Hamtronics receiver issue with AllStar RTCM

AllStarLink
1

For a voter project, we got the hamtronics VHF receiver pretuned to the repeaters input frequency. The idea is to use hamtronics receivers for every voted receive site for equivalent audio characteristics.

http://www.hamtronics.com/r303.htm

When hooked up to the discriminator on the hamtronics board, I could not get the RTCM to calibrate squelch. It usually told me the audio was too low weather the RX level was bumped up or down. I then hooked it up to a motorola SM50 and it calibrated shortly after adjusting RX levels.

So… I hooked a cheap sound card up to audacity, and took a look at the spectrum of each receiver. The hamtronics obviously looks like it lacks high frequency noise on the discriminator output.

Here is the SM50 discriminator out:

amsatnet.info/SM50.png

Here is the hamtronics discriminator out:

amsatnet.info/HAMTRONICS.png

Here is an audio sample comparing them (you can probably guess which radio is first):

amsatnet.info/Sm50_hamtron_DISC.wav

Does anybody else have experience with hamtronics receivers?

Thanks,

Skyler KD0WHB

2

Try adding JP1 in the RTCM. This gives some gain to the squelch noise amp.

If that works you’ll want to turn on the RTCM’s BEW (#17 on the main menu). If it’s not on that menu you’ll need to download the proper firmware and upgrade. This help radios with low out of band discriminator noise not false the squelch on voice peaks. There 3 settings 0) off, 1) on, and 3) on with more aggressive locking.

But first make sure you can calibrate the squelch with JP1 in. Otherwise your SOL and there’s no reason to upgrade. In that case you’ll have to buy some other radios for your voters.

···

On Sun, Mar 27, 2016 at 2:12 PM, Skyler F electricity440@gmail.com wrote:

For a voter project, we got the hamtronics VHF receiver pretuned to the repeaters input frequency. The idea is to use hamtronics receivers for every voted receive site for equivalent audio characteristics.

http://www.hamtronics.com/r303.htm

When hooked up to the discriminator on the hamtronics board, I could not get the RTCM to calibrate squelch. It usually told me the audio was too low weather the RX level was bumped up or down. I then hooked it up to a motorola SM50 and it calibrated shortly after adjusting RX levels.

So… I hooked a cheap sound card up to audacity, and took a look at the spectrum of each receiver. The hamtronics obviously looks like it lacks high frequency noise on the discriminator output.

Here is the SM50 discriminator out:

amsatnet.info/SM50.png

Here is the hamtronics discriminator out:

amsatnet.info/HAMTRONICS.png

Here is an audio sample comparing them (you can probably guess which radio is first):

amsatnet.info/Sm50_hamtron_DISC.wav

Does anybody else have experience with hamtronics receivers?

Thanks,

Skyler KD0WHB

App_rpt-users mailing list

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http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users

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–

–

Tim

3

Ok, so JP1 is just for the squelch amp? the RX levels are fine. When I ignored squelch, I could easily get a 3khz tone to show at 3khz on the menu.

···

On Sun, Mar 27, 2016 at 4:23 PM, Tim Sawyer tisawyer@gmail.com wrote:

Try adding JP1 in the RTCM. This gives some gain to the squelch noise amp.

If that works you’ll want to turn on the RTCM’s BEW (#17 on the main menu). If it’s not on that menu you’ll need to download the proper firmware and upgrade. This help radios with low out of band discriminator noise not false the squelch on voice peaks. There 3 settings 0) off, 1) on, and 3) on with more aggressive locking.

But first make sure you can calibrate the squelch with JP1 in. Otherwise your SOL and there’s no reason to upgrade. In that case you’ll have to buy some other radios for your voters.

–

On Sun, Mar 27, 2016 at 2:12 PM, Skyler F electricity440@gmail.com wrote:

For a voter project, we got the hamtronics VHF receiver pretuned to the repeaters input frequency. The idea is to use hamtronics receivers for every voted receive site for equivalent audio characteristics.

http://www.hamtronics.com/r303.htm

When hooked up to the discriminator on the hamtronics board, I could not get the RTCM to calibrate squelch. It usually told me the audio was too low weather the RX level was bumped up or down. I then hooked it up to a motorola SM50 and it calibrated shortly after adjusting RX levels.

So… I hooked a cheap sound card up to audacity, and took a look at the spectrum of each receiver. The hamtronics obviously looks like it lacks high frequency noise on the discriminator output.

