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Re: VK4PP uBitx LPF BANK add-on Board

 

Warren,

The relays are not that bad, primary issue on the uBitx is how the board is routed.?

Look at the uBitx schematic, find KT1 near the 30m LPF of L11,12,13.
Assume the relays are in the relaxed state as drawn, for operation at 30m.

The 32dB number is for isolation from KT1 pin 14 to 16.
So when operating at 30mhz, we have 32dB of loss going from pin 14 to pin 16,?
through the 20m filter at L14,15,16, and then another 32dB of loss
going from KT1 pin 1 to 3 at the other side of the filters.? A total of 64dB down
to sneak around the KT1 filter by that path.? The third filter is not a factor for this
since it is an additional 64dB down.??

The roughly 40dB loss in going around the 30m LPF from KT1 pin 12 to 5
is the primary factor that the relays themselves contribute to blow-by,
that's acceptable unless the PA is putting out harmonics that are as strong as the fundamental.
That 40dB path disappears if we use 3 additional relays at the far side of the LPF's.
?
Blow-by when operating on 30m is the primary consideration,
operating at lower frequencies will have proportionally less capacitive coupling through the relays.



Someone proposed the scheme below a few weeks ago using?a total of 4 DPDT relays
which I have named RA, RB, RC, RD.
I forget exactly who brought this up, it came as a web pointer to schematics for a board in production.?
There's blow-by when operating on 30m of 32+32=64dB through RB, RD, and the 20m LPF.
There is also a path of path across RA, RC, and the 40m LPF of 32+32=64dB.
And a path across the RB and RD relay sections of 40+40=80dB through that same 40m LPF.
With all three blow-by paths of 64,64, and 80 dB in parallel, we have a net of about 57dB of blow-by.
Not bad for just 4 relays, and the board routes sort out nicely.

? ? ? ? ? ? ? ? ? ? o---------[10m]---------o
? ? ? ? ? ? ? ?+----o RB? ? ? ? ? ? ? ? ?RD o----+
? ? ? ? ? ? ? ?|? ? o---------[20m]---------o? ? |
? ? ? ? ? ? ? ?|? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?|
? ? ? ? ?o-----+? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?+--------o
---------o RA? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? RC o---------
? ? ? ? ?o-----+? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?+--------o
? ? ? ? ? ? ? ?|? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?|
? ? ? ? ? ? ? ?|? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?|
? ? ? ? ? ? ? ?|? ? o---------[40m]---------o? ? |
? ? ? ? ? ? ? ?+----o RB? ? ? ? ? ? ? ? ?RD o----+
? ? ? ? ? ? ? ? ? ? o---------[80m]---------o

Jerry, KE7ER
?


On Fri, Aug 31, 2018 at 06:01 AM, Warren Allgyer wrote:
That 32 dB number is the killer for the uBitx relay scheme. It gets at least 3 dB worse with each relay added to the chain and all four relays are in the chain.
4.2" Nextion Bezel? #3d_printing #ubitx-help

 

I am using the 4.2" Nextion?touch screen on my Ubitx. Does anyone know where I can get a small black bezel/frame for it? I only need about 1/4-inch on all sides. Unfortunately, I don't have access to a 3D printer. Thank you for any leads the group may provide.
Re: ATU for mBITX

 

look at the "Bias Tee" link at <>
for a way to remote the Elecraft T1 and run power on the coax.

Each of the two Bias Tee units will fit the traditional Altoids tin.
The T1 tuner and its Bias Tee can be fitted into a weatherproof box at the antenna
At the Tx end an SWR meter is needed to monitor/verify the match.

N5IB
Re: ATU for mBITX

 

I've built 3 of them and they remote very easily but you do have to use well shielded cables as any RF pickup tends to mess up the tuning.

Elecraft's software is NOT hackable and is proprietary, not open-source. ?

Jim

------ Original Message ------
From: "W2CTX" <w2ctx@...>
Sent: 8/31/2018 10:04:33 AM
Subject: Re: [BITX20] ATU for mBITX


There is already a jack to remote control it.? See manual.


rOn

On August 31, 2018 at 8:50 AM "Tom, wb6b" <wb6b@...> wrote:

On Thu, Aug 30, 2018 at 09:36 AM, ajparent1/KB1GMX wrote:
T1 its the ideal pocket sized ATU
That's a cool Auto Tuner. Did not realize Elecraft made a reasonable cost Auto ATU. Wonder how hard it would be to hack it, so I could put in in a weather proof box at my antenna and remotely control it?

Tom, wb6b
Re: ATU for mBITX

 


There is already a jack to remote control it.? See manual.


rOn

On August 31, 2018 at 8:50 AM "Tom, wb6b" <wb6b@...> wrote:

On Thu, Aug 30, 2018 at 09:36 AM, ajparent1/KB1GMX wrote:
T1 its the ideal pocket sized ATU
That's a cool Auto Tuner. Did not realize Elecraft made a reasonable cost Auto ATU. Wonder how hard it would be to hack it, so I could put in in a weather proof box at my antenna and remotely control it?

Tom, wb6b
Re: BITX40 Saving Settings Issue

Gary K4VIG
 

Thanks Allard. I will check for ground loops.?

Also so I was not clear. When I do a reset to the default, it does sense the cw present and I have the cw configuration in settings. However when I turn off the rig and then back on, it does not sense the cw.?

