Date   
newbee here...just made the order...antenna question on old G5RV

Don - KM4UDX
 

Finally, after a year or more of hand ringing and second guessing myself, I finally pulled the switch and ordered my uBITX! 

 

Believe it or not, it came down to the ICOM7300 or the uBITX.  I picked the uBITX because I love to solder and build, and when things are hard, they are much more satisfying when you finally get over the hill.  And what I learn with the uBITX will apply to any more complex and capable transceiver downstream. So I pulled the plug.  Should start the build in a few weeks. Also ordered the normal white plastic case from BG, and bnc to SO239 connectors, etc.

 

Questions to the wise ones: Can I hook up the uBITX my G5RV? I have a length of coax (which has a simple choke) that connects to the twinlead, which then goes to the dipole aerial WITHOUT an antenna tuner?

 

I borrowed 100W transceiver, and the G5RV worked just fine. But the 100W rig had an internal antenna turner, which I’m told the G5RV needs.  The uBITX does not have a antenna tuner…will it work well enough directly connected with the G5RV?

 

If I have to get an antenna tuner…(rats!), then I’m thinking of the ZM-2 or the like.

https://steadynet.com/emtech/zm2-kit-uhf-connectors

 

Guidance please!

 

Thank you o wise ones!

 

Don

KM4UDX

 

 

 

From: John P
Sent: Sunday, July 1, 2018 3:04 PM
To: BITX20@groups.io
Subject: Re: [BITX20] BITX QSO Afternoon/Evening, Sunday, July 1, 3PM & 7PMLocal Time, 7277 kHz in North America, 7177 kHz elsewhere.

 

I'm calling CQ on 7277. Hearing nuttin but noise!

--
John - WA2FZW

 

Re: RFI from uBitx TX after AGC and other mods installed

John KC9OJV
 

Thanks Rick- ditto on the electrolytic. I tried a 1000uF 16v electrolytic at the board and didn't notice any effect at all.

John
KC9OJV

Re: RFI from uBitx TX after AGC and other mods installed

Don, ND6T
 

Thank you!! I tried that TWICE and got this screaming tone. Perhaps the third time is in order. I wonder sometimes if I am living in an alternative universe. Goes to show that you should always question the "experts". Thank you very much for hanging in there, Rick. Good suggestion Lawrence. 73, Don

Re: RFI from uBitx TX after AGC and other mods installed

Rick Price
 

Don, please don't think I was questioning the experts, just was running out of options, suggestions, and like I said nothing ventured nothing gained and had tried everything else. Will always take advice from those that have been there before! Thanks again,
 
Rick

 


From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Don, ND6T via Groups.Io
Sent: Sunday, July 01, 2018 3:56 PM
To: BITX20@groups.io
Subject: Re: [BITX20] RFI from uBitx TX after AGC and other mods installed

Thank you!! I tried that TWICE and got this screaming tone. Perhaps the third time is in order. I wonder sometimes if I am living in an alternative universe. Goes to show that you should always question the "experts". Thank you very much for hanging in there, Rick. Good suggestion Lawrence. 73, Don

Re: newbee here...just made the order...antenna question on old G5RV

Jerry Gaffke
 

You wanted wise ones, but I'll jump in till one shows up.

The uBitx will want to see 50 ohms, ideally under a 2 to 1 SWR, though I suspect it will
survive most anything if you power the IRF510's from not much beyond 12v.

The G5RV antenna is not resonant, the impedance it presents will be all over the map.
You really need a tuner between it and the 50 ohm coax to the uBitx.

That ZM-2 might be sufficient, I don't really know.


The fact that you cannot adjust inductance is not a plus in my book, that could be getting 
inefficient as frequencies go up and capacitive coupling between windings gets out of hand.
It claims to be good to 15 Watts, though does not really say under what conditions that might be true.
Max power it can handle will vary considerably with operating frequency and antenna impedance.

I'm happy enough with my MFJ-949E tuner/swr/dummyload
Build quality varies on the MFJ stuff, you want to lift the lid when you get it and check the solder job.

If you want to build your own tuner, you need an SWR indicator such as Diz's Tandem Match SWR indicator:
    http://www.kitsandparts.com/bridge1.4.php
Generally the tuner itself can be a couple tuning caps from some old tube type broadcast receiver
and a hand wound inductor with an alligator clip to tap into it somewhere, check the various handbooks on that.

