Date   

Re: Antenna Question #antennas #v3

Gordon Gibby
 

Measure the noise during the day and during the night and if it is vastly different that will let you know that you’re picking up noise from the inverters. 

You can measure the audio output AC voltage with the volume control in the same position each time, at empty places in the band. 


On Mar 13, 2020, at 20:35, Gordon Gibby via Groups.Io <docvacuumtubes@...> wrote:

Those solar panels and their associated inverters may  create a huge amount of RF noise for you


On Mar 13, 2020, at 19:37, Curt via Groups.Io <wb8yyy@...> wrote:

Chris

there is a bit of 'science' to feeding an effective antenna, particularly if coax is involved.  as well as Gordon's query regarding metal on the roof (but if there is maybe you can be much more than about 5 feet away). 

you can buy or construct an end-few halfwave.  myantennas has some, but since you only need around 10 watts for the ubitx - you may look at various sources including qrpguys.  (i see they have a matching unit kit for $20 that I think should work even if you are limited to a 40m size (around 65 feet length).  i mention them as ordering one ferrite toroid can be a challenge - note their shipping cost around $6 might tempt you to order a couple things at once). 

do network with the gang to implement an effective antenna.  glad your new friends are using your fun for a break in the monotony.  keep everyone safe.

73 curt


Re: Antenna Question #antennas #v3

Gordon Gibby
 

Those solar panels and their associated inverters may  create a huge amount of RF noise for you


On Mar 13, 2020, at 19:37, Curt via Groups.Io <wb8yyy@...> wrote:

Chris

there is a bit of 'science' to feeding an effective antenna, particularly if coax is involved.  as well as Gordon's query regarding metal on the roof (but if there is maybe you can be much more than about 5 feet away). 

you can buy or construct an end-few halfwave.  myantennas has some, but since you only need around 10 watts for the ubitx - you may look at various sources including qrpguys.  (i see they have a matching unit kit for $20 that I think should work even if you are limited to a 40m size (around 65 feet length).  i mention them as ordering one ferrite toroid can be a challenge - note their shipping cost around $6 might tempt you to order a couple things at once). 

do network with the gang to implement an effective antenna.  glad your new friends are using your fun for a break in the monotony.  keep everyone safe.

73 curt


Re: Antenna Question #antennas #v3

Curt
 

Chris

there is a bit of 'science' to feeding an effective antenna, particularly if coax is involved.  as well as Gordon's query regarding metal on the roof (but if there is maybe you can be much more than about 5 feet away). 

you can buy or construct an end-few halfwave.  myantennas has some, but since you only need around 10 watts for the ubitx - you may look at various sources including qrpguys.  (i see they have a matching unit kit for $20 that I think should work even if you are limited to a 40m size (around 65 feet length).  i mention them as ordering one ferrite toroid can be a challenge - note their shipping cost around $6 might tempt you to order a couple things at once). 

do network with the gang to implement an effective antenna.  glad your new friends are using your fun for a break in the monotony.  keep everyone safe.

73 curt


Re: Antenna Question #antennas #v3

Christopher Miller
 

The roof is covered in solar panels. The plan as it stands is to run the dipole along the edge of the roof. This is not ideal but works. The main drive is to keep idiots from getting ref burns.

This seems like my best option.

Chris KF4FTR


Re: uBitx v6 Microphone #v6

 

Ugh!

That would mess things up :-(

Good luck getting it all straight.  The main thing is to keep the connections well plugged in, and to make sure you get a good ground connection at each screw or stand-off.

That mis-alignment is pretty bad though.  Are there different size stand-offs in the kit?  Maybe different ones on the main board would raise it enough so the front will line up?

73,


Mark.


Re: CW Filter

laurent.bury@...
 

Hi Reg,

tnx for your reply; I saw this LED AGC, running at audio stage, before choosing this one, running at RF stage:
https://shop.kit-projects.com/index.php?route=product/product&product_id=101

I'm quite confused as this last AGC has a wire connected to the yellow wire of the volume pot:
I'm not sure I can insert the Sotabeams filter in line between the tip of the pot and the wire coming from the AGC PCB ?

Did you insert yours this way ?

73, Laurent F5FIE.


Re: Antenna Question #antennas #v3

Gordon Gibby
 

Be mindful of a lot of metal on the roof. We have installed antennas on the top of two professional buildings, that both had extensive metal flashing and extensive  lightning arresting systems.  

These appear to create RF coupling to the antenna that we placed, and we had to move the antenna as far away from them as possible to get in and impedances to look anything like what we are used to.   When the antenna was 5-8 feet or so above all of this metal, impedances in the five ohm range were measured which should have been 50 to 75     We were forced to move antennas way off the roof to the side or above to get manageable impedances.   

Gordon. KX4z 




On Mar 13, 2020, at 16:38, Joel Caulkins/N6ALT <caulktel@...> wrote:

Good news Chris! It never hurts to have the landlords blessing. I hope it all works out out.

Joel
N6ALT


Re: Antenna Question #antennas #v3

 

Good news Chris! It never hurts to have the landlords blessing. I hope it all works out out.

Joel
N6ALT


Re: Antenna Question #antennas #v3

Christopher Miller
 

This is true, the maintenance manager is in fact a cber. I am still thrilled at the prospect at having a dipole at 40 feet. And my landlord wants it.


Re: Antenna Question #antennas #v3

iz oos
 

That's great! Long life to CBers and SWL!


Il 13/mar/2020 20:32, "Christopher Miller" <djmalak2k6@...> ha scritto:
Ok, so the sky’s opened and a choir of angles sang. 

