Date   
Re: BITX 14MHz Build #bitx20

Aaron K5ATG
 

Thanks Jason,

Yeah those are nice videos. I have not seen his Youtube page before.

 

72

Aaron K5ATG

K5ATG Blog

 

From: Jason Pirok
Sent: Tuesday, April 7, 2020 11:06 AM
To: BITX20@groups.io
Subject: Re: [BITX20] BITX 14MHz Build #bitx20

 

W2AEW (Alan Wolke) has a great video on the layout of Manhattan style PCB building. 

This one illustrates the island method, but the techniques can be used for Manhattan.
https://www.youtube.com/watch?v=blalAktxFoI  

 

This one goes over several other construction techniques.
https://www.youtube.com/watch?v=kH110yjYZ2g  

 

--

Jason Pirok

W4UNX

 

Re: BITX 14MHz Build #bitx20

Aaron K5ATG
 

Thanks Mark,

Like I said, I’m a newbie so I will start identifying the VFO, BFO and AF amp and PA.

 

 

72

Aaron K5ATG

K5ATG Blog

 

From: Mark - N7EKU
Sent: Tuesday, April 7, 2020 11:09 AM
To: BITX20@groups.io
Subject: Re: [BITX20] BITX 14MHz Build #bitx20

 

Hi Aaron,

I not used MeSquares, but have done quite a bit of "dead bug" construction (which is just placing parts - upside down or not - over an unetched PCB).  Basically I just follow the schematic as it pretty much already organizes the parts in the place you want them on the board.  Start with the receiver antenna connector (or short piece of coax or twisted line) and just start building out.  The receive bandpass filter is first, then the RF amp, mixer, etc all follow.  The build will probably end up long an narrow, but that is good as it keeps the higher level signals away from the lower level ones.  Reading the description of Farhan's build you will see he did it this way too.  You might want to build the VFO, BFO, and AF amp on separate PCB's.  This will allow you to shield the RF one's and also allow you to keep the build from getting too long.  For sure I would put the PA on a separate board.

When soldering parts to the ground plane, remember that is one big piece of copper that you are heating up.  It will take higher heat and a longer heating time than the parts.  Clean then wet the tip of the iron with fresh solder, place the tip on the board where you want to solder, and wait until solder placed on the PCB near the tip will melt by itself.  Then you can place the part to be soldered to it onto the board.  This will keep the part from over heating.

You can place parts upside down or rightside up -- whatever is easiest and makes connections the simplest.

73,


Mark

PS:  Ferrite core toroids or old TV baluns will work much better than tap washers for transformers and inductors as the designer found out in the end.

PSS: If you can't find Toko type transformers for the bandpass filter, you can use fixed inductors and accomplish the filter adjustment by making the capacitors variable instead (trimmer caps). 

 

Re: uBitx V5 can't make a contact on ft8

Gavin
 

Thanks Nigel for helping me understand more about audio levels  and how having a power meter will help me get those correct!

And thanks for the others who suggested getting the cheap cb power/swr meters for $20-$25, I found one that was suggested on amazon and ordered it. I'm sure it will give me enough information to get it working much better and combined with getting my antenna up higher, I'm sure I'll be on my way!

Re: uBitx V5 can't make a contact on ft8

Gordon Gibby
 

Buy a cheap CB SWR meter for $25 on Amazon

Hamfest they go for $10 but everything is shut down


On Apr 7, 2020, at 07:15, Mick <Mgsebele@...> wrote:

Gavin,
I agree with Scott’s antenna suggestion. Another improvement I discovered was to use a USB dongle sound device (see below, the one I use) The sound volume and quality are greatly improved compared to direct to computer connection.
You will have to make sure the PTT connection from the dongle is disconnected or it will constantly trigger your TX.
I eventually mounted a second set of 3.5mm jacks on the back of my rig (wired to the audio jack) through a selector switch (Dpdt on-off-on) on the front of my rig.


--
 

73
Mick VA3EPM 

Re: uBitx V5 can't make a contact on ft8

Nigel G4ZAL
 

Nobody mentioned setting the audio levels?
Set the speaker audio to a very low level and watch the power out on a power meter (you really ought to get one) step it up a level at a time until you get your normal full output and set it there.
Mine is typically around 8 - 15 on all my rigs, anything more will just cause splatter/overdrive yor radio (kind of like screaming into your microphone).

