开云体育

Tony,

Thanks.? I stuck with the original layout (3 ferrites and 4 iron powder) and have not had issues.

What I settled on for an enclosure was an old Hershey's chocolate tin.? And for the broadcast band notch for my local station, a small paint can.? I appreciate your links, however.? Well, the BNC's soldered to the tin.? It wasn't easy and took a lot of heat, but with their Teflon centers, they didn't melt.

At some point, I may go back and try to tune the filter a bit so it doesn't go so far into 160 meters, but that's a project for another day.

The only images I see are in longwave itself.? I come across the strongest NDB several times throughout the band, which I find odd.? Other than that, no broadcast activity.

Jon


On 7/7/21 10:35 AM, Tony_AD0VC wrote:

Just a heads up. I have been using the filter I built and I have a problem. I am seeing lots of IMD images of BC stations on the NDB band when my filter is installed. I tried installing an inline attenuator ahead of the filter because I thought maybe the low passband impedance was messing with the active loop amplifier but the images remained. Without the filter, no images so it is not coming from the loop amp. Finally, an alarm went off in my head as my poor memory dragged up an old recollection. I am pretty sure it is caused by the ferrites I chose for the filter. I have seen this before. I will have to try and locate some Txx cores in my junk box that will work in order to prove this.

As far as enclosures, I bought this pack of 3 from a**zon:

Amazon.com: 3 pcs 1590A Small Enclosure Box incl. Step Drill, PCB, Aluminum Guitar Effect Pedal Case, unpainted: Home Improvement<>

It includes a step drill which works fantastically well for the BNCs. But your filter is probably a bit too big for these boxes.

Tony

________________________________
From: [email protected] <[email protected]> on behalf of JonI via groups.io <ji425bt@...>
Sent: Tuesday, July 6, 2021 4:51 AM
To: [email protected] <[email protected]>
Subject: Re: [softrock40] homemade chebyshev 7th order BB band stop to begin soon

Here, it looks like your message came through twice, Gary, once last
night and then once today.? Sometimes it takes a while to show after you
send it.

Unfortunately, don't own the Nano, but Tiny sure came in handy
yesterday, so much so that I ran down the battery and had to recharge
it.? I'm not sure whether it takes on noise/ spurs/ harmonics if powered
via its port and didn't want to take any chances so let it charge for an
hour or so.

Well, about the only thing remaining with the filter is suitable
containment that's cheap!? I found that I don't like the circuit board
containment I was originally going to use.? I had soldered on three
sides and left one side open to make the filter, but found that I had
trouble getting the soldering iron into certain spots so decided to
remove the opposite side.? It sure was a bear!? A "bud" box is too
expensive for me for now.? Any cheap alternative ideas welcome. With
the filter of course, I would like to have it shielded as well as
possible into the container.

Thanks,

Jon


On 7/6/21 5:50 AM, Gary wrote:

Let's try this again.? I sent this message at 7 p.m. last night and it
hasn't shown up by 6 a.m. today.? Did I commit some high crime and
misdemeanor?

Something that might be of interest is that the Surrey Amateur Radio
Club, VE7SAR, < <>ve7sar.net > has a wonderful newsletter that
comes out bi-monthly.? The newsletter is usually around 110 pages.
The last several issues have had articles titled, Measurements with
the NanoVNA".? The Nov - Dec 2020 article deals specifically with
"Establishing the Characteristics of Unknown Toroids".

73,
Gary - W6GVS
Dowagiac, MI

At 11:18 AM 7/5/2021, you wrote:

Thanks!? Those are some good instructions, something I was looking
for yesterday on how to align the sections.? Any advice to keep the
toroid turns in place once aligned? I find they can move quite a bit
during installation. Was thinking hot glue, but might hurt the enamel.

Jon


On 7/5/21 11:04 AM, Nick wrote:

On 05/07/2021 14:12, JonI via groups.io wrote:

I did check the inductance of the toroids before installation using
a separate capacitor, dip meter, and frequency counter.
Unfortunately, my dip meter doesn't go low enough to check the
resonances you indicate.

You should be able to do this with your noise source and TinySA.

Make up a test jig with a piece of scrap PCB and two BNC connectors.

Remove the resonators one by one from the filter and align as follows.

For the series resonators L1/C1 etc connect the two BNC centers and
strap the series resonator from there to ground.

