Topics

Yet Another Network Analyzer (Yana)

Thomas Berger
 

Hi


I'm uploading files on Yana (Yet Another Network Analyzer) in the footsteps of PHSNA.  My goals are:

1. Easy to dupllcate.

2. Low in cost.

3. Self-contained, complete, and handheld.

At this point Yana has:

1.  Scalar Network Analyzer.

2. SWR Meter/Antenna Bridge.

3. Power Meter.

I left the pictures in the Build file big so people could enlarge them.  So I don't know how to add it (100Mb) with a 10Mb upload limit.  Yana has been working for over a year and I have built a prototype and a "release" model.  Yana is 3 3/4x2 5/8x1 7/8 (100x68x50). Color TFT screen.  One knob with built in button.  Run by an Arduino Nano. Needs 7-12v batteries. (I use two 18650 Li-Ion from a dead laptop.) Yana is mostly eBay modules plugged together with pin headers.  So wiring is mostly just making the wiring harness for which I have a Fritzing color picture.  Lots of photos in the build instructions.  All current stuff is in the folder Yana_K1TRB.


To give some idea, I've uploaded one picture of the prototype (different case) measuring a 6m bandpass filter and response graph of an 80m bandpass filter.


Unless someone has a hint, I will chop the Build instructions into many 10Mb files.  Email me at trberger@... if you want to transfer the Build document via the web.  (Explain your best way.)


There's more, preliminary notes exist for Design and Operation.  Further, I am working on a sequence of Experiments that show how to use Yana in its various modes.  (There are two different 40db taps enabling power measurements to 100 watts.)


Since I am the only one using Yana, I consider her to be in beta.  


Anybody interested?


regards

tom

.

k1trb



Nick Kennedy
 

Sounds great so far and it seems you've put in a lot of work already.  Good luck with it.

73-

Nick, WA5BDU

Thomas Berger
 

I compressed all the pictures and uploaded the Build instructions.

Everything is here to duplicate Yana.

I believe it is the easiest PHSNA to make.

regards
tom
.
k1trb

EB4APL
 

I would add some pictures of the YANA working. I would like to see the screen in operation.

I own an original PHSNA and I'm very satisfied with it, but I'm following this new project with great interest.

73 de Ignacio, EB4APL


El 12/02/2017 a las 6:39, 'charudatt uplap' charudattu@... [PHSNA] escribió:
 

Hello Tom,

 

Looks like you have taken a lot of efforts in creating a folder and uploading all your stuff into that, a little more efforts and you could have also included the YANAxx.ino file and a schematic of the project.

 

I know nothing different, but it would have served someone better.

 

regards

charudatt – vu2upx

 

From: PHSNA@... [mailto:PHSNA@...]
Sent: Sunday, February 12, 2017 10:51 AM
To: PHSNA@...
Subject: [PHSNA] Re: Yet Another Network Analyzer (Yana)

 

 

I compressed all the pictures and uploaded the Build instructions.

 

Everything is here to duplicate Yana.

 

I believe it is the easiest PHSNA to make.

 

regards

tom

.

k1trb

 


Posted by: "charudatt uplap"

EB4APL
 

Well, the pictures are there, I had missed them.

Ignacio, EB4APL


El 12/02/2017 a las 14:45, EB4APL escribió:

I would add some pictures of the YANA working. I would like to see the screen in operation.

I own an original PHSNA and I'm very satisfied with it, but I'm following this new project with great interest.

73 de Ignacio, EB4APL


El 12/02/2017 a las 6:39, 'charudatt uplap' charudattu@... [PHSNA] escribió:
 

Hello Tom,

 

Looks like you have taken a lot of efforts in creating a folder and uploading all your stuff into that, a little more efforts and you could have also included the YANAxx.ino file and a schematic of the project.

 

I know nothing different, but it would have served someone better.

 

regards

charudatt – vu2upx

 

From: PHSNA@... [mailto:PHSNA@...]
Sent: Sunday, February 12, 2017 10:51 AM
To: PHSNA@...
Subject: [PHSNA] Re: Yet Another Network Analyzer (Yana)

 

 

I compressed all the pictures and uploaded the Build instructions.

 

Everything is here to duplicate Yana.

 

I believe it is the easiest PHSNA to make.

