Date   
Re: RF out with RF OFF: Clock feed through

Clifford Heath
 

On 10 Jul 2017, at 10:06 AM, EB4APL eb4apl@... [PHSNA] <PHSNA@...> wrote:
The 180 MHz component is intrinsic to the DDS design, any frequency generated by the DDS is sampled by the 180 MHz reference clock.
In theory the elliptical filter fitted is -91dB at 180MHz, so if it wasn't for
low-quality components being used, there shouldn't be any. Unless it's
getting in some other way... It's so far from the passband that it should
be easy to deal with anyhow.

But 30MHz? That's right in the clear. If you do not want a notch there,
the best solution is not to produce any 30MHz. There *will* be 30MHz
in the ground plane, and there is nothing to stop it appearing at the
output. Differential coupling will reduce it dramatically.

I guess AD figure that the sort of person who cares, will not be the kind
who need to buy an evaluation board...

Clifford Heath.

Maybe you are right and this type of connection causes the DAC to output more clock energy that should be. Probably using the transformer or the opamp the clock component will be reduced but a trap at 180 MHz could suffice. In fact my external 30 MHz LPF removes the clock (leakage or whatever) quite well.

Regards,

Ignacio, EB4APL


El 10/07/2017 a las 1:29, Clifford Heath clifford.heath@... [PHSNA] escribió:

Filtering is the wrong solution here. You need to fix the problem at the source.

The evaluation board (and the Chinese clones) use asymmetrical outputs,
with one DAC output terminated to ground and one to the filter. The output
of this kind of DAC is fully differential current-steering, and you cannot get
good performance by taking one side to ground.

Instead, you should fit a transformer or a suitable op-amp (with good CMMR)
to subtract the two outputs. You can see this in the schematic for the AD9959
evaluation boards. Note that the transformers they use there are $10/each,
so the Chinese boards generally don't provide them, or only provide 2 of the
four channels.

Alternatively, here's a cheap op-amp that'd do the job:
<http://www.analog.com/en/products/amplifiers/operational-amplifiers/high-speed-amplifiers-bandwidth-greaterthanequalto-50mhz/ad8055.html>
Use a normal differencing setup (four resisters) and feed the output into the
filter.

Clifford Heath.

On 10 Jul 2017, at 3:10 AM, EB4APL eb4apl@... [PHSNA] <PHSNA@...>wrote:


This is exactly what I did, I have a connectorized 30 MHz LP filter and I inserted it between the input and the output of the PHSNA. This time it is not a harmonic problem, it is the 180 MHz refclock frequency which is not well filtered out.

Ignacio, EB4APL


El 09/07/2017 a las 18:44, mendiola_loyola@... [PHSNA] escribió:

Try putting a low pass filter of 30mhz at the output of the dds-60. The amplifier of the dds60 also adds harmonics.

OA4AJP

Posted by: mendiola_loyola@...


Posted by: Clifford Heath <clifford.heath@...>

Re: RF out with RF OFF: Clock feed through

EB4APL
 

The 180 MHz component is intrinsic to the DDS design, any frequency generated by the DDS is sampled by the 180 MHz reference clock. Maybe you are right and this type of connection causes the DAC to output more clock energy that should be.  Probably using the transformer or the opamp the clock component will be reduced but a trap at 180 MHz could suffice. In fact my external 30 MHz LPF removes the clock (leakage or whatever) quite well.

Regards,

Ignacio, EB4APL


El 10/07/2017 a las 1:29, Clifford Heath clifford.heath@... [PHSNA] escribió:
 

Filtering is the wrong solution here. You need to fix the problem at the source.

The evaluation board (and the Chinese clones) use asymmetrical outputs,
with one DAC output terminated to ground and one to the filter. The output
of this kind of DAC is fully differential current-steering, and you cannot get
good performance by taking one side to ground.

Instead, you should fit a transformer or a suitable op-amp (with good CMMR)
to subtract the two outputs. You can see this in the schematic for the AD9959
evaluation boards. Note that the transformers they use there are $10/each,
so the Chinese boards generally don't provide them, or only provide 2 of the
four channels.

Alternatively, here's a cheap op-amp that'd do the job:

Use a normal differencing setup (four resisters) and feed the output into the
filter.

Clifford Heath.

> On 10 Jul 2017, at 3:10 AM, EB4APL eb4apl@... [PHSNA] wrote:
>
>
> This is exactly what I did, I have a connectorized 30 MHz LP filter and I inserted it between the input and the output of the PHSNA. This time it is not a harmonic problem, it is the 180 MHz refclock frequency which is not well filtered out.
>
> Ignacio, EB4APL
>
>
> El 09/07/2017 a las 18:44, mendiola_loyola@... [PHSNA] escribió:
>>
>> Try putting a low pass filter of 30mhz at the output of the dds-60. The amplifier of the dds60 also adds harmonics.
>>
>> OA4AJP
>>
>> Posted by: mendiola_loyola@...
>
>
>


Posted by: Clifford Heath


Re: RF out with RF OFF: Clock feed through

Clifford Heath
 

Filtering is the wrong solution here. You need to fix the problem at the source.