Here is the SM50 discriminator out:

amsatnet.info/SM50.png

Here is the hamtronics discriminator out:

amsatnet.info/HAMTRONICS.png

Here is an audio sample comparing them (you can probably guess which radio is first):

amsatnet.info/Sm50_hamtron_DISC.wav

Does anybody else have experience with hamtronics receivers?

Thanks,

Skyler KD0WHB

App_rpt-users mailing list

App_rpt-users@ohnosec.org

http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users

To unsubscribe from this list please visit http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users and scroll down to the bottom of the page. Enter your email address and press the “Unsubscribe or edit options button”

You do not need a password to unsubscribe, you can do it via email confirmation. If you have trouble unsubscribing, please send a message to the list detailing the problem.

–

Tim

–

Skyler Fennell
amsatnet.info

KDØWHB

electricity440@gmail.com

4

Honestly…With $25 Maxtracs all over the place…why…WHY would you want to screw around with anything Hamtronics makes…seriously…

···

On Sun, Mar 27, 2016 at 3:23 PM, Tim Sawyer tisawyer@gmail.com wrote:

Try adding JP1 in the RTCM. This gives some gain to the squelch noise amp.

If that works you’ll want to turn on the RTCM’s BEW (#17 on the main menu). If it’s not on that menu you’ll need to download the proper firmware and upgrade. This help radios with low out of band discriminator noise not false the squelch on voice peaks. There 3 settings 0) off, 1) on, and 3) on with more aggressive locking.

But first make sure you can calibrate the squelch with JP1 in. Otherwise your SOL and there’s no reason to upgrade. In that case you’ll have to buy some other radios for your voters.

App_rpt-users mailing list

App_rpt-users@ohnosec.org

http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users

To unsubscribe from this list please visit http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users and scroll down to the bottom of the page. Enter your email address and press the “Unsubscribe or edit options button”

You do not need a password to unsubscribe, you can do it via email confirmation. If you have trouble unsubscribing, please send a message to the list detailing the problem.

On Sun, Mar 27, 2016 at 2:12 PM, Skyler F electricity440@gmail.com wrote:

For a voter project, we got the hamtronics VHF receiver pretuned to the repeaters input frequency. The idea is to use hamtronics receivers for every voted receive site for equivalent audio characteristics.

http://www.hamtronics.com/r303.htm

When hooked up to the discriminator on the hamtronics board, I could not get the RTCM to calibrate squelch. It usually told me the audio was too low weather the RX level was bumped up or down. I then hooked it up to a motorola SM50 and it calibrated shortly after adjusting RX levels.

So… I hooked a cheap sound card up to audacity, and took a look at the spectrum of each receiver. The hamtronics obviously looks like it lacks high frequency noise on the discriminator output.

Here is the SM50 discriminator out:

amsatnet.info/SM50.png

Here is the hamtronics discriminator out:

amsatnet.info/HAMTRONICS.png

Here is an audio sample comparing them (you can probably guess which radio is first):

amsatnet.info/Sm50_hamtron_DISC.wav

Does anybody else have experience with hamtronics receivers?

Thanks,

Skyler KD0WHB

App_rpt-users mailing list

App_rpt-users@ohnosec.org

http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users

To unsubscribe from this list please visit http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users and scroll down to the bottom of the page. Enter your email address and press the “Unsubscribe or edit options button”

You do not need a password to unsubscribe, you can do it via email confirmation. If you have trouble unsubscribing, please send a message to the list detailing the problem.

–

Tim

–

5

Because the Denver Radio club wants to

···

On Sun, Mar 27, 2016 at 5:05 PM, Kirk Just Kirk wb6egr@gmail.com wrote:

Honestly…With $25 Maxtracs all over the place…why…WHY would you want to screw around with anything Hamtronics makes…seriously…

–

On Sun, Mar 27, 2016 at 3:23 PM, Tim Sawyer tisawyer@gmail.com wrote:

Try adding JP1 in the RTCM. This gives some gain to the squelch noise amp.

If that works you’ll want to turn on the RTCM’s BEW (#17 on the main menu). If it’s not on that menu you’ll need to download the proper firmware and upgrade. This help radios with low out of band discriminator noise not false the squelch on voice peaks. There 3 settings 0) off, 1) on, and 3) on with more aggressive locking.