Noise generator on one side, TinySA on the other.? You should see a
sharp dip at the resonant frequency of 919kHz.?? Squeeze or stretch
the toroid's turns to get that frequency, then reinstall the
resonator in the filter.

For the parallel resonators L2/C2 etc connect the resonator between
the two BNC centers.? You should see a sharp dip at the resonant
frequency of 941kHz. Squeeze or stretch the toroid's turns to get
that frequency, then reinstall the resonator in the filter.

HTH

Nick

Just a heads up. I have been using the filter I built and I have a problem. I am seeing lots of IMD images of BC stations on the NDB band when my filter is installed. I tried installing an inline attenuator ahead of the filter because I thought maybe the low passband impedance was messing with the active loop amplifier but the images remained. Without the filter, no images so it is not coming from the loop amp. Finally, an alarm went off in my head as my poor memory dragged up an old recollection. I am pretty sure it is caused by the ferrites I chose for the filter. I have seen this before. I will have to try and locate some Txx cores in my junk box that will work in order to prove this.

As far as enclosures, I bought this pack of 3 from a**zon:

Amazon.com: 3 pcs 1590A Small Enclosure Box incl. Step Drill, PCB, Aluminum Guitar Effect Pedal Case, unpainted: Home Improvement<>

It includes a step drill which works fantastically well for the BNCs. But your filter is probably a bit too big for these boxes.

Tony

________________________________
From: [email protected] <[email protected]> on behalf of JonI via groups.io <ji425bt@...>
Sent: Tuesday, July 6, 2021 4:51 AM
To: [email protected] <[email protected]>
Subject: Re: [softrock40] homemade chebyshev 7th order BB band stop to begin soon

Here, it looks like your message came through twice, Gary, once last
night and then once today. Sometimes it takes a while to show after you
send it.

Unfortunately, don't own the Nano, but Tiny sure came in handy
yesterday, so much so that I ran down the battery and had to recharge
it. I'm not sure whether it takes on noise/ spurs/ harmonics if powered
via its port and didn't want to take any chances so let it charge for an
hour or so.

Well, about the only thing remaining with the filter is suitable
containment that's cheap! I found that I don't like the circuit board
containment I was originally going to use. I had soldered on three
sides and left one side open to make the filter, but found that I had
trouble getting the soldering iron into certain spots so decided to
remove the opposite side. It sure was a bear! A "bud" box is too
expensive for me for now. Any cheap alternative ideas welcome. With
the filter of course, I would like to have it shielded as well as
possible into the container.

Thanks,

Jon


On 7/6/21 5:50 AM, Gary wrote:

Let's try this again. I sent this message at 7 p.m. last night and it
hasn't shown up by 6 a.m. today. Did I commit some high crime and
misdemeanor?

Something that might be of interest is that the Surrey Amateur Radio
Club, VE7SAR, < <>ve7sar.net > has a wonderful newsletter that
comes out bi-monthly. The newsletter is usually around 110 pages.
The last several issues have had articles titled, Measurements with
the NanoVNA". The Nov - Dec 2020 article deals specifically with
"Establishing the Characteristics of Unknown Toroids".

73,
Gary - W6GVS
Dowagiac, MI

At 11:18 AM 7/5/2021, you wrote:

Thanks! Those are some good instructions, something I was looking
for yesterday on how to align the sections. Any advice to keep the
toroid turns in place once aligned? I find they can move quite a bit
during installation. Was thinking hot glue, but might hurt the enamel.

Jon


On 7/5/21 11:04 AM, Nick wrote:

On 05/07/2021 14:12, JonI via groups.io wrote:

I did check the inductance of the toroids before installation using
a separate capacitor, dip meter, and frequency counter.
Unfortunately, my dip meter doesn't go low enough to check the
resonances you indicate.

You should be able to do this with your noise source and TinySA.

Make up a test jig with a piece of scrap PCB and two BNC connectors.

Remove the resonators one by one from the filter and align as follows.

For the series resonators L1/C1 etc connect the two BNC centers and
strap the series resonator from there to ground.

Noise generator on one side, TinySA on the other. You should see a
sharp dip at the resonant frequency of 919kHz.? Squeeze or stretch
the toroid's turns to get that frequency, then reinstall the
resonator in the filter.