The evaluation board (and the Chinese clones) use asymmetrical outputs,
with one DAC output terminated to ground and one to the filter. The output
of this kind of DAC is fully differential current-steering, and you cannot get
good performance by taking one side to ground.

Instead, you should fit a transformer or a suitable op-amp (with good CMMR)
to subtract the two outputs. You can see this in the schematic for the AD9959
evaluation boards. Note that the transformers they use there are $10/each,
so the Chinese boards generally don't provide them, or only provide 2 of the
four channels.

Alternatively, here's a cheap op-amp that'd do the job:
<http://www.analog.com/en/products/amplifiers/operational-amplifiers/high-speed-amplifiers-bandwidth-greaterthanequalto-50mhz/ad8055.html>
Use a normal differencing setup (four resisters) and feed the output into the
filter.

Clifford Heath.

On 10 Jul 2017, at 3:10 AM, EB4APL eb4apl@... [PHSNA] <PHSNA@...> wrote:


This is exactly what I did, I have a connectorized 30 MHz LP filter and I inserted it between the input and the output of the PHSNA. This time it is not a harmonic problem, it is the 180 MHz refclock frequency which is not well filtered out.

Ignacio, EB4APL


El 09/07/2017 a las 18:44, mendiola_loyola@... [PHSNA] escribió:

Try putting a low pass filter of 30mhz at the output of the dds-60. The amplifier of the dds60 also adds harmonics.

OA4AJP

Posted by: mendiola_loyola@...

Re: RF out with RF OFF: Clock feed through

EB4APL
 

This is exactly what I did, I have a connectorized 30 MHz LP filter and I inserted it between the input and the output of the PHSNA. This time it is not a harmonic problem, it is the 180 MHz refclock frequency which is not well filtered out.

Ignacio, EB4APL


El 09/07/2017 a las 18:44, mendiola_loyola@... [PHSNA] escribió:
 

Try putting a low pass filter of 30mhz at the output of the dds-60. The amplifier of the dds60 also adds harmonics.

OA4AJP


Posted by: mendiola_loyola@...

Re: RF out with RF OFF: Clock feed through

Alfredo Mendiola Loyola
 

Try putting a low pass filter of 30mhz at the output of the dds-60. The amplifier of the dds60 also adds harmonics.

OA4AJP

Re: RF out with RF OFF: Clock feed through

EB4APL
 

Hi,

I must say that the feedthrough issue was discovered by Camille Farrougia, F4IBA, who emailed me about this. He is also building the French language support file. As Nick says, the forthcoming version will have multilingual support, the user will be able to make his own translation.

Regards,

Ignacio, EB4APL


El 09/07/2017 a las 15:19, Nick Kennedy kennnick@... [PHSNA] escribió:
 

Got an email from Ignacio EB4APL where he talks about RF output still existing with RF OFF in effect. He says it’s the 30 MHz oscillator and/or the 180 MHz clock that results from the x6 multiplication in the AD9851 that comes through. I verified it with a couple of readings using my hardware.


I thought I’d check at two frequencies and arbitrarily chose 3.5 MHz and 30 MHz. It didn’t make much difference though.


My floor with things hooked up but no RF input is about -72 dBm. 


Here with the DDS output connected to the AD8307 box' input:

  

MHz

RF ON

dBm

RF OFF

dBm

3.5

0.1

-44.9

30

-0.1

-43.0

 

So with RF OFF, I have output that’s about 27 dB higher than my measurement floor but 44 dB lower than my RF ON output level.


Ignacio says that a spectrum analyzer shows a small pip at 30 MHz and a larger one at 180 MHz. He and I are both using DDS-60 boards.


Of course, we don’t do measurements with RF OFF, but assuming that the spurs are present when RF is ON, they could have an effect. Ignacio points out that this thing shouldn’t affect measurements of lowpass and bandpass filters or crystals, but could affect highpass filter measurements.


Now I wonder what people see with eBay boards and custom filters, both with AD9850 and AD9851 chips.  Anyone?


Regarding  the “RF OFF” function, it’s accomplished by setting the DDS frequency to zero. 


**


Otherwise, there hasn't been a lot of work on the PHSNA software on either side of the Atlantic for some time. However, there are still some nice improvements by Ignacio in the pipeline. I think we've got log scale graphs with some user options to come. Also, improved handling of baud mismatches between the Arduino and PC, plus a system that will allow changing PHSNA message and button labeling text for non-English users.