 

regards

tom

.

k1trb

 


Posted by: "charudatt uplap"

Pravin
 

Just had a preliminary glance through the YANA files posted yesterda. Is it possible to have an addon bigger display with greater resolution ? Also can anybody write a code for Si570 VHF/UHF chip so that we can have truly versatile PHSNAs from HF through 1GHz ! We can get sample chips directly from Silicon Labs free of cost!
Thanks Tom for the potentially useful YANA with no tither to a computer.

73
DE AB9XC
(Pravin )

--------------------------------------------

On Sun, 2/12/17, EB4APL eb4apl@... [PHSNA] <PHSNA@...> wrote:

Subject: Re: [PHSNA] Re: Yet Another Network Analyzer (Yana)
To: "PHSNA@..." <PHSNA@...>
Date: Sunday, February 12, 2017, 9:31 AM

Well, the pictures are
there, I had missed them.

Ignacio, EB4APL


El 12/02/2017 a las 14:45,
EB4APL escribió:
>
>
I would add some pictures of the YANA working. I would like
to see the
> screen in operation.
>
> I own an original
PHSNA and I'm very satisfied with it, but I'm
> following this new project with great
interest.
>
> 73 de
Ignacio, EB4APL
>
>
> El 12/02/2017 a las 6:39, 'charudatt
uplap' charudattu@...

> [PHSNA] escribió:
>>
>> Hello Tom,
>>
>> Looks like
you have taken a lot of efforts in creating a folder and
>> uploading all your stuff into that, a
little more efforts and you
>> could
have also included the YANAxx.ino file and a schematic of
the
>> project.
>>
>> I know
nothing different, but it would have served someone
better.
>>
>>
regards
>>
>>
charudatt – vu2upx
>>
>> *From:*PHSNA@...
[mailto:PHSNA@...]
>> *Sent:* Sunday, February 12, 2017
10:51 AM
>> *To:* PHSNA@...
>> *Subject:* [PHSNA] Re: Yet Another
Network Analyzer (Yana)
>>
>> I compressed all the pictures and
uploaded the Build instructions.
>>
>> Everything is here to duplicate
Yana.
>>
>> I
believe it is the easiest PHSNA to make.
>>
>> regards
>>
>> tom
>>
>> .
>>
>> k1trb
>>
>>
>>
------------------------------------------------------------------------
>> Posted by: "charudatt uplap"
<charudattu@...>
>>
------------------------------------------------------------------------

Nick Kennedy
 

​The problem with the Si570 for this application is that it has a square wave output. The test signal from the PHSNA needs to be as free of harmonics as possible.

73-

Nick, WA5BDU​


Also can anybody write a code for Si570 VHF/UHF chip so that we can have truly versatile PHSNAs from HF through 1GHz ! We can get sample chips directly from Silicon Labs free of cost!


Pravin
 

Hi Nick,
                Thanks for responding to my post promptly. Yes I understand many of these DDS and Clock generators like Si570 does not give sine wave output . But I think introducing frequency dependent Low Pass Filters at appropriate intervals can solve the problem. For a SNA to work from 30MHz to about 960 MHz using Si570 chip according to my calculations it may require at the maximum 5 switchable LPFs with appropriate cutoffs . If we use Arduino NANO it is having at least 8 analog pins out of which 5 we can easily dedicate to automatically switch filters in and out of the circuit depending on frequency. It may not be as compact as current PHSNA but nevertheless using miniature VHF/UHF relays and SMT components for filter part it can be made fairly compact.
              Sometime ago I built a similar one for the HF portion from 3MHz to 30MHz to use as a local Oscillator for a receiver project as the AD9850 I find rich in harmonics especially at the lower frequencies.
               Kindly let me know about your thoughts on the same.

73
DE AB9XC
(Pravin)
 




From: "Nick Kennedy kennnick@... [PHSNA]"
To: PHSNA@...
Sent: Sunday, February 12, 2017 9:38 AM
Subject: Re: [PHSNA] Re: Yet Another Network Analyzer (Yana)

 
​The problem with the Si570 for this application is that it has a square wave output. The test signal from the PHSNA needs to be as free of harmonics as possible.

73-

Nick, WA5BDU​


Also can anybody write a code for Si570 VHF/UHF chip so that we can have truly versatile PHSNAs from HF through 1GHz ! We can get sample chips directly from Silicon Labs free of cost!




Thomas Berger
 

Hi

just moved tons of snow anticipating a very big storm.  My hands are shaking.  Broke a shear pin.  Well ... it is beautiful.

