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Re: schematic ambiguities
LM78L05 datasheet recommends 0.33uF within 3 inches of the input pin. ?The Bitx40 likely has that already. ?It is ?not being loaded very heavily. ? I doubt there's an issue, but would add a cap if the board were rolled.
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Re: BITX40 Band pass filter
quote == Did anybody recalculated (or can recalculate) BPF filter to 7.0 to 7.2 MHz (stock is 7.0 to 7.3)
Mac , SP9MRN
unquote === It is highly unlikely that a BPF built for 7.0 -7.3 MHz? (ITU Zone 2) would give any problem with any TX supposed to operate only on the 7.0 -7.2? MHz ? (ITU Zone 1)
Frank ,? GM0CSZ / kN6WH????? in IO87AT
On Tue, Jan 3, 2017 at 12:53 PM, sp9mrn@... [BITX20] <BITX20@...> wrote:
?
Did anybody recalculated (or can recalculate) BPF filter to 7.0 to 7.2 MHz (stock is 7.0 to 7.3)
Mac
mrn
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Re: Sad reality of stock vfo
thanks Alf, so, did you end up with C95 47pF or 82pF? jer aa1of
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? ? Ashhar Farhan, thank you, was my question because I will adjust my linear but 200 mv pep is very I think, maybe 100 mv pep? Jorge PY2PVT _._
?
If I was to injection a 1k sine wave into the mic connection for troubleshooting purposes. What's the safe peak to peak voltage?
I'm troubleshooting a dead transmitter.
Bill
-- ? 73 de Jorge PY2PVT
? Campinas SP
? GG67MD
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Did anybody recalculated (or can recalculate) BPF filter to 7.0 to 7.2 MHz (stock is 7.0 to 7.3) Mac mrn
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Re: Sad reality of stock vfo
quote ====
I changed C91, C92 to 680pF polystyrene, C94, C95 to 47pF polypropylene,
C96 to 150pF polystyrene, C95 to 82pF polystyrene, just what I had in
the junk box, stability very good.
unquote ==== Yes ,polystyrene caps are excellent for VFOs I built a single FET 80 m VFO? (ugly construction)for the " UK Intermediate Licence" training , running on a 9V battery , all on an open chassis. Once in operation for 5 minutes drift was no more than 50 Hz longer term . Frank? ,? GM0CSZ / KN6WH??????? in IO87AT
On Mon, Jan 2, 2017 at 11:53 PM, Alfred fpdbase@... [BITX20] <BITX20@...> wrote:
?
ohwenzelph@... [BITX20] wrote:
>
> Who has "changed the on-board chip capacitors to leaded polystyrene
> types and report
> good stability." With the BitX40v3, and
>
>
> which caps did you replace and with what values?
>
> Jer aa1of
>
> ?
>
> .
>
>
I changed C91, C92 to 680pF polystyrene, C94, C95 to 47pF polypropylene,
C96 to 150pF polystyrene, C95 to 82pF polystyrene, just what I had in
the junk box, stability very good.
Cheers Alf vk2yac
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Re: It stopped transmitting
A friend had a similar problem. ?
The base & emitter voltages around Q13 were around 1 volt rather than 3.7v (base) and 3.1v (emitter). ?We fixed it by replacing Q13. ?If you're careful you can use a leaded transistor as the replacement.? Described at? | | | | | | A repair of a 'no power on transmit' fault suffered by a friend's Bitx40. | | | | Preview by Yahoo | | | ? ?
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A use for that BNC connector cover supplied...
... why not make it part of a tiny hand microphone??
| | | | | | Using the BNC antenna socket cover supplied with the Bitx40 as a case for a tiny handheld microphone ideal for portable use. | | | | Preview by Yahoo | | |
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Re: schematic ambiguities
we might need an additional cap at regulator IN to gnd. you may call it C143A
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Re: It stopped transmitting
Hi Bill,
What you observe means that the final stage is fine . Please set the
current back to the recommended
level and check the previous stages.
While in TX mode and not speaking in the mic - Check the Q13 and 14 base
to emitter voltage.
It should be around 0.7V +-0.1 - if 0 or >1V then replace
transistor.
Raj
t 02-01-2017, you wrote:
toggle quoted message
Show quoted text
?
I tested and getting 330 ohms.? Receive current is 100ma no
signal.
Transmit is anywhere from 180 ma to almost one amp depending where RV 1
is set to
On Jan 2, 2017, at 6:00 AM, Raj
vu2zap@... [BITX20]
<BITX20@...
