Date   
Re: antenna tuner for uBitx

K9HZ <bill@...>
 

I suppose the false supposition here is that you must tune under full power.   It is considered a good design to tune with just the amount of power needed in order to tune… not full power.  This can very easily be implemented on the uBITx with a relay that substitutes in a “Tune RV1” set for a much loser tune power.

 

 

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From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of David Wilcox via Groups.Io
Sent: Monday, March 19, 2018 8:00 AM
To: BITX20@groups.io
Subject: Re: [BITX20] antenna tuner for uBitx

 

While I agree somewhat I am not in favor of an automatic antenna tuner because if your wire (especially with a new antenna or experimental antennas) and supporting arrangement leave you without a close match the time it takes the automatic tuner to get a match it may be too long out of tune and blow your finals.  With a manual tuner you can key down for a short time while tuning, let it rest a few seconds, try again getting closer, and finally get your match.  Keeps the finals cool and prevents the smoke from being released.  

 

I have a Z 11 Pro and while I have not blown any finals I am very touchy with my antennas and check them with an analyzer before using it, just to make sure I am close.

 

I prefer a small Z match like the Emtec, 4SQRP tuner, GQRP tuner, etc.  At the home shack I use an MFJ 300 watt roller inductor tuner.  The reason I like manual tuners at home is I can look at the numbers on the dials and if they are different from what I usually see I look for antenna trouble, ie., antenna down, ice coated, wrong antenna, a short somewhere.  With the automatic tuner it just tunes and you don't know if its the antenna or the tuner that is making your xmtr happy. And even at 5 watts or less we can fry a 510.

 

I admit I am a nerd and like to tinker versus those who like to "just get on the air and make a contact". My preference.  This is a wonderful hobby and we all are different.

 

Dave K8WPE


On Mar 19, 2018, at 6:37 AM, Curt M. <Kc3hjp@...> wrote:

I use my LDG Z-11ProII with an end fed wire and my Bitx40. The tuner only requires 100mW of signal to auto tune. 

http://www.ldgelectronics.com/c/252/products/21/9/1 


Virus-free. www.avg.com

Re: ubitx michrophone

Brian
 

I have a 78L05 regulator in the Bitx and feed 5v dc down the multicore mic cable to a MAX9812L module from Ebay. No need to shout any more!
73 Brian VK4BAP.

BITX40 and Data FT8/JT65 et al.

jeff.goodley@...
 

May I have some opinions about using a BITx40 on data modes?  I am just venturing into qrp after being a 100 watts and a wire man for many years.  I will be ordering a kit very soon but because of hearing challenges am moving to text based modes. 

Will the BITX40 cope with vox data?  I currently use an Easy data connected to the mike socket of my TS520SE but have been getting hits into Vu and VK on 40 mtrs   200 mW WSPR through a 6 mtr long whip from up here in IO92. 




Re: BITX40 and Data FT8/JT65 et al.

Gordon Gibby <ggibby@...>
 

Did you mean perhaps you were using a easydigi?




On Mar 19, 2018, at 20:52, jeff.goodley via Groups.Io <jeff.goodley@...> wrote:

May I have some opinions about using a BITx40 on data modes?  I am just venturing into qrp after being a 100 watts and a wire man for many years.  I will be ordering a kit very soon but because of hearing challenges am moving to text based modes. 

Will the BITX40 cope with vox data?  I currently use an Easy data connected to the mike socket of my TS520SE but have been getting hits into Vu and VK on 40 mtrs   200 mW WSPR through a 6 mtr long whip from up here in IO92. 




Re: ubitx michrophone

Michael Hagen
 

Yes, no SHOUTING!

The IC is Tiny, might be tough to mount for some.

Here is the PCB schematic of a small PCB.

Fits in the Mic case.

73's

MIKE


On 3/19/2018 5:31 PM, Brian wrote:
I have a 78L05 regulator in the Bitx and feed 5v dc down the multicore mic cable to a MAX9812L module from Ebay. No need to shout any more!
73 Brian VK4BAP.