You will want a fan on the PA if you intend to do anything more than an odd QSO.

Nigel
G4ZAL

ubitx V3 with panadapter #ubitx

Impulsive.force@...
 

I have a V3 ubitx. I have added the I.F (45Mhz) 50Mhz buffer board (https://ubitx.net/2018/07/21/full-sdr-receive-with-g4hup-buffer-amp/) and taken this to an SDRplay RSP1A. I have added a USB hub and soundcard (soundblaster) in with the ubitx so a single USB lead runs the radiono and the soundblaster.
This arrangement means I can switch the audio into FLDIGI between the soundblaster or the RSP1A and I have full CAT control of the ubitx and RSP1A. The RSP1A has its LO set to 45Mhz and USB for digital modes.
The ubitx is as supplied and I have not changed the calibration etc

I have noticed that the 'audio frequency' of a known BPSK31 signal appears at a slightly different frequency between the soundblaster and the RSP1A. I think it is about 200Hz but might be 700Hz as its difficult to measure it without an actual fixed reference. Also for instance, if I tune the ubitx to a morse signal, the signal is not in the same place via the RSP1A.

Does anyone know why there is (appears to be) this difference? I cant see a reason from the ubitx documentation

Thank you for any explanation

Re: How to design crystal filter using NANOVNA #filters #nano

iz oos
 

A few months ago I tested a nice 10.7 Mhz crystal filter I bought years ago. Most likely I did damage it with a 7dbm dds, but I cannot remember exactly. Testing using an attenuator and Antuino in SNA mode it was clear there was something wrong in the shape and insertion loss. I dismantled it, it contained a tuned coil at the input and one on the output. I tested each of the 4 crystals inside, three looked absolutely fine but one was clearly jeopardising the whole filter. You can also start practicing testing each crystal, then see what changes adding similar crystals in series or in parallel and then matching the input and the output with a small transformer or a LC circuit. Learning on books is fine, but practicing in your own way is even better. That's my two cents.


Il 05/apr/2020 23:26, <ashok.das81@...> ha scritto:
Hi all,
Can anyone guide me how to use VNA to design crystal filter. I am completely new to this VNA. Many forums mention this abt VNA and crystal filter but i cannot find any proper guide how to design crystal filter using VNA. I will use NANO VNA

Regards
Ashok 

Re: uBitx V5 can't make a contact on ft8

_Dave_ AD0B
 

The height is probably fine.  Is your antenna working, probably not well.

I am using an efhw that is 10' high at one end and 20' at the other end. I have made phone contacts into eastern europe on my ubitx v3 .  The end fed is 64' of wire driven by a  49:1 unun. Resonates well on all ham bands above 40.  On 80 and 160 I am using my big loop.  All done with the same radio.

--
73
Dave
ADOB
Raduino bracket and Ham_Made_Keys

Re: uBitx v.4 build information

Rubens Kamimura
 

Evan,

Ok, tks.

73 de Rubens py2pvb 
--
Saudações fraternais, 73/51 PY2PVB

Rubens Kamimura
Tel. (18) 3746-8680 ramal 116
Cel. (18) 9-9819-2225 WhatsApp ou (18) 9-9819-2255 


Em ter., 7 de abr. de 2020 às 14:16, Evan Hand <elhandjr@...> escreveu:

Rubens,

Most likely it was heat that fried your finals.  Digital modes have been reported to have this issue on all of the uBiTx models, as they keep the transmitter on for 15 seconds at a time at full power.  Before going back on the air I would suggest that you add a fan, larger heatsinks, or both.  Remember that the stock radio does not have electrical isolation of the heatsinks.  Either keep the new heatsinks isolated, or add the insulators for the IRF510s.  The alternative is to reduce the output power with the RV1 adjustment.  I would adjust RV1 using an RF power meter and keep it under 10 watts for 40 meters.  Monitor your finals temperature to verify that they are not getting too hot.  As long as you can keep your finger on them right after the end of transmission, then they should be OK.  I would send a continuous tune signal for at least 15 seconds into a dummy load, turn off the power and immediately check the finals.  I did learn that if you do not turn off the power, there is a large risk that you will move the heatsink and short it out, usually just blowing the fuse.

