Re: 2nd run of the spectrum test on the V5
#ubitx
Hi Jim
Have you run these tests on any other radios yet. Say your k3? Something that is supposed to be top notch.
Sounds like a neat tool.
Dave
|
2nd run of the spectrum test on the V5
#ubitx
I wasn't totally happy with the screen captures I got yesterday when I posted the initial spectrum test with the new SSA 3021x spectrum analyzer so I re-ran them this morning and paid a lot more attention to detail.? I set the fundamental carrier as close to 0db as I could get it (20 meters is the only one that wouldn't quite get there by about 2dB so you'll have to do the math on that one but it is not really pretty. My 2nd V5 board should be here tomorrow (latest Wednesday) as it's left DHL Leipzig, Germany enroute their Cincinnati customs inspection point before continuing to Wichita, KS and as soon as I get it, I'll put it in the test fixture so I can run the same tests on it before building it into a new case.? Someone mentioned open frame coupling to the spectrum analyzer so I covered everything with a metal cooking pan and used short clip leads to ground the pan to the rig.? I did not notice any difference in readings with the shield over the rig vs removed so I left it in place just to be sure. This time I ran through all the bands the stock uBITX covers - 80/60/40/30/20/17/15/12 and 10 meters.? Each plot is labeled by band in the screen shots attached.? None of the pictures are edited and I tried to make sure the markers were close to the right frequency peak with marker 1 as fundamental, 2 as 2nd harmonic, 3 as third and 4 as fourth.? Only have the luxury of 4 on screen markers so the 5th harmonic and beyond if even present in the display will have to be taken for granted. As stated before in yesterday's thread, I do not have a two-tone test oscillator (yet) so no SSB spur pix until I get one.? If someone else with a decent spectrum analyzer wants to do them in my stead, please do so as it will probably be a couple weeks before Pacific Antenna ships me the kit and a couple hours after that to build it. Here are the pix from today's spectrum tests - SSA 3021X Spectrum Analyzer, 50 ohm RF sampler with variable attenuator and terminated by a Microwave Associates 50 ohm, 20 watt dummy load.? No actual power measurements were taken at this time, only checking for harmonic levels related to the fundamental carrier level in dB. Jim Sheldon, W0EB TSW Project Coordinator         
|
Re: Bitx-40 Arrived Today - Advice Solicited on My Plan
OK then, assembly and testing at the bench before it goes in the case!
Assemble it and test it to make sure it works. Are you going to do the amunter mods to add CW, etc? If so, just assemble it and make the mods one at a time and test.?
When you have a fully functional radio put it in the case and keep the wires as short as possible. Twist the wires going to each jack, plug, button, etc. Make sure you have a common ground for everything.?
If going in a plastic or wood case you don¡¯t have a case to provide a common ground. Connect negative and antenna ground to the corner of the board with a ground lug. All control grounds also need to be connected to the board as well. Use a ground lug on the corners, keeping the wires short as possible. Thanks, good suggestions all. I assume you do as much of the wire up as possible on the bench, and then put it in the case?
Pat
Just a few things. I would do some partial assembly of the raduino, main board etc to get a feel for things. Many in qrp community like bnc, of course idea is to do it the way you want it. For some folk in the world, that ptt and microphone element get them on the air. Yes normally open ptt.
I suggest wiring up both headphone and speaker. You may find audio output lacking to drive a speaker. Some folk use an external amplified speaker, or add an internal audio amplifier.
I suggest you visit some websites from around the world that describe bitx assembly.
Curt
|
Re: Initial spectrum test on the V5 with my new spectrum analyzer
#ubitx
Not a problem, Jim. When I get mine I'll do the test. For spurs you shouldn't need a two-tone generator, just a simple audio oscillator. You might want to make sure you aren't seeing some kind of weird coupling on 20m between the SA and the rig since you have it open frame. Like sticking a big metal box down over the ubitx while transmitting to see if it changes the level on the SA. In any case, it looks like v5 was worth waiting for! Thanks, tim ab0wr On Sun, 24 Feb 2019 20:03:07 -0600 "Jim Sheldon" <w0eb@...> wrote: I'll let someone else do those. I only operate CW myself and don't
even have a microphone made up for any of my uBITX rigs.