-- 
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID  "MotDog@..."
Mike@...

Re: BITX40 and Data FT8/JT65 et al.

John P
 

I just started using the BitX-40 for FT-8. I'm using a homebrew VOX gimmick to key it. I need to clean up the documentation a little then I'll publish it here. Hopefully by tomorrow. 

In only 4 days I've managed to work 13 states from NJ, including WA and AZ, so it seems to work pretty well! 

--
John - WA2FZW

Re: BITX40 and Data FT8/JT65 et al.

RCC WB5YYM
 

Ran bitx40 with duinovox for several months until laptop hard drive crash. It works great. 50 states worked with 46  confirmed and 49 countries with 35 confirmed. 

Re: SSM2167 #ubitx

John <passionfruit88@...>
 

Hello Lee

I don't have an oscilloscope so I can't give you values.

But I can say is that it is not critical. When I had it all the way up I was told, when I asked, that the voice was "quite readable but the compression could be turned down a little".

So I don't think you risk over driving it to the point of making it unpleasant.

I adjust it to the point of having the power meter at about two third in average on normal talk.

Hope this helps.

73, John (VK2ETA)

For sale micro bitx

W7zim@...
 

Just received number 546/3 with the dreaded WX op amp.

It's for sale for $109 postage paid any where in USA. Brand new and untouched.

Prefer paypal.

If interested please contact me off line.

w7zim at Yahoo dot com

Fred, W7ZIM

Re: two-tone test on ubitx

Tim Gorman
 

For those wondering how the -3dbm levels for the each of the tones comes
out to a total of 10 watt output.

10*log(10000) = 10*log(10**4) = 40db

An output of 5 watts per tone going into 40db of padding is the same as
5w/10000 = .0005w or .5mw.

0dbm represents a power of .001watt or 1mw. 0.5mw is 3db below 0dbm,
i.e. -3dbm. So each tone represents 5watts of power.

Average power output is merely the sum of the power in the two tones
which equals 10 watts.

PEP output is twice the average power or 20watts PEP.

I also need to redo the carrier suppression measurement. According to
the ARRL test methods it should be measured with a single tone input to
the transmitter, not a 2-tone input.


tim ab0wr






On Mon, 19 Mar 2018 16:45:55 -0500
"Tim Gorman" <tgorman2@...> wrote:

Attached is a screen save from my spectrum analyzer for a two-one test
of my new ubitx.

The tones were driving the finals to about 10watts output (not quite,
but close). I had a 30db external pad and a 10db internal pad in the
SA.

The carrier was only down about 20db (marker 1). That's not as good as
I expected. I'll have to look at that and see what can be done to
improve it.

The 3rd order IMD (marker 4) was down about 34.5db which is adequate.

The heat sinks get *hot* while running a key down measurement like
this. If you are going to use the rig for a digital mode it probably
needs to be set for about half-power out of the rig. That or a
significant increase in heat-sink capability should be installed.

tim ab0wr


Micro BIT X for sale

W7zim@...
 

The radio is sold. Thanks everyone.

Re: Mechanical work is done...

Steve
 

Looks good Nelson.  I do like that speaker grill....The pic of your test bench is...um...awesome!  (as Steve asks himself- "what does all that stuff DO??")  Aloha, Steve

Virus-free. www.avg.com

Re: two-tone test on ubitx

Henning Weddig
 

Tim, this is a nice measurement- 
At which output power did You take the measurement? What is the attenauation of the power attenuator between the output of the uBITX and the Input of the spectrum analysser?
 
Your measaurement shows a thrid intermodulation of 34 dB/ related to a tone, in relation to PEP please add 6 dB results in 40 dB of d3!
 
BUT: marker 1 shows the supressed carrier is only 20 dB below the carrier, or 26 dB to PEP. Commercial rigs suppress by at least 40 dB or better.  This result is a"proof" of my worries concerning the unsuffiecient carrier Suppression of the balanced modulator and xtal-filter..
 
Henning Weddig
DK5LV.
 