For the price of the 7300, you can have a half dozen uBitx's go up in flames
and try out several MFJ tuners plus some homemade ones. 
And learn an awful lot in the process.

Jerry, KE7ER


On Sun, Jul 1, 2018 at 12:32 pm, Don - KM4UDX wrote:

Finally, after a year or more of hand ringing and second guessing myself, I finally pulled the switch and ordered my uBITX! 

 

Believe it or not, it came down to the ICOM7300 or the uBITX.  I picked the uBITX because I love to solder and build, and when things are hard, they are much more satisfying when you finally get over the hill.  And what I learn with the uBITX will apply to any more complex and capable transceiver downstream. So I pulled the plug.  Should start the build in a few weeks. Also ordered the normal white plastic case from BG, and bnc to SO239 connectors, etc.

 

Questions to the wise ones: Can I hook up the uBITX my G5RV? I have a length of coax (which has a simple choke) that connects to the twinlead, which then goes to the dipole aerial WITHOUT an antenna tuner?

 

I borrowed 100W transceiver, and the G5RV worked just fine. But the 100W rig had an internal antenna turner, which I’m told the G5RV needs.  The uBITX does not have a antenna tuner…will it work well enough directly connected with the G5RV?

 

If I have to get an antenna tuner…(rats!), then I’m thinking of the ZM-2 or the like.

https://steadynet.com/emtech/zm2-kit-uhf-connectors

 

Guidance please!

 

Thank you o wise ones!

 

Don

KM4UDX

Re: #uBITX #ubitx

SM6MOJ
 

Dear Michael

Thank you for your wise words. Now all I have to do is work out why there
is no current drain.

Andrew

Re: #uBITX #ubitx

Lowell Haney NE4EB
 

If there is no current drain, what shows up on the LCD? Is the back light lit?

What method are you using to measure the current draw?

Re: RFI from uBitx TX after AGC and other mods installed

Don, ND6T
 

Rick, I'm saying that you really SHOULD! A little history: I originally had a .01 uF across the input audio and well, surprise! Then Kees slipped it in on his re-make so I tried again with the same result. I sure hope that it helps Rowland, Alan, Mark and the rest. I'll try again and include that in the web pages. 73, Don

Re: BITX QSO Afternoon/Evening, Sunday, July 1, 3PM & 7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere.

kc1at
 

calling also but nothing heard. This week unlike the last 2 weeks I have my antenna connected. Don't ask.

don, still listening

Re: newbee here...just made the order...antenna question on old G5RV

Ralph Mowery
 

With almost any antenna designed to work over a large frequency range you will need a tuner of some sort.  Either a built in one or external.
The G5RV is not really that good of an antenna for all bands.  It was designed for 20 meters and a certain pattern.  It will give a reasonable SWR over many of the ham bands, but still a tuner is needed.  I like an off center fed antenna for working most ham bands .  It still needs an antenna tuner.  Look for the plans of a Carolina Windom if you want to build one.

As you are going to need a SWR bridge I wold look at a tuner that has a SWR meter built in.  Much as I hate say it about getting a MFJ, that may be the best for the dollar.  Open it up and check for loose parts and bad solder connections.  Lots of the mfj stuff seems to be about 99% built. and you need the extra 1%.
LDG makes some good automatic tuners at a reasonable price.

73 de ku4pt





On Sun, Jul 1, 2018 at 3:32 PM, Don - KM4UDX <dontAy155@...> wrote:

Finally, after a year or more of hand ringing and second guessing myself, I finally pulled the switch and ordered my uBITX! 

 

Believe it or not, it came down to the ICOM7300 or the uBITX.  I picked the uBITX because I love to solder and build, and when things are hard, they are much more satisfying when you finally get over the hill.  And what I learn with the uBITX will apply to any more complex and capable transceiver downstream. So I pulled the plug.  Should start the build in a few weeks. Also ordered the normal white plastic case from BG, and bnc to SO239 connectors, etc.

 

Questions to the wise ones: Can I hook up the uBITX my G5RV? I have a length of coax (which has a simple choke) that connects to the twinlead, which then goes to the dipole aerial WITHOUT an antenna tuner?

 

I borrowed 100W transceiver, and the G5RV worked just fine. But the 100W rig had an internal antenna turner, which I’m told the G5RV needs.  The uBITX does not have a antenna tuner…will it work well enough directly connected with the G5RV?