On Feb 24, 2019, at 7:31 PM, Tim Gorman <tgorman2@...> wrote:
Nice job.
It looks like all the bands except 20m are pretty good. I assume
this was straight cw. I don't see any spurs.
It would be interesting to see the same sweeps with an audio tone
feeding the microphone for the same output levels. That would get
all the mixers into play as well.
I assume you are going to do two-tone and carrier suppression tests
at some point? I'm waiting on my v5 to come. I ordered back on 2/7
like Ron did but I've not heard anything on it. When I get it going
I'll duplicate your measurements using my less expensive Rigol 815!
tim ab0wr
On Sun, 24 Feb 2019 14:24:04 -0800
"Jim Sheldon" <w0eb@...> wrote:
My wife was very nice to me and bought me a brand new Siglent SSA
3021X spectrum analyzer for my upcoming 77th birthday.
I have 1 Version 5 uBITX and another on the way. The one I have I
built up on my old, ugly open frame aluminum chassis for ease of
getting at test points, etc. I did not do a power output check,
but during my spectral purity tests into a 20 watt dummy load, it
was warming up the load pretty good even on 10 meters with the
power control right where the factory set it.
Attached pictures are screen saves from the spectrum analyzer
in .jpg format as they were being measured. No editing has been
done on any of them. As I was uploading the pictures, I realized
I did not save pictures for 30 and 12 meters so I'll re-do them
and post the results at a later date. These are posted "as-is"
for people to see and make their own conclusions from them.
Though I got a calibration certificate with it from the Siglent
factory, I don't know how far I can trust that. I do have a GPS
Disciplined oscillator feeding the 10 MHz external reference. As I
get more experience with the SA, I may be able to get closer
indications that this first run, right out of the box.
Jim Sheldon, W0EB
TSW Project Coordinator
-=-=-=-=-=-=-=-=-=-=-=-
Groups.io Links: You receive all messages sent to this group.
|
Harvey
I am not familiar with what these voltages should be, but a factor of 10 in voltage doesn't readily sound excessive. I honestly would consider whether your microphone is giving enough drive, or are you testing with an audio generator?? I am doing fine with a surplus HT hand mike, while other local builders aren't satisfied and the are adding audio gain.
Curt
|
What frequency is the signal going INTO the 45MHz filter?
-a
On Mon, 25 Feb 2019 at 09:42, Harvey < mandh@...> wrote: I'm troubleshooting low SSB output, about 2 watts, from my V4 uBITX. In making measurements I find I have a 400mv SSB signal going into the 45MHz filter, Y1, but only 40mv coming out of the filter at at C214/C215 junction. This 20db loss through the 45MHz filter seems extreme to me. Could I have a bad crystal filter since I'm measuring the signal levels at the input/output of the crystal filter? Any suggestions appreciated.
Harvey, WA2AAE
|
Re: Bitx-40 Arrived Today - Advice Solicited on My Plan
Assemble it and test it to make sure it works. Are you going to do the amunter mods to add CW, etc? If so, just assemble it and make the mods one at a time and test.?
When you have a fully functional radio put it in the case and keep the wires as short as possible. Twist the wires going to each jack, plug, button, etc. Make sure you have a common ground for everything.?
If going in a plastic or wood case you don¡¯t have a case to provide a common ground. Connect negative and antenna ground to the corner of the board with a ground lug. All control grounds also need to be connected to the board as well. Use a ground lug on the corners, keeping the wires short as possible.
Thanks, good suggestions all. I assume you do as much of the wire up as possible on the bench, and then put it in the case?
Pat
Just a few things. I would do some partial assembly of the raduino, main board etc to get a feel for things. Many in qrp community like bnc, of course idea is to do it the way you want it. For some folk in the world, that ptt and microphone element get them on the air. Yes normally open ptt.
