Re: BITX 40 - DDS right connection
Thanks, It is a good solution.
73.
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Well, technically it arrived Friday, but I wasn't able to go to the post office to pick it up until this morning. That is going to be so much fun when I get time to put it together, get an antenna built, and so on...
I am thinking of making one mod almost right away, though. I want to replace the microphone and earphone connectors with a TRRS jack ( - Goes to Mouser) so I can use my cellphone headset with it. It's a 3.5mm TRRS plug, works with my laptop, cell phone, and with an adapter my desktop PC. (I'm guessing to split the + line on SPK1 for T and R1, + line for MIC (not labeled, but I assume is the 2-pin to the right of SPK1) to R2, and combine - on both SPK1 and MIC to S.) I'll probably also get a 10-turn pot and some nice knobs from Adafruit.
My only concerns so far are that C103 appears unpopulated, and L5 next to it is a piece of wire rather than an inductor.
Everything looks good, though, and I can't wait to dig in.
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Did you add it to the red wire or black wire?
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Re: BITX 40 - DDS right connection
The VFO we built for the Forty-9er (March, 2016, QST or see:?)?has buffered output if needed. Two sets of header pins?
allow the user to pick off the drive they need. Farrukh charges $7 for a good quality PCB and he also has a kit with some of the parts for $15 (not including the AD9850 or the Nano). The software to drive the Nano is a free download. You can download the assembly manual I wrote for the article, which should give you a good feel for what's involved.
73, Jack, W8TEE
From: "ik8yfw@... [BITX20]"
To: BITX20@...
Sent: Monday, November 28, 2016 1:27 AM
Subject: [BITX20] Re: BITX 40 - DDS right connection
?
Thanks Mike, this is a good news. I will try to use a small amplifier to output the 9850, mybe it will help a lot. I've used the 9850 with a ne602 based receiver with success. I think that a couple of 2n2222 will solve the problem.I Hope to test it in the next days or in the weekend.? 73 ik8yfw
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Re: FCC Rules of Operation
I was curious when this would come up. I'm sure the quality of the products are good, but I'm not sure how this could be checked without a spectrum analyser etc.
Im pretty sure the FCC really isn't after people using qrp rigs though.
On Nov 27, 2016 8:16 PM, "Ashhar Farhan farhanbox@... [BITX20]" < BITX20@...> wrote:
?
John, this reminds me
I have tested for the BITX40 for the spurs to be all below -50dbc on my home built spectrum analyzer. I just hope someone else will also doubly test this just to be sure.
- f
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Ian I inserted a second pot with value 500 ohms in series with the tune pot.? It makes a very nice bandspread. ? 73, joe
On Sun, Nov 27, 2016 at 7:52 PM, Ian Gerard iank3hql@... [BITX20] <BITX20@...> wrote:
?
?
I dont mind a little drift, I can work with that. 1 khz per min makes it a little difficult to listen to one signal for very long. To tune a single signal, I must tap the tuning control on top till I get it. It wouldnt be so bad on CW, but within a minute the voice becomes unintelligible.
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I agree about the resistors. In North America and Europe, they are very easy to get without ordering from India. I'm going to build an external analog VFO dead-bug style and see what I can accomplish with it (and maybe add a digital readout). This is a great kit at a very, very affordable price! The bonus is the learning and experience gained through adding various modifications, fixes, and improvements. :-) Mike Haynes? KE0KRY
On Mon, Nov 28, 2016 at 12:48 AM, ik8yfw@... [BITX20] <BITX20@...> wrote:
?
Hi Mark, I confirm the drift problem, if you change the six resistor from 100 to 220 ohm this help realy in RX mode. But in TX mode the problem return mybe becauae the PA warm up all the PCB...and make difficult voice qso and impossibile the use with Digital modes. I decide to move to DDS, already Done some tests and it work well. You Can use also an external analog VFO if you want. More info on blog site of hack page.? 73 de ik8yfw Giuseppe.
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Hi Mark, I confirm the drift problem, if you change the six resistor from 100 to 220 ohm this help realy in RX mode. But in TX mode the problem return mybe becauae the PA warm up all the PCB...and make difficult voice qso and impossibile the use with Digital modes. I decide to move to DDS, already Done some tests and it work well. You Can use also an external analog VFO if you want. More info on blog site of hack page.? 73 de ik8yfw Giuseppe.
