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Re: #ubitx. Increasing power output
¿ªÔÆÌåÓýI¡¯m glad you brought these parts up.? I¡¯ve been designing commercially with the BFR106 and BFR182 lately and they are wonderful devices to work with.? In a uBITx design they would work very well for all stages except the PA driver/ PA (and there are better devices for the audio stage).? If someone eventually releases block design boards for the uBITx, these parts would make excellent choices for the build. ? ? From: [email protected] [mailto:[email protected]] On Behalf Of ajparent1/KB1GMX ? Not as good as it has low peak current capability. -- ¡_. _._ |
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Re: uBitX CW bandwith
W2CTX,
Well maybe CEC firmware needs to be fixed, or maybe it has and you need a newer version.? To me that is a legit issue that needs attention and can be fixed. What is funny to me in AOs are not new, I remember '50s articles and comments in CQ and QST about them.? The number of SSB? radios with CW are too numerous to list and many of them are far worse.? Try CW on a HW101 without the CW filter, then with.? Its then you realize it keys terribly.? ?;) Switchable or adjustable filters were a big deal and you could have them at significant cost or the price of a radio that offered that.? I think its forgotten. Then again I got to know a lot of old time CW ops that used what ever they had and? Ran nets and QSOs in what sounded like beeping soup.? They could even recognize a particular fist!? Skill and knowledge. Allison |
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Re: uBitX CW bandwith
¿ªÔÆÌåÓýAllison:
Well, I bought the uBitx thinking of it as a learning platform, and a way to get involved again in a hobby I pretty much abandoned for 50 years. I expected it to be legal and useful, but not the same as a commercial product. As we now know, we all got less then that as far as legal is concerned, but it some ways more, in that we can learn more from it. As you know, I have been working (or at least attempting to work) on solutions for the problems, and I have never complained about that. There are lots of really serious issues to complain about these days, but uBitx isn't one of them. If you can't learn from it and enjoy it, put is in the closet, or sell it. Don't complain about it. Howard PS I didn't expect an answer, thanks for taking the time. On 8/19/2018 12:44 PM, ajparent1/KB1GMX wrote: Howard,
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uBITX new build, quiet audio
#ubitx
Apologies, I suspect this is a common question but my poor google-fu hasn't turned up anything other than a blown TDA2822, which I don't think is my issue.
I just finished my ?BITX build (v3 board... arrived the week before v4 came out :) ) and my receive audio is very quiet, both through headphones and through an 8 ohm speaker.? Even with the volume turned up to 100% even reasonably strong clear signals are almost swamped by hum (which I believe is power supply related, I don't think that's anything to do with the ?BITX). I do get audio, so I believe the fundamental wiring is correct and the volume does modulate with the volume pot.? I'm running off a 12V wall wart (reads at 12.2), so the power is a little below 14.1 but I'm not looking at the TX side yet.? The front panel of my case is metal, with the volume pot, rotary encoder and all the 3.5mm jacks mounted in it but I've tried removing them from the metal plate and it didn't seem to change the behavior at all. This is my first real radio build, so while I get the high level concepts I don't know where to look for mistakes when things don't work right.? Can anyone provide any guidance on where to find my screw-ups? Thanks, -Ben |
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Re: uBitX CW bandwith
Allison ? This is only my opinion;? but I feel that we are talking about the age of "appliance" operators. The buyer sees that CW is supported and assumes it works.? I have yet to see anyone post that the CEC software SPLIT doesn't work properly! rOn On August 19, 2018 at 12:05 PM ajparent1/KB1GMX <kb1gmx@...> wrote: |
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Re: uBitX CW bandwith
Howard,
It is rhetorical to a point and its also a chance to ask first hand.? Hey you bought this and then...? I know I'm probing human nature maybe but its of interest to my inner engineer who asks how do we fix this?? As we first have to understand what the problem is. Part of me says build a SSB only radio and sell it as such and watch the fur fly. I bet a penny the first is can it do CW and the second is can it do FT8. I say that as I've already seen how to I do hook up PSK31 with a Rockmite! Allison |
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Re: Modular uBitx - "Ex: Harmonics"