I suggest wiring up both headphone and speaker. You may find audio output lacking to drive a speaker. Some folk use an external amplified speaker, or add an internal audio amplifier.
I suggest you visit some websites from around the world that describe bitx assembly.
Curt
|
I'm troubleshooting low SSB output, about 2 watts, from my V4 uBITX. In making measurements I find I have a 400mv SSB signal going into the 45MHz filter, Y1, but only 40mv coming out of the filter at at C214/C215 junction. This 20db loss through the 45MHz filter seems extreme to me. Could I have a bad crystal filter since I'm measuring the signal levels at the input/output of the crystal filter? Any suggestions appreciated.
Harvey, WA2AAE
|
Re: Initial spectrum test on the V5 with my new spectrum analyzer
#ubitx
Didn't mean to confuse anyone,
Thought I'd talked about the new layout making for improvements?? But made a mistake mentioning yours as a V4 when it's a V5 so sorry about that.? Regardless, all my measurements and pictures state that it is from a V3.
73,
Mark.
|
Re: Initial spectrum test on the V5 with my new spectrum analyzer
#ubitx
Jim,
I have used the following tone generator on my PC with a simple jumper cable made from a PC headphone jack and the standard Tip Ring Sleeve that us used in the uBitx.? I also added a slide switch to put the rig in transmit mode so I would have my hands free to adjust things.
Generator:
I had actually run the tone generator on a laptop, and an audio spectrum analyzer on a desktop to validate the purity of the signal.? It was better than the signal from the dual transistor generator circuit, and just as good as a kit I bought.? The advantage is you can adjust tones and volume on the software version, while you do not have the capability on either the 2 transistor tone generator, or the kit.? For those the tones are fixed.
73
Evan
AC9TU
|
Re: Initial spectrum test on the V5 with my new spectrum analyzer
#ubitx
The way you stated it though might have confused newbies. ?You need to make certain they know WHY you are posting V3/V4 info in relation to V5, not just post your measurements. ?If you don't you might scare some away from the improved (but not totally right yet) Version 5. ?I'm not absolutely certain my tests were done correctly and have stated that. ?I intend to re-run them and also run the SSB spur tests when I get my hands on a 2 tone generator which I don't currently have.
Not being critical here, just trying to clarify things so the guys just getting into this don't get confused with conflicting data. ?The V5 is too new yet and not all who ordered them have them in hand yet.
Jim
------ Original Message ------
Sent: 2/25/2019 10:01:12 AM
Subject: Re: [BITX20] Initial spectrum test on the V5 with my new spectrum analyzer #ubitx
Once again,
Yes Jim I understand that.? I thought you/we/someone might be interested in seeing the improvements in the new version.
Anyway, your tests are fun to see.? Thanks for all your efforts!? It must be great to have such a nice new instrument, and I am sure there is tons to learn about all the measurements you can make with it.
73,
Mark.
|
Andy, Well, that's over my head. I did get some PCB's from a Chinese firm using these files, but as I've not built it up yet, I have no idea whether or not it's done right. I have no problems reading schematics, but I'm out of my league when it comes to designing a PCB from a schematic.
Ben - K6QV
|
Re: Initial spectrum test on the V5 with my new spectrum analyzer
#ubitx
Once again,
Yes Jim I understand that.? I thought you/we/someone might be interested in seeing the improvements in the new version.
Anyway, your tests are fun to see.? Thanks for all your efforts!? It must be great to have such a nice new instrument, and I am sure there is tons to learn about all the measurements you can make with it.
73,
Mark.
|
Hi Doug
Sorry, making assumptions here.
It's the uBITX multiband radio.
I did get this a few weeks ago from HFsignals.com.
Bob
On 25/02/2019 15:12, Doug W wrote:
Bob,
What radio do you actually have?? This list covers the entire BITX
family.? The name is a hold over from Farhan's first BITX, the 20.?