For the parallel resonators L2/C2 etc connect the resonator between
the two BNC centers. You should see a sharp dip at the resonant
frequency of 941kHz. Squeeze or stretch the toroid's turns to get
that frequency, then reinstall the resonator in the filter.

HTH

Nick

That would be my recommendation. For a single frequency, a simple series LC
circuit is easy to build and tune.

73, Zack W9SZ

On Tue, Jul 6, 2021 at 12:19 AM Alan G4ZFQ <alan4alan@...> wrote:

a
frequency notch for one broadcast band station. This would be used
during times when I'd want to listen to the BB, but not be overwhelmed
by the station close to me.

Jon

Be aware that moving the LO frequency will move these "harmonic"
responses away from a wanted frequency. A response 3 times the wanted
frequency moves 3 times as fast as the wanted signal. Any signals still
getting through your filter may be shifted away.

Top marks for perseverance!

A simple series adjustable resonance inductance/capacitance is often
used as a notch.

73 Alan G4ZFQ

a
frequency notch for one broadcast band station. This would be used
during times when I'd want to listen to the BB, but not be overwhelmed
by the station close to me.

Jon

Be aware that moving the LO frequency will move these "harmonic"
responses away from a wanted frequency. A response 3 times the wanted
frequency moves 3 times as fast as the wanted signal. Any signals still
getting through your filter may be shifted away.

Top marks for perseverance!

A simple series adjustable resonance inductance/capacitance is often
used as a notch.

73 Alan G4ZFQ

Let's try this again.? I sent this message at 7 p.m. last night and it hasn't shown up by 6 a.m. today.? Did I commit some high crime and misdemeanor?

Something that might be of interest is that the Surrey Amateur Radio Club, VE7SAR, < <>ve7sar.net > has a wonderful newsletter that comes out bi-monthly.? The newsletter is usually around 110 pages.? The last several issues have had articles titled, Measurements with the NanoVNA".? The Nov - Dec 2020 article deals specifically with "Establishing the Characteristics of Unknown Toroids".

73,
Gary - W6GVS
Dowagiac, MI

At 11:18 AM 7/5/2021, you wrote:

Thanks!? Those are some good instructions, something I was looking for yesterday on how to align the sections.? Any advice to keep the toroid turns in place once aligned? I find they can move quite a bit during installation. Was thinking hot glue, but might hurt the enamel.

Jon


On 7/5/21 11:04 AM, Nick wrote:

On 05/07/2021 14:12, JonI via groups.io wrote:

I did check the inductance of the toroids before installation using a separate capacitor, dip meter, and frequency counter. Unfortunately, my dip meter doesn't go low enough to check the resonances you indicate.

You should be able to do this with your noise source and TinySA.

Make up a test jig with a piece of scrap PCB and two BNC connectors.

Remove the resonators one by one from the filter and align as follows.

For the series resonators L1/C1 etc connect the two BNC centers and strap the series resonator from there to ground.

Noise generator on one side, TinySA on the other.? You should see a sharp dip at the resonant frequency of 919kHz.?? Squeeze or stretch the toroid's turns to get that frequency, then reinstall the resonator in the filter.

For the parallel resonators L2/C2 etc connect the resonator between the two BNC centers.? You should see a sharp dip at the resonant frequency of 941kHz. Squeeze or stretch the toroid's turns to get that frequency, then reinstall the resonator in the filter.

HTH

Nick

Thanks! Those are some good instructions, something I was looking for yesterday on how to align the sections. Any advice to keep the toroid turns in place once aligned? I find they can move quite a bit during installation. Was thinking hot glue, but might hurt the enamel.

Jon


On 7/5/21 11:04 AM, Nick wrote:

On 05/07/2021 14:12, JonI via groups.io wrote:

I did check the inductance of the toroids before installation using a separate capacitor, dip meter, and frequency counter. Unfortunately, my dip meter doesn't go low enough to check the resonances you indicate.

You should be able to do this with your noise source and TinySA.

Make up a test jig with a piece of scrap PCB and two BNC connectors.

Remove the resonators one by one from the filter and align as follows.

For the series resonators L1/C1 etc connect the two BNC centers and strap the series resonator from there to ground.

Noise generator on one side, TinySA on the other. You should see a sharp dip at the resonant frequency of 919kHz.? Squeeze or stretch the toroid's turns to get that frequency, then reinstall the resonator in the filter.