As to how to set up the bias values for the new finals, there are instructions on the HF Signals and ubitx.net sights.  I have used HF Signals for the bias adjustment:
https://www.hfsignals.com/index.php/ubitx-tuneup/

You should not need to adjust the BFO or frequency calibration.

The above are just suggestions.  There may be better ways to do the testing, however, the ones that I know of would require an IR measurement device.
73
Evan
AC9TU

Re: REPLACEMENT IRF510 ON uBITX V4

Rubens Kamimura
 

Tks
--
Saudações fraternais, 73/51 PY2PVB

Rubens Kamimura
Tel. (18) 3746-8680 ramal 116
Cel. (18) 9-9819-2225 WhatsApp ou (18) 9-9819-2255 


Em ter., 7 de abr. de 2020 às 14:19, Evan Hand <elhandjr@...> escreveu:

I use the HF Signals direction:
https://www.hfsignals.com/index.php/ubitx-tuneup/

Requires an amp meter in the power to the finals, or just look for a difference of 100 ma for each setting.

73
Evan
AC9TU

Re: REPLACEMENT IRF510 ON uBITX V4

Evan Hand
 

I use the HF Signals direction:
https://www.hfsignals.com/index.php/ubitx-tuneup/

Requires an amp meter in the power to the finals, or just look for a difference of 100 ma for each setting.

73
Evan
AC9TU

Re: uBitx v.4 build information

Evan Hand
 

Rubens,

Most likely it was heat that fried your finals.  Digital modes have been reported to have this issue on all of the uBiTx models, as they keep the transmitter on for 15 seconds at a time at full power.  Before going back on the air I would suggest that you add a fan, larger heatsinks, or both.  Remember that the stock radio does not have electrical isolation of the heatsinks.  Either keep the new heatsinks isolated, or add the insulators for the IRF510s.  The alternative is to reduce the output power with the RV1 adjustment.  I would adjust RV1 using an RF power meter and keep it under 10 watts for 40 meters.  Monitor your finals temperature to verify that they are not getting too hot.  As long as you can keep your finger on them right after the end of transmission, then they should be OK.  I would send a continuous tune signal for at least 15 seconds into a dummy load, turn off the power and immediately check the finals.  I did learn that if you do not turn off the power, there is a large risk that you will move the heatsink and short it out, usually just blowing the fuse.

As to how to set up the bias values for the new finals, there are instructions on the HF Signals and ubitx.net sights.  I have used HF Signals for the bias adjustment:
https://www.hfsignals.com/index.php/ubitx-tuneup/

You should not need to adjust the BFO or frequency calibration.

The above are just suggestions.  There may be better ways to do the testing, however, the ones that I know of would require an IR measurement device.
73
Evan
AC9TU

REPLACEMENT IRF510 ON uBITX V4

Rubens Kamimura
 

ALL

I have uBITX v4 and use it only for FT8 in 40m, but the IRF510 outputs are burned, I am changing them, how do I check if the bias and power settings are correct?
a) I check the tension in the GATE or,
b) the current in the DRAIN?
c) the output power on FT8 at 40m (7,074 MHz), adjusted on VR1?

If I choose to use two IRF520 in place of the IRF510, should I make any changes? any recommendations?
73 from py2pvb
--
Rubens Kamimura
Tel. (18) 3746-8680 ramal 116
Cel. (18) 9-9819-2225 WhatsApp ou (18) 9-9819-2255 

Re: uBitx v.4 build information

Rubens Kamimura
 


ALL

I have uBITX v4 and use it only for FT8 in 40m, but the IRF510 outputs are burned, I am changing them, how do I check if the bias and power settings are correct?
a) I check the tension in the GATE or,
b) the current in the DRAIN?
c) the output power on FT8 at 40m (7,074 MHz), adjusted on VR1?