You referred to a BITX20 kit delivered via India post so I am
assuming you bought it from HFsignals.com.? If that is correct,
they currently sell two transceivers neither of which is the BITX20.?
The BITX40 that covers the 40m band and the ?BITX
that is a multi band radio.? There are also BITX20 kits in the
wild so I may be off base in my assumptions.? Either way, once we
know what you have we can be of more help.
--
--
Bob Head, Rotronics Systems Limited, 01252 722686
|
No paste
No problem? Sorry to hear about your friend.?
Thanks for the status update
Dan W3BU
toggle quoted message
Show quoted text
On Feb 25, 2019, at 2:26 AM, N8DAH < Dherron@...> wrote: Just wanted to update people on the status of this. We had a delay at the fab house, boards are in product and we hope to have them soon!
I have had a death of a very close friend and will be out of town this coming weekend. If you have any questions please e-mail info@... and Tim or myself will be able to get back with you.
I truly apologize for the delay, we will have more ready once they arrive and we fulfill the pre-orders.
--
David
?N8DAH
|
Bob,
What radio do you actually have?? This list covers the entire BITX family.? The name is a hold over from Farhan's first BITX, the 20.? You referred to a BITX20 kit delivered via India post so I am assuming you bought it from HFsignals.com.? If that is correct, they currently sell two transceivers neither of which is the BITX20.? The BITX40 that covers the 40m band and the ?BITX that is a multi band radio.? There are also BITX20 kits in the wild so I may be off base in my assumptions.? Either way, once we know what you have we can be of more help.
--
|
Re: Initial spectrum test on the V5 with my new spectrum analyzer
#ubitx
All, I was going to say "let someone who operates SSB do this", as I don't even have the microphone audio connected on any of my uBITX radios, but I came to the conclusion that I'd be doing the group a disservice by not doing all the testing. ?Also, there have been several comments from people saying my results were quite different from theirs, but they were comparing the older V3 boards to what I posted for the NEW Version 5's. ?
I do not currently have a two-tone test generator, so I just ordered a kit from "Pacific Antenna" for $49.50 ($45 plus $4.50 shipping). ?When that gets here and I get it built (may be a couple weeks) I'll connect the microphone audio to a front panel jack on my "ugly open frame V5" and run the two tone test to see if I can't capture any spurs on screen (I'm sure there will be some - hopefully minimal) and post them here.
I'm still learning the SSA3021x, so if anyone on this list has the same SA and knows how to properly set it up to measure the spurs from such a two tone test, I'd appreciate some setup info. That would help get me in the right area and I surely would learn something new. ?At almost 77, that is easy to do, but retention of the information is the difficult part - LOL.
Please remember, I have a Siglent SSA 3021x, NOT a RIGOL and setup for the RIGOL will almost certainly be different (how much I don't know) from the Siglent.
I'm trying to get this stuff right and be objective rather than alarming. ?I'm not sure I had all the settings right on the preliminary harmonic tests and plan on re-running them (with subsequent posts here) so people can compare the readings. ?My original spectrum analyzer was an old GW Instek GSP-810 and it was quite limited in what you could set it up to do. Also it had come out of a Tech School environment so it's calibration was certainly in question. ?The new SA came with a Calibration Certificate from the factory and hopefully will be much more accurate as far as measurements are concerned.
I have a second V5 uBITX on order and it has been shipped. ?DHL tracking shows it having left Bangalore India so it's somewhere between Bangalore and Leipzig, Germany which is the path they usually take when coming my way. ?Projected delivery date is this coming Wednesday (Central US time). ?Once I get it in a case with one of our BITeensio cards and a 3.2" Color TFT touch screen display, I'll run that one through the tests as well for comparison.
Jim Sheldon, W0EB TSW Project Coordinator
------ Original Message ------
Sent: 2/24/2019 9:18:01 PM
Subject: Re: [BITX20] Initial spectrum test on the V5 with my new spectrum analyzer #ubitx
Jim
Nice work with the new instrument.? I don't think too many of us are concerned with the frequency accuracy, relative measurements of spurious are wonderful data.