My apartment manager and the head maintenance guy came over to view the splendor of the UBITx.

They both were impressed that I got wwv at 10 MHz. They wanted to know what it meant.... I simply said it means the radio is calibrated and working.

They looked disappointed but then the magic happened.

They want to install a long wire or dipole on my roof. I told them I wasn’t going 40 feet up but my maintenance guy who has cb experience wants to do it. 

So I now have a bitx with a 20 meter dipole at 40 feet. This should be fun.

KF4FTR


Re: Antenna Question #antennas #v3

Christopher Miller
 

Ok, so the sky’s opened and a choir of angles sang. 

My apartment manager and the head maintenance guy came over to view the splendor of the UBITx.

They both were impressed that I got wwv at 10 MHz. They wanted to know what it meant.... I simply said it means the radio is calibrated and working.

They looked disappointed but then the magic happened.

They want to install a long wire or dipole on my roof. I told them I wasn’t going 40 feet up but my maintenance guy who has cb experience wants to do it. 

So I now have a bitx with a 20 meter dipole at 40 feet. This should be fun.

KF4FTR


Thank you

Christopher Miller
 

I hope this works, this is my first attempt to post. I received my bitx v3 yesterday and took a long time before connecting it to power because I didn’t want to smoke anything. With help from the original Elmer whom can be identified if they wish, and another ham cheering me on I had the guts to power on my first uBITx v3. I have tuned to wwv and with my dipole a mess across the floor I can clearly hear it at 10.000 with a half wave 20 meter dipole.

I am over the moon, the case is even the color of the tempo one my dad purchased for my twin and I as kids. I want to thank the community at large and the ham that sent me a rig. I have to find out how to pay it back now.

Hams are the best.

Chris KF4FTR


Re: Crystal Filter Termination

iz oos
 

Mini Circuits transformers are really good and many really wideband. Having said this, I think up to 15mhz winding one is cheaper and will be adequate. For higher frequencies higher than 15mhz it is likely to notice a difference.


Il 13/mar/2020 13:01, "Ravi Miranda" <ravimiranda@...> ha scritto:
Hi,

Doing some further research, are there any off-the-shelf transformers
that can be used for T5 and T6 (Crystal filter Termination)
https://www.hfsignals.com/wp-content/uploads/2019/02/ubitx_v5.pdf

Such as this: https://www.minicircuits.com/pdfs/T2-1T-KK81.pdf

Would this work instead of winding one?

Best 73,

Ravi/M0RVI

--
I'm here to add more value to the world than I'm using up.




Re: Crystal Filter Termination

 

Hi again,

Mini-circuits says (except for DC isolation) RF performance is similar between the types:

https://www.minicircuits.com/app/AN20-001.pdf

73,


Mark


Re: Crystal Filter Termination

 

Hi,

I suspect to simplify construction, they wind all these transformers the same.  Then to use them in that part of the circuit (simplify the traces?) they used them as autotransformers.  Unless, the schematic is not following what was done in the actual construction.  T8 is like that too.  I most often see regular transformers used in situations like this -- not sure if one way is better than the other.

73,


Mark


Re: Crystal Filter Termination

 

The better way would be to use the primary and secondary windings to make a 1:4 transformer..

At 13/03/2020, you wrote:
Hi,

Doing some further research, are there any off-the-shelf transformers
that can be used for T5 and T6 (Crystal filter Termination)
https://www.hfsignals.com/wp-content/uploads/2019/02/ubitx_v5.pdf

Such as this: https://www.minicircuits.com/pdfs/T2-1T-KK81.pdf

Would this work instead of winding one?

Best 73,

Ravi/M0RVI


Re: Crystal Filter Termination

 

Hi Ravi,

I think the ohm ratio is wrong on that one.  From the schematic, the originals look like 2:1 winding ratio autotransformers which will give a 4:1 ohm ratio.  Otherwise I don't see why you can't switch.

73,


Mark.


Re: Transmit Output Power (CW) #v5

 

Hi Rob,

It would be interesting to see "before" measurements.

One trick on viewing SMD parts is to take a good picture with a smartphone or digital camera and then zoom in to view the fine print.  SMD parts typically don't have real names on them like "2n3904" but have codes.  There are code lists on the web to help translate them though.

To check power at lower power levels (like the ubitx) you can use a diode RF probe.  Easy to make from scratch or as a kit.  Some QRP dummy loads have them built in (e.g. Elecraft, QRPGuys, QRP-Labs all have them).

If I remember correctly, I think changing Q90 and its biasing makes the biggest different in evening the output.

73,


Mark


Re: Crystal Filter Termination

 

Go for it Ravi, good find! much smaller fooprint.

Raj

At 13/03/2020, you wrote:
Hi,

Doing some further research, are there any off-the-shelf transformers
that can be used for T5 and T6 (Crystal filter Termination)
https://www.hfsignals.com/wp-content/uploads/2019/02/ubitx_v5.pdf

Such as this: https://www.minicircuits.com/pdfs/T2-1T-KK81.pdf

Would this work instead of winding one?

Best 73,

Ravi/M0RVI


Crystal Filter Termination

Ravi Miranda
 

Hi,

Doing some further research, are there any off-the-shelf transformers
that can be used for T5 and T6 (Crystal filter Termination)
https://www.hfsignals.com/wp-content/uploads/2019/02/ubitx_v5.pdf

Such as this: https://www.minicircuits.com/pdfs/T2-1T-KK81.pdf

Would this work instead of winding one?

Best 73,

Ravi/M0RVI

--
I'm here to add more value to the world than I'm using up.