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Re: RF Power transistor attached using header/socket?

 

Thanks for the suggestions. ?That is truly a small design! ? I agree that a push-pull design is advantageous and plan to use one in my next build. ?Still today I am working on finishing my RF386. ? I have been working on the final stage but using a MOSFET different than the IRF510. ? ?Maybe I should first build it as Ashhar Farhan designed, and then go for modifications... ?Anyway, I now have a RD06HHF1 as the final power MOSFET and am working through the biasing and shielding. ? So far so good... ? I am going to start a new "topic" about the difficulties I had getting the RD16HHF1 to work.

Thanks for the advice and the great links!

73
Lee
kf7yrs
Re: Si5351 as VFO and BFO

Mathis Schmieder
 

Thanks Ken, it really helps a lot!

Also, the double density singularity made me chuckle. :)

Ken Hough kenhough@... [BITX20] wrote:



Mathis,

I am using an Arduino/Si5351 to provide BFO and VFO to a Hendricks BITX20A.
It's working very well. Find the Arduino software in the Files section
of this
Yahoo group under the directory named "DDS_for_BITX_v_0_1_0_KH".

I'm not an expert wrt diode mixers, but as far as I understand, they
work well
when fed with square waves. AFAIK, the switching action of the diodes
effectively generates square wave action.

I built my BITX20A as per the original design complete with Xtal generated
BFO, and normal VFO. That way, I was able to establish that the rig
performed
correctly before modifying it.

I then blocked operation of these oscillators by loading their inputs with
0.1microF capacitors that were connected to ground via 390 Ohm resistors.
Signals from CLK0 and CLK2 of the Si5351 were connected to the junctions of
the capacitors and the resistors.

This arrangement works well. I haven't yet experimented with any form of
attenuation of the clock signals. The "strength" of the clock signals
was set
in software to 6mA.

Hope that this helps.

Regards

Ken Hough (M0KOH)

On Saturday 14 November 2015 19:08:32 you wrote:
Hi,

I want to replace the VFO and BFO on my current Bitx built with a DDS
solution. The Si5351 seems like a really versatile module and people
have been using it together with a Bitx. I am wondering though, as far
as I understood it the Si5351 only generates a square wave form. Am I
wrong there or is some kind of filtering needed to get a sine wave?

Also, can I just use the Si's 3Vss signal or do I need to build an
attenuator?

Would one or two AD9890s be the better choice?

Thanks,
Mathis / DB9MAT
Re: Si5351 as VFO and BFO

Ken Hough
 

Mathis,

I am using an Arduino/Si5351 to provide BFO and VFO to a Hendricks BITX20A.
It's working very well. Find the Arduino software in the Files section of this
Yahoo group under the directory named "DDS_for_BITX_v_0_1_0_KH".

I'm not an expert wrt diode mixers, but as far as I understand, they work well
when fed with square waves. AFAIK, the switching action of the diodes
effectively generates square wave action.

I built my BITX20A as per the original design complete with Xtal generated
BFO, and normal VFO. That way, I was able to establish that the rig performed
correctly before modifying it.

I then blocked operation of these oscillators by loading their inputs with
0.1microF capacitors that were connected to ground via 390 Ohm resistors.
Signals from CLK0 and CLK2 of the Si5351 were connected to the junctions of
the capacitors and the resistors.

This arrangement works well. I haven't yet experimented with any form of
attenuation of the clock signals. The "strength" of the clock signals was set
in software to 6mA.

Hope that this helps.

Regards

Ken Hough (M0KOH)

On Saturday 14 November 2015 19:08:32 you wrote:
Hi,

I want to replace the VFO and BFO on my current Bitx built with a DDS
solution. The Si5351 seems like a really versatile module and people
have been using it together with a Bitx. I am wondering though, as far
as I understood it the Si5351 only generates a square wave form. Am I
wrong there or is some kind of filtering needed to get a sine wave?

Also, can I just use the Si's 3Vss signal or do I need to build an
attenuator?

Would one or two AD9890s be the better choice?

Thanks,
Mathis / DB9MAT
Re: Si5351 as VFO and BFO

 

thanks lol
?
Jerry K7ANQ Skcc# 10843 10-10 # 76401



On Saturday, November 14, 2015 10:40 PM, "Ashhar Farhan farhanbox@... [BITX20]" <BITX20@...> wrote:


?
double density singularity of knowledge got you. now, you will can never know what ..

