Date   

Re: End Fed antennas w/ uBITX #ubitx

Mark M
 

Jerry...In my email client I set up a folder for the BITX20 group. I then added a filter to route anything with 'BITX20' in the subject to that folder. Keeps the main inbox less cluttered and makes it easier to see all the BITX20 stuff in one place. I use the Thunderbird email client but I think most of the others have a similar capability. 

Mark   AA7TA


Re: hacking bitx40 for 20 metre #bitx40

Guy N7BIR <sgbridge@...>
 

Go to QRPKITS.COM and you can find manuals for both BitX20 & 17. 


Re: [UNTRIED IDEA] Bitx40 conversion for 6 & 2 metres #bitx40 #6meters

Jerry Gaffke
 

Not a trivial hack.
I'd suspect you are replacing the first mixer, the bidi RF amp in front of that, the 7mhz BPF, the entire transmit amplifier chain including silicon and transformers, and the output LPF.  So ripping out half the radio and redesigning/replacing all that stuff.

And of course, the next question is:  How about FM?
The answer is:  No.

Jerry


On Sun, Jul 29, 2018 at 02:48 PM, Peter Parker wrote:

Many would have the old Bitx40 (especially the free running VFO version) and have little use for it now they have a uBitx. 

A possible idea could be to convert it to 6 metres and potentially 2 metres as well. That would make it a great field day portable rig. 

 


[UNTRIED IDEA] Bitx40 conversion for 6 & 2 metres #bitx40 #6meters

Peter Parker
 

Many would have the old Bitx40 (especially the free running VFO version) and have little use for it now they have a uBitx. 

A possible idea could be to convert it to 6 metres and potentially 2 metres as well. That would make it a great field day portable rig. 

Even a few hundred milliwatts to a small yagi should cover several hundred km under a good path. 

*** These are ideas only - I have only done a small amount of work towards this. ***

1. The first thing is that you will need to add a DDS-based VFO. I used the CDV from OzQRP.  

Video at https://www.youtube.com/watch?v=K5Vtih9Nxhc

More about the CDV including manual at http://www.ozqrp.com/CDVindex.html 

Most notable is that it goes up to 100 MHz (which could be significant - see later).  

2. Next you will need USB rather than LSB. This can be done without fiddling with the carrier oscillator by flipping the local oscillator to the other side of the 12 MHz crystal filter. 

Eg instead of the LO for 7 MHz being 5 MHz it needs to be 19 MHz.  That will give USB on 7 MHz.  I needed to make menu setting adjustments in the CDV to do this.  This includes getting the dial frequency right. 

3. With a USB receiver set up (Eg FT817) move up to other bands - eg 10, 14, MHz and up and transmit. You will hear yourself though it will be weak since the band pass filters and pi network won't be right. 

And the receiver will be insensitive.  Keep moving up to 50 MHz. 

4. For testing purposes you can remove the 7 MHz band pass filter. This will dramatically improve receiver sensitivity. But you might get breakthrough from other signals. On transmit you will get a bit more output
(your RF power meter needle will wriggle slightly) but it will still be low due to the 7 MHz pi network in the output and the likely low gain of the IRF510 on 50 MHz. But at least it should sound good on the FT817 giving  you something to go on. 

5. (haven't got this far yet) Add a 50 MHz band pass filter where the 7 MHz filter was.  That should make the receiver OK though I wouldn't be surprised if it's deaf - you will likely need to add a FET RF preamp. 

6. As for the transmitter you will probably need to remove the IRF510 and try another configuration (possibly 2 transistors).  You might only get 500mW to 1w output. But that might still be OK with a good antenna. 

7. What about 2m? You will need a transverter. The CDV VFO has a second fixed output that can go up to 100 MHz.  50 MHz + 94 MHz = 144 MHz.  So it might be possible to use this in combination with transmit and receive mixers to get 2m.  This could be built in the same box as the Bitx to make a portable QRP VHF package for field days etc. RF transistor are hard to get but even 500mW to 1w on 2m can do well eg video below. 

https://www.youtube.com/watch?v=RC3F4wv04RE

 

73, Peter VK3YE

 

 

 

 

 


Re: VK3YE AGC pcb.

 

Hi Arv,

Not me, I would rather it looks professional so I would probably spend the 5 bucks, and in fact i did. I will report back and let everyone know how it works.

Joel
N6ALT


Re: VK3YE AGC pcb.

Arv Evans
 

Joel

Given the $5 price, most of us would probably dig in the junk box for a LDR, LED, and
some heat shrink tube to connect them face-to-face. 

For those who are not old enough ( or too old ) to remember LDRs, you can find them here:


Re: uBitx for sale

K4LXY <zehrhj2@...>
 

A sale is pending.  I'm keeping inquiries on file in case it becomes available again.
Thanks for your interest
73 Howard


Re: VK3YE AGC pcb.