If I choose to use two IRF520 in place of the IRF510, should I make any changes? any recommendations?
73 from py2pvb
--
Saudações fraternais, 73/51 PY2PVB

Rubens Kamimura
Tel. (18) 3746-8680 ramal 116
Cel. (18) 9-9819-2225 WhatsApp ou (18) 9-9819-2255 


Em ter., 31 de mar. de 2020 às 11:49, flatpickn via Groups.Io <flatpickn=yahoo.com@groups.io> escreveu:

Like some other folks, I have an unbuilt v.4. I've waited to build it until the dust settled over the fix for the harmonics and spurs. I've begun putting it together and realized how hard it is to find good information specific to the v.4. Not because it isn't there but because at the time the fixes and mods were written up they weren't identified as v.4. I'm not saying anyone was lacking in any way, it was the current version and people wrote issues, mods, and fixes. They didn't know that we'd later have a v.6 that was quite different from the v.4. 

Based on a comment by Curt in an earlier post (ubitx 4 - want a fresh start, need guidance) he posted a link with some great uBitx v.4 build information.             https://k3pzn.net/ubitx/

I just wanted to put it here with an easily searchable title for other v.4 builders

 

Re: uBitx V5 can't make a contact on ft8

Don - KM4UDX
 

Russ, if you have rig based CAT controlling the PPT and freq change function, and it appears you do, then you are good to go.   

Using a cheap external USB sound card dongle may be better...but...I have never been able to tell a difference between the external sound card dongle and the direct connect between uBITX mic/speaker and the laptop speaker/mic.  But my laptop audio jack broke, so I had to use a external sound card.  Get the $7.99 version if you want to use the external sound card.  Is it better? Beats me. 

You do need some idea of power output, and using the cheapest CB meter will get you started. 

https://www.amazon.com/Astatic-PDC1-100-Watt-Meter/dp/B004ULN610/ref=sr_1_3?dchild=1&keywords=swr+meter&qid=1586276536&sr=8-3

If you hang with any other radio folks, someone will have an old MFJ antenna tuner or SWR/POWER meter that they will pass on to you.  If you find a group of hams, then you will find a group of folks very happy to help you. 

On the topic of tuning your antenna...it is generally a pointless procedure. (Don is ducking now to avoid the flying erasures and tomatoes).  At uBITX power levels, matching the antenna to the uBITX is a fine activity while under CV19 lockdown.  But.  Your antenna and your uBITX will never send a post card saying "thank you", and you will never make a QSO that wouldn't have made without "matching". 

It is good to know you power levels and your SWR. Really good.  But your antenna is what it is, and matching it to your rig makes little difference to the receiving public. And if you jump bands with abandon, then you either "re-match" every time, or you get a automatic antenna tuner with a memory that will snap to your new frequency.  And that complexity will cost you about the same as your uBITX, and produce near zero added value for the uBITX.

Old tube rigs and old timers (said with total respect and humility) have a different view on this. With hundreds or thousands of watts, matching becomes more important. But for us QRP uBITXers, to bother with matching is to stay busy. Not a bad thing at all. And a good learning exercise. But matching will not add any extra FT8 QSOs.

So get a grip on your PWR and your SWR levels, adjust as required, and go fourth into the airwaves. (hahaha...I loved the sound of that!)

Don

Re: uBitx V5 can't make a contact on ft8

Gavin
 

Thanks for the replies! It sounds like my first thing to do is to get it up higher. My best option will be from the top of my roof. 

Does anyone have success with putting this an antenna right on or just above a cement tile roof? I think if i pull it tight from the top to my pergola again, it will be touching to several feet above it on the angle to it. If I decide to leave it slack, it would just be resting on it.

I'm guessing it might not be ideal, but a lot better to be up twice as high or so as it is now, even near the roof.
If that doesn't result in some contacts I'll get a swr meter (maybe I'll get one anyway) to check if I need to make any adjustments to this antenna. 