From Han's posting in the QRP-LABs group - Who will be the first to install this into a uBITX? Randy, K7AGE I hope to write up some details of the PA board in the next couple of days. This PA board is so GOOD that it will be made available also as a standalone 10W HF Linear PA kit. It is ready for production and should be the first of the QSX modules ready for sale. The requirement for expensive Mitsubishi RD16HHF1 etc transistors in a decent amp is an absolute misconception. In reality they are very very expensive and not necessary in HF applications such as this. This amplifier is proud to use two inexpensive IRF510 transistors. A great deal of attention has been paid to a symmetric and compact layout for best performance.? I am very grateful to Allison KB1GMX for her advice, encouragement, support and testing during the development of this Linear PA. More details soon but briefly: 1. Two IRF510 in push-pull, two BS170 in push-pull as the driver. 2. Gain 26-28dB, better than 2dB gain flatness from 2-30MHz. Still only 4dB down even at 6m, and respectable even to 4m. 3. Can easily achieve 10W across 160-10m using 12V supply 4. 80m band tested harmonic levels 2nd -38dBc, 3rd -31dBc. Thats BEFORE a low pass filter is added - addition of the LPF will result in a very clean output. 5. Very large heatsink for the 10W power rating. Ran continuous 100% duty cycle at 10W output for 1 hour without failure or degradation 6. Tested to 20V supply voltage; tested open load; tested shorted; tested with 20W 100% duty cycle for 10 minutes... all with no failure or degradation 7. Quite easily delivers a lot more than 10W too... Above results are for the PA module alone, not integrated within the QSX. I think it is very unlikely that that you would be able to replace the PA module in the QSX with anthing that could deliver as good performance, even assuming you are willing to spend a lot more money. Anyone who thinks IRF510s aren't good for the job, will need to reconsider their view after this. 73 Hans G0UPL ? On Sun, Aug 19, 2018 at 8:07 AM, Eric Flores <floreseric1981@...> wrote:
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Re: Low Power Output for Hendricks BitX20A - Watt meters and Scope readings do not agree....
#bitx20
Jerry,
using Andy's? ? V^2 pk /100=P There is an assumption of sinewave power and 50 ohms. If measured at the drain of the mosfet the latter is likely not true. Then there is O'Scope error.? Scopes are generally better at measuring an events timing than accurate voltages. Allison |
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Re: Low Power Output for Hendricks BitX20A - Watt meters and Scope readings do not agree....
#bitx20
Glenn,
1db error cannot be heard at the other end. However most do better than 1DB more like less than .1db. However you then need to know the loads and attenuators accurately. If you using random cables you have to measure them especially at upper HF and above.? for example 1M of RG402 at 1.5ghz can eat many db.? I have measured mine to better than .1db and frequency and keep a record.? both for the precision cables and attenuators.? If it changes as in broken and two its not constant over dc to UHF and higher.? So a record is then good for building a calibration tree. However the solution is a calibration source to assure that what ever device being used is indeed indicating accurately. Its not hard to build and once conformed you write it on the box and use that as a reference.? I do that even with a recent calibration as that assures me I didn't grab a bad cable or fry something.? Then if suspect or just need to know the answer is use the calibration source and verify. Same for loads, a peak reading load for more than a few milliwatts can be verified with a power supply and a known accurate voltmeter. The last items is sanity check the numbers.? If it seems inconsistent it might be. For example a case of an insistence it can hear to -140dbm simple radio. Problem was his RF source leaked like a sieve and the radio heard well to about -118dbm!? Once he got near that level all the attenuators in the world were overridden by leakage. Allison |
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Re: uBitX CW bandwith
Hi Allison,
toggle quoted message
Show quoted text
And why do they buy a ten watt radio and then push it hard into a corner to get it to 15 watts? It makes no difference whatsoever at the distant receiver (where it counts) but shortens rig life and most likely generates all kinds of ill mannered splatter. Once upon a time I had a Ten Tec Argonaut 509. That fine radio (I'm sorry I let it go) had an SSB bandwidth crystal filter. No CW bandwidth filter of any kind in the I.F. chain. just like the uBitx. It relied on an active filter for it's CW selectivity and it worked very well. So now we all know what we have to do for CW selectivity with our uBitx boxes:) I have NEScaf audio filter that I will be using on CW. Today I will be installing a pot to adjust the sidetone level and probably installing the CEC software in my own radio. I will also be using low pass filters, one for each band, external to the radio and doing business on the CW bands. Digital comes later. See you on the air uBitx style. 73, Bill KU8H On 08/19/2018 12:05 PM, ajparent1/KB1GMX wrote:
Please do not answer as if this is a troll. --
bark less - wag more |
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Re: uBitX CW bandwith
¿ªÔÆÌåÓýI hope this is a rhetorical question.