 

If I have to get an antenna tuner…(rats!), then I’m thinking of the ZM-2 or the like.

https://steadynet.com/emtech/zm2-kit-uhf-connectors

 

Guidance please!

 

Thank you o wise ones!

 

Don

KM4UDX


Re: BITX QSO Afternoon/Evening, Sunday, July 1, 3PM & 7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere.

John P
 

On Sun, Jul 1, 2018 at 01:36 pm, kc1at wrote:
I have my antenna connected. Don't ask.
Been there! Done that! Look for you this evening.
 
--
John - WA2FZW

Re: RFI from uBitx TX after AGC and other mods installed

Lawrence Galea
 

First of all glad that you had good progress.
I hadn't looked at the μbitx board but at the circuit diagram and there is no capacitor showing on pin 7 of the TDA2822.
My thinking was and is that the Q1 base - emitter junction is acting as a detector and feeding back the audio to the AF gain control through the input capacitor C1.
So you can try a higher value and see whether all the RFI will go away.
Regarding filtering at the voltage regulators, I always put the capacitors I suggested on both input and output as close as possible to the regulator, if possible across the leads on the pcb and also a 10 to 22μF capacitor on both input and output and never had a problem with RF on the regulators.
Furthermore, when a big voltage drop is required such as from 12V to 5V I usually put in a 7809 or 7808 before the 7805, splitting the heat between them.
They are cheap so better regulation (within their capacity) and less heat in each component and better component life.
Regards

As a note, we used to use different capacitor values when we used leaded components because due to the lead inductance they would not decouple efficiently at some frequencies.
We also used certain capacitor values with a particular leads length where the capacity with the leads length formed a series resonant circuit to efficiently decouple a particular frequency especially in screen grid circuits.



On Sun, Jul 1, 2018 at 9:02 PM, Rick Price <rickprice48@...> wrote:
John, Don Lawrence, others
Interesting Outcome! Shielding was no help, replacing pcb with perfboard agc helped a little, but back to pcb. bypass's on 78L05 were .68 on input and .1 on output still no help and removed 78Ll05. Did not try 1nf,10nf,100nf in parallel on 78L05 because I had already removed it.  Because pin 7 of U1 (TDA2822) is already bypassed with C78 did not do. Don suggested to filter the 5v supply. I get the 5 volts from the radino pin 3 (green wire) and use it for both AGC and mike preamp. Used a 470uf and .01 on the 5V no improvement.  Don suggested not to try the emitter-base capacitor because of forming a blocking oscillator. It looked to me that because the emitter was already grounded that it probably just bypass any unwanted signal to ground and not oscillate, connecting to the collector might have been another story.. What the heck nothing ventured nothing gained. Tried the .01 and turned on expecting possible oscillations of some sort. AGC off transmitting nothing as before, AGC on transmitting at full volume only occasionally get a very small occasional hint of audio coming through the speaker no oscillations of any kind. Before as soon as audio was present from the mike it started coming through and sometimes went into oscillations.  Hardly ever run at full volume so it looks like your theory and suggestion Lawrence may work. ARC still appears to work as before but will need a strong signal to verify.  Still have to experiment with a couple of different values to see what's best. Hope this spells relief with the agc on for the few of this it affects. Thanks to all for the input and suggestions.
 
Rick 
KN4AIE 


From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Lawrence Galea
Sent: Sunday, July 01, 2018 12:28 PM

To: BITX20@groups.io
Subject: Re: [BITX20] RFI from uBitx TX after AGC and other mods installed

Also try putting a 100n directly across Q1 base-emitter on the AGC board.
It will cut off some of the higher AF as it would be in series with C1 to earth across the Af gain control.  
However, this would not be of any serious consequences.
If you don't want as much AF HF cut off you can try a smaller capacitor, say 10n.
I am thinking that Q1 base-emitter junction is acting as a detector and the AF is being coupled back to the AF gain control since the level is varying with the AF Gain control.
One could also add say a 10n capacitor directly on pin 7 of the TDA2822 or across the AF Gain control as an rf decoupling.
Can you try and report?


On Sun, Jul 1, 2018 at 5:33 PM, Lawrence Galea <9h1avlaw@...> wrote:
Did you put 100n, 10n, 1n filter capacitors  all in parallel on both input and output directly across the 78L05 leads?
.