For the parallel resonators L2/C2 etc connect the resonator between the two BNC centers. You should see a sharp dip at the resonant frequency of 941kHz. Squeeze or stretch the toroid's turns to get that frequency, then reinstall the resonator in the filter.

HTH

Nick

Thanks! Those are some good instructions, something I was looking for yesterday on how to align the sections. Any advice to keep the toroid turns in place once aligned? I find they can move quite a bit during installation. Was thinking hot glue, but might hurt the enamel.

Jon


On 7/5/21 11:04 AM, Nick wrote:

On 05/07/2021 14:12, JonI via groups.io wrote:

I did check the inductance of the toroids before installation using a separate capacitor, dip meter, and frequency counter. Unfortunately, my dip meter doesn't go low enough to check the resonances you indicate.

You should be able to do this with your noise source and TinySA.

Make up a test jig with a piece of scrap PCB and two BNC connectors.

Remove the resonators one by one from the filter and align as follows.

For the series resonators L1/C1 etc connect the two BNC centers and strap the series resonator from there to ground.

Noise generator on one side, TinySA on the other. You should see a sharp dip at the resonant frequency of 919kHz.? Squeeze or stretch the toroid's turns to get that frequency, then reinstall the resonator in the filter.

For the parallel resonators L2/C2 etc connect the resonator between the two BNC centers. You should see a sharp dip at the resonant frequency of 941kHz. Squeeze or stretch the toroid's turns to get that frequency, then reinstall the resonator in the filter.

HTH

Nick

Excellent! Glad you found it. Hope it does the job for you.

Tony

________________________________
From: [email protected] <[email protected]> on behalf of JonI via groups.io <ji425bt@...>
Sent: Monday, July 5, 2021 7:45 PM
To: [email protected] <[email protected]>
Subject: Re: [softrock40] homemade chebyshev 7th order BB band stop to begin soon

All taken care of. The culprit turned out to be a bad polystyrene
capacitor. Nick's suggestion to test and tune each stage outside of
circuit is the way I discovered it. One stage resonated far below AM
broadcast, hence the reason for the large insertion loss. Since
replacing that cap and tuning the entire filter, it's now operating as
it should! I get about 1-1.5 dB insertion loss. Not going to post any
more images, but a quick check with signal generator input shows the
start of reduction around 475 Khz (-3 dB). It does reach a bit higher
into 160 meters than I liked, around 9 db reduction at 1.8 and -5 dB at
1.9 Mhz, but otherwise it's operating as it should. I lack smaller
sized polystyrene for too fine of adjustments. Core turns compression/
expansion helped quite a bit, especially with the iron powder toroids.

Thanks again to everyone who helped here. Without your encouragement,
patience, and knowledge, I'd have given up on this project after yesterday.

Jon


On 7/5/21 9:03 PM, Tony_AD0VC wrote:

Jon,

In your link below with the antenna, take a close look at the range from 0-500Khz. Note that the upper picture baseline (top of window) is 0db while the lower trace baseline is -10db. Now, To my eyes, the range between 0 and 500Khz is darn near identical. A 6db loss would be very evident here and it is not showing one. As soon as we hit 500Khz, the filter kills everything and all of the BC station pips disappear.

This picture shows the filter working correctly as far as I can tell. If you notice differences when you connect it to the radio instead of the SA then the cause is related to the connection to the radio. Maybe a bad/intermittent connector/cable? Some kind of common mode issue? I don't know. But I think all your tuning effort is barking up the wrong tree.

Tony
________________________________
From: [email protected] <[email protected]> on behalf of JonI via groups.io <ji425bt@...>
Sent: Saturday, July 3, 2021 1:35 PM
To: [email protected] <[email protected]>
Subject: Re: [softrock40] homemade chebyshev 7th order BB band stop to begin soon

And here is the performance when hooked up to my antenna, same frequency
span:



Top image no filter. Notice the big AM station spike around 1.5 Mhz.
Bottom image with the filter. Seems to reduce the station by almost 30
dB. I notice a loss with the filter in place though of about 6 dB and I
think the spectra shows this. Not sure why the higher loss.

Jon


On 7/3/21 3:14 PM, JonI via groups.io wrote:

Ok, here we are:



Top image shows spectra of the filter; bottom is noise source only.
Both have 50 ohm termination.