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Re: BITX 40 - DDS right connection
Thanks Mike, this is a good news. I will try to use a small amplifier to output the 9850, mybe it will help a lot. I've used the 9850 with a ne602 based receiver with success. I think that a couple of 2n2222 will solve the problem.I Hope to test it in the next days or in the weekend.? 73 ik8yfw
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Re: Ebay Store Kits Out Of Stock?
On Nov 28, 2016 10:29 AM, "Sandeep Lohia" <sandeeplohia12@...> wrote:
>
> On Nov 28, 2016 6:05 AM, "Baruch Atta baruchatta@... [BITX20]" <BITX20@...> wrote:
> >
> > ?
> >
> > Are the surface mount parts mounted by the woman's group? ?
>
> Ha ha! By machineries, as to decrease labor cost & time, otherwise it cannot be so cheap...
> BTW, torroids finds way frm pretty soft hands...
> Personally inspected & serial by Farhan (Y)
> ( not hands but BITX, joks apart ;)
>
> Above all previously mentioned already by 'F'
> Hats off, a new trend..
>
> ( mailed mobile )
>
> >
Again machineries cannot do everything, soft hands is for sure...
Charity (Y)
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Re: Ebay Store Kits Out Of Stock?
On Nov 28, 2016 6:05 AM, "Baruch Atta baruchatta@... [BITX20]" <BITX20@...> wrote:
>
> ?
>
> Are the surface mount parts mounted by the woman's group? ?
Ha ha! By machineries, as to decrease labor cost & time, otherwise it cannot be so cheap...
BTW, torroids finds way frm pretty soft hands...
Personally inspected & serial by Farhan (Y)
( not hands but BITX, joks apart ;)
Above all previously mentioned already by 'F'
Hats off, a new trend..
( mailed mobile )
>
> On Sun, Nov 27, 2016 at 6:46 PM, Mike Haynes mike.haynes08@... [BITX20] <BITX20@...> wrote:
>>
>> ?
>>
>> Thanks for answering John. I didn't know as much about the history.?
>> I have Ashar's SMD version, and it works great, but I wouldn't mind a through-hole version in case I needed or wanted to replace a component. Replacing those teeny tiny SMD parts can be quite a challenge. :-)
>>
>> On Sun, Nov 27, 2016 at 5:26 PM, iam74@... [BITX20] <BITX20@...> wrote:
>>>
>>> ?
>>>
>>> Mark, Sunil Lakhani and Asher Farhan are in completely different companies.
>>>
>>> Sunil brought out the BITX20 v.3 some years ago (with Farhan's blessing). He has since expanded the line considerably; parts are available from only circuit boards to complete rigs as kits. Sunil has a long and respected tradition in the BITX arena, but he has no smd kits as far as I know. I have bought several kits from him over the years and have always been treated well. They have become more expensive over time.
>>>
>>> Farhan invented the BITX and has been involved with the various permutations over the years from start-up.
>>> He has decided to market the smd BITX40 partly (or mainly) as an aid to a womens' group in India. At first, the kit was available only in India, but has recently become available internationally. It is only the second smd version that I know of; the first was by eliamady back in 2009. I have the BITX40 and also the eliamady smd version of the rig. (I will probably post pictures of both for comparison to the group shortly).
>>>
>>> As to which one to use...that is kind of a personal question -- it depends...
>>>
>>> Sunil's rigs are through-the-hole construction and are designed more or less for complete assemblage by the user, except for making the pcb. Their principal advantage is that missing or different parts are commonly available most everywhere -- including where you live. Asher's rig is pre-assembled and smd, but one has to figure out how to put it in a box and make it work without assembling the main board (or boards). Both are essentially the same design.The one radically different BITX was probably the BITX20A with its push-pull dual output PA. That also is still available.
>>>
>>> Every single BITX has been tweaked and modified over the years for one purpose or another. Both Sunil and Asher (as well as everybody else) encourage innovation to make things more to the user's liking. The best general summary I know of for the circuit is that of F8VOA, which has all the good mods in it. It is an excellent reference. The next best reference is this list. Search for any topic and you will probably find it discussed somewhere on this list.