Sure start with cw, but if you have a simple audio oscillator (I use the one on 4stateqrp rf test set) others will be curious on the ssb path.
73 Curt
|
Hello all.
I've just received my new BITx20 transceiver via IndiaPost.
It arrived quicker than predicted and the 'kit' is very nicely assembled.
Checked it mechanically and all is well, toroids all connected.
Reading the notes the designer mentions 'better than 0.1uV sensitivity.'
Having lashed it together on the bench it seemed a bit deaf, I checked everything was connected as per the instructions, but still the same.
Compared sensitivity with my Yaesu and that was much more sensitive.
So out with the Marconi signal generator, the Yaesu sensitivity is about 1uV and a reasonable tone heard. The BITX20 was more like 100uV to get a reasonable tone heard.
That was at 7MHz but it's the same at other frequencies.
I'm happy to do some research, but thought I had better see if anybody out there has had a low sensitivity unit?
Thanks for any assistance,
BobM0RHE
toggle quoted message
Show quoted text
--
Bob Head, Rotronics Systems Limited, 01252 722686
|
Re: Initial spectrum test on the V5 with my new spectrum analyzer
#ubitx
Mark, You're comparing apples to oranges here. ?My tests were on the new Version 5 board with the new LPF switching sequence and new IF frequency, NOT a V3 or V4. ?
Jim
toggle quoted message
Show quoted text
On Feb 24, 2019, at 9:08 PM, Mark McNabb < n7eku@...> wrote: Hi Jim,
Good for the sampler -- wanted to make sure I was reading the pictures correctly as the print is a bit small (and doing my math correctly).
Yes, I understand you are checking for harmonics. You mentioned calibration so that got me thinking you were concerned about power accuracy.? My mistake.
If interested, you can check your results against mine.? In the files section I have a spreadsheet under my callsign with harmonics and power out measurements.
Also in the photos section under my callsign, I posted pictures of my SA measurement screen.? In all pictures I centered the fundamental near the zero reference line (2nd peak from the left).? I used a 20dB power attenuator then a selectable low power attenuator as needed.? These measurements were done with CW as well.? On a v3 board as delivered.
My 20m looked a lot different from yours.? 80, 40, and 30m showed a lot of upper harmonics getting past the LPF -- probably why there are alternate filter plans for these now and a new layout I think on your v4 board...?? There's less of this on 20m and above, but there's also way way less power.? Power max was 14.5W on 75m and goes down to 0.7W on 10m.
73,
Mark - N7EKU
|
Re: Bitx-40 - Where I Am Today
Exactly Frahan. I have never bought a commercial antenna and have always made my own including a 2 El Quad for 20, 15 and 10M.
This includes antennas from 160 to 2M, including 6 and 4M.
Have a look at a simple vertical using a fibreglass extendable fishing rod.
I used to do the MARL Magazine between 2005 - 2011 in both Maltese and English, but then other priorities and lack of time took over. You can go to? and download all the issues? Regards Lawrence
On Mon, Feb 25, 2019 at 3:59 AM Ashhar Farhan < farhanbox@...> wrote: Why would you buy it? Just get 66 feet of any wire from home depot and wind your own transformer. - f
On Mon 25 Feb, 2019, 3:30 AM Truffies, < truffies@...> wrote:
look at;? ?
-----Original Message-----
>From: Donald <donwestpwl@...>
>Sent: Feb 24, 2019 2:37 PM
>To: [email protected]
>Subject: Re: [BITX20] Bitx-40 - Where I Am Today
>
>Pat,
>
>I have heard that end-fed antennas are becoming popular with RVers.
>Palomar is just one company selling them:
>
>
>
>Their site also has some information on that type of antenna.
>
>Donald, KB5PWL
>
>
>
>
|
_Dave_ AD0B
Jim Sheldon