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Re: Speaker
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On Feb 24, 2017, at 9:35 PM, G8JCF <g8jcf@...> wrote:
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Re: Speaker
? Roy WA0YMH Carrollton, TX On Feb 24, 2017 9:35 PM, "G8JCF" <g8jcf@...> wrote: Could you please post the eBay URL to these speakers. |
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Re: Blinking red light
Jack Purdum
Peter: You're right. Not everyone wants to get under the hood. I used to tell my students about being at my cabin in Canada, about 350 miles north of Toronto. As I pulled out from the gravel road, I saw a man standing beside a brand new Lamborghini Countach with the hood up, arms folded. I'll bet he kinda wished he had spent a little time under the hood. Jack, W8TEE From: G8JCF <g8jcf@...> To: [email protected] Sent: Friday, February 24, 2017 9:13 PM Subject: Re: [BITX20] Blinking red light Hi Jack Personally I really enjoy fishing and have been doing so for over 45 years now, and think that everyone should learn to fish, but fishing is not to everyone's taste :) I think that many (most ?) people don't want to be programmers (novice or otherwise), just users. Those who do the programming and want to share their efforts with those who can't/don't program could post their .HEX file to a "well known" place, eg files section on this group (and the .HEX is tiny), and then post the URL to the file to the group. I do think that perhaps the files section should have a firmware folder/directory into which programmers could place their .HEX files for others to download. 73 Peter - GM8JCF -- I am using the free version of SPAMfighter. SPAMfighter has removed 91067 of my spam emails to date. Get the free SPAMfighter here: Do you have a slow PC? Try a Free scan |
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Re: Delivery times to Canada
Long path? Randy On Fri, Feb 24, 2017 at 6:21 PM Dana Marcy <ve6kbi@...> wrote:
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Re: Blinking red light
Hi Jack
Personally I really enjoy fishing and have been doing so for over 45 years now, and think that everyone should learn to fish, but fishing is not to everyone's taste :) I think that many (most ?) people don't want to be programmers (novice or otherwise), just users. Those who do the programming and want to share their efforts with those who can't/don't program could post their .HEX file to a "well known" place, eg files section on this group (and the .HEX is tiny), and then post the URL to the file to the group. I do think that perhaps the files section should have a firmware folder/directory into which programmers could place their .HEX files for others to download. 73 Peter - GM8JCF -- I am using the free version of SPAMfighter. SPAMfighter has removed 91067 of my spam emails to date. Get the free SPAMfighter here: Do you have a slow PC? Try a Free scan |
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Re: Speaker
Ed Vignati
yes $6.75 for two shipped, I'm using one of them, I tried all the speakers I have in stock and these are the best. Look at the size of the magnet. On Fri, Feb 24, 2017 at 6:17 PM, Roy Appleton <twelveoclockhigh@...> wrote:
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Re: bitx40 newbie build, if touched IRF510 switches and locks to transmit, takes 3A
It really doesn't need a large gate voltage to oscillate. All it needs is adequate
drain capacitance to ground, which Andrew is providing with his finger touching the heatsink. Very likely, his heatsink is not isolated from the IRF510, so the heatsink acts as an antenna. It is also possible that it is isolated and merely the presence of hand capacitance near the tab is enough to make it go into oscillation. Having the mag loop antenna provides a high Z load -- that is probably enough to trigger the oscillation in this case. One cannot use a mag loop without a good tuner. Another possibility is a bad relay which is providing a continuous transmit signal. That should be easily determined by knowing the frequency of oscillation. Probably it is low VHF. I suspect this is happening when he tries to transmit. But he cannot because the self-oscillation is drowning out the control. Try first a good 50 ohm dummy load on transmit and see what happens... Welcome to the wonderful world of the MOSFET. Once oscillation begins, there is feedback through the gate; hence installing a suppressor resistor there is the usually the best fix for the problem. This from the experience of many PA builders. Even WA2EBY met this problem head on. john AD5YE |
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Re: CW or not to CW?