Thanks for the quick replies.  There are many choices for PHSNA now.  DuWayne's is an excellent one.  So is Midnight Solutions NAT.  All of these 
violate one or more of my goals.  With other excellent choices, I won't be 
deviating from those goals with Yana.  I think currently Yana is about $40.
You can browse eBay and make your own estimate.  The parts list is in
Parts.  There are no PCB's to buy, make, or populate.  Oh, at this price, you
will accept compromises.

The C code supporting Yana is flexible.  It is evolving so needs some cleaning.
But others could implement much larger screens.  Touch screens are not included
and may require more work (which I won't be doing).  Incidentally, I tried a slightly larger screen and did not like the results.  The ST7735 128x160 screen is very 
bright and vivid.  I'll post a scan and the Home screen from the prototype.  If you 
want very high resolution then build PHSNA and connect it to your computer.

Saving data is not yet implemented but is part of the plan.  

I have, in rough draft, experiments on how to both measure and tune filters 
(Dishal's method).  Measurement of a wideband amplifier.  With two possible 40db
 taps (of different design), measurements of the power output of my Icom 718 
tansceiver from 1 to 100 watts on all bands.  I have a list of experiments hams do
frequently and plan to do them and write them up.  I helped a friend tune up a random wire antenna.  (If you have not done this with a scanning swr bridge
then you ought to.  Tuning becomes a no brainer.  Just move the swr dip to 
where you want it, then optimize.)  I plan to do my W0BTU 75ohm version
of the G5RV antenna and write that up.

I can measure the performance of Yana (and have done some of that in the 
design) and will do that and write it up.  Alas, everything takes time and at my
age, I'm slow.

I'm hoping I get some duplicators who then can help make Yana better and easier.

regards
tom
.
k1trb




Hans Summers
 

Hi all

I recently did a similar experiment, at HF only, using the QRP Labs Si5351A $33 Synth VFO/SigGen kit http://qrp-labs.com/vfo which has a sinewave output. I wanted to try the results of a switched LPF to attenuate the harmonics and turn it into a sinewave. So I also used the QRP Labs 6-band relay switch http://qrp-labs.com/ultimatelpf and six LPF kits http://qrp-labs.com/lpfkit for 60, 40, 30, 20, 15 and 10m. 

The result was that over the range 2.9MHz to 34MHz, I had a sinewave output 10.8dBm +/- 0.4dBm (very nice and flat), and the worst case harmonic was -45dBc. Pretty good results! Here's a chart of my measurement:
and here's a chart over the wider range 1 to 45MHz. Below 2.9MHz the harmonic content rises because the lowest filter is 60m (5MHz); above 34MHz the fundamental starts to drop off because of the highest filter 10m (30MHz). 

It's worth mentioning also that no optimisation was done here. The frequencies where the filter is switched were just set, without measurement of cut-off frequencies, at 5, 7, 10, 14 and 21MHz. No measurement of inductors was done in building the LPFs or measurement on a spectrum analyser. Just counting turns as per the assembly instructions. The unit lay unshielded on the workbench. Still, good performance in this worst case construction! 

The frequency range can be widened, or less LPFs needed, if you choose a 2:1 ratio between adjacent LPFs. However the harmonic content does increase in that case because at certain frequencies the 2nd harmonic has no attenuation at all. I measured -23dBc harmonic content at some frequencies, when using a 2:1 filter ratio. 

73 Hans G0UPL



Thanks for responding to my post promptly. Yes I understand many of these DDS and Clock generators like Si570 does not give sine wave output . But I think introducing frequency dependent Low Pass Filters at appropriate intervals can solve the problem. For a SNA to work from 30MHz to about 960 MHz using Si570 chip according to my calculations it may require at the maximum 5 switchable LPFs with appropriate cutoffs . If we use Arduino NANO it is having at least 8 analog pins out of which 5 we can easily dedicate to automatically switch filters in and out of the circuit depending on frequency. It may not be as compact as current PHSNA but nevertheless using miniature VHF/UHF relays and SMT components for filter part it can be made fairly compact.

Sandeep Lohia
 

 Possible to display results on Android phones ?