I'm still waiting for an antenna adapter for my V6 but am interested in setting it up for FT8.  So exactly how did you disconnect the PTT connection on the dongle?I'm not sure how the dpdt switch is connected or when you would activate it.  Sorry for being such a dummy.
I didn't do anything special, (maybe I should have?) although maybe this explains why sometimes when I plug in this way from my usb sound card my radio will just start rapidly switching on and off tx, but it doesn't always do this, only sometimes depending on who knows what? haha I'm the dummy not you :)

Receive Noise with USB #cat

Doug
 

Hi Group
I have an Ubitx V.5 working well. One problem I found is that when I
connect an USB cable to my Ubitx from the computer for CAT control,
my receive level noise increases substantially. I have an USB cable that
is well shielded for RF and the cable has a ferrite bead on each end. The
Ubitx is well grounded. Maybe I'm expecting too much for a under $200 rig.
You can only ask. Hi Hi.... Any suggestions would be welcomed.
Thanks in advance
Doug WA3ZHG

Re: BITX 14MHz Build #bitx20

Aaron K5ATG
 

I’m starting fresh with a blank PCB board.

 

72

Aaron K5ATG

K5ATG Blog

 

From: Arv Evans
Sent: Tuesday, April 7, 2020 10:45 AM
To: BITX20@groups.io
Subject: Re: [BITX20] BITX 14MHz Build #bitx20

 

If you are not using a Bitx pcb, then your question is questionable.  Build instructions are for using a bitx pcb.  For one-off builds using manattan or ugly method you just need to decide your own layout and construction sequence.

 

Arv. K7HKL

_-_

 

 

On Tue, Apr 7, 2020, 6:58 AM Aaron Scott via groups.io <k5atg=yahoo.com@groups.io> wrote:

Hello everyone,
I'm going to start building the BITX 14MHz build. It's going to be my first homebrew transceiver project so I will be learning as I go. The instructions say to solder the transistors first but since this is my first go around, I'm not really sure where I should put them on the PCB. I'm going to use Manhattan construction using the QRPme Little MeSquares. So if anyone has any tips or pointers for a newbie, I will be greatly appreciated.  

 

Re: Calibration needed ? #calibration #v6

Evan Hand
 

Belthur,

Reading between the lines of your post I will assume that you are operating SSB below 10 MHz, lower sideband (LSB), on a v6 uBiTx. 

The issue that is reported to you is that your output signal is bleeding into the upper sideband (USB).  This can be caused by the BFO not in alignment with the SSB filter.  It can also be caused by overdriving the audio input on the rig.

The procedure that Ashhar Farhan outlines in the video post is the correct one for the alignment of the BFO.  Just be careful to go more towards the 3 KHz red marker than the 500 Hz for the BFO adjustment.  As Reed stated, it will sound a little tinny.

Monitoring your signal is the only way short of a spectrum analyzer (SA) to verify your output signal. To check your own signal, you might want to find a Web-based SDR  site to monitor for yourself.  There are a number of them around the work listed at
http://www.websdr.org/
Find one in an area where you have received the bleed issue report if possible, otherwise one that can hear your transmission.

If you do want to go the SA route, I have been having good results recently with an RSP2 SDRPlay.  They no longer make that model, however, the specifications of the RSP1a are better and list price is currently $109 US.  The SA software is free and is now able to do all of the signal purity measurements that the prior releases could not. You will also need a directional tap. I made one from this article: 
http://www.ad5x.com/images/Articles/Tap50dbRevA.pdf
And a step attenuator like this one:
https://www.ebay.com/itm/NEW-0-82DB-VARIABLE-STEP-ATTENUATOR-OHM-for-Ham-Radio-Transmitter-DC-to250MHZ/183306489164?hash=item2aadeb0d4c:g:~scAAOSwCTBbPGyN
So far this is the lowest cost approach that I have found for a SA.  The total cost including all parts, adapters, and cables should be less than $200 US, less if you shop around.  There is a homebrew SA built with parts from eBay that I plan to try.  I do not recommend an RTL-SDR dongle, the RF Explorer, nor the Analog Discover 2.  I have tried all three and they have not produced results that are consistent or require multiple setups to do the harmonic tests.  This is not the case that others have reported, so it may be that I do not have the correct setup for them.

Above are just suggestions, you are responsible for the signal purity of your radios.
73
Evan
AC9TU

Re: Find an older style Raduino #raduino

 

There seem to be many Raduino PCB patterns in the files section here.

73,


Mark