-----Ursprüngliche Mitteilung-----
Von: Tim Gorman <tgorman2@...>
An: BITX20 <BITX20@groups.io>
Verschickt: Mo, 19. Mrz 2018 22:46
Betreff: [BITX20] two-tone test on ubitx

Attached is a screen save from my spectrum analyzer for a two-one test
of my new ubitx.

The tones were driving the finals to about 10watts output (not quite,
but close). I had a 30db external pad and a 10db internal pad in the
SA.

The carrier was only down about 20db (marker 1). That's not as good as
I expected. I'll have to look at that and see what can be done to
improve it.

The 3rd order IMD (marker 4) was down about 34.5db which is adequate.

The heat sinks get *hot* while running a key down measurement like
this. If you are going to use the rig for a digital mode it probably
needs to be set for about half-power out of the rig. That or a
significant increase in heat-sink capability should be installed.

tim ab0wr




Re: antenna tuner for uBitx

David Wilcox
 

I think that is a good choice. I like the Emtech ZM-2 one better as it has air variables whereas the 4SQRP one uses poly variables. I am old fashioned and just like the larger "tougher" air variables, especially if running over 10 watts.

Dave K8WPE

On Mar 19, 2018, at 6:08 PM, Tim Gorman <tgorman2@...> wrote:

This tuner is not automatic but it does provide a good load to the
transmitter while adjusting the tuner.

http://www.4sqrp.com/4stuner.php

As soon as I get a little money ahead I'm going to order one.

tim ab0wr

On Mon, 19 Mar 2018 09:00:24 -0400
"David Wilcox via Groups.Io" <Djwilcox01=yahoo.com@groups.io> wrote:

While I agree somewhat I am not in favor of an automatic antenna
tuner because if your wire (especially with a new antenna or
experimental antennas) and supporting arrangement leave you without a
close match the time it takes the automatic tuner to get a match it
may be too long out of tune and blow your finals. With a manual
tuner you can key down for a short time while tuning, let it rest a
few seconds, try again getting closer, and finally get your match.
Keeps the finals cool and prevents the smoke from being released.

I have a Z 11 Pro and while I have not blown any finals I am very
touchy with my antennas and check them with an analyzer before using
it, just to make sure I am close.

I prefer a small Z match like the Emtec, 4SQRP tuner, GQRP tuner,
etc. At the home shack I use an MFJ 300 watt roller inductor tuner.
The reason I like manual tuners at home is I can look at the numbers
on the dials and if they are different from what I usually see I look
for antenna trouble, ie., antenna down, ice coated, wrong antenna, a
short somewhere. With the automatic tuner it just tunes and you
don't know if its the antenna or the tuner that is making your xmtr
happy. And even at 5 watts or less we can fry a 510.

I admit I am a nerd and like to tinker versus those who like to "just
get on the air and make a contact". My preference. This is a
wonderful hobby and we all are different.

Dave K8WPE

On Mar 19, 2018, at 6:37 AM, Curt M. <Kc3hjp@...> wrote:

I use my LDG Z-11ProII with an end fed wire and my Bitx40. The
tuner only requires 100mW of signal to auto tune.

http://www.ldgelectronics.com/c/252/products/21/9/1


Re: Voltage/Waveform chart?

bobolink
 

I prefer the Weller soldering station ...

But I think that would be a fantastic idea. If I understand correctly. Like the old SAMS schematic series. 

For a constant tone mic input interface circuit for TX and some kind of low cost rf test signal with a si5351/Arduino for RX (or another bitx in a test mode).

Sure would help out some of the posters here.

A simple VOX control circuit for the BitX-40 to allow it to be used for FT-8

John P
 

As promised, I uploaded the description of the simple VOX interface between my PC and the BitX-40 that I've been using for FT-8. I suppose it will also work for other digital modes, and should really be able to work with almost any radio provided the PTT voltage & current don't exceed the specifications of the SSR I used.

Those of you who know me know that I'm a real hacker when it comes to hardware, so all suggestions for improvement are always welcome (email: my call at ARRL.net). Or post here so all can kibitz!