On Sun, Jul 1, 2018 at 2:31 PM, Rick Price <rickprice48@...> wrote:
John, Don, others,
Yesterday I attached a 78L05 (TO220) directly to the back of the AGC board that is mounted to the RF gain control on the front panel. Bypassed all power leads and ran a separate power lead to the 12V regulator that powers my uBitx. In other words the AGC board had its own isolated(?) power source. Stll heard the audio when transmitting.  Beginning to think that radiated power is being absorbed by the AGC board and then recitifed and then coupled into the audio system. I also have the pop click board installed and not sure if this was a problem before it was installed. My AGC board is one I fabricated using Don's technique of cutting pcb with an x-acto knife.  I also have a AGC board made on perf board using through hole parts.  May sub that in and see if there are any changes. I eventually plan on installing the JackAl mod when it becomes available so this problem should go away for me but its beginning to become a challenge to fix.
 
Rick KN4AIE


From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of John KC9OJV
Sent: Sunday, July 01, 2018 8:05 AM
To: BITX20@groups.io
Subject: Re: [BITX20] RFI from uBitx TX after AGC and other mods installed

Don,
I spent part of yesterday applying ferrites to this and that to little success. I also tried wrapping the 5v line around the twisted pair coming from the volume pot and that did some good. This morning I was thinking about fixing a 7805 to the metal base of my case, drilling a hole in the ground plane and routing a wire through that hole to feed the AGC board. It could be driven off the 12v relay (K1?). Has anyone else had any ideas/success?

John
KC9OJV




Re: BITX QSO Afternoon/Evening, Sunday, July 1, 3PM & 7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere.

Tom VE3THR
 

Thanks John...spent the afternoon "celebrating Canada Day" Back in port now and monitoring 7.277. Will be on the ubitx for a while. Still 34c or 88f deg outside.
Tom VE3THR/MM QRP

Re: BITX QSO Afternoon/Evening, Sunday, July 1, 3PM & 7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere.

John P
 

On Sun, Jul 1, 2018 at 03:58 pm, Tom VE3THR wrote:
Still 34c or 88f deg outside.
It hit 100 here today!
 
--
John - WA2FZW

Re: BITX QSO Afternoon/Evening, Sunday, July 1, 3PM & 7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere.

Vince Vielhaber
 

I'm hearing someone on 7277 calling cq bitx but only got bits and pieces of a call. Maybe n4dr? Also heard n2cqr?. Don't have a worthwile SWR on 40 right now so I can't go back to either.

Vince - K8ZW.

On 07/01/2018 07:04 PM, John P wrote:
On Sun, Jul 1, 2018 at 03:58 pm, Tom VE3THR wrote:

Still 34c or 88f deg outside.

It hit 100 here today!

--
John - WA2FZW

Re: BITX QSO Afternoon/Evening, Sunday, July 1, 3PM & 7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere.

John P
 

I just had a QSO with K2OCA who is only a couple of miles away. He was running significant power, so even if you didn't hear me, you might have heard him. I'm getting some significant QRM from 2275 this evening.
--
John - WA2FZW

Re: Bitx40 75KHz Spurious, How to solve it. #bitx40

Allard PE1NWL
 

Raj,
thanks for testing, but the issue that Akira san reported, is with BitX40,
not ubitx.
If possible, could you please repeat the same check with BitX40 and let us
know the results?

Many Thanks, 73
Allard PE1NWL

On Sun, July 1, 2018 15:59, Raj vu2zap wrote:
Correction 500KHz span!

At 01-07-18, you wrote:
Akira,

I just put my uBitxr4 on the spectrum analyzer and found nothing +-250
Khz. That is 500 Khz BW.

I think your measurements are being affected by switch mode power supply
in one of the items.

Raj

At 25-06-18, you wrote:
Hi!

I built Bitx40 about 2 weeks ago.

I measured the spurious of Bitx40 by using the spectrum analyzer.
The level of spurious of harmonics were under 50db. So this is fine.
But the spurious at 75KHz was observed.
The spurious might be the multiple of 25KHz.
It would be much appreciated if you could advise me the cause and
solution of this spurious of Bitx40.

In Japan, we must prove to the authority that the spurious of the
transceiver meets the criteria to obtain the certification of the
transceiver from the authority.
So if i could not resolve this spurious, I will not be able to use
Bitx40 in Japan.