But first make sure you can calibrate the squelch with JP1 in. Otherwise your SOL and there’s no reason to upgrade. In that case you’ll have to buy some other radios for your voters.

App_rpt-users mailing list

App_rpt-users@ohnosec.org

http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users

To unsubscribe from this list please visit http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users and scroll down to the bottom of the page. Enter your email address and press the “Unsubscribe or edit options button”

You do not need a password to unsubscribe, you can do it via email confirmation. If you have trouble unsubscribing, please send a message to the list detailing the problem.

On Sun, Mar 27, 2016 at 2:12 PM, Skyler F electricity440@gmail.com wrote:

For a voter project, we got the hamtronics VHF receiver pretuned to the repeaters input frequency. The idea is to use hamtronics receivers for every voted receive site for equivalent audio characteristics.

http://www.hamtronics.com/r303.htm

When hooked up to the discriminator on the hamtronics board, I could not get the RTCM to calibrate squelch. It usually told me the audio was too low weather the RX level was bumped up or down. I then hooked it up to a motorola SM50 and it calibrated shortly after adjusting RX levels.

So… I hooked a cheap sound card up to audacity, and took a look at the spectrum of each receiver. The hamtronics obviously looks like it lacks high frequency noise on the discriminator output.

Here is the SM50 discriminator out:

amsatnet.info/SM50.png

Here is the hamtronics discriminator out:

amsatnet.info/HAMTRONICS.png

Here is an audio sample comparing them (you can probably guess which radio is first):

amsatnet.info/Sm50_hamtron_DISC.wav

Does anybody else have experience with hamtronics receivers?

Thanks,

Skyler KD0WHB

App_rpt-users mailing list

App_rpt-users@ohnosec.org

http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users

To unsubscribe from this list please visit http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users and scroll down to the bottom of the page. Enter your email address and press the “Unsubscribe or edit options button”

You do not need a password to unsubscribe, you can do it via email confirmation. If you have trouble unsubscribing, please send a message to the list detailing the problem.

–

Tim

–

Skyler Fennell
amsatnet.info

KDØWHB

electricity440@gmail.com

6

Yes, I have a number of them in place and find they work perfectly with the
RTCM. It can give about 2v P-P on the discriminator pin, and has the high
frequency compute the RTCM squelch needs.

My prime setup is here:

1000×563 95.2 KB

Note you'll want to put a cap in line, as the discriminator is DC coupled in
the hamtronics. Can you put a scope on the discriminator line and measure the
voltage? You might have a problem with the receiver.

73's

···

On 3/27/16 5:12 PM, Skyler F wrote:

For a voter project, we got the hamtronics VHF receiver pretuned to the
repeaters input frequency. The idea is to use hamtronics receivers for
every voted receive site for equivalent audio characteristics.

So... I hooked a cheap sound card up to audacity, and took a look at the
spectrum of each receiver. The hamtronics obviously looks like it lacks
high frequency noise on the discriminator output.

Does anybody else have experience with hamtronics receivers?

--
Bryan Fields

727-409-1194 - Voice
727-214-2508 - Fax
http://bryanfields.net

7

My scope does not really work very well anymore but I’ll see if I can get a P-P reading. What value cap should I put on the discriminator line?

73

···

On Sun, Mar 27, 2016 at 5:08 PM, Bryan Fields Bryan@bryanfields.net wrote:

On 3/27/16 5:12 PM, Skyler F wrote:

For a voter project, we got the hamtronics VHF receiver pretuned to the

repeaters input frequency. The idea is to use hamtronics receivers for

every voted receive site for equivalent audio characteristics.

So… I hooked a cheap sound card up to audacity, and took a look at the

spectrum of each receiver. The hamtronics obviously looks like it lacks

high frequency noise on the discriminator output.

Does anybody else have experience with hamtronics receivers?

Yes, I have a number of them in place and find they work perfectly with the

RTCM. It can give about 2v P-P on the discriminator pin, and has the high

frequency compute the RTCM squelch needs.

My prime setup is here:

http://gallery.keekles.org/d/28384-2/0330141929a.jpg

Note you’ll want to put a cap in line, as the discriminator is DC coupled in

the hamtronics. Can you put a scope on the discriminator line and measure the

voltage? You might have a problem with the receiver.

