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I have checked SSB output for the Ubitx using a Softrock sdr receiver. The carrier is well aligned and the filter gives a very good shape. Whistling is gives full output with the stock mic element. The output seems clean but the average power during normal speech seems to me a bit low. Is there an easy way to increase it? 73, Franco
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On Fri, Apr 27, 2018 at 9:22 AM, iz oos <and2oosiz2@...> wrote: I have checked SSB output for the Ubitx using a Softrock sdr receiver. The carrier is well aligned and the filter gives a very good shape. Whistling is gives full output with the stock mic element. The output seems clean but the average power during normal speech seems to me a bit low. Is there an easy way to increase it? 73, Franco
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Specifically a Compressor¡. ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton ¨C J68HZ Soufriere, St. Lucia W.I. Rent it: Like us on Facebook! ? Moderator ¨C North American QRO Group at Groups.IO. ? email:? bill@... ? ?
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From: [email protected] [mailto:[email protected]] On Behalf Of Lawrence Galea
Sent: Friday, April 27, 2018 8:19 AM
To: [email protected]
Subject: Re: [BITX20] Ubitx average SSB output ? ? On Fri, Apr 27, 2018 at 9:22 AM, iz oos <and2oosiz2@...> wrote: I have checked SSB output for the Ubitx using a Softrock sdr receiver. The carrier is well aligned and the filter gives a very good shape. Whistling is gives full output with the stock mic element. The output seems clean but the average power during normal speech seems to me a bit low. Is there an easy way to increase it? 73, Franco
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External ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton ¨C J68HZ Soufriere, St. Lucia W.I. Rent it: Like us on Facebook! ? Moderator ¨C North American QRO Group at Groups.IO. ? email:? bill@... ? ?
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From: [email protected] [mailto:[email protected]] On Behalf Of iz oos
Sent: Friday, April 27, 2018 8:37 AM
To: [email protected]
Subject: Re: [BITX20] Ubitx average SSB output ? External audio processor or is there a way to adjust it in the Ubitx? 73 Franco ? Il 27/apr/2018 15:19, "Lawrence Galea" <9h1avlaw@...> ha scritto: ? On Fri, Apr 27, 2018 at 9:22 AM, iz oos <and2oosiz2@...> wrote: I have checked SSB output for the Ubitx using a Softrock sdr receiver. The carrier is well aligned and the filter gives a very good shape. Whistling is gives full output with the stock mic element. The output seems clean but the average power during normal speech seems to me a bit low. Is there an easy way to increase it? 73, Franco
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Yes. Change R63 to 24 ohms. The earlier
rev boards had 100 ohms there, and V3 has 47. I put another 47 ohm
resistor in parallel with the one on the board. Now I don't need
to yell into the mic.
Howard WB2VXW
On 4/27/2018 3:22 AM, iz oos wrote:
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I have checked SSB output for the Ubitx using a Softrock sdr
receiver. The carrier is well aligned and the filter gives a
very good shape. Whistling is gives full output with the stock
mic element. The output seems clean but the average power during
normal speech seems to me a bit low. Is there an easy way to
increase it? 73, Franco
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Howard did you also change out R65 that was posted here too. By the way the parts showed up here yesterday, thanks a lot. Now to find time to install them.
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On Apr 27, 2018, at 09:57, Howard Fidel < sonic1@...> wrote:
Yes. Change R63 to 24 ohms. The earlier
rev boards had 100 ohms there, and V3 has 47. I put another 47 ohm
resistor in parallel with the one on the board. Now I don't need
to yell into the mic.
Howard WB2VXW
On 4/27/2018 3:22 AM, iz oos wrote:
I have checked SSB output for the Ubitx using a Softrock sdr
receiver. The carrier is well aligned and the filter gives a
very good shape. Whistling is gives full output with the stock
mic element. The output seems clean but the average power during
normal speech seems to me a bit low. Is there an easy way to
increase it? 73, Franco
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I recently ordered a MAX9814 mic preamp
board with AGC. on eBay for $3.32. I will post about how it works
after I get it and test it.
Howard WB2VXW
On 4/27/2018 9:36 AM, iz oos wrote:
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External audio processor or is there a way to adjust it in the
Ubitx? 73 Franco
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Skip:
I didn't touch R65. Changing its value changes the DC operating
point at the collector of Q6. R63 has almost no effect on that,
since the current is set mostly by R64 which is bypassed for
audio.
Looking closer at the circuit, it is Ok to change R65 to 2K and
get the same result since the DC operating point will move down
from about 10V to 8V. It is easier thought to do the rework by
tacking a resistor across R63 rather then removing and replacing
R65. Either way works.