Thanks in advance,
Akira
JJ1EPE


Re: newbee here...just made the order...antenna question on old G5RV

Jerry Gaffke
 

I've heard good things about the G5RV.
Never had one.
Since you got one up, I suggest you go ahead and use it.
It is resonant on 20m, will give a 50 ohm match there if the ladder line is cut to the correct length.
I would recommend at least borrowing an SWR meter to determine
over what range of frequencies it gives a reasonable match.
For multiband use on the G5RV you do need a transmatch of some sort, but it could be cobbled together cheaply.
Ladder line has much less loss than coax even at high SWR, so a transmatch between the ladder line and the coax
can make this an efficient multiband antenna system.

Ralph's off-center fed dipole can be easier to put up than a center fed dipole, but does require a transmatch.
The end-fed is an extreme case, I have one of these:
    https://myantennas.com/wp/product/efhw-8010/
That particular EFHW is done well, is a good radiator, and with the matchbox provided can give
a good 50 ohm match across most of the HF ham bands with no tuner. 
I would still recommend having an SWR meter to determine if things are working properly.
If you might have ice loading in the winter then going to heavier antenna wire is a good idea,
buy the MEF-330-1k matchbox and the 14 gauge antenna wire separately:
    https://myantennas.com/wp/product-category/accessories/wire/
    https://myantennas.com/wp/product-category/antennas/efhw-transformers/
Check out the March 2016 QST review:
    http://www.arrl.org/files/file/ProductReviewsForDeb/2016/pr032016.pdf

Jerry


On Sun, Jul 1, 2018 at 01:55 pm, Ralph Mowery wrote:
With almost any antenna designed to work over a large frequency range you will need a tuner of some sort.  Either a built in one or external.
The G5RV is not really that good of an antenna for all bands.  It was designed for 20 meters and a certain pattern.  It will give a reasonable SWR over many of the ham bands, but still a tuner is needed.  I like an off center fed antenna for working most ham bands .  It still needs an antenna tuner.  Look for the plans of a Carolina Windom if you want to build one.
 
 

Re: TX frequency? of uBitx at CWL and CWU mode #ubitxcw

Ian Lee
 

jj1epe, michael and all

CW is a way to generate and transmit one frequency, 
To hear the unmodulated frequency, we move the frequency a little in SSB(We call it Side tone)
In LSB, it is necessary to increase the frequency by Side tone, and in USB, it must be lowered by Side Tone.

If you want to display the actual frequency transmitted to the screen, selected the following in uBITX Manager.
 - Enabled Adjust CW Frequency
 - Shift Display Frequency on CWL, CWU Mode

Various opinions about CW frequency display method have been continued.
A few months ago I created the option 'Shift Display Frequency on CWL, CWU Mode' by OM's  opinion  in  this community group.

If you select this function, the LCD will show the frequency at which the radio will be transmitted.

Ian KD8CEC

2018-07-01 22:11 GMT+09:00 Michael Babineau <mbabineau.ve3wmb@...>:

Akira-san : 

The uBITX display frequency in CWU/CWL is the RX frequency not the TX frequency. The norm in CW on most commercial rigs is to always display the TX frequency.
You can however set the RX offset. It seems that yours must be 1.5 Khz which is a lot. Typically it would be something in the range of 500 to 800 Hz. 

There is a related issue which I have reported and that is that changing CW modes is "broken". When switching back and 
forth between CWU/CWL modes the TX frequency changes and the RX frequency does not which is wrong. This means that 
if you properly tune in a CW station (RX tone matches your offset) on CWU and switch to CWL the other station is no longer audible and 
he can't hear you. It should be possible to switch back and forth between CWU and CWL and still maintain contact.

See message #51983 for more details.

Cheers

Michael VE3WMB 



--
Best 73
KD8CEC / Ph.D ian lee
kd8cec@...
www.hamskey.com (my blog)

Re: BITX QSO Afternoon/Evening, Sunday, July 1, 3PM & 7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere.

Glenn Anderson
 

I'm just using my test leads for my multimeter (I'm at work) as an antenna... If you guys are having this much trouble it's no wonder I can't hear anything... HIHI



On Sun, Jul 1, 2018 at 7:25 PM, John P <j.m.price@...> wrote:
I just had a QSO with K2OCA who is only a couple of miles away. He was running significant power, so even if you didn't hear me, you might have heard him. I'm getting some significant QRM from 2275 this evening.
--
John - WA2FZW




--
73 de Glenn VE3JAU
Thunder Bay, Ontario