 


Re: uBitx for sale

Scot McMath
 

I’m interested, do you have a picture?

Scot WB7AVU

 

From: BITX20@groups.io <BITX20@groups.io> On Behalf Of K4LXY
Sent: Sunday, July 29, 2018 12:47 PM
To: BITX20@groups.io
Subject: [BITX20] uBitx for sale

 

uBitx assembled and in a nice case with built-in speaker. All cables to front and back panels have connectors for easy removal. I have added an internal BCI filter, updated the audio amp IC and made the sidetone volume adjustable.  A muting circuit has been added to eliminate audio pop when switching between receive and transmit.  The latest KD8CED firmware – v1.8 – is installed. 

 
I have only used this on cw. A mic comes with it, and the output shows modulation on SSB, but from the discussion on this group, it may need a mic preamp to get full power output. I have not tried it on the air with SSB.

 

Selling this to move on to new projects.

$100 plus shipping.  For another $20, will include a Hi-Per-Mite audio filter module that makes it much more useable on cw.  Email for external photos.

 
73 Howard


Re: End Fed antennas w/ uBITX #ubitx

Jerry Gaffke
 

Yup, I finally figured that out from Arv's post.
Had been using the website to avoid inbox clutter.
I guess the solution is to establish a separate gmail account for bitx20 traffic.

For those using the groups.io website who wish to move to email messaes so they can shut down threads,
  go to https://groups.io/g/BITX20/messages
  click the "Groups.io" logo in the upper left corner of the webpage
  click the button to select the Bitx20 group
  click "Actions" on the bottom of the webpage
  click "All email"
  click "Yes" to verify the action

Sun, Jul 29, 2018 at 10:41 AM, Ken Hansen wrote:

If you view the group in email, it has the following set of clickable options, which includes "Mute This Topic"


Re: uBitx for sale

K4LXY <zehrhj2@...>
 

I installed it in the audio line before the speaker.  This way, for SSB, one would use earphones and for cw, the speaker or earphones (using an additional phone jack I installed at the speaker).   It could of course be wired with a switch to take it in and out of the circuit.  It's modular in that it can be easily inserted or removed by switching plugs internally.  Since I don't do SSB, I didn't bother installing a switch.
73 Howard


Re: End Fed antennas w/ uBITX #ubitx

m5fra2@...
 

Exactly!

 

From: BITX20@groups.io <BITX20@groups.io> On Behalf Of MadRadioModder
Sent: 29 July 2018 16:47
To: BITX20@groups.io
Subject: Re: [BITX20] End Fed antennas w/ uBITX

 

Not if it were antennas@groups.io...

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of m5fra2 via Groups.Io
Sent: Sunday, July 29, 2018 8:32 AM
To: BITX20@groups.io
Subject: Re: [BITX20] End Fed antennas w/ uBITX

 

Maybe it was a bit off topic?

 

From: BITX20@groups.io <BITX20@groups.io> On Behalf Of ieand@...
Sent: 29 July 2018 10:30
To: BITX20@groups.io
Subject: Re: [BITX20] End Fed antennas w/ uBITX

 

I really fail to see a serious problem with this thread. Sure if ppl don't like a bit of controversy and vigorous discussion then by all means hide the thread but personally  I have learned more from this thread than any other I can remember in the bitx20 group.

Now Ill just have to build a couple efhw  antennas and and do some hands on testing.
Ian 

 

Virus-free. www.avast.com


--

…_. _._


Re: hacking bitx40 for 20 metre #bitx40

Arv Evans
 

On Sun, Jul 29, 2018 at 04:38 AM, <terryhugheskirkcudbright@...> wrote:
tHacking bitx40 for 20 metre
Terry GM4DSO

Way back in the early BITX  days there were several band conversion projects, and even some
band conversion kits.  Methodology was to determine the impedance of LC networks at the
original frequency and then determine the L and C values to obtain the same impedance at the
new frequency.  This usually involved using the calculator at https://toroids.info and then changing 
LO frequencies for the new band.  If the IF frequency is also changed the BFO will also need to be
changed. 

Arv K7HKL
_._


Re: Nextion TFT

Björn Pasteuning
 

A note to bigger Nextion screens.

I have a whole range nextion displays, the bigger the display the stronger the PWM backlit interference on the uBitx.

What I did to most of them is disabling the PWM signal from the uC, cut the trace and pulled up the backlit to maximum backlit.


--
73' Björn de PD5DJ
www.pd5dj.nl


Re: Receive pitch shifts when confirming.... #arduino #ubitx #ubitx-help

mtrager1@...
 

Hi Ion,

OK I lowered the BFO until I was satisfied with the high end. Right now it is at 11996200 and I may move it up a bit.