Howard WB2VXW
On 4/27/2018 10:03 AM, Skip Davis via Groups.Io wrote:
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Howard did you also change out R65 that was posted here too.
By the way the parts showed up here yesterday, thanks a lot.
Now to find time to install them.
Skip Davis, NC9O?
On Apr 27, 2018, at 09:57, Howard Fidel < sonic1@...>
wrote:
Yes. Change R63 to 24 ohms. The
earlier rev boards had 100 ohms there, and V3 has 47. I
put another 47 ohm resistor in parallel with the one on
the board. Now I don't need to yell into the mic.
Howard WB2VXW
On 4/27/2018 3:22 AM, iz oos wrote:
I have checked SSB output for the Ubitx using a
Softrock sdr receiver. The carrier is well aligned and
the filter gives a very good shape. Whistling is gives
full output with the stock mic element. The output seems
clean but the average power during normal speech seems
to me a bit low. Is there an easy way to increase it?
73, Franco
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If R63=24ohm what value should R65 be?
Il 27/apr/2018 16:03, "Skip Davis via Groups.Io" <skipnc9o= [email protected]> ha scritto: Howard did you also change out R65 that was posted here too. By the way the parts showed up here yesterday, thanks a lot. Now to find time to install them. On Apr 27, 2018, at 09:57, Howard Fidel < sonic1@...> wrote:
Yes. Change R63 to 24 ohms. The earlier
rev boards had 100 ohms there, and V3 has 47. I put another 47 ohm
resistor in parallel with the one on the board. Now I don't need
to yell into the mic.
Howard WB2VXW
On 4/27/2018 3:22 AM, iz oos wrote:
I have checked SSB output for the Ubitx using a Softrock sdr
receiver. The carrier is well aligned and the filter gives a
very good shape. Whistling is gives full output with the stock
mic element. The output seems clean but the average power during
normal speech seems to me a bit low. Is there an easy way to
increase it? 73, Franco
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I think I may currently leave it like it is. The modulated audio sounds really good and the power seems enough to drive a small amplifier. I would opt for an external compressor in case I use it without the PA. 73 Franco
Il 27/apr/2018 16:26, "Howard Fidel" < sonic1@...> ha scritto:
1K. Change one or the other, not both.
On 4/27/2018 10:14 AM, iz oos wrote:
If R63=24ohm what value should R65 be?
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I have changed just R63 so now it is 24 ohm (I added 2 ordinary 100ohms resistors in parallel) as suggested. I confirm it increases the average power to the right level given the stock mic element. Could it be further decreased, let's say 10 ohms?
Il 27/apr/2018 16:26, "Howard Fidel" < sonic1@...> ha scritto:
1K. Change one or the other, not both.
On 4/27/2018 10:14 AM, iz oos wrote:
If R63=24ohm what value should R65 be?
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Quick question. I think that what your doing is the following: Presumably the audio from the mic's audio line that carries the ac with a dc offset is first passed through a capacitor to block the dc and then used as input into a small preamp, perhaps an op-amp before anything else occurs. If so, then I imagine by changing the value of the named resistor you are increasing the gain associated with the op-amps behavior and consequently the audio's amplification above that of what otherwise occurs.
If my conjecture is near valid I am wondering if there is another way to do this such as by using a little stand alone pre-amp immediately after the microphone and prior to the assumed dc blocking filter. I only wonder because one could then control the gain and I do not have the right stuff for SMD removal or replacement.
I have changed just R63 so now it is 24 ohm (I added 2 ordinary 100ohms resistors in parallel) as suggested. I confirm it increases the average power to the right level given the stock mic element. Could it be further decreased, let's say 10 ohms?
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Indeed, I initially thought to add a mic compressor, but reducing the value of R63 by adding a discrete resistor was the simplest thing to do. No smd was removed. It increased, probably doubled the average SSB power so I can more easily drive a small amplifier or whatever.
Il 26/mag/2018 00:14, "Mike aka KC2WVB" < rb5363@...> ha scritto: Quick question. I think that what your doing is the following: Presumably the audio from the mic's audio line that carries the ac with a dc offset is first passed through a capacitor to block the dc and then used as input into a small preamp, perhaps an op-amp before anything else occurs. If so, then I imagine by changing the value of the named resistor you are increasing the gain associated with the op-amps behavior and consequently the audio's amplification above that of what otherwise occurs.
If my conjecture is near valid I am wondering if there is another way to do this such as by using a little stand alone pre-amp immediately after the microphone and prior to the assumed dc blocking filter. I only wonder because one could then control the gain and I do not have the right stuff for SMD removal or replacement.