Jon


On 7/3/21 2:32 PM, Nick wrote:

Looks good Jon.

When you post the noise plots from the TinySa please can you include
a straight through one to show how flat the noise source is?

73
Nick

On 03/07/2021 16:50, JonI via groups.io wrote:

Ok, looks like those didn't go through. Here they are:

filter schematic ->

constructed filter ->

Jon

On 7/3/21 11:43 AM, JonI via groups.io wrote:

Attached is the tweaked version and the components (and presumably
values) I used.

All the caps are polystyrene, just whatever I had in my parts box.

Also attaching the filter itself.

Thanks,

Jon

Jon,

In your link below with the antenna, take a close look at the range from 0-500Khz. Note that the upper picture baseline (top of window) is 0db while the lower trace baseline is -10db. Now, To my eyes, the range between 0 and 500Khz is darn near identical. A 6db loss would be very evident here and it is not showing one. As soon as we hit 500Khz, the filter kills everything and all of the BC station pips disappear.

This picture shows the filter working correctly as far as I can tell. If you notice differences when you connect it to the radio instead of the SA then the cause is related to the connection to the radio. Maybe a bad/intermittent connector/cable? Some kind of common mode issue? I don't know. But I think all your tuning effort is barking up the wrong tree.

Tony
________________________________
From: [email protected] <[email protected]> on behalf of JonI via groups.io <ji425bt@...>
Sent: Saturday, July 3, 2021 1:35 PM
To: [email protected] <[email protected]>
Subject: Re: [softrock40] homemade chebyshev 7th order BB band stop to begin soon

And here is the performance when hooked up to my antenna, same frequency
span:



Top image no filter. Notice the big AM station spike around 1.5 Mhz.
Bottom image with the filter. Seems to reduce the station by almost 30
dB. I notice a loss with the filter in place though of about 6 dB and I
think the spectra shows this. Not sure why the higher loss.

Jon


On 7/3/21 3:14 PM, JonI via groups.io wrote:

Ok, here we are:



Top image shows spectra of the filter; bottom is noise source only.
Both have 50 ohm termination.

Jon


On 7/3/21 2:32 PM, Nick wrote:

Looks good Jon.

When you post the noise plots from the TinySa please can you include
a straight through one to show how flat the noise source is?

73
Nick

On 03/07/2021 16:50, JonI via groups.io wrote:

Ok, looks like those didn't go through. Here they are:

filter schematic ->

constructed filter ->

Jon

On 7/3/21 11:43 AM, JonI via groups.io wrote:

Attached is the tweaked version and the components (and presumably
values) I used.

All the caps are polystyrene, just whatever I had in my parts box.

Also attaching the filter itself.

Thanks,

Jon

I give up! I've spent the day trying to research such filters, changed
out some caps, switched out toroids, but to no avail. Still have
excessive loss even though the filtering seems to be where it should
be. <snip>...

I'm going to continue working on mine as time permits.? Is it possible
that since I built it on double sided copper clad I am having issues?

Lets see if this works:





Tony

________________________________
From: [email protected] <[email protected]> on behalf of Tony_AD0VC <canthony15@...>
Sent: Monday, July 5, 2021 1:10 PM
To: [email protected] <[email protected]>
Subject: Re: [softrock40] homemade chebyshev 7th order BB band stop to begin soon

Type FT37-61.

________________________________
From: [email protected] <[email protected]> on behalf of Tony_AD0VC <canthony15@...>
Sent: Monday, July 5, 2021 1:08 PM
To: [email protected] <[email protected]>
Subject: Re: [softrock40] homemade chebyshev 7th order BB band stop to begin soon

I built this filter today with very good results.

The cores were FT37-11. The 13uh cores were 15 turns and measured about 13.2uh. The 3uh were 7 turns and measured about 3.1uh. The 2uh were 5 turns and measured 1.8 and 1.9uh. Adding a turn on the 1.8uh made it 2.4uh so I stayed with the 1.8uh. Caps are ceramic. I used the LCR meter to check the caps and I did toss out one of the 10nf that measure 9.1nf.

I used my noise generator (Micronetics) to test with. I'll probably keep this. Let me go ook at imgur. Maybe I'll set up a login there so I can post some pics.