>>>
>>> Hope this helps.
>>>
>>> john
>>> AD5YE
>>>
>>>
>>>
>>> ---In BITX20@..., wrote :
>>>
>>> Thanks Mike!
>>>
>>> I have a few questions:
>>>
>>> 1. What is story behind the two different sellers?
>>> There's like you mentioned, and then what I was referring to:
>>> Sunil Lakhani VU3SUA at
>>> and he's selling his kits on eBay as sunillakhani
>>>
>>> The kit I was thinking I wanted to buy was:
>>>
>>>
>>>
>>> 2.?Would I want the through-hole version referenced or the SMD version you linked to?
>>> Which would be better for experimenting or modifying for other bands?
>>> I also see that the SMD version is already assembled, and cheaper! $45?
>>>
>>> I appreciate the input.
>>>
>>> Thanks!
>>>
>>> Mark, KC9DZT
>>
>>
>>
>>
>> --
>> Mike Haynes
>
>
>
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Re: New Surface Mount Kit Not Working, Current Draw?
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After about 30 minutes warm-up, it becomes pretty stable.?
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Re: FCC Rules of Operation
John, this reminds me
I have tested for the BITX40 for the spurs to be all below -50dbc on my home built spectrum analyzer. I just hope someone else will also doubly test this just to be sure.
- f
On Mon, Nov 28, 2016 at 8:31 AM, iam74@... [BITX20] <BITX20@...> wrote:
?
Don't forget, guys,that EVERY transmitter must meet the rules of operation and emission for your country, no matter how it is originally set up or modified.
In the USA, that means meeting the Part 97 FCC Rules. Note that ALL spurious emissions must be at least 43 dB below the transmitting frequency. The responsibility for measuring and verifying this lies with the operator -- that's you, the builder of the rig. You shouldn't rely on any given design. You must verify that it is within limits.
"(d) For transmitters installed after January 1, 2003, the mean power of
any spurious emission from a station transmitter or external RF power
amplifier transmitting on a frequency below 30 MHz must be at least 43
dB below the mean power of the fundamental emission. For transmitters
installed on or before January 1, 2003, the mean power of any spurious
emission from a station transmitter or external RF power amplifier
transmitting on a frequency below 30 MHz must not exceed 50 mW and must
be at least 40 dB below the mean power of the fundamental emission. For a
transmitter of mean power less than 5 W installed on or before January
1, 2003, the attenuation must be at least 30 dB. A transmitter built
before April 15, 1977, or first marketed before January 1, 1978, is
exempt from this requirement."
john AD5YE
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Don't forget, guys,that EVERY transmitter must meet the rules of operation and emission for your country, no matter how it is originally set up or modified.
In the USA, that means meeting the Part 97 FCC Rules. Note that ALL spurious emissions must be at least 43 dB below the transmitting frequency. The responsibility for measuring and verifying this lies with the operator -- that's you, the builder of the rig. You shouldn't rely on any given design. You must verify that it is within limits.
"(d) For transmitters installed after January 1, 2003, the mean power of
any spurious emission from a station transmitter or external RF power
amplifier transmitting on a frequency below 30 MHz must be at least 43
dB below the mean power of the fundamental emission. For transmitters
installed on or before January 1, 2003, the mean power of any spurious
emission from a station transmitter or external RF power amplifier
transmitting on a frequency below 30 MHz must not exceed 50 mW and must
be at least 40 dB below the mean power of the fundamental emission. For a
transmitter of mean power less than 5 W installed on or before January
1, 2003, the attenuation must be at least 30 dB. A transmitter built
before April 15, 1977, or first marketed before January 1, 1978, is
exempt from this requirement."
