India is a big place.听 Mumbai is about 700km from the home of the BITX.
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uBITX40 : audio is meowing and not understandable.
I need help to solve a malfunction.
I have a version 3 kit with the famous TDA 2822 in the WX version which for the moment does not produce smoke and the output is good.
The problem is that in SSB, even with strong signals, the audio is meowing and not understandable.
The same problem with 8/16 and 20 ohm speakers.
What can I do?
Thanks for the appreciated advice.
73 de IV3XHM, Toni
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Re: Harmonics and Relay Replacement
Hi Nigel do you have a link for your UK supplier Thanks Graham
Sent from my Samsung Galaxy smartphone.
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-------- Original message -------- From: Nigel G4ZAL <nigel@...> Date: 15/10/2018 12:45 (GMT+00:00) Subject: Re: [BITX20] Harmonics and Relay Replacement
With reference to the article, where the听 AXICOM type D2n V23105-A5476-A201 is described as the best relay
I have located some of these in the UK as they are British Telecom specified relays with coil resistance of 280 ohms and power consumption of 515mW and operating current of 27mA
I paid听 just under 1GBP each, (US$1.30) delivered.
Relay spec (scroll down to find the BT spec)
I have no means of testing the harmonic difference before and after installation, but hope they will not upset anything with the extra power demand?
Nigel - G4ZAL
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Re: Harmonics and Relay Replacement
With reference to the article, where the听AXICOM type D2n V23105-A5476-A201 is described as the best relay
I have located some of these in the UK as they are British Telecom specified relays with coil resistance of 280 ohms and power consumption of 515mW and operating current of 27mA
I paid听 just under 1GBP each, (US$1.30) delivered.
Relay spec (scroll down to find the BT spec)
I have no means of testing the harmonic difference before and after installation, but hope they will not upset anything with the extra power demand?
Nigel - G4ZAL
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Taxes may make the difference and it is well possible you buy goods at more favorably prices (and sometimes of better quality) outside the country. It's called microeconomics.
Il 15/ott/2018 12:10, "Dexter N Muir" < dexy@...> ha scritto: By any god/s you care to name! I'd be astonished to find NZ produce cheaper overseas! What sort of upside-down system are you living in?
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I would be willing to pay extra just for the chance to meet ashar.
KF4FTR
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By any god/s you care to name! I'd be astonished to find NZ produce cheaper overseas! What sort of upside-down system are you living in?
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All
Be careful using SMD inductors in Low Pass Filters: they may have trouble handling the required power, and the lower Q may affect the filter characteristics.听
Also be careful using SMD inductors in Band Pass Filters and Low Pass Filters because they will more easily saturate, this will limit the dynamic range and IP3 of the receiver. The lower Q will also increase the insertion loss of some Band Pass Filter designs.
SMD inductors may also lack the inherent self-shielding properties of the toroidal inductor shape.听
This page听 is a very educational study on what size toroids are necessary to avoid them becoming the limiting factor for dynamic range and IP3. But you need a very good mixer otherwise the mixer is already limiting the performance.听听 听
In the uBITX the dynamic range and IP3 are already limited elsewhere so the type of inductor used is not likely to be a limiting factor.听
SMD or pre-wound axial inductors make things easy. But toroids make things high performance. Everything being a trade-off as usual.听
73 Hans G0UPL
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Re: Harmonics and Relay Replacement
Am 14.10.2018 um 23:57 schrieb Joe Puma: Yea but changing the relays looks like the real winner here.
Hello Joe, It is not a big problem to get the HFD27 desoldered. A good desolder litz (I used 2,5mm from Felder) and a bit judding and pulling an they will come out without any damages at the PCB and the relais. Desoldered all 5. They will go in the scrapbox and this evenig the AXICOMs will take their places. 73, Matthias DD7NT
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It picks up TX signal just like L5.