> wrote:
?
Bill,
While looking at the diagram again it occurred to me that if Q14 was
shorted, the power supply would get
2.2 + 10 Ohm load and that would draw almost 1 amp from a 12V power
supply.
Please check Q14 collector to emitter continuity with the power
off.
At 02/01/2017, you wrote:
?
Without speaking
On Jan 1, 2017, at 10:22 PM, Raj
vu2zap@... [BITX20]
<BITX20@...
> wrote:
?
Bill,
One question, when you switch to transmit does the current jump to 1A
when you speak into the mic or without speaking?
Raj
At 01/01/2017, you wrote:
?
- At 31/12/2016, Bill Kittilson
bill@... [BITX20]
wrote:
- >
- >
- >I managed to kill my bitx40. It was working great until I decided
to tune up the big rig. I can still receive. No power at all on transmit.
I replace the 510 transistor. Sill no output. The current does jump up to
over 1 amp when I switch to transmit.
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When you reply to someone please leave the previous reply intact and do not delete or we wont know
who you have replied to.
I presume you have replied to me.
Either way you connect the pot, it will work fine. The wrong way means when you turn clockwise the
RX frequency will go down instead of upwards!
toggle quoted message
Show quoted text
At 03-01-2017, you wrote:
You still didn't answer the question. Which lug does the red wire connect to so that the VFO freq
increases when you turn it clockwise. Before I can trim or look for anything I need to know which way to turn the knob. There are hardly any signals to work it out and the wiring up description says
Solder the red wire of the 3-pin connector to right lug of the tuning control
??? Solder the brown wire of the 3-pin connector to the middle lug of the tuning control
??? p; Solder the black wire of the 3-pin connector to the right lug of the tuning control
and in the photo it shows the red wire connected to the right lug!!!
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Re: troubleshooting the bitx40 receiver
Thank you for the info :) VE7BEE
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Thank you . I will do that for sure :) VE7BEE
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write to hfsignals@..., for the difference of $14 per piece, they will ship the Raduinos to you.
- f
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keep it to less than 200 mv peak to peak.
- f
On Tue, Jan 3, 2017 at 4:39 AM, Bill Kittilson bill@... [BITX20] <BITX20@...> wrote:
?
If I was to injection a 1k sine wave into the mic connection for troubleshooting purposes. What's the safe peak to peak voltage?
I'm troubleshooting a dead transmitter.
Bill
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Re: Band Pass Filter High Attenuation
As I recall, this BPF is about 200 ohms in and out. If you used the IF transformers supplied with the kit, suspect first the coils of these transformers.? They are quite fragile and it is easy to get a poor or nonexixtent connection through them. First, were they oriented right? Second, it is easy to pull one of the pins out of alignment and even break the connection internally. Check them very carefully. Third, there is a specific and quite narrow window which creates the bandpass. Triple check your alignment. The proper final inductance should be about 4 uH (for 20m). Hope this helps. john AD5YE ---In BITX20@..., <marktbaldridge@...> wrote : Greetings all.
I seem to have an issue with my Band Pass Filter.
This was built using the components from Sunil Lakhani on eBay.
----
The entire schematic is here:?
-- Mark Baldridge 608.561.3853
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Re: 3d printable enclosures?
Tried that on another project (a "Klopik-2" from Russia). Problem is, it STILL uses OpenSCAD, and I couldn't get it to do what I wanted it to do...
Rich KC8MWG
On Monday, January 2, 2017 9:54 PM, "mark.g0nmy@... [BITX20]" wrote:
?
Well off the same site maybe this is what you are after?
scroll down to thebottom of the page to download.
| | | | | | The file include now the Panel Maker. Check below in the Experimental area to download it. My first try with OpenScad, the box is fully customizable. I hope y... | | | | Preview by Yahoo | | |
Hope that helps Happy 2017
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Re: 3d printable enclosures?
Actually, the 3D printed case
referenced was created using Ultimate box maker.
Jim - KA9BGT
On 1/2/17 8:53 PM, mark.g0nmy@... [BITX20] wrote:
toggle quoted message
Show quoted text
?
Well off the same site maybe this is what you are after?
scroll down to thebottom of the page to download.
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The file include now
the Panel Maker. Check below in the
Experimental area to download it. My first
try with OpenScad, the box is fully
customizable. I hope y...
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Preview by Yahoo
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Hope that helps
Happy 2017
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Raj vu2zap