john AD5YE
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toggle quoted message
Show quoted text
On 27-Nov-2016 11:15 am, "'Mark W' k3mrk1@... [BITX20]" < BITX20@...> wrote:
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Thanks Arv, Are they SMD resistors? If so, what size are they? Physical size. I don¡¯t work with SMD enough to tell by looking. I have a multiturn pot on the way. My tuning is super touchy. It takes quite a while to tune a signal in correctly. I literally have to tap the shaft to fine tune. Thanks for the info Mark K3MRK ? ? ? ? Mark. K3MRK
Either 10K or 100K, or anything in between, will work fine for the tuning pot.? A 10-turn type pot makes tuning much easier if you Resistors for decreasing heat generation are 220 ohms. ? On Sat, Nov 26, 2016 at 8:56 PM, 'Mark W' k3mrk1@... [BITX20] <BITX20@...> wrote: ? No I did not receive any resistors. What size are they? I¡¯ll try to find some. I also noticed that my tuning pot is 10k. The board info on the website says it should be 100k. Which is correct? I have received my enclosure and am almost done installing. Mark K3MRK ? ? ? ? mark,
you must have received a strip of 220 ohm resistors in the pack. if you replace the 100 ohm emitter resistors of the six amps with these, the drift will drastically reduce. the details are on the blog.
- f On 25-Nov-2016 4:58 am, "Mark Walton k3mrk1@... [BITX20]" <BITX20@...> wrote: >?
> ?
>
> It might be worse since there is no enclosure at all. Maybe not really warming up at all. I'm hoping the enclosure itself will have some heat retention. There are some transistors that can be used as heaters. I'll wait till I get the enclosure and see how it is. I realize that this circuit is prone to some drift on warm-up, but I think mine may be excessive. Bad cap? I haven't really started digging in yet. I have all the parts for a DDS and may just go that way from the start. I'm no engineer and will have to figure out how that is done as well.
> Mark
> K3MRK
>
>
> On Nov 24, 2016 4:21 PM, "Thomas Noel tnoel@... [BITX20]" <BITX20@...> wrote: >>?
>> ?
>>
>> What would happen if you added an intentional heater to the enclosure? I'm thinking of something like the flat stick-on pads used to warm reptile tanks, stuck on the underside of the radio enclosure? Thinking a giant version of an oven controlled crystal oscillator?
>>
>> Tom
>> KF7RSF
>>
>> Sent from my iPhone
>>
>> On Nov 24, 2016, at 12:53, Mark Walton k3mrk1@... [BITX20] <BITX20@...> wrote:
>> >>> ?
>>>
>>> I recently received my BitX-40 board. Until I get the enclosure, I only hooked it up for receive. Worked right out of the box. The only issues I've found is the drift is pretty bad even after being powered up for an hour. What should I be looking at to try to improve the stability? I do plan to build a DDS VFO for it over the winter.
>>> The only other issue is the running is very touchy. I have coming a multiturn pot to fix that.
>>> Any ideas on the drift?
>>> Other than that , I'm very happy with the board and look forward to building onto it in the near future.
>>> Thanks
>>> Mark. K3MRK
>
>
> ?
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Re: Bitx40 arrived but unfortunately DOA
Might be a bit of a stretch Mike to hear you lot in north America. In VK3
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Re: New Surface Mount Kit Not Working, Current Draw?
the current draw is 90ma in receive
- f
On 28-Nov-2016 4:24 am, " qrpbuilder@... [BITX20]" < BITX20@...> wrote:
?
A buddy bought a SMD pre-assembled board and says it's completely deaf, while he can hear lots of band activity with his FT-817ND. I volunteered to go over it with my scope and diagnose it.
First things first: What's the typical approximate current draw in milliamps for these boards on a 12.0 volt power supply in receive mode? (Knowing the expected current draw will allow me a rough determination of any gross circuit faults before I start tracing and probing.)
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On Sunday, November 27, 2016 6:22 PM, "Mark Walton k3mrk1@... [BITX20]" wrote:
?
I dont mind a little drift, I can work with that. 1 khz per min makes it a little difficult to listen to one signal for very long. To tune a single signal, I must tap the tuning control on top till I get it. It wouldnt be so bad on CW, but within a minute the voice becomes unintelligible.
On Sun, Nov 27, 2016 at 12:49 AM, k7tfc@... [BITX20] <BITX20@...> wrote:
?
--- wrote :
We starting including the resistors after the reports of the drift. the pads are big enough for you to solder regular 1/4 watt in place of wthe smd resistors (in manhattan style). if you do really want them, drop a mail to and they will post a 'pinch' of them to you for free, though the cost of postage is prohibitive but they have agreed to bear it.? - f
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