Hope to have it out in a week or so.


73-


Nick, WA5BDU


RF out with RF OFF: Clock feed through

Nick Kennedy
 

Got an email from Ignacio EB4APL where he talks about RF output still existing with RF OFF in effect. He says it’s the 30 MHz oscillator and/or the 180 MHz clock that results from the x6 multiplication in the AD9851 that comes through. I verified it with a couple of readings using my hardware.


I thought I’d check at two frequencies and arbitrarily chose 3.5 MHz and 30 MHz. It didn’t make much difference though.


My floor with things hooked up but no RF input is about -72 dBm. 


Here with the DDS output connected to the AD8307 box' input:

  

MHz

RF ON

dBm

RF OFF

dBm

3.5

0.1

-44.9

30

-0.1

-43.0

 

So with RF OFF, I have output that’s about 27 dB higher than my measurement floor but 44 dB lower than my RF ON output level.


Ignacio says that a spectrum analyzer shows a small pip at 30 MHz and a larger one at 180 MHz. He and I are both using DDS-60 boards.


Of course, we don’t do measurements with RF OFF, but assuming that the spurs are present when RF is ON, they could have an effect. Ignacio points out that this thing shouldn’t affect measurements of lowpass and bandpass filters or crystals, but could affect highpass filter measurements.


Now I wonder what people see with eBay boards and custom filters, both with AD9850 and AD9851 chips.  Anyone?


Regarding  the “RF OFF” function, it’s accomplished by setting the DDS frequency to zero. 


**


Otherwise, there hasn't been a lot of work on the PHSNA software on either side of the Atlantic for some time. However, there are still some nice improvements by Ignacio in the pipeline. I think we've got log scale graphs with some user options to come. Also, improved handling of baud mismatches between the Arduino and PC, plus a system that will allow changing PHSNA message and button labeling text for non-English users.


Hope to have it out in a week or so.


73-


Nick, WA5BDU

Re: Introduction, and new project description

Clifford Heath
 

Will do. The posts might go to the group <mailto:vk2specan@...>.
Mind if I add you as a subscriber to that list? You'll always be able to unsubscribe
yourself of course.

Clifford Heath.

On 22 Jun 2017, at 1:55 AM, bellrossjr@... [PHSNA] <PHSNA@...> wrote:


Hi Cliff:
I am interested in the SNA/VNA project please email me with futher developments @K7RSB

Re: Introduction, and new project description

Ross Bell
 

Hi Cliff:
I am interested in the SNA/VNA project please email me with futher developments bellrossjr@...

Re: Introduction, and new project description

Nick Kennedy
 

​Sounds like a really nice project. I hope it comes out well.

73-,

Nick, WA5BDU​


On Sat, Jun 17, 2017 at 2:05 AM, Clifford Heath clifford.heath@... [PHSNA] <PHSNA@...> wrote:

A few of us locally (Sydney/Melbourne) are starting a design for a $100 SNA/VNA
using the AD9959 quad-DDS module, which is good to 200MHz (500MHz core).
The design will use an Arduino with a touch-screen LCD, and an AD8302 gain/
phase chip. This will provide an indication of phase as well as amplitude, though
the phase is not terribly accurate. The main benefit from going with the AD9959 is
extending to 200MHz and having four channels, with digitally controllable phase



Re: Introduction, and new project description

Gary Winblad
 

Hi,
This project is really made of separate modules, you don't really need a PCB.
See a photo of the inside of mine in the photos area:
P1030298

You do need a PCB for the RFpower meter but now you can get one of those from china:
http://www.ebay.com/itm/AD8307-RF-Power-Detector-Module-DC-500MHz-Transmitter-Power-Test-92dbm-/222169973695?hash=item33ba5cc3bf:g:RpwAAOSwOVpXc6w4

I used a DDS-60 board that has a workable filter, etc.
I added an LCD and encoder too but you don't need that.

73,
Gary
WB6OGD

Introduction, and new project description

Clifford Heath
 

A few of us locally (Sydney/Melbourne) are starting a design for a $100 SNA/VNA
using the AD9959 quad-DDS module, which is good to 200MHz (500MHz core).
The design will use an Arduino with a touch-screen LCD, and an AD8302 gain/
phase chip. This will provide an indication of phase as well as amplitude, though
the phase is not terribly accurate. The main benefit from going with the AD9959 is
extending to 200MHz and having four channels, with digitally controllable phase
shifts. The unit will embed a USB power pack to make it portable, yet easy to charge.

We plan to extend it to a VNA following the path of <http://n2pk.com/VNA/VNAarch.html>,
who added a mixer, DC filter and 24-bit ADC to an I/Q signal generator. That part of
our circuit will be implemented with a large input bandwidth (1GHz) to allow use of a
higher-frequency LO (e.g. ADF4351) to act as a direct-conversion spectrum analyser,
though we have to investigate switchable filter options for that to work well.