73’s

–

Bryan Fields

727-409-1194 - Voice

727-214-2508 - Fax

http://bryanfields.net

App_rpt-users mailing list

App_rpt-users@ohnosec.org

http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users

To unsubscribe from this list please visit http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users and scroll down to the bottom of the page. Enter your email address and press the “Unsubscribe or edit options button”

You do not need a password to unsubscribe, you can do it via email confirmation. If you have trouble unsubscribing, please send a message to the list detailing the problem.

–

Skyler Fennell
amsatnet.info

KDØWHB

electricity440@gmail.com

8

I am getting 2v P-P

···

On Sun, Mar 27, 2016 at 5:33 PM, Skyler F electricity440@gmail.com wrote:

My scope does not really work very well anymore but I’ll see if I can get a P-P reading. What value cap should I put on the discriminator line?

73

–

On Sun, Mar 27, 2016 at 5:08 PM, Bryan Fields Bryan@bryanfields.net wrote:

On 3/27/16 5:12 PM, Skyler F wrote:

For a voter project, we got the hamtronics VHF receiver pretuned to the

repeaters input frequency. The idea is to use hamtronics receivers for

every voted receive site for equivalent audio characteristics.

So… I hooked a cheap sound card up to audacity, and took a look at the

spectrum of each receiver. The hamtronics obviously looks like it lacks

high frequency noise on the discriminator output.

Does anybody else have experience with hamtronics receivers?

Yes, I have a number of them in place and find they work perfectly with the

RTCM. It can give about 2v P-P on the discriminator pin, and has the high

frequency compute the RTCM squelch needs.

My prime setup is here:

http://gallery.keekles.org/d/28384-2/0330141929a.jpg

Note you’ll want to put a cap in line, as the discriminator is DC coupled in

the hamtronics. Can you put a scope on the discriminator line and measure the

voltage? You might have a problem with the receiver.

73’s

–

Bryan Fields

727-409-1194 - Voice

727-214-2508 - Fax

http://bryanfields.net

App_rpt-users mailing list

App_rpt-users@ohnosec.org

http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users

To unsubscribe from this list please visit http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users and scroll down to the bottom of the page. Enter your email address and press the “Unsubscribe or edit options button”

You do not need a password to unsubscribe, you can do it via email confirmation. If you have trouble unsubscribing, please send a message to the list detailing the problem.

–
Skyler Fennell
amsatnet.info

KDØWHB

electricity440@gmail.com

Skyler Fennell
amsatnet.info

KDØWHB

electricity440@gmail.com

9

Hi Bryan, can you send me the exact wiring between your hamtronics and your RTCM? What value DC blocking capacitor, any jumpers in the RTCM selected etc…?

73,

Skyler

···

On Sun, Mar 27, 2016 at 5:08 PM, Bryan Fields Bryan@bryanfields.net wrote:

On 3/27/16 5:12 PM, Skyler F wrote:

For a voter project, we got the hamtronics VHF receiver pretuned to the

repeaters input frequency. The idea is to use hamtronics receivers for

every voted receive site for equivalent audio characteristics.

So… I hooked a cheap sound card up to audacity, and took a look at the

spectrum of each receiver. The hamtronics obviously looks like it lacks

high frequency noise on the discriminator output.

Does anybody else have experience with hamtronics receivers?

Yes, I have a number of them in place and find they work perfectly with the

RTCM. It can give about 2v P-P on the discriminator pin, and has the high

frequency compute the RTCM squelch needs.

My prime setup is here:

http://gallery.keekles.org/d/28384-2/0330141929a.jpg

Note you’ll want to put a cap in line, as the discriminator is DC coupled in

the hamtronics. Can you put a scope on the discriminator line and measure the

voltage? You might have a problem with the receiver.

73’s

–

Bryan Fields

727-409-1194 - Voice

727-214-2508 - Fax

http://bryanfields.net

App_rpt-users mailing list

App_rpt-users@ohnosec.org

http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users

To unsubscribe from this list please visit http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users and scroll down to the bottom of the page. Enter your email address and press the “Unsubscribe or edit options button”

You do not need a password to unsubscribe, you can do it via email confirmation. If you have trouble unsubscribing, please send a message to the list detailing the problem.