On Feb 13, 2017 12:36 PM, "Hans Summers hans.summers@... [PHSNA]" <PHSNA@...> wrote:
 

Hi all

I recently did a similar experiment, at HF only, using the QRP Labs Si5351A $33 Synth VFO/SigGen kit http://qrp-labs.com/vfo which has a sinewave output. I wanted to try the results of a switched LPF to attenuate the harmonics and turn it into a sinewave. So I also used the QRP Labs 6-band relay switch http://qrp-labs.com/ultimatelpf and six LPF kits http://qrp-labs.com/lpfkit for 60, 40, 30, 20, 15 and 10m. 

The result was that over the range 2.9MHz to 34MHz, I had a sinewave output 10.8dBm +/- 0.4dBm (very nice and flat), and the worst case harmonic was -45dBc. Pretty good results! Here's a chart of my measurement:
and here's a chart over the wider range 1 to 45MHz. Below 2.9MHz the harmonic content rises because the lowest filter is 60m (5MHz); above 34MHz the fundamental starts to drop off because of the highest filter 10m (30MHz). 

It's worth mentioning also that no optimisation was done here. The frequencies where the filter is switched were just set, without measurement of cut-off frequencies, at 5, 7, 10, 14 and 21MHz. No measurement of inductors was done in building the LPFs or measurement on a spectrum analyser. Just counting turns as per the assembly instructions. The unit lay unshielded on the workbench. Still, good performance in this worst case construction! 

The frequency range can be widened, or less LPFs needed, if you choose a 2:1 ratio between adjacent LPFs. However the harmonic content does increase in that case because at certain frequencies the 2nd harmonic has no attenuation at all. I measured -23dBc harmonic content at some frequencies, when using a 2:1 filter ratio. 

73 Hans G0UPL



Thanks for responding to my post promptly. Yes I understand many of these DDS and Clock generators like Si570 does not give sine wave output . But I think introducing frequency dependent Low Pass Filters at appropriate intervals can solve the problem. For a SNA to work from 30MHz to about 960 MHz using Si570 chip according to my calculations it may require at the maximum 5 switchable LPFs with appropriate cutoffs . If we use Arduino NANO it is having at least 8 analog pins out of which 5 we can easily dedicate to automatically switch filters in and out of the circuit depending on frequency. It may not be as compact as current PHSNA but nevertheless using miniature VHF/UHF relays and SMT components for filter part it can be made fairly compact.


EB4APL
 

I would be interested in the Si5351 solution for the higher frequencies only, say 60 to 200 MHz and maybe higher, which would be easier to filter. It could be conceived as an extension to the current PHSNA which already covers the HF region.

Another solution which could be explored id to use the AD9851 above the Nyquist limit, using the sampling images. Analog Devices application notes AN-939 is about this topic and this also is used in AN-543.

An alternative would be using the AD9912 which can generate directly up to 500 MHz, but I assume it could be pricey.

Regards,

Ignacio, EB4APL


El 13/02/2017 a las 8:00, Hans Summers hans.summers@... [PHSNA] escribió:
 
Hi all

I recently did a similar experiment, at HF only, using the QRP Labs Si5351A $33 Synth VFO/SigGen kit http://qrp-labs.com/vfo which has a sinewave output. I wanted to try the results of a switched LPF to attenuate the harmonics and turn it into a sinewave. So I also used the QRP Labs 6-band relay switch http://qrp-labs.com/ultimatelpf and six LPF kits http://qrp-labs.com/lpfkit for 60, 40, 30, 20, 15 and 10m. 

The result was that over the range 2.9MHz to 34MHz, I had a sinewave output 10.8dBm +/- 0.4dBm (very nice and flat), and the worst case harmonic was -45dBc. Pretty good results! Here's a chart of my measurement:
and here's a chart over the wider range 1 to 45MHz. Below 2.9MHz the harmonic content rises because the lowest filter is 60m (5MHz); above 34MHz the fundamental starts to drop off because of the highest filter 10m (30MHz). 

It's worth mentioning also that no optimisation was done here. The frequencies where the filter is switched were just set, without measurement of cut-off frequencies, at 5, 7, 10, 14 and 21MHz. No measurement of inductors was done in building the LPFs or measurement on a spectrum analyser. Just counting turns as per the assembly instructions. The unit lay unshielded on the workbench. Still, good performance in this worst case construction! 

The frequency range can be widened, or less LPFs needed, if you choose a 2:1 ratio between adjacent LPFs. However the harmonic content does increase in that case because at certain frequencies the 2nd harmonic has no attenuation at all. I measured -23dBc harmonic content at some frequencies, when using a 2:1 filter ratio. 