I have changed just R63 so now it is 24 ohm (I added 2 ordinary 100ohms resistors in parallel) as suggested. I confirm it increases the average power to the right level given the stock mic element. Could it be further decreased, let's say 10 ohms?
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Wow, you must have a rock steady hand to parallel a through hole resistor alongside the SMD resistor. I would not say I have Parkinson disease but my hands are not that steady.
I think I will see if I can find out what the immediate amplifier is after the microphone and the ac component of the audio from the Mic is and see if I can bring about the idea of a pre-amp with gain control. I think the only real problem would be clipping but if you check everything out rather than just stick a guess in it should pan out.
By the way thanks 'all' for the info. I would probably take that route too If I could keep my hands steady.
Mike
Indeed, I initially thought to add a mic compressor, but reducing the value of R63 by adding a discrete resistor was the simplest thing to do. No smd was removed. It increased, probably doubled the average SSB power so I can more easily drive a small amplifier or whatever.
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He says he put a "discrete" resistor in parallel.? Could be SMD or thru-hole.
Sticking a discrete SMD resistor on top of an existing SMD resistor is quite easy.
As Allison says, it's like stacking bricks.?
Easier on the board than trying to remove the old one first.
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On Fri, May 25, 2018 at 05:05 pm, Mike aka KC2WVB wrote:
Wow, you must have a rock steady hand to parallel a through hole resistor alongside the SMD resistor. I would not say I have Parkinson disease but my hands are not that steady.
?
I think I will see if I can find out what the immediate amplifier is after the microphone and the ac component of the audio from the Mic is and see if I can bring about the idea of a pre-amp with gain control. I think the only real problem would be clipping but if you check everything out rather than just stick a guess in it should pan out.
?
By the way thanks 'all' for the info. I would probably take that route too If I could keep my hands steady.
?
Mike
. . .
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Indeed, I initially thought to add a mic compressor, but reducing the value of R63 by adding a discrete resistor was the simplest thing to do. No smd was removed. It increased, probably doubled the average SSB power so I can more easily drive a small amplifier or whatever.
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Thanks Jerry for telling me the slick way of stacking the discrete resistor on top of the SMD. Still in all I'd like to practice on something that I will not miss if I goober things up. Honestly my hands have developed a terrible tremor at times and I have to find things to brace against when soldering.
On Fri, May 25, 2018, 8:28 PM Jerry Gaffke via Groups.Io <jgaffke= [email protected]> wrote: He says he put a "discrete" resistor in parallel.? Could be SMD or thru-hole.
Sticking a discrete SMD resistor on top of an existing SMD resistor is quite easy.
As Allison says, it's like stacking bricks.?
Easier on the board than trying to remove the old one first.
On Fri, May 25, 2018 at 05:05 pm, Mike aka KC2WVB wrote:
Wow, you must have a rock steady hand to parallel a through hole resistor alongside the SMD resistor. I would not say I have Parkinson disease but my hands are not that steady.
?
I think I will see if I can find out what the immediate amplifier is after the microphone and the ac component of the audio from the Mic is and see if I can bring about the idea of a pre-amp with gain control. I think the only real problem would be clipping but if you check everything out rather than just stick a guess in it should pan out.
?
By the way thanks 'all' for the info. I would probably take that route too If I could keep my hands steady.
?
Mike
. . .
?
Indeed, I initially thought to add a mic compressor, but reducing the value of R63 by adding a discrete resistor was the simplest thing to do. No smd was removed. It increased, probably doubled the average SSB power so I can more easily drive a small amplifier or whatever.
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I didn't find difficult. I mounted them vertically. I tinned before both the through hole resistors and the pads on r63. I used a small tip 8watts iron and kept the resistor by hand. I have pliers that are normally closed and that sometimes helps in keeping the part steady. Maybe you could ask another person to help you. The small iron helps a lot.
Il 26/mag/2018 02:05, "Mike aka KC2WVB" < rb5363@...> ha scritto: Wow, you must have a rock steady hand to parallel a through hole resistor alongside the SMD resistor. I would not say I have Parkinson disease but my hands are not that steady.
I think I will see if I can find out what the immediate amplifier is after the microphone and the ac component of the audio from the Mic is and see if I can bring about the idea of a pre-amp with gain control. I think the only real problem would be clipping but if you check everything out rather than just stick a guess in it should pan out.
By the way thanks 'all' for the info. I would probably take that route too If I could keep my hands steady.
Mike
Indeed, I initially thought to add a mic compressor, but reducing the value of R63 by adding a discrete resistor was the simplest thing to do. No smd was removed. It increased, probably doubled the average SSB power so I can more easily drive a small amplifier or whatever.
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K9HZ
Skip Davis