Topics

Testing Crystal Filters maximum dbm

iz oos
 

I am a proud owner of Antuino. I think it delivers around +10dbm in SNA plot function (correct me if I am wrong) at the RF out and at RF in on SWR plot function. Even if it shows - 20db on the plot. I have seen specs of crystal filters suggesting a maximum level of - 10dbm. So around 20db attenuator should be carefully added between the the Antuino and the crystal filter. Is this correct? I have seen however a datasheet of a crystal filter saying -10dbm max, however +16dbm for less than 10 seconds. So I am a bit confused on how to test safely crystal filters with an antenna analyzer or Antuino.

ajparent1/KB1GMX <kb1gmx@...>
 

Iz,

think about that.... 
-10dbm is about .1milliwatt,  +16dbm is 40milliwatts or about 400 times greater power.

Crystal filter and crystals in singular use generally have a max power of about
1mW (0dbm) for most while some of the older slab rocks in FT243 cases could
take much more.

Why the limit, two things its mechanical vibration and the consequence is heat.
Too much heat and crystals crack or lead bonds fail.

I have swept filters and generally I use -10dbm for safety. Since the average filter is 
about 3-8db loss that is more than enough drive to see a signal on the other side.
So a source side 20db attenuator is pretty much required.  Also the source
impedance is then solidly known making it easier to add the needed transformer
or network to match the input of the filter.  You will likely have to have the same
network to match the detector side as well.

Allison

iz oos
 

Great advices and explanation Allison! What about testing SAW filters, is there a so stringent limit to - 10dbm (like crystal filters) to test them safely?


Il 21/ott/2019 18:17, "ajparent1/KB1GMX" <kb1gmx@...> ha scritto:
Iz,

think about that.... 
-10dbm is about .1milliwatt,  +16dbm is 40milliwatts or about 400 times greater power.

Crystal filter and crystals in singular use generally have a max power of about
1mW (0dbm) for most while some of the older slab rocks in FT243 cases could
take much more.

Why the limit, two things its mechanical vibration and the consequence is heat.
Too much heat and crystals crack or lead bonds fail.

I have swept filters and generally I use -10dbm for safety. Since the average filter is 
about 3-8db loss that is more than enough drive to see a signal on the other side.
So a source side 20db attenuator is pretty much required.  Also the source
impedance is then solidly known making it easier to add the needed transformer
or network to match the input of the filter.  You will likely have to have the same
network to match the detector side as well.

Allison

iz oos
 

I would add the same question for ceramic filters and resonators.


Il 22/ott/2019 11:21, "iz oos via Groups.Io" <and2oosiz2=gmail.com@groups.io> ha scritto:

Great advices and explanation Allison! What about testing SAW filters, is there a so stringent limit to - 10dbm (like crystal filters) to test them safely?


Il 21/ott/2019 18:17, "ajparent1/KB1GMX" <kb1gmx@...> ha scritto:
Iz,

think about that.... 
-10dbm is about .1milliwatt,  +16dbm is 40milliwatts or about 400 times greater power.

Crystal filter and crystals in singular use generally have a max power of about
1mW (0dbm) for most while some of the older slab rocks in FT243 cases could
take much more.

Why the limit, two things its mechanical vibration and the consequence is heat.
Too much heat and crystals crack or lead bonds fail.

I have swept filters and generally I use -10dbm for safety. Since the average filter is 
about 3-8db loss that is more than enough drive to see a signal on the other side.
So a source side 20db attenuator is pretty much required.  Also the source
impedance is then solidly known making it easier to add the needed transformer
or network to match the input of the filter.  You will likely have to have the same
network to match the detector side as well.

Allison

Balasubramanyan Cp
 

😀😀😀   😁😀😁😊😀😁😊😀😁😊   

On Mon, Oct 21, 2019 at 6:21 PM iz oos <and2oosiz2@...> wrote:

I am a proud owner of Antuino. I think it delivers around +10dbm in SNA plot function (correct me if I am wrong) at the RF out and at RF in on SWR plot function. Even if it shows - 20db on the plot. I have seen specs of crystal filters suggesting a maximum level of - 10dbm. So around 20db attenuator should be carefully added between the the Antuino and the crystal filter. Is this correct? I have seen however a datasheet of a crystal filter saying -10dbm max, however +16dbm for less than 10 seconds. So I am a bit confused on how to test safely crystal filters with an antenna analyzer or Antuino.

 

Iz,

The antuino is designed to output -20dbm at SNA port but a lot of them have escaped the plant
at -10db and -10dbm saturates the AD8307 and flatten the peaks. Change R20 to 1.2K and the
in/out short show display -20dbm on the display.

Raj


At 21-10-19, you wrote:

I am a proud owner of Antuino. I think it delivers around +10dbm in SNA plot function (correct me if I am wrong) at the RF out and at RF in on SWR plot function. Even if it shows - 20db on the plot. I have seen specs of crystal filters suggesting a maximum level of - 10dbm. So around 20db attenuator should be carefully added between the the Antuino and the crystal filter. Is this correct? I have seen however a datasheet of a crystal filter saying -10dbm max, however +16dbm for less than 10 seconds. So I am a bit confused on how to test safely crystal filters with an antenna analyzer or Antuino.