On Sun, Nov 15, 2015 at 11:53 AM, kj6ntl@... [BITX20] <BITX20@...> wrote:
?
I just have a question, does that stand for double density singularity or?
Re: Si5351 as VFO and BFO

 

double density singularity of knowledge got you. now, you will can never know what ..

On Sun, Nov 15, 2015 at 11:53 AM, kj6ntl@... [BITX20] <BITX20@...> wrote:
?

I just have a question, does that stand for double density singularity or?
Re: Si5351 as VFO and BFO

 

I just have a question, does that stand for double density singularity or?
BitX17A for sale

 

Hi all,


I'm selling some of my QRP rigs to finance another radio I want to get, so I'm selling my BitX17A housed in a small custom blue case with a N3ZI blue digital display. It works great and looks great, in fact I worked Antartica at Mirny station this summer from Southern Oregon USA on 8 watts. If anybody is interested please contact me directly at caulktel@... The sale will be for the radio only, no cables, mic or other accessories. Thanks


Joel

KB6QVI
Re: Si5351 as VFO and BFO

Ken Chase
 

?
It does work with a diode mixer. I use it in Pete Juliano's N6QW LBS project.
?
73
?
Ken VA3ABN
?

----- Original Message -----
Sent: Saturday, November 14, 2015 2:08 PM
Subject: Re: [BITX20] Si5351 as VFO and BFO

?

Bill, thanks a lot! Let's hope that it works with "traditional" diode
mixers, too. But I guess it should, SBL-1s are basically nothing else.

I'll share my results!

73 Mathis DB9MAT

Bill Meara n2cqr@... [BITX20] wrote:
>
>
> Mathis: I use an Si5351 for VFO and BFO on my BITX rig. I run the
> outputs from my Adafruit Si51 boards directly into the SBL-1 diode ring
> mixers. No attenuation, no filtering, no nothing! Works great. We use
> CLK 0 and CLK 2, leaving CLK1 unused to avoid bleedover problems. Good
> luck. Let us know how this works for you. 73 Bill N2CQR
>
>
>
> On Saturday, November 14, 2015 1:08 PM, "Mathis Schmieder mathis
> @giev.de [BITX20]" wrote:
>
>
>
> Hi,
>
> I want to replace the VFO and BFO on my current Bitx built with a DDS
> solution. The Si5351 seems like a really versatile module and people
> have been using it together with a Bitx. I am wondering though, as far
> as I understood it the Si5351 only generates a square wave form. Am I
> wrong there or is some kind of filtering needed to get a sine wave?
>
> Also, can I just use the Si's 3Vss signal or do I need to build an
> attenuator?
>
> Would one or two AD9890s be the better choice?
>
> Thanks,
> Mathis / DB9MAT
>
>
>

Re: Si5351 as VFO and BFO

Mathis Schmieder
 

Bill, thanks a lot! Let's hope that it works with "traditional" diode
mixers, too. But I guess it should, SBL-1s are basically nothing else.

I'll share my results!

73 Mathis DB9MAT

Bill Meara n2cqr@... [BITX20] wrote:



Mathis: I use an Si5351 for VFO and BFO on my BITX rig. I run the
outputs from my Adafruit Si51 boards directly into the SBL-1 diode ring
mixers. No attenuation, no filtering, no nothing! Works great. We use
CLK 0 and CLK 2, leaving CLK1 unused to avoid bleedover problems. Good
luck. Let us know how this works for you. 73 Bill N2CQR



On Saturday, November 14, 2015 1:08 PM, "Mathis Schmieder mathis
@giev.de [BITX20]" <BITX20@...> wrote:



Hi,

I want to replace the VFO and BFO on my current Bitx built with a DDS
solution. The Si5351 seems like a really versatile module and people
have been using it together with a Bitx. I am wondering though, as far
as I understood it the Si5351 only generates a square wave form. Am I
wrong there or is some kind of filtering needed to get a sine wave?

Also, can I just use the Si's 3Vss signal or do I need to build an
attenuator?

Would one or two AD9890s be the better choice?