Another member of the group wants to use an STM32F4 instead of the Arduino, to
allow low-IF SDR and spec-an, perhaps 100KHz bandwidth. So that's also a possible
path.

During my research for this design, I found the PHSNA and joined the group; though
I've already implemented something similar before finding PHSNA.

I just thought I'd mention the project to see what interest exists.

Clifford Heath, VK3CLF, http://github.com/cjheath

PHSNA latest version PCB assistance

vu2esh@...
 

Hi all ,I am new in this group.can some one guide me to the latest documents on PHSNA with pcb design ,Bom,exec files.i want to build one myself.


Re: AD9850 or AD9851 Type I/II adapter PCBs Useage Option

Larry Humphrey
 

Sorry folks.  I posted this message to wrong group.  I need to post on
https://groups.yahoo.com/neo/groups/SoftwareControlledHamRadio/info
reflector.

Larry, W2HHV

AD9850 or AD9851 Type I/II adapter PCBs Useage Option

Larry Humphrey
 

Read the
PHSNA Type II Details 21 MAR 2014.pdf
file (especially page 3) on https://groups.yahoo.com/neo/groups/PHSNA/info reflector.. Using the toroid transformer interface between AD9850 (or AD9851) output and external LPF and MMIC amplifier works even with OUT_A and OUT_B current sources reversed. See page 4 of file.  Since I am planning on using the modifications described this file, there is no need to rework "reverse connection" described by Mike, K5ESS in off line email to people who bought his Type I/II adapter PCBs. This pdf file is located in
https://groups.yahoo.com/neo/groups/PHSNA/files/Type-2%20PHSNA%20-%20version%20using%20Type-2%20DDS%20module%20%26%20Arduino%20UNO/
Files subdirectory.

Larry, W2HHV

Test Equipment and Station Gear from the Estate of Jerry, W5JH

John Stevens <jwsteven@...>
 

The following is a partial listing of what is available from the estate of Jerry, W5JH.  All equipment is represented correctly to the best of my knowledge. All equipment is in very good condition and was in frequent use in a Non-smoking environment. It was well maintained and not abused. More items will be released in separate lists as I am able to go through them. Waiting in the wings are an ICOM-R70 receiver and refurbished SB-200.

Please reply directly off list and reference W5JH in the subject line to minimize the chance of your reply being overlooked. All manuals and accessories that are associated with each item will be included if I am able to locate and identify them all. Chances are good since the area is not excessively large nor cluttered.

Original boxes will be used if available. Prices are less shipping. Pictures of most gear can be seen at <https://www.qrz.com/db/w5jh>. I have additional photos upon request.

If you are interested in building a fully equipped test bench, this list is for you... It's ALL here. Jerry was very particular about the test equipment on his bench. The HP8640B Signal Generator and Fluke Digital Multimeter in the photos are already spoken for.

Wavetek Model 164 30 MHz Sweep/Function Generator. Commercial laboratory quality. Extremely versatile.    $275

Tektronix 2213 Dual Channel 60 MHz Oscilloscope $!00.

OWON DS7102V dual channel Storage Oscilloscope. Color display. Records data from each channel   Like New  $350

Rigol Spectrum Analyzer DSA815-TG (9kHz - 1.5GHz) with Tracking Generator    Like New   $1100

Kenwood TS-590s Transceiver.  LIke New $825

Dentron Clipperton-L Amplifier.  Very clean with tubes. $600

MFJ-962 Versa Tuner III 1.5 KW Tuner    $150

LP-100A Digital Vector RF Wattmeter w/optional dual coupler. Like New $425
More info at <http://www.telepostinc.com/lp100.html#P>

AADE DFD4 Frequency Counter  $35

AADE LC Meter  $85

LDG Z100 Auto Tuner  $90

So here we go...

73 John  K5JS

PHSNA windows source code

William Heller
 

I am trying to do a port of the contrl program to my android tablet does anyone have the sorce code for the windows application that I can look at as a starting point?


Re: Yet Another Network Analyzer (Yana)

Thomas Berger
 

Additional files and experiments are available for Yana at

Rudi DL5FA has produced Yana-BT, an enhanced bluetooth enabled version
of Yana

Yana is a good club or individual project.

Re: PHSNA PC boards

k7wxw@...
 

i duuno but probably not a good choice for me. nine grand for the "base" model is more than i've paid for all my ham and test gear together at this point. ;)

73 de bill k7wxw

Re: Yet Another Network Analyzer (Yana)

Thomas Berger
 

Rudi

Please contact me by email.  My email address appears right after the copyright
information in the file "Yana: C Sketch" on my website:

regards
tom
.
k1trb