 

I forgot to mention the SNA out is square wave.


At 22-10-19, you wrote:
Iz,

The antuino is designed to output -20dbm at SNA port but a lot of them have escaped the plant
at -10db and -10dbm saturates the AD8307 and flatten the peaks. Change R20 to 1.2K and the
in/out short show display -20dbm on the display.

Raj

At 21-10-19, you wrote:

I am a proud owner of Antuino. I think it delivers around +10dbm in SNA plot function (correct me if I am wrong) at the RF out and at RF in on SWR plot function. Even if it shows - 20db on the plot. I have seen specs of crystal filters suggesting a maximum level of - 10dbm. So around 20db attenuator should be carefully added between the the Antuino and the crystal filter. Is this correct? I have seen however a datasheet of a crystal filter saying -10dbm max, however +16dbm for less than 10 seconds. So I am a bit confused on how to test safely crystal filters with an antenna analyzer or Antuino.

Mike KK7ER
 

Raj, 

Are the production Antuinos affected or is it just the early ones sold at Hamvention?

73, Mike KK7ER 

 

Current one too!

Just connect a short cable between in and out and check reading on SNA mode. It should
read -20dbm. If not change R20 to suit.

Raj

At 23-10-19, you wrote:
Raj,

Are the production Antuinos affected or is it just the early ones sold at Hamvention?

73, Mike KK7ER

iz oos
 

Thanks Raj for pointing out that the output in the SNA mode is a safe -20dbm. What are the outputs in the SWR or PWR modes (I haven't used the PWR mode so far)? -20dbm would not deliver enough drive for the LO port of a typical passive mixer.

Attached you find an SNA test of a NOS 5.645Mhz Drake Blue filter matched with 1:9 Minicircuits transformers and about 10db attenuation. Not bad for a 50y old filter!!!

Il 23/ott/2019 05:41, "Raj vu2zap" <rajendrakumargg@gmail.com> ha scritto:
>
> Current one too!
>
> Just connect a short cable between in and out and check reading on SNA mode. It should
> read -20dbm. If not change R20 to suit.
>
> Raj
>
> At 23-10-19, you wrote:
> >Raj,
> >
> >Are the production Antuinos affected or is it just the early ones sold at Hamvention?
> >
> >73, Mike KK7ER 
>
>
>
>

 

Is,

You got to check the reading by looping in to out and see the reading. Adjust r20 to get
-20dbm on the display in SNA mode. It may be -10dbm and that flattens the plot top.
SNA and SWR dBm displayed readings are accurate +-1dB.

The SWR is also -10-12dbm (just checked a couple of boards) the open cal process
takes care of that.

Raj


At 27-10-19, you wrote:

Thanks Raj for pointing out that the output in the SNA mode is a safe -20dbm. What are the outputs in the SWR or PWR modes (I haven't used the PWR mode so far)? -20dbm would not deliver enough drive for the LO port of a typical passive mixer.

Attached you find an SNA test of a NOS 5.645Mhz Drake Blue filter matched with 1:9 Minicircuits transformers and about 10db attenuation. Not bad for a 50y old filter!!!

Il 23/ott/2019 05:41, "Raj vu2zap" <rajendrakumargg @ gmail.com> ha scritto:
>
> Current one too!
>
> Just connect a short cable between in and out and check reading on SNA mode. It should
> read -20dbm. If not change R20 to suit.
>
> Raj
>
> At 23-10-19, you wrote:
> >Raj,
> >
> >Are the production Antuinos affected or is it just the early ones sold at Hamvention?
> >
> >73, Mike KK7ER 
>
>

 

Sorry the reading is -20 to -25 dBm .. on SWR mode.


At 27-10-19, you wrote:
Is,

You got to check the reading by looping in to out and see the reading. Adjust r20 to get
-20dbm on the display in SNA mode. It may be -10dbm and that flattens the plot top.
SNA and SWR dBm displayed readings are accurate +-1dB.

The SWR is also -10-12dbm (just checked a couple of boards) the open cal process
takes care of that.

Raj


At 27-10-19, you wrote:

Thanks Raj for pointing out that the output in the SNA mode is a safe -20dbm. What are the outputs in the SWR or PWR modes (I haven't used the PWR mode so far)? -20dbm would not deliver enough drive for the LO port of a typical passive mixer.

Attached you find an SNA test of a NOS 5.645Mhz Drake Blue filter matched with 1:9 Minicircuits transformers and about 10db attenuation. Not bad for a 50y old filter!!!

Il 23/ott/2019 05:41, "Raj vu2zap" <rajendrakumargg @ gmail.com> ha scritto:
>
> Current one too!
>
> Just connect a short cable between in and out and check reading on SNA mode. It should
> read -20dbm. If not change R20 to suit.
>
> Raj
>
> At 23-10-19, you wrote:
> >Raj,
> >
> >Are the production Antuinos affected or is it just the early ones sold at Hamvention?
> >
> >73, Mike KK7ER