–

Skyler Fennell
amsatnet.info

KDØWHB

electricity440@gmail.com

10

I added a 10µF electrolytic capacitor in series with the Discriminator output of my hamtronics, but was still not able to get the squelch calibrated. Here was the diagnostic output:
Testing level at 1000 Hz for De-Emphasized Audio

Testing level at 2000 Hz for De-Emphasized Audio

Error – Measured 9581, should have been between 4380 and 6155

Testing level at 3200 Hz for De-Emphasized Audio

Error – Measured 10030, should have been between 2271 and 3073

Testing level at 3200 Hz for Squelch Noise Detector

Error – Measured 279, should have been between 0 and 50

Testing level at 6000 Hz for Squelch Noise Detector

Testing level at 7200 Hz for Squelch Noise Detector

Error – Measured 211, should have been between 500 and 1023

···

On Sun, Mar 27, 2016 at 10:53 PM, Eric Guth eric@efratnetworks.net wrote:

10 Uf , 35VDC will usually do the job.

73,

Eric Guth

4Z1UG

Allstar: 28422

QSO Today

From: app_rpt-users-bounces@ohnosec.org [mailto:app_rpt-users-bounces@ohnosec.org]
On Behalf Of Skyler F
Sent: Monday, March 28, 2016 7:35 AM
To: Bryan Fields
Cc: app_rpt-users@ohnosec.org
Subject: Re: [App_rpt-users] Hamtronics receiver issue with AllStar RTCM

Hi Bryan, can you send me the exact wiring between your hamtronics and your RTCM? What value DC blocking capacitor, any jumpers in the RTCM selected etc…?

73,

Skyler

On Sun, Mar 27, 2016 at 5:08 PM, Bryan Fields Bryan@bryanfields.net wrote:

On 3/27/16 5:12 PM, Skyler F wrote:

For a voter project, we got the hamtronics VHF receiver pretuned to the

repeaters input frequency. The idea is to use hamtronics receivers for

every voted receive site for equivalent audio characteristics.

So… I hooked a cheap sound card up to audacity, and took a look at the

spectrum of each receiver. The hamtronics obviously looks like it lacks

high frequency noise on the discriminator output.

Does anybody else have experience with hamtronics receivers?

Yes, I have a number of them in place and find they work perfectly with the

RTCM. It can give about 2v P-P on the discriminator pin, and has the high

frequency compute the RTCM squelch needs.

My prime setup is here:

http://gallery.keekles.org/d/28384-2/0330141929a.jpg

Note you’ll want to put a cap in line, as the discriminator is DC coupled in

the hamtronics. Can you put a scope on the discriminator line and measure the

voltage? You might have a problem with the receiver.

73’s

–

Bryan Fields

727-409-1194 - Voice

727-214-2508 - Fax

http://bryanfields.net

App_rpt-users mailing list

App_rpt-users@ohnosec.org

http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users

To unsubscribe from this list please visit
http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users and scroll down to the bottom of the page. Enter your email address and press the “Unsubscribe or edit options button”

You do not need a password to unsubscribe, you can do it via email confirmation. If you have trouble unsubscribing, please send a message to the list detailing the problem.

–

Skyler Fennell

amsatnet.info

KDØWHB

electricity440@gmail.com

–

Skyler Fennell
amsatnet.info

KDØWHB

electricity440@gmail.com

11

Actually, the normal audio output is probably what is needed, not de-emph. Again with the 10µF capacitor.

Here is my entire output when I get Normal Audio as good as I can get it. Everything passes except for 3200Hz.

Testing level at 100 Hz for Normal Audio

Testing level at 320 Hz for Normal Audio

Testing level at 500 Hz for Normal Audio

Testing level at 1000 Hz for Normal Audio

Testing level at 2000 Hz for Normal Audio

Testing level at 3200 Hz for Normal Audio

Error – Measured 10755, should have been between 6929 and 9374

Testing level at 100 Hz for CTCSS Filtered Audio

Error – Measured 11719, should have been between 100 and 451

Testing level at 320 Hz for CTCSS Filtered Audio

Testing level at 500 Hz for CTCSS Filtered Audio

Testing level at 1000 Hz for CTCSS Filtered Audio

Testing level at 2000 Hz for CTCSS Filtered Audio

Error – Measured 12326, should have been between 8989 and 12162

Testing level at 3200 Hz for CTCSS Filtered Audio

Error – Measured 11827, should have been between 6929 and 9374

Testing level at 1000 Hz for De-Emphasized Audio

Error – Measured 45868, should have been between 9798 and 13257

Testing level at 2000 Hz for De-Emphasized Audio

Error – Measured 41568, should have been between 4380 and 6155

Testing level at 3200 Hz for De-Emphasized Audio

Error – Measured 43439, should have been between 2271 and 3073

Testing level at 3200 Hz for Squelch Noise Detector

Error – Measured 436, should have been between 0 and 50

Testing level at 6000 Hz for Squelch Noise Detector

Testing level at 7200 Hz for Squelch Noise Detector

Error – Measured 264, should have been between 500 and 1023

···

On Mon, Mar 28, 2016 at 11:22 AM, Skyler F electricity440@gmail.com wrote:

I added a 10µF electrolytic capacitor in series with the Discriminator output of my hamtronics, but was still not able to get the squelch calibrated. Here was the diagnostic output:
Testing level at 1000 Hz for De-Emphasized Audio

Testing level at 2000 Hz for De-Emphasized Audio

Error – Measured 9581, should have been between 4380 and 6155

Testing level at 3200 Hz for De-Emphasized Audio

Error – Measured 10030, should have been between 2271 and 3073

Testing level at 3200 Hz for Squelch Noise Detector

Error – Measured 279, should have been between 0 and 50

Testing level at 6000 Hz for Squelch Noise Detector

Testing level at 7200 Hz for Squelch Noise Detector

Error – Measured 211, should have been between 500 and 1023

–

On Sun, Mar 27, 2016 at 10:53 PM, Eric Guth eric@efratnetworks.net wrote:

10 Uf , 35VDC will usually do the job.

73,

Eric Guth

4Z1UG

Allstar: 28422

QSO Today

From: app_rpt-users-bounces@ohnosec.org [mailto:app_rpt-users-bounces@ohnosec.org]
On Behalf Of Skyler F
Sent: Monday, March 28, 2016 7:35 AM
To: Bryan Fields
Cc: app_rpt-users@ohnosec.org
Subject: Re: [App_rpt-users] Hamtronics receiver issue with AllStar RTCM

Hi Bryan, can you send me the exact wiring between your hamtronics and your RTCM? What value DC blocking capacitor, any jumpers in the RTCM selected etc…?

73,

Skyler

On Sun, Mar 27, 2016 at 5:08 PM, Bryan Fields Bryan@bryanfields.net wrote:

On 3/27/16 5:12 PM, Skyler F wrote:

For a voter project, we got the hamtronics VHF receiver pretuned to the

repeaters input frequency. The idea is to use hamtronics receivers for

every voted receive site for equivalent audio characteristics.

So… I hooked a cheap sound card up to audacity, and took a look at the

spectrum of each receiver. The hamtronics obviously looks like it lacks

high frequency noise on the discriminator output.

Does anybody else have experience with hamtronics receivers?

Yes, I have a number of them in place and find they work perfectly with the

RTCM. It can give about 2v P-P on the discriminator pin, and has the high

frequency compute the RTCM squelch needs.

My prime setup is here:

http://gallery.keekles.org/d/28384-2/0330141929a.jpg

Note you’ll want to put a cap in line, as the discriminator is DC coupled in

the hamtronics. Can you put a scope on the discriminator line and measure the

voltage? You might have a problem with the receiver.

73’s

–

Bryan Fields

727-409-1194 - Voice

727-214-2508 - Fax

http://bryanfields.net

App_rpt-users mailing list

App_rpt-users@ohnosec.org

http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users

To unsubscribe from this list please visit
http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users and scroll down to the bottom of the page. Enter your email address and press the “Unsubscribe or edit options button”

You do not need a password to unsubscribe, you can do it via email confirmation. If you have trouble unsubscribing, please send a message to the list detailing the problem.

–

Skyler Fennell

amsatnet.info

KDØWHB

electricity440@gmail.com

–
Skyler Fennell
amsatnet.info

KDØWHB

electricity440@gmail.com

Skyler Fennell
amsatnet.info

KDØWHB

electricity440@gmail.com

12

Here is the schematic of the hamtronics output:
amsatnet.info/r303out.png

Isn’t R34 and C44 a lowpass??

···

On Mon, Mar 28, 2016 at 11:51 AM, Skyler F electricity440@gmail.com wrote:

I think normal would be disc., the only other display is deemphasized and CTCSS filtered

–

On Mon, Mar 28, 2016 at 11:36 AM, Steve Agee n5zua@earthlink.net wrote:

` For this exercise, audio is either referenced as pre-emphasized
(discriminator) or de-emphasized (speaker). So, by “normal” do
you mean discriminator?