Thanks,
Mathis / DB9MAT
Re: Si5351 as VFO and BFO

 

Mathis:? I use an Si5351 for VFO and BFO on my BITX rig.? I run the outputs from my Adafruit Si51 boards directly into the SBL-1 diode ring mixers.? No attenuation, no filtering, no nothing!? Works great.? We use CLK 0 and CLK 2, leaving CLK1 unused to avoid bleedover problems.? Good luck.? Let us know how this works for you.?? 73? Bill N2CQR



On Saturday, November 14, 2015 1:08 PM, "Mathis Schmieder mathis@... [BITX20]" wrote:


?
Hi,

I want to replace the VFO and BFO on my current Bitx built with a DDS
solution. The Si5351 seems like a really versatile module and people
have been using it together with a Bitx. I am wondering though, as far
as I understood it the Si5351 only generates a square wave form. Am I
wrong there or is some kind of filtering needed to get a sine wave?

Also, can I just use the Si's 3Vss signal or do I need to build an
attenuator?

Would one or two AD9890s be the better choice?

Thanks,
Mathis / DB9MAT
Si5351 as VFO and BFO

Mathis Schmieder
 

Hi,

I want to replace the VFO and BFO on my current Bitx built with a DDS
solution. The Si5351 seems like a really versatile module and people
have been using it together with a Bitx. I am wondering though, as far
as I understood it the Si5351 only generates a square wave form. Am I
wrong there or is some kind of filtering needed to get a sine wave?

Also, can I just use the Si's 3Vss signal or do I need to build an
attenuator?

Would one or two AD9890s be the better choice?

Thanks,
Mathis / DB9MAT
Re: Bitx20 V3B VFO Voltages off

Mathis Schmieder
 

Hey,

thanks for your answer. I checked the resistors and they all are
correct. I am fed up with VFO problems so I will build a DDS and be done
with it. Hopefully. :)

Thanks again, vy 73 de Mathis DB9MAT

mvs_sarma@... [BITX20] wrote:



Please check whether R62 is 4K7 or lower like 470 by an error.
likewise the bias resistor across Q17 could be changed a little say
56K or 39K to get proper voltage at the emitter resistor 390
Re: PS for Bitx Ver 3b

 

OH - but: if you're referring to the PCBs - they DO have markings that imply 24 VAC.
HOWEVER: the values given for the capacitors indicate this should be only 18VAC.

YET: according to the schematics:? BITX3B SCH PSU_PA.pdf

This seems to indicate 15 VAC - like just a 15 VAC wall transformer, maybe 1.5 Amps.

Everything AFTER the REGULATOR however, is 12 VDC (not 13.8 VDC) - and this includes pretty much everything on the main board, and the relays (i.e. but NOT the PA). So, you can use 12 VDC for testing and building the main board, no worries. 12 VDC is exactly what's called for that part of the rig.

The PA is driven DIRECTLY from the rectified, filtered input (whether it's 15 VAC, 18 VAC, or, maybe
19.5 VDC as in my situation, using an old Laptop switching supply) - less the diode drop after the rectifier.

Sorry for 2 messages / clarification...

Mike Yancey, KM5Z
Dallas, Texas
Re: PS for Bitx Ver 3b

 

I gotta say: I had VERY poor results powering the whole thing with 13.8 VDC.
The PA would break into some sort of oscillation - and just TX switching would cause a burst of
RF.

I was only able to get the PCB's to work well with 18 VAC or I'm also using an old
Laptop supply - 19.5 VDC which works. well.

After I moved to around 18 VDC or above - all worked perfectly.

On thing I also found - I removed the TX/RX power switching relay (K1 in the BITX3B SCH PSU_PA.pdf schematics), and setup a DPDT relay, such that switching to TX causes RX+ to be grounded, and switching back to RX causes TX+ to be grounded.

That one change (DPST relay to DPDT, grounding alternate / unused power) seemed to get rid of some odd noise in the Mic circuit on TX.
I used the PCBs from

Mike Yancey, KM5Z
Dallas, Texas

?
Re: Bitx20 V3B VFO Voltages off

[email protected]
 

Please check whether R62 is 4K7? or lower like 470 by an error.
?likewise the bias resistor across Q17 could be changed a little? say 56K? or 39K to get proper voltage? at the? emitter resistor 390
Re: Bitx20 V3B VFO Voltages off

[email protected]
 

try to check the Q5 voltages after stooping the oscillator. disconnection of X capacitor and one between gate and drain stops oscillations. While oscillating the voltages differ.
Bitx20 V3B VFO Voltages off

Mathis Schmieder
 

Hey,

I am currently restarting the built of a Bitx20 V3B. Right now I am
doing the VFO and am measuring slightly different voltages:

Q5 Source: 2.78V (supposedly: 3.87)
Q5 Drain 8.11V (good)

Q6 Emitter: 2.03V (3.09)
Q6 Base: 2.68V (3.79)
Q6 Collector: 8.10V (good)

Q17 Emitter: 4.16V (3.63)
Q17 Base: 4.84V (3.89)
Q17 Collector: 6.5V (good)

Does anyone have an explanation for the differences or maybe has an idea
how to debug it? I checked all the resistors and capacitors but could
not find a wrong value.