73 Hans G0UPL



Thanks for responding to my post promptly. Yes I understand many of these DDS and Clock generators like Si570 does not give sine wave output . But I think introducing frequency dependent Low Pass Filters at appropriate intervals can solve the problem. For a SNA to work from 30MHz to about 960 MHz using Si570 chip according to my calculations it may require at the maximum 5 switchable LPFs with appropriate cutoffs . If we use Arduino NANO it is having at least 8 analog pins out of which 5 we can easily dedicate to automatically switch filters in and out of the circuit depending on frequency. It may not be as compact as current PHSNA but nevertheless using miniature VHF/UHF relays and SMT components for filter part it can be made fairly compact.

Pravin
 

Hi all,
            With the increased availability of 2 mtrs/70cms radios ( at least in US)  it has become extremely important to design and test the dual band antennas and the need for such test equipment like PHSNA which goes to at least 500MHz is very much felt. I am glad we are having such a good HF PHSNA thanks to Jim and Nick and it is natural to wish one for VHF/UHF also . I think Si570 with its free samples availability is the chip to be used along with a switched filter bank to reduce harmonics . I am sure with the coding and RF skills of many hams its is very much possible to have such an equipment almost at the same cost as of a HF PHSNA.

73
DE AB9XC
(Pravin)



From: "EB4APL eb4apl@... [PHSNA]"
To: PHSNA@...
Sent: Monday, February 13, 2017 5:17 AM
Subject: Re: [PHSNA] Re: Yet Another Network Analyzer (Yana)

 
I would be interested in the Si5351 solution for the higher frequencies only, say 60 to 200 MHz and maybe higher, which would be easier to filter. It could be conceived as an extension to the current PHSNA which already covers the HF region.
Another solution which could be explored id to use the AD9851 above the Nyquist limit, using the sampling images. Analog Devices application notes AN-939 is about this topic and this also is used in AN-543.
An alternative would be using the AD9912 which can generate directly up to 500 MHz, but I assume it could be pricey.
Regards,
Ignacio, EB4APL

El 13/02/2017 a las 8:00, Hans Summers hans.summers@... [PHSNA] escribió:
 
Hi all

I recently did a similar experiment, at HF only, using the QRP Labs Si5351A $33 Synth VFO/SigGen kit http://qrp-labs.com/vfo which has a sinewave output. I wanted to try the results of a switched LPF to attenuate the harmonics and turn it into a sinewave. So I also used the QRP Labs 6-band relay switch http://qrp-labs.com/ultimatelpf and six LPF kits http://qrp-labs.com/lpfkit for 60, 40, 30, 20, 15 and 10m. 

The result was that over the range 2.9MHz to 34MHz, I had a sinewave output 10.8dBm +/- 0.4dBm (very nice and flat), and the worst case harmonic was -45dBc. Pretty good results! Here's a chart of my measurement:
and here's a chart over the wider range 1 to 45MHz. Below 2.9MHz the harmonic content rises because the lowest filter is 60m (5MHz); above 34MHz the fundamental starts to drop off because of the highest filter 10m (30MHz). 

It's worth mentioning also that no optimisation was done here. The frequencies where the filter is switched were just set, without measurement of cut-off frequencies, at 5, 7, 10, 14 and 21MHz. No measurement of inductors was done in building the LPFs or measurement on a spectrum analyser. Just counting turns as per the assembly instructions. The unit lay unshielded on the workbench. Still, good performance in this worst case construction! 

The frequency range can be widened, or less LPFs needed, if you choose a 2:1 ratio between adjacent LPFs. However the harmonic content does increase in that case because at certain frequencies the 2nd harmonic has no attenuation at all. I measured -23dBc harmonic content at some frequencies, when using a 2:1 filter ratio. 

73 Hans G0UPL



Thanks for responding to my post promptly. Yes I understand many of these DDS and Clock generators like Si570 does not give sine wave output . But I think introducing frequency dependent Low Pass Filters at appropriate intervals can solve the problem. For a SNA to work from 30MHz to about 960 MHz using Si570 chip according to my calculations it may require at the maximum 5 switchable LPFs with appropriate cutoffs . If we use Arduino NANO it is having at least 8 analog pins out of which 5 we can easily dedicate to automatically switch filters in and out of the circuit depending on frequency. It may not be as compact as current PHSNA but nevertheless using miniature VHF/UHF relays and SMT components for filter part it can be made fairly compact.