73,
Gary K4 VI G
Re: ATU for mBITX

 

You can't go wrong with it :) how much power can the polyvaricon handle?


Il 31/ago/2018 15:09, "Tom, wb6b" <wb6b@...> ha scritto:
On Fri, Aug 31, 2018 at 04:44 AM, Peter Parker wrote:
I would go for a simple manual ATU.
This may now be my favorite antenna tuner.



Tom, wb6b


Re: Any Gerber Experts Round Here? #kicad #ubitx

 

please go thro the link
?It might help you.


On Fri, Aug 31, 2018 at 5:31 PM <lynatmts@...> wrote:
Hi Ben,

Send me your RS274D files....? lynatmts@...

Lyn WA4GEH

--
"You see, wire telegraph is a kind of a very, very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? And radio operates exactly the same way: you send signals here, they receive them there. The only difference is that there is no cat."

Re: Raduino setting

 

¿ªÔÆÌåÓý

That's the display contrast setting?



Sent from my Samsung Galaxy smartphone.

-------- Original message --------
From: SaMa photo SaMa photo <infosamaphoto@...>
Date: 31/08/2018 14:15 (GMT+00:00)
Subject: [BITX20] Raduino setting

Good evening
the trimmer mounted on raduino what is it for?
thank you
Raduino setting

 

Good evening
the trimmer mounted on raduino what is it for?
thank you
Re: ATU for mBITX

 

On Fri, Aug 31, 2018 at 04:44 AM, Peter Parker wrote:
I would go for a simple manual ATU.
This may now be my favorite antenna tuner.



Tom, wb6b
Re: VK4PP uBitx LPF BANK add-on Board

Warren Allgyer
 

Glenn

That 32 dB number is the killer for the uBitx relay scheme. It gets at least 3 dB worse with each relay added to the chain and all four relays are in the chain.

WA8TOD
Re: ATU for mBITX

 

On Thu, Aug 30, 2018 at 09:36 AM, ajparent1/KB1GMX wrote:
T1 its the ideal pocket sized ATU
That's a cool Auto Tuner. Did not realize Elecraft made a reasonable cost Auto ATU. Wonder how hard it would be to hack it, so I could put in in a weather proof box at my antenna and remotely control it?

Tom, wb6b
Re: Nextion 3.2 for CEC 1.097 #ubitx

  

Some work still needs to be done.

Nikos SV9CVJ

nikos1 ubitx Art page 0.HMI
nikos1 ubitx Art page 0.HMI

Re: Any Gerber Experts Round Here? #kicad #ubitx

 

Hi Ben,

Send me your RS274D files....? lynatmts@...

Lyn WA4GEH

--
"You see, wire telegraph is a kind of a very, very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? And radio operates exactly the same way: you send signals here, they receive them there. The only difference is that there is no cat."
Re: ATU for mBITX

 

I would go for a simple manual ATU.? The configuration depending on the antenna being used.?

Some ideas at?

73, Peter VK3YE
Re: Personal Best Distance, SSB Phone #ubitx

 

But otherwise many contacts between VK and USA or Europe with 5w.? Eg

?

https://www.youtube.com/watch?v=6U1fmp_CKxE
Re: Personal Best Distance, SSB Phone #ubitx

 

About 2600km on 80m - with a half-collapsed wire antenna

https://www.youtube.com/watch?v=pZcXBVX-tJk
Re: VK4PP uBitx LPF BANK add-on Board

 

I was wondering why the Softrock TXRX had just 3 close bands (mine 10-12-15m). Now I know there were good reasons for that!


Il 31/ago/2018 12:17, "Warren Allgyer" <allgyer@...> ha scritto:

Suggestions based on experience and good practice are all good. It is my experience however that some fairly simple measurements can and need to be made in order to confirm a layout.

First, simply connect up the input and output on a completely unpopulated board and measure the attenuation. If you find less than 80 dB of attenuation at any frequency below 100 MHz, you are probably not going to like the end result. I would then add the relays and check it again. At this point your attenuation needs to be at least 70 dB. Add all remaining components except the filters themselves and check it again. Finally, one at a time, add the filters and check after each one is added.

If, at any step in the process, your input to output crosstalk gets higher than -60 dB, you are not going to be very happy with the outcome. Note all of these measurements are made with the relays deactivated so there is no actual intended path between input and output.

When working on a similar project with Tony Parks for an all-band Softrocks RXTX our first two prototype filter boards measured less than 30 dB isolation between input and output. And we thought we were following good layout and RF principles.

BTW, on the Softrocks project we finally got there........ only to realize that the radio would never make compliance goals without a similarly switched interstage filter prior to the RF drive chain. At that point we had pushed the cost of the radio beyond the target and the project was scrapped.

My bottom line reaction is: layout as best you know how but test, test, test.

WA8TOD
Re: VK4PP uBitx LPF BANK add-on Board

 

All good points Warren.?? I did some checks of isolation using a typical DIP relay, type HK19F. DPDT

I made a small jig to hold the relays and measure isolation across contacts etc.
Typically it was -34dB across open contacts,
-32dB from one set of contacts to the other. (common terminal)
-41dB from open terminals on each side
-39dB from common of one pole to open on the other pole.
-48db from common to coil.
?At 30MHz.? Better as freq drops of course.
That's without effects of a PCB and various other traces.

glenn
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