There is a very real sense in how multiplying two voltages together and emitting the resultant number as a voltage is not linear: the units do not work out. ?If I travel 60km in 3 hours, I went at an average speed of 60km/3hours = 20 kilometers per hour. ? If I measure 3 volts at one port and 2 volts at the other, multiply those two numbers and present 6 volts at the output, that's cheating because for the units to work the output would be volts-squared. ?Volts-squared is a mathematical concept, not physical reality. On Fri, Feb 24, 2017 at 03:05 pm, Jerry Gaffke wrote:
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Re: CW or not to CW?
This is one approach. Probably the best example I know of this is Eliamady's
smdBITX. Look in the files section for the "M0ZHN smdBITX". this design allows for USB, LSB, and CW (Carrier) by loading the BFO oscillator with different capacitors and using pin diodes to switch between them. The VFO oscillator is the user's option, presumably a DDS. The other approach is that of "PY0OHH BITX40", also in the files section. Looking at his schematic, one can easily see a separate keyer controlled oscillator for CW. It is connected after the crystal filter and is switched in and out for mode control. Anything other than these methods is sort of impractical. These have been built and work. But you may come up with something else. Build it and they will come... john AD5YE |
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Re: Blinking red light
Peter, thanks for the info! Roy WA0YMH Carrollton, TX On Feb 24, 2017 3:18 PM, "G8JCF" <g8jcf@...> wrote: Hi Roy |
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Re: Bits internal swr bridge
That looks really good, about what I would want on my Bitx40. ?Not a resistive bridge, so can keep it in line and know when the wind in the trees snaps my antenna. ?Assuming we can keep a couple analog pins available for it, should work well with the Nano. ?Weird that the webpage you pointed to does not mention what kind of meter you need to hook up to it. ?(I think I could dig up a natural-gas meter, would that do?) ?And weird that the spanish translation says 10 Watts max, whereas the English says 100 Watts. ?Let me know if you get either of those resolved. On Fri, Feb 24, 2017 at 02:56 pm, Randy Hall wrote:
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Re: CW or not to CW?
The ideal mixer simply multiplies the two incoming signals, effectively measuring the voltage at both input ports at each instant in time, multiplies those values together and places the result on the output port. ?If the two inputs are both sine waves, then the result is only the sum and difference, no nasty extra products, as per that trig function in my previous post. ?I'd call that linear, but in this case anything other than summation of voltages is considered non-linear by them RF guys. ?So I guess you are right. On Fri, Feb 24, 2017 at 02:24 pm, Dr Fred Hambrecht wrote:
To mix two frequencies requires a non-linear device, in this case the diodes. ? ? |
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Re: Bits internal swr bridge
Hi I bought this , with the idea to use it with the BITX40. It is still unbuilt. Maybe using two of the analog input pins on the NANO, we could read the sensor, calculate the SWR and show it on the display. Randy, K7AGE BITX40 #139 On Fri, Feb 24, 2017 at 2:31 PM, Shaun Ruscoe <Bumblemittens@...> wrote:
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Re: CW or not to CW?
John, Hope that rant on mixers wasn't too far over the top. ?One of the reasons I find this forum (and the Bitx40) compelling is that I am learning a good deal. ?Trying to explain something like that mixer is fun and compelling. ?Or figure out why some rig might "transmit" when the IRF510 is touched. ?Forces me to reason it through, not leaving any loose ends. My plan for CW is still basically this: ?/g/BITX20/message/20933? ? I have the iambic keyer mentioned in this post working under the Nano: ?/g/BITX20/message/19374? Unfortunately, that was so much fun that I am getting sucked into other code for the Raduino to fill out some of the Bitx40 features. ?Haven't actually tried the radio yet. Jerry, KE7ER On Fri, Feb 24, 2017 at 02:27 pm, John Backo wrote:
Now how does one change a BITX into a CW rig? ? |
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Re: bitx40 newbie build, if touched IRF510 switches and locks to transmit, takes 3A
Maybe oscillating, but I really don't understand this one. ?My impression is he's not hitting the PTT button, just touching the heat-sink with his finger. ?So no 12v TX rail into the 5v regulator used to supply bias to the gate, the gate should be near ground. ?That IRF510 shouldn't be doing much of anything. Andrew: what is the voltage at the IRF510 gate when you are trying to receive? On Fri, Feb 24, 2017 at 02:29 pm, John Backo wrote: It is probably going into self-oscillation. ? |
Allard PE1NWL