Tony



________________________________
From: [email protected] <[email protected]> on behalf of JonI via groups.io <ji425bt@...>
Sent: Monday, July 5, 2021 12:50 PM
To: [email protected] <[email protected]>
Subject: Re: [softrock40] homemade chebyshev 7th order BB band stop to begin soon

Ok, here is the test set up and results for the first LC in series.



Unfortunately, I can't tell where resonance is as there are quite a few
small peaks.

Jon


On 7/5/21 11:36 AM, Nick wrote:

I've used a glue gun on toroids in the past and not had a problem.
Use it sparingly though just in case you have to remove it later.

BTW do you have a link to the Nooelec filter you mentioned?

Nick

On 05/07/2021 16:18, JonI via groups.io wrote:

Thanks! Those are some good instructions, something I was looking
for yesterday on how to align the sections. Any advice to keep the
toroid turns in place once aligned? I find they can move quite a
bit during installation. Was thinking hot glue, but might hurt the
enamel.

Jon


On 7/5/21 11:04 AM, Nick wrote:

On 05/07/2021 14:12, JonI via groups.io wrote:

I did check the inductance of the toroids before installation using
a separate capacitor, dip meter, and frequency counter.
Unfortunately, my dip meter doesn't go low enough to check the
resonances you indicate.

You should be able to do this with your noise source and TinySA.

Make up a test jig with a piece of scrap PCB and two BNC connectors.

Remove the resonators one by one from the filter and align as follows.

For the series resonators L1/C1 etc connect the two BNC centers and
strap the series resonator from there to ground.

Noise generator on one side, TinySA on the other. You should see a
sharp dip at the resonant frequency of 919kHz. Squeeze or stretch
the toroid's turns to get that frequency, then reinstall the
resonator in the filter.

For the parallel resonators L2/C2 etc connect the resonator between
the two BNC centers. You should see a sharp dip at the resonant
frequency of 941kHz. Squeeze or stretch the toroid's turns to get
that frequency, then reinstall the resonator in the filter.

HTH

Nick

Jon

With a parallel resonator strapped across the line you will get a broad peak not a null.

The output impedance of the noise generator (low) and your resistive divider (low) are shunting the resonator, so very low Q.

Try this...

NOISE GEN--------.--------20:1 DIVIDER---------TINYSA
???????????????? .
???????????????? L
???????????????? .
???????????????? .
???????????????? C
???????????????? .
???????????????? .
??????????????? GND

i.e.

For the series resonators L1/C1 etc connect the two BNC centers and
strap the series resonator from there to ground.

The depth of the null will be limited by the Q of the inductor.

Nick

PS:

On 05/07/2021 19:50, JonI via groups.io wrote:

Ok, here is the test set up and results for the first LC in series.



Unfortunately, I can't tell where resonance is as there are quite a few small peaks.

Jon


On 7/5/21 11:36 AM, Nick wrote:

I've used a glue gun on toroids in the past and not had a problem. Use it sparingly though just in case you have to remove it later.

BTW do you have a link to the Nooelec filter you mentioned?

Nick

On 05/07/2021 16:18, JonI via groups.io wrote:

Thanks!? Those are some good instructions, something I was looking for yesterday on how to align the sections.? Any advice to keep the toroid turns in place once aligned?? I find they can move quite? a bit during installation.? Was thinking hot glue, but might hurt the enamel.

Jon


On 7/5/21 11:04 AM, Nick wrote:

On 05/07/2021 14:12, JonI via groups.io wrote:

I did check the inductance of the toroids before installation using a separate capacitor, dip meter, and frequency counter. Unfortunately, my dip meter doesn't go low enough to check the resonances you indicate.

You should be able to do this with your noise source and TinySA.

Make up a test jig with a piece of scrap PCB and two BNC connectors.

Remove the resonators one by one from the filter and align as follows.

For the series resonators L1/C1 etc connect the two BNC centers and strap the series resonator from there to ground.

Noise generator on one side, TinySA on the other.? You should see a sharp dip at the resonant frequency of 919kHz.? Squeeze or stretch the toroid's turns to get that frequency, then reinstall the resonator in the filter.

For the parallel resonators L2/C2 etc connect the resonator between the two BNC centers.? You should see a sharp dip at the resonant frequency of 941kHz. Squeeze or stretch the toroid's turns to get that frequency, then reinstall the resonator in the filter.

HTH

Nick