Thanks a lot, vy 73 de Mathis DB9MAT
Re: PS for Bitx Ver 3b

[email protected]
 

¿ªÔÆÌåÓý

Thanks John,

?

This clears up a lot for me.? I¡¯ve received help from several in the group for which I am grateful for.? Will read some more and start the build over the weekend

?

Larry

?

From: BITX20@... [mailto:BITX20@...]
Sent: Wednesday, November 11, 2015 6:08 PM
To: BITX20@...
Subject: [BITX20] Re: PS for Bitx Ver 3b

?

?

Use 12-14v on the exciter board direct and RX/TX (via the relay). It would be nice to use 18 or24v on the drain of the IRF510 if you can get away with it,

One mode of feeding power uses a bridge rectifier into the power amp board, voltage regulation for the other needs, and probably feeding the first filtered power to the IRF510.? This has thw advantage of providing what ever the feed voltage is to the final RF amplifier; it has the disadvantage of dropping a lot of voltage over the voltage regulators that feed the rest of the rig. The alternative is to feed a 12-14v into the bridge and use that for the entire rig, which is good for the VR's but not so good for the IRF520.

Note that the RF mosfets use a native 12v; do not feed 24v to it if it is used.

Since you are feeding a bridge rectifier, it can be either AC or DC. Be sure to provide a good filter if it is AC and good bypass filtering if it is DC. In fact, make a good bypass filter to keep RF out of the voltage supply. That eliminates a number of headaches.

Also try to keep a common point for all ground returns to minimize ground loops. Some shielding is in order also as there is RF radiation and feedback in the design (especially to the mic circuit). Consult the BITX message list often -- most of these things have been met with and discussed in the past.

Hope this helps.

john
AD5YE



---In BITX20@..., <larry-bratcher@...> wrote :

Im gettting ready to start building my verr 3 b. ?Have been reviewig all the documents I can to hopefully?

preventt mistakes. ?I do have one question about power. ?The build doc stated to use 244v AC or DC for some testig. ? The schmatic showss 12v power. ?What is the corrrect power for the finished radio?

?

Thanks

Larry

?AB5CL

?

?

?
Re: PS for Bitx Ver 3b

 

Use 12-14v on the exciter board direct and RX/TX (via the relay). It would be nice to use 18 or24v on the drain of the IRF510 if you can get away with it,

One mode of feeding power uses a bridge rectifier into the power amp board, voltage regulation for the other needs, and probably feeding the first filtered power to the IRF510.? This has thw advantage of providing what ever the feed voltage is to the final RF amplifier; it has the disadvantage of dropping a lot of voltage over the voltage regulators that feed the rest of the rig. The alternative is to feed a 12-14v into the bridge and use that for the entire rig, which is good for the VR's but not so good for the IRF520.

Note that the RF mosfets use a native 12v; do not feed 24v to it if it is used.

Since you are feeding a bridge rectifier, it can be either AC or DC. Be sure to provide a good filter if it is AC and good bypass filtering if it is DC. In fact, make a good bypass filter to keep RF out of the voltage supply. That eliminates a number of headaches.

Also try to keep a common point for all ground returns to minimize ground loops. Some shielding is in order also as there is RF radiation and feedback in the design (especially to the mic circuit). Consult the BITX message list often -- most of these things have been met with and discussed in the past.

Hope this helps.

john
AD5YE


---In BITX20@..., <larry-bratcher@...> wrote :

Im gettting ready to start building my verr 3 b. ?Have been reviewig all the documents I can to hopefully?

preventt mistakes. ?I do have one question about power. ?The build doc stated to use 244v AC or DC for some testig. ? The schmatic showss 12v power. ?What is the corrrect power for the finished radio?


Thanks

Larry

?AB5CL
PS for Bitx Ver 3b

[email protected]
 

Im gettting ready to start building my verr 3 b. ?Have been reviewig all the documents I can to hopefully?

preventt mistakes. ?I do have one question about power. ?The build doc stated to use 244v AC or DC for some testig. ? The schmatic showss 12v power. ?What is the corrrect power for the finished radio?


Thanks

Larry

?AB5CL
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