L1 is the worst. If you put uBitx on the analyzer and bring your finger
near L1
you will see huge comb like oscillations. SMD removes that.
Probably due to Hi Q of the toroids!
Raj
At 15/10/2018, you wrote:
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Raj, what is wrong with the
stock 30mhz LPF?
Il 15/ott/2018 07:26, "Raj vu2zap"
<
rajendrakumargg@...> ha scritto:
- It is exactly the same. S+M seems the brand.
- To replicate my board best to use these. Thanks for locating the
source.
- Also buy some 331 for the 30MHz LPF filter.. 4 per board.
- Raj
- At 14/10/2018, you wrote:
- The parts in the photo appear to be these parts:
-
- Not sure they are Murata parts.
- I would concur that a part marked 芒鈧�681k芒鈧劉 is normally 680uH, but
these seem not to follow that convention.
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can you forward me the email that you wrote to hfsiganls? i will follow it up with them
- f
good evening
I have a problem with a BITX40 that never worked! I replaced the motherboard because I thought the problem was there. It is not so! Only the raduino remains! I wrote an email to HF-signals to find out how much the raduino costs, but they did not even answer me! Now I'm going to buy the kit on qrp-labs but I have a doubt! I had a raduino checked by a technician and a test with oscilloscope actually comes out the frequency of 5 mhz as it should be! Only when I connect it to the motherboard it totally changes the result!
听
Is this correct or does it have problems?
听
How can I test the radio with the old tuning system without the raduino?
What changes do I have to make?
听
Thanks Sergio
听
Sorry for my English!
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it is easier (and probably cheaper) to buy it abroad. there are extra taxes in india.
- f
I am travelling to India soon and would like to pick. A coupe Bitx40's any idea where I might find any near Mumbai?听
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Re: Harmonics and Relay Replacement
Would be there at significant advantage to replace all the 5 relays, or is enough to replace only the three at the PA LPFs?
Il 15/ott/2018 02:20, "Ripley" < bob.ripley@...> ha scritto: Here are snapshots for 20 and 10 meters after the relays were replaced with the Axicom components. Sorry, I didn鈥檛 capture the harmonics profile at 14.2 and 28.8 Mhz before the relay change but there nothing exceeding the -43 dB threshold for FCC compliance. Once again Yellow = SSB and magenta is CW 听 听 Picture 1 is of harmonics and spurs on 28.8 Mhz Picture 2 is the harmonic profile at 14.2 Mhz 听 A couple of other notes: using a 12 volt 50 watt power supply my power out is 10 watts on 80, 40, and 20 meters, dropping down to 8 watts on 15 meters and 6 watts at 10 meters. 听 Ripley 听 听 Sent from for Windows 10 听 From: Ripley
Sent: Sunday, October 14, 2018 7:52 PM
To: [email protected]
Subject: RE: [BITX20] Harmonics and Relay Replacement 听 Hello All, 听 I installed the Axicom relays in my uBITX (ver 4) test bed this afternoon and ran tests 3.8, 7.2, and 14.2 Mhz. Here are the before and after snapshots. Yellow is SSB and magenta CW. 听 Pic #1 is 7.2 MHz before relay change Pic #2; 7.2 Mhz after relay change. Note that the CW third order harmonic was brought down by about 7 dBs but still exceeds the -43 dBs threshold for FCC compliance Pic #3; 3.8Mhz before relay change Pic #4; 3.8 Mhz after relay change 听 The biggest drops were in SSB mode as others have pointed out already. 听 So you know the base line of my build. The 45 Mhz crystal for spur reduction has been installed but only the crystal itself. Driver transistors Q92, Q93, Q96, Q97 were replaced with metal can 2N2222A and the emitter resistor changed to 11 ohms. AGC was added along with a manual RF gain control. 听 Ripley KD8UYQ 听 听 Sent from for Windows 10 听 From: Joe Puma
Sent: Sunday, October 14, 2018 5:57 PM
To: [email protected]
Subject: Re: [BITX20] Harmonics and Relay Replacement 听 Yea but changing the relays looks like the real winner here.听 Joe 听 Looking at pic #2 seems to me that adding a 47nF capacitor to ground at each coil terminal as Arv hypothesized would make the uBitx a leap close to be legal compliant with respect to the harmonics. Il 14/ott/2018 20:31, "Kees T" <windy10605@...> ha scritto:
>
> Plots of the coupling between N/C contacts on either side of the relay (which will include the armature) and what they look like with the addition of a 47nF capacitor to ground at each coil terminal.听 You can see the dB of isolation improvement.