I can see the difference in the transmission on my K3's P3 Panadapter......much clearer.

I will have to check into the AGC mod also.

73's Michael
n2zdb


Re: uBITX and nulling the carrier #ubitx-help

mtrager1@...
 

Ok I lowered the BFO to 11996200 and it is much better as far as the high end.

I can see the difference in the transmission on my Elecraft's P3...in fact it may be too high.

Yes the carrier is also much further down.....

Thanks guys!

73's Michael
n2zdb


Re: hacking bitx40 for 20 metre #bitx40

ajparent1/KB1GMX <kb1gmx@...>
 

Very reasonable if your using Raduino or other digital signal source for VFO and BFO.

The very original BITX was the BITX20.  So ther eiss a schematic for that and you can
get the bandpass filter and low pass filter from that.

The two big things are the band pass filters and replacing the low pass filter.
Of course the Raduino sketch has a few changes as well (set up the correct frequencies.).

Allison


Re: uBitx for sale

Kevin Rea
 

Hi Howard,

I was just wondering where you would install the Hi-Per-Mite audio filter

Kit ?

 

Thanks,

Kevin rea

K6rea

 

From: BITX20@groups.io <BITX20@groups.io> On Behalf Of K4LXY
Sent: Sunday, July 29, 2018 12:47 PM
To: BITX20@groups.io
Subject: [BITX20] uBitx for sale

 

uBitx assembled and in a nice case with built-in speaker. All cables to front and back panels have connectors for easy removal. I have added an internal BCI filter, updated the audio amp IC and made the sidetone volume adjustable.  A muting circuit has been added to eliminate audio pop when switching between receive and transmit.  The latest KD8CED firmware – v1.8 – is installed. 

 
I have only used this on cw. A mic comes with it, and the output shows modulation on SSB, but from the discussion on this group, it may need a mic preamp to get full power output. I have not tried it on the air with SSB.

 

Selling this to move on to new projects.

$100 plus shipping.  For another $20, will include a Hi-Per-Mite audio filter module that makes it much more useable on cw.  Email for external photos.

 
73 Howard


uBitx for sale

K4LXY <zehrhj2@...>
 

uBitx assembled and in a nice case with built-in speaker. All cables to front and back panels have connectors for easy removal. I have added an internal BCI filter, updated the audio amp IC and made the sidetone volume adjustable.  A muting circuit has been added to eliminate audio pop when switching between receive and transmit.  The latest KD8CED firmware – v1.8 – is installed. 

 
I have only used this on cw. A mic comes with it, and the output shows modulation on SSB, but from the discussion on this group, it may need a mic preamp to get full power output. I have not tried it on the air with SSB.

 

Selling this to move on to new projects.

$100 plus shipping.  For another $20, will include a Hi-Per-Mite audio filter module that makes it much more useable on cw.  Email for external photos.

 
73 Howard


Re: End Fed antennas w/ uBITX #ubitx

Jack, W8TEE
 

I did see where that antenna (Norway??) was knocked over in a storm. I imagine that's going to cost a few bucks to get back up. My EFHW (the 8010 from MyAntenna) is really not bad, I just envy those who have a tower and rotatable beam. I've talked to Roberto near Milan Italy and he has a 40M beam on a 160' tower. However, he also points out that he's not even above the surround hilltops, so we all have problems, no matter what. I'm lucky to have tall trees, plus I'm about 700' higher than the Ohio river.

Jack, W8TEE

On Sunday, July 29, 2018, 10:40:31 AM EDT, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:


Jack,

It's unfortunate she had you take down that other antenna.
If it's high enough the neighbors won't even see it, especially on a cloudy day.
    https://groups.io/g/BITX20/message/24965

So, exactly what do you have in the way of a crappy EFHW, and what matching network?
Why is it crappy?
Then I'll know what not to do.

If you want stealth, that's a good way to go.
Some skinny wire, perhaps galvanized steel for strength, and a matchbox on the side of the house
are much harder to see than coax going up to the middle of a dipole.

Jerry

On Sun, Jul 29, 2018 at 06:58 AM, Jack Purdum wrote:
I think everyone here knows that, when working QRP, the antenna system is a HUGE factor in one's success, or lack thereof. The good news: I'm fortunate in one manner, in that I am surrounded by 80' trees on almost 3 acres. The bad news: The XYL will not abide ANY antenna that is visible. She voted this one down:
 
My antenna situation poses a true dilemma (i.e., two choices, both bad), in that I really enjoy QRP work, but with my crappy EFHW, I really need more power to be effective. So, any time I see an antenna article that might even hint at being stealthy, I'm reading it. Indeed, I would like to see more posts about people who are successfully using their µBITX with stealthy antennas. When JackAl is done, a mag loop and controller are in my future.
 
Jack, W8TEE