    N5ZUA

  `

On 3/28/2016 12:30 PM, Skyler F wrote:

    Actually, the normal audio output is probably what

is needed, not de-emph. Again with the 10µF capacitor.

        Here is my entire output when I get Normal Audio as good

as I can get it. Everything passes except for 3200Hz.

            Testing level at 100 Hz for

Normal Audio

            Testing level at 320 Hz for

Normal Audio

            Testing level at 500 Hz for

Normal Audio

            Testing level at 1000 Hz for

Normal Audio

            Testing level at 2000 Hz for

Normal Audio

            Testing level at 3200 Hz for

Normal Audio

            Error -- Measured 10755, should

have been between 6929 and 9374

            Testing level at 100 Hz for CTCSS

Filtered Audio

            Error -- Measured 11719, should

have been between 100 and 451

            Testing level at 320 Hz for CTCSS

Filtered Audio

            Testing level at 500 Hz for CTCSS

Filtered Audio

            Testing level at 1000 Hz for

CTCSS Filtered Audio

            Testing level at 2000 Hz for

CTCSS Filtered Audio

            Error -- Measured 12326, should

have been between 8989 and 12162

            Testing level at 3200 Hz for

CTCSS Filtered Audio

            Error -- Measured 11827, should

have been between 6929 and 9374

            Testing level at 1000 Hz for

De-Emphasized Audio

            Error -- Measured 45868, should

have been between 9798 and 13257

            Testing level at 2000 Hz for

De-Emphasized Audio

            Error -- Measured 41568, should

have been between 4380 and 6155

            Testing level at 3200 Hz for

De-Emphasized Audio

            Error -- Measured 43439, should

have been between 2271 and 3073

            Testing level at 3200 Hz for

Squelch Noise Detector

            Error -- Measured 436, should

have been between 0 and 50

            Testing level at 6000 Hz for

Squelch Noise Detector

            Testing level at 7200 Hz for

Squelch Noise Detector

            Error -- Measured 264, should

have been between 500 and 1023

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      On Mon, Mar 28, 2016 at 11:22 AM,

Skyler F electricity440@gmail.com
wrote:

          I added a 10µF electrolytic capacitor in

series with the Discriminator output of my hamtronics, but
was still not able to get the squelch calibrated. Here was
the diagnostic output:
Testing level at 1000 Hz for De-Emphasized
Audio

                Testing level at 2000 Hz for De-Emphasized

Audio

                Error -- Measured 9581, should have been

between 4380 and 6155

                Testing level at 3200 Hz for De-Emphasized

Audio

                Error -- Measured 10030, should have been

between 2271 and 3073

                Testing level at 3200 Hz for Squelch Noise

Detector

                Error -- Measured 279, should have been between

0 and 50

                Testing level at 6000 Hz for Squelch Noise

Detector

                Testing level at 7200 Hz for Squelch Noise

Detector

                Error -- Measured 211, should have been between

500 and 1023

–
Skyler Fennell
amsatnet.info

KDØWHB

electricity440@gmail.com

                On Sun, Mar 27, 2016 at 10:53

PM, Eric Guth eric@efratnetworks.net
wrote:

                          10

Uf , 35VDC will usually do the job.

                        73,

                          Eric

Guth

4Z1UG

                          Allstar:

28422

QSO
Today

From:
app_rpt-users-bounces@ohnosec.org
[mailto:app_rpt-users-bounces@ohnosec.org ]
On Behalf Of Skyler F
Sent: Monday, March 28, 2016 7:35
AM
To: Bryan Fields
Cc: app_rpt-users@ohnosec.org
Subject: Re: [App_rpt-users]
Hamtronics receiver issue with AllStar
RTCM

                              Hi Bryan, can you

send me the exact wiring between your
hamtronics and your RTCM? What value
DC blocking capacitor, any jumpers in
the RTCM selected etc…?

73,

Skyler

                                On Sun, Mar 27,

2016 at 5:08 PM, Bryan Fields <Bryan@bryanfields.net >
wrote:

                                On 3/27/16 5:12

PM, Skyler F wrote:

                                > For a voter project, we got the

hamtronics VHF receiver pretuned to
the

                                > repeaters input frequency. The

idea is to use hamtronics receivers
for

                                > every voted receive site for

equivalent audio characteristics.