>
> #1 HK16F-SHG "16 pin" relay (like the original uBITX relays)
> #2听 same as #1 but with the 2 capacitors added (see less coupling ....a good thing).
> #3 NAIS TQ2-H "10 pin" smaller relay which does not have the long armature
> #4 same as #3 but with the 2 capacitors added (less coupling .....a good thing)
> #5 Axicom .....TBD waiting for the relays.
> #6 same as #5 but with the 2 capacitors added (less coupling .....a good thing)
>
> 73 Kees K5BCQ
>
>
>
>
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Raj, what is wrong with the stock 30mhz LPF?
Il 15/ott/2018 07:26, "Raj vu2zap" < rajendrakumargg@...> ha scritto:
It is exactly the same. S+M seems the brand.
To replicate my board best to use these. Thanks for locating the
source.
Also buy some 331 for the 30MHz LPF filter.. 4 per board.
Raj
At 14/10/2018, you wrote:
The parts in the photo appear to
be these parts:
Not sure they are Murata parts.
I would concur that a part marked 鈥�681k鈥� is normally 680uH, but these
seem not to follow that convention.
|
Re: Emissions allowed In Band Segments
Indeed, 60m, 4m, 1.25m and 33cm are not allowed in many countries.
Il 15/ott/2018 04:41, "Curt via Groups.Io" <wb8yyy= [email protected]> ha scritto: You didn't specify which nation or itu region. This looks like maybe a USA list, no 4m band etc. These nuances do vary some around the world.
Curt
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Good morning Brian
yes the raduino is connected right, it's the first thing I looked at ..
It has never worked! They replaced my motherboard but nothing changed! So only the raduino is left! Before buying the qrp-labts model I wanted to try the bitx with the analog vfo. I thought about inserting the l4 coil and the variable capacitor or the varicap diode.
Yes capacitors c91 and c92 are mounted.
听
Thanks Sergio
|
It is exactly the same. S+M seems the brand.
To replicate my board best to use these. Thanks for locating the
source.
Also buy some 331 for the 30MHz LPF filter.. 4 per board.
Raj
At 14/10/2018, you wrote:
toggle quoted message
Show quoted text
The parts in the photo appear to
be these parts:
Not sure they are Murata parts.
I would concur that a part marked �681k� is normally 680uH, but these
seem not to follow that convention.
|
Hi,
Sometimes the calibrations are off enough to reverse the USB and LSB settings. I assume they were initially set correctly, but somehow get changed. If you hunt around in the messages you will find others that have had the same USB/LSB issues and in other messages recalibration instructions.听
Tom, wb6b
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I am travelling to India soon and would like to pick. A coupe Bitx40's any idea where I might find any near Mumbai?听
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Re: Emissions allowed In Band Segments
Yes USA.听 Direct copy of FCC part 97 Para. 305. Mike K5ESS 听
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From: [email protected] [mailto:[email protected]] On Behalf Of Curt via Groups.Io
Sent: Sunday, October 14, 2018 9:42 PM
To: [email protected]
Subject: Re: [BITX20] Emissions allowed In Band Segments 听 You didn't specify which nation or itu region. This looks like maybe a USA list, no 4m band etc. These nuances do vary some around the world.
Curt
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Raj vu2zap
Ben Johnson