Pravin
 

Hi Sandeep,
                 I think it is very much possible to use the Android phone if somebody is willing too develop an app for that. In the current PHSNA board there is a provision to have a Bluetooth module also . Anyway I am not a code expert so somebody like Nick will be better qualified to comment on this.

73
DE AB9XC
(Pravin)
 




From: "Sandeep Lohia sandeeplohia12@... [PHSNA]"
To: PHSNA@...
Sent: Monday, February 13, 2017 5:03 AM
Subject: Re: [PHSNA] Re: Yet Another Network Analyzer (Yana)

 
 Possible to display results on Android phones ?

On Feb 13, 2017 12:36 PM, "Hans Summers hans.summers@... [PHSNA]" <PHSNA@...> wrote:
 
Hi all

I recently did a similar experiment, at HF only, using the QRP Labs Si5351A $33 Synth VFO/SigGen kit http://qrp-labs.com/vfo which has a sinewave output. I wanted to try the results of a switched LPF to attenuate the harmonics and turn it into a sinewave. So I also used the QRP Labs 6-band relay switch http://qrp-labs.com/ ultimatelpf and six LPF kits http://qrp-labs.com/lpfkit for 60, 40, 30, 20, 15 and 10m. 

The result was that over the range 2.9MHz to 34MHz, I had a sinewave output 10.8dBm +/- 0.4dBm (very nice and flat), and the worst case harmonic was -45dBc. Pretty good results! Here's a chart of my measurement:
and here's a chart over the wider range 1 to 45MHz. Below 2.9MHz the harmonic content rises because the lowest filter is 60m (5MHz); above 34MHz the fundamental starts to drop off because of the highest filter 10m (30MHz). 

It's worth mentioning also that no optimisation was done here. The frequencies where the filter is switched were just set, without measurement of cut-off frequencies, at 5, 7, 10, 14 and 21MHz. No measurement of inductors was done in building the LPFs or measurement on a spectrum analyser. Just counting turns as per the assembly instructions. The unit lay unshielded on the workbench. Still, good performance in this worst case construction! 

The frequency range can be widened, or less LPFs needed, if you choose a 2:1 ratio between adjacent LPFs. However the harmonic content does increase in that case because at certain frequencies the 2nd harmonic has no attenuation at all. I measured -23dBc harmonic content at some frequencies, when using a 2:1 filter ratio. 

73 Hans G0UPL



Thanks for responding to my post promptly. Yes I understand many of these DDS and Clock generators like Si570 does not give sine wave output . But I think introducing frequency dependent Low Pass Filters at appropriate intervals can solve the problem. For a SNA to work from 30MHz to about 960 MHz using Si570 chip according to my calculations it may require at the maximum 5 switchable LPFs with appropriate cutoffs . If we use Arduino NANO it is having at least 8 analog pins out of which 5 we can easily dedicate to automatically switch filters in and out of the circuit depending on frequency. It may not be as compact as current PHSNA but nevertheless using miniature VHF/UHF relays and SMT components for filter part it can be made fairly compact.



Pravin
 

Hi Hans,
             Thanks a lot for your observations on using a switched filter bank  for HF . I think we can adopt a similar method to reduce harmonics from any chip for any frequency range.

73
DE AB9XC
(Pravin)
 




From: "Hans Summers hans.summers@... [PHSNA]"
To: phsna@...
Sent: Monday, February 13, 2017 12:00 AM
Subject: [PHSNA] Re: Yet Another Network Analyzer (Yana)

 
Hi all

I recently did a similar experiment, at HF only, using the QRP Labs Si5351A $33 Synth VFO/SigGen kit http://qrp-labs.com/vfo which has a sinewave output. I wanted to try the results of a switched LPF to attenuate the harmonics and turn it into a sinewave. So I also used the QRP Labs 6-band relay switch http://qrp-labs.com/ultimatelpf and six LPF kits http://qrp-labs.com/lpfkit for 60, 40, 30, 20, 15 and 10m. 

The result was that over the range 2.9MHz to 34MHz, I had a sinewave output 10.8dBm +/- 0.4dBm (very nice and flat), and the worst case harmonic was -45dBc. Pretty good results! Here's a chart of my measurement:
and here's a chart over the wider range 1 to 45MHz. Below 2.9MHz the harmonic content rises because the lowest filter is 60m (5MHz); above 34MHz the fundamental starts to drop off because of the highest filter 10m (30MHz). 