On 8/19/2018 12:05 PM, ajparent1/KB1GMX wrote: Please do not answer as if this is a troll.
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Re: uBitX CW bandwith
R. E. Klaus
Allison, I refer to it as the Walmart syndrome. Some people expect more than what they are paying for and then complain when they get what they pay for. Next they want to return it because it doesn't live up to something 5 times the price even when they can see it's specifications before they buy it. I see it every day working in retail. Flame suit on, off soap box. Roxie -- K1AUS |
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Re: uBitX CW bandwith
Please do not answer as if this is a troll.
Why is it that people buy a simple and low cost SSB radio that can do CW with only one filter and then complain about?CW performance??? It seems inconsistant that if one desires CW a radio optimized for that would be the goal. I'd like a serious answer please.?? Allison |
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Re: New file in Photo section "ubitx T11 specturm"
#ubitx
Adrian,
You can also get that with one or more stages (usually in the low level parts) are running near overload.? Like the low IF or even the balanced modulator. Henning, The assumption is the system is clean and its the source signal. Other flaws like carrier leakage,? and low level stage overload (clipping) can look like that. If the power amp is suspected than go back to T8 or T2. Allison |
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Re: New file in Photo section "ubitx T11 specturm"
#ubitx
jim
On Sunday, August 19, 2018, 2:41:51 AM PDT, Henning Weddig via Groups.Io <hweddig@...> wrote:
Jim, Your photo does not show a good two tone signal: the envelope should have a zero crossings. So either the two
tones are not exactlx equal, or not equal amplified (ripple within
the xtal filter!) or the carrier suppression is not sufficient! Another possibility could be ripple and insufficient
carrier suppression. Henning Weddig DK5LV Ah ha ....Someone noticed ....Indeed you are correct.? By feeding the two-tone levels through the 12 mhz filter (which we know is not linear at ~630 and ~2100 hz the modulation is NOT exactly "correct" ...I'll fiddle with the two-tone oscillator levels and see what I see. Jim |
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Re: Modular uBitx - "Ex: Harmonics"
Eric Flores
The desired signal at Q10 is always right around 45mhz. Has to be, or it won't go through the 45mhz crystal filter Ah, I mixed that up then. I had glance through the circuit description and assumed the first LO was 45Mhz (but that was the desired IF). I went back and saw this:? the first oscillator tunes from 45 MHz to 75 Mhz So in the RTL, you would always have to account for a variable frequency offset when tuning the RX. Eric On Sun, Aug 19, 2018 at 07:47 Jerry Gaffke via Groups.Io <jgaffke=[email protected]> wrote: The desired signal at Q10 is always right around 45mhz. |
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Re: Modular uBitx - "Ex: Harmonics"
Gordon Gibby
¿ªÔÆÌåÓýHi John Brock I¡¯m not sure exactly which project you were referring to, but if the external low pass filter relay project:1. You basically want to do the wiring so the RF signal don¡¯t get mixed into HIGHER low pass filters. ? I do that by grounding the higher low pass filters when no longer in use. ?On the Little board that someone pointed out the relay contacts are right
there for you, so you can wire them with short or shielded wires and minimize cross talk. ?You¡¯re trying to reduce capacitance between circuits that shouldn¡¯t know about each other
2. ?You also want to avoid blow by getting around through the coil connections which are wired on both input and output of the filters and communicate by way of the DC wiring. ?Decoupling bypass capacitors or ?the optical coupling are good solutions for
that
3. ?Relays have been used to switch transmit/receive/ filter signals for a bunch of years. ?My heathkits ?had them. ?Sometimes the Contacts get a little oxidized and less signal gets through, a bit of paper used to burnish them and they work better. ?
That is, if you can even get to them. ?
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Re: #bitx40help BITX40 LSB Winlink
#bitx40help
With feedback.
You should see the amp for the QRPlabs QSX.. makes that look pitiful. Allison |
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