module below.? Or you can reverse it depending on whether you need/want the female header on top or bottom but the long pins that go through the board and make the male headers on the other side is very convenient! Here is the Nooelec auction for 200 of the 6 pin female stackable headers: They do seem to be better quality than the ones I have bought from some of the Chinese sellers. When I was looking at Mouser I see that 3M also makes a lot of the male headers and suspect that they have some female headers too but did not look for those specifically. You can also just use a regular 40 pin wide (.6 inch wide) IC socket for I think the Nano in a pinch but IC sockets are not really deep enough.? The stackable ones mentioned above are .4" deep as I recall and an IC socket is maybe 1/16" inch deep or so! I hope that helps. Good luck. Jim Pruitt WA7DUY On 11/8/2019 10:48 AM, Bob Macklin
wrote:
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Re: Send in your QRP Pictures!
Lee, Not really interested in refurbishing. I want to make something my own. This is almost like the OMs who answer my homebrewing questions with "why not just go buy ___?". I know people mean well but I would rather make a boatanchor than buy one. Actually, I've been making some mild steel enclosures to build skill for my eventual 50-lb radio. I'm wanting something more capable than a one-tube oscillator-amplifier. At very least, a MOPA transmitter. I'm also not going to buy FT-243 crystals (too rare and too constricting). I'm either going to figure out a VFO, or I'm going to drive the oscillator stage with a DDS generator. At very least, I'll buy some QRP crystals in the HC-49 case, 3D print or scroll-saw some cases, and build some up that way. If I were using smaller crystals, I'd limit the oscillator stage to 45-75 volts, meaning the crystal heating should be low. Right now I'm finishing up a 6SN7 twin plex receiver. It will do until I can make some kind of superheterodyne rig. A full-blown phone transceiver might be a bit much for working in tubes. I'm not sure what I want to do but I get very little time to build, let alone operate, these days. Ed AE7TE On Fri, Nov 8, 2019 at 9:22 PM Leland L. Bahr <w5drc@...> wrote:
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Re: Send in your QRP Pictures!
You guys are awesome- thanks so much for the support in uploading your photos. Six photos gave me enough to build a header banner for the group. Go to the groups main page to check it out:
/g/qrptech Feel free to keep uploading, the more the better! It might be cool to have a builders gallery too, and they can be used for that. -- Ryan Flowers W7RLF
https://miscdotgeek.com |
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Re: Send in your QRP Pictures!
开云体育Ed, If you want to do more things with tubes you have lots of choices
but may I suggest building a true clone of the PARASET, or
Philmore NT-200 Novice transmitter.? These won't be fast or cheap
if you want a true clone but they are fun to build and use.?
Besides they hold lots of history.? There is a lot of support for
the PARASET .? The NT-200 puts out a very usable signal.? Both for
the most part can be reproduced with parts after doing some
scrounging.? Refurbishing a transmitter such as a Heathkit DX-60
can be interesting and fun and actually cost you less then doing
one of the two above suggestions.? Here you would replace poor
tubes, replace out of spec resistors and caps such as tubular
paper ones as well as the electrolytic capacitors.? Then clean the
radio, controls and switches.? Sometimes repaint transformers and
covers too.? Lee, w0vt? On 11/8/2019 10:22 PM, Jon Edwards
wrote:
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Re: Send in your QRP Pictures!
Sent some pictures of the Ugly Weekender Transceiver I built in 2014. I'd like to have more projects to send but I have no photos of them (for some damn reason). I want to do more things with tubes. Ed AE7TE On Thu, Nov 7, 2019 at 10:28 PM wb6ogd <garywinblad@...> wrote: Working now, thanks! |
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Re: Headers / Pins / Crimper Solutions for Off-board Items?
Rob
开云体育I use wire wrap pins and nixie tube sockets as my off PCB connectors. On 11/08/2019 12:41 PM, Kirk
Kleinschmidt via Groups.Io wrote:
Hi, gang, |
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Re: 2010 smdBITXv4 kit for sale
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On Nov 8, 2019, at 12:53 PM, Ryan Flowers <geocrasher@...> wrote:
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Re: Arduino Connectors?
Bob Macklin
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Re: Arduino Connectors?
Graham
There are a number of manufacturers but if you search on Mouser for Samtec headers you will start going in the right direction. cheers, Graham ve3gtc On Fri, Nov 8, 2019 at 1:48 PM Bob Macklin <macklinbob@...> wrote:
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Trystan G0KAY
Alan N8WQ
Newt N4EWT
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