It's worth mentioning also that no optimisation was done here. The frequencies where the filter is switched were just set, without measurement of cut-off frequencies, at 5, 7, 10, 14 and 21MHz. No measurement of inductors was done in building the LPFs or measurement on a spectrum analyser. Just counting turns as per the assembly instructions. The unit lay unshielded on the workbench. Still, good performance in this worst case construction! 

The frequency range can be widened, or less LPFs needed, if you choose a 2:1 ratio between adjacent LPFs. However the harmonic content does increase in that case because at certain frequencies the 2nd harmonic has no attenuation at all. I measured -23dBc harmonic content at some frequencies, when using a 2:1 filter ratio. 

73 Hans G0UPL



Thanks for responding to my post promptly. Yes I understand many of these DDS and Clock generators like Si570 does not give sine wave output . But I think introducing frequency dependent Low Pass Filters at appropriate intervals can solve the problem. For a SNA to work from 30MHz to about 960 MHz using Si570 chip according to my calculations it may require at the maximum 5 switchable LPFs with appropriate cutoffs . If we use Arduino NANO it is having at least 8 analog pins out of which 5 we can easily dedicate to automatically switch filters in and out of the circuit depending on frequency. It may not be as compact as current PHSNA but nevertheless using miniature VHF/UHF relays and SMT components for filter part it can be made fairly compact.


Thomas Berger
 

Thank you for all the very quick responses.  People have been especially generous
in remarking on their own enhancements to PHSNA.  It would be nice if someone
put a file on the group giving websites for all the enhancements to PHSNA.  I think
some builders even seem to be unaware of this great group.

With Yana, however, I set very different goals aimed at a much wider audience: 
easy to duplicate, cheap, handheld.

Yana is nothing more than a simplified PHSNA connected to a Nano using cheap,
easily available prebuilt modules from eBay.  So, yes,  there are compromises.

Yana is intended as an inexpensive club project that handy but non-expert makers
can duplicate.  The finished product is nice looking and compact and does not
spread out across the bench.  Yana's measurements are reasonably accurate and usable.
(Among other things, I've used my N2PK VNA and HP 8656 to verify aspects of the design.)

Comment on 2m:  I had thought of this and plan to experiment with a tripler for the
DDS that would add 2m to Yana.  But that's tough since it must be cheap, simple,
and attach to Yana (handheld).  Ideas welcome.

Comment on the Si5351:  With three clocks that can be phase adjusted, the Analyzer 
should be a full VNA.  Because it can incorporate a narrow band detector, it should
also contain a spectrum analyzer.  The analyzer by AQRP sold by K5BCQ looks very
nice but measures only what you get from S11: (PHSNA does |S11| and |S21|).  I also
don't call it cheap.  (Yeah, I know, compared with Keysight, it's a steal.)   (Aside ...
K5BCQ&K5JHF make awesome kits.)

thank you
tom
.
k1trb


john
 

Tom,

I posted a pdf in files called "build a high frequency spectrum analyzer using two filter ic's" I purchased these 2 ic's but due to health problems I didn't pursue it further. Maybe something in it would be useful, this is meant for info only.

John, kd8paf

Thomas Berger
 

John

I glanced at the article and will have to look more closely.  Thank you
very much for the reference.

regards
tom
.
k1trb

Thomas Berger
 

Ooops.

The DDS library file is the wrong one.  A few minor tweaks are necessary to the
recommended library (which works for the AD9850).  I thought I could get away
with changing a constant and go back to the original library.  Wrong.

It is possible to generalize this library to include both AD9850, AD9851.  I've taken the
cheap route and just make a couple changes to DDS.cpp to switch it to the AD9851.

_TrimFreq = 180000000;  // modified
int32_t freq = frequency * 4294967296/_TrimFreq; // modified
shiftOut(_DATA, _W_CLK, LSBFIRST, 0x01);  // modified

The critical change is the 0x01 to put the dds into 6x clock mode.  

To generalize this library, a public value for mode must be added to DDS.h
so the user can set the 6x mode in the sketch.

I hate to forsake this library since it is simple and works very well.

regards
tom
.
k1trb


Thomas Berger