--
John - WA2FZW

Re: Voltage/Waveform chart?

bobolink
 

I should add that it would also be a lot of work!
You could combine the graphics with some theory and make an ebook or YouTube.
And charge for an ebook, like SAMS did.
One of the author guys maybe.

Re: two-tone test on ubitx

Tim Gorman
 

Henning,

I used 40db of padding between the ubitx and the SA, 30db in an
external pad and 10db inside the SA.

Based on this the total power output of the ubitx was 10watts average,
5watts in each of the two tones. This is 20watts PEP.

I redid the carrier suppression this morning using a single tone at
10watt output from the ubitx. I still only shows about 20db of carrier
suppression. With a single tone this should be a PEP measurement so 6db
probably shouldn't be added.

I'm going to have to investigate the balanced modulator in the ubitx to
see if there are any simple mods that might help.

tim ab0wr

On Tue, 20 Mar 2018 05:29:59 -0400
"Henning Weddig via Groups.Io" <hweddig=aol.com@groups.io> wrote:

Tim, this is a nice measurement-
At which output power did You take the measurement? What is the
attenauation of the power attenuator between the output of the uBITX
and the Input of the spectrum analysser? Your measaurement shows a
thrid intermodulation of 34 dB/ related to a tone, in relation to PEP
please add 6 dB results in 40 dB of d3! BUT: marker 1 shows the
supressed carrier is only 20 dB below the carrier, or 26 dB to PEP.
Commercial rigs suppress by at least 40 dB or better. This result is
a"proof" of my worries concerning the unsuffiecient carrier
Suppression of the balanced modulator and xtal-filter..

Henning Weddig
DK5LV.

-----Ursprüngliche Mitteilung-----
Von: Tim Gorman <tgorman2@...>
An: BITX20 <BITX20@groups.io>
Verschickt: Mo, 19. Mrz 2018 22:46
Betreff: [BITX20] two-tone test on ubitx

Attached is a screen save from my spectrum analyzer for a two-one test
of my new ubitx.

The tones were driving the finals to about 10watts output (not quite,
but close). I had a 30db external pad and a 10db internal pad in the
SA.

The carrier was only down about 20db (marker 1). That's not as good as
I expected. I'll have to look at that and see what can be done to
improve it.

The 3rd order IMD (marker 4) was down about 34.5db which is adequate.

The heat sinks get *hot* while running a key down measurement like
this. If you are going to use the rig for a digital mode it probably
needs to be set for about half-power out of the rig. That or a
significant increase in heat-sink capability should be installed.

tim ab0wr




Re: RD16HHF1 power curve flattening...some

John <passionfruit88@...>
 

Nik,

Agree with Lawrence here as I had feedback issues too on the higher frequency bands. I could minimise the feedback by using a better shielded microphone, but the issue would still be there on some bands (24 and 28Mhz in particular).

I placed a 100uH inductor (a Jaycar LF1534)  and a 1nF cap to the ground on the input of the SSM2167 and the feedback disappeared.

The test for me was to remove the microphone plug and get the uBitx in TX (SSB) and check that there was no power at the antenna. Then simply placing a short wire on the mic pin would trigger the feedback, but removing it would remove the feedback too. So I concluded that it was not an internal oscillation, but linked to RF getting into the mic input. This test might not be 100% certain but is a good pointer IMO.

73, John (VK2ETA)

Re: antenna tuner for uBitx

 

Love the Emtech ZM-2, it is my go to for 15w or less. I also use the older version of the Z-11 LDG (LDG QRP) and it works pretty good.

After looking at the 4-State tuner if you are a new builder it would be the better choice. The ZM-2 just rocks and tunes everything I have ever thrown at it, but it can be tough for new builders.

The other bonus to the ZM-2 is you can get BNC or SO-239 and built/kit.

I agree with Dave K8WPE, care should be taken in any case auto or not. I never push the UBitx/Bitx40 finals and have them both set to 5W max. You don't have to go to that extent but you should be mindful of TX time and high SWR.
--
David

 N8DAH
Kit-Projects.com