                                > So... I hooked a cheap sound

card up to audacity, and took a look
at the

                                > spectrum of each receiver. The

hamtronics obviously looks like it
lacks

                                > high frequency noise on the

discriminator output.

                                > Does anybody else have

experience with hamtronics
receivers?

                                Yes, I have a number of them in

place and find they work perfectly
with the

                                RTCM.  It can give about 2v P-P on

the discriminator pin, and has the
high

                                frequency compute the RTCM squelch

needs.

                                My prime setup is here:

                                [http://gallery.keekles.org/d/28384-2/0330141929a.jpg](http://gallery.keekles.org/d/28384-2/0330141929a.jpg)



                                Note you'll want to put a cap in

line, as the discriminator is DC
coupled in

                                the hamtronics.  Can you put a scope

on the discriminator line and
measure the

                                voltage?  You might have a problem

with the receiver.

                                73's

                                --

                                  Bryan Fields



                                  727-409-1194                                         -

Voice

                                  727-214-2508                                         -

Fax

                                  [http://bryanfields.net](http://bryanfields.net)

                                    App_rpt-users mailing list

                                    App_rpt-users@ohnosec.org

                                    [http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users](http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users)



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–

                                    Skyler

Fennell

amsatnet.info

KDØWHB

electricity440@gmail.com

–
Skyler Fennell
amsatnet.info

KDØWHB

electricity440@gmail.com

Skyler Fennell
amsatnet.info

KDØWHB

electricity440@gmail.com

13

I added a 10µF electrolytic capacitor in series with the Discriminator
output of my hamtronics, but was still not able to get the squelch
calibrated. Here was the diagnostic output:

<snip>

Strange, are you 100% sure you're on the discriminator output?

From what you have it looks like you're on the lowpass filtered and amp'd

speaker output.

···

On 3/28/16 1:22 PM, Skyler F wrote:

--
Bryan Fields

727-409-1194 - Voice
727-214-2508 - Fax
http://bryanfields.net

14

Skyler;

1) Make sure the receiver First Local Oscillator is adjusted

correctly on frequency. (Fo -10.700 MHz) Likewise the second LO
should be at around 10.2450 MHz. The second LO is not adjustable, so
any minor error would have to be made up with the TCXO U3. After
this second step:

Then :

2) Make sure the general alignment is set properly, especially the

discriminator coil T2 which responds to 10.7000 MHz from a signal
generator, has an S curve response.� In my experience with these
sort of Quadrature� Detector chips, you can get a false sense of IF
centering where the noise component is suppressed. You might try
adjusting for maximum noise first without the 10.7000 MHz signal. Be
careful you don’t jam the coil slug.

Joe Leikhim
···

On 3/27/2016 7:48 PM, Skyler F wrote:

I am getting 2v P-P

      On Sun, Mar 27, 2016 at 5:33 PM, Skyler

F electricity440@gmail.com
wrote:

          My scope does not really work very well

anymore but I’ll see if I can get a P-P reading. What
value cap should I put on the discriminator line?

73

                On Sun, Mar 27, 2016 at 5:08

PM, Bryan Fields <>
wrote:

                    On

3/27/16 5:12 PM, Skyler F wrote:

                    > For a voter project, we got the hamtronics

VHF receiver pretuned to the

                    > repeaters input frequency. The idea is to

use hamtronics receivers for

                    > every voted receive site for equivalent

audio characteristics.

                                          > So... I hooked a cheap sound

card up to audacity, and took a look at the

                    > spectrum of each receiver. The hamtronics

obviously looks like it lacks

                    > high frequency noise on the discriminator

output.

                                          > Does anybody else have

experience with hamtronics receivers?

                                        Yes, I have a number of them in place and

find they work perfectly with the

                  RTCM.� It can give about 2v P-P on the

discriminator pin, and has the high

                  frequency compute the RTCM squelch needs.



                  My prime setup is here:

                  [http://gallery.keekles.org/d/28384-2/0330141929a.jpg](http://gallery.keekles.org/d/28384-2/0330141929a.jpg)



                  Note you'll want to put a cap in line, as the

discriminator is DC coupled in

                  the hamtronics.� Can you put a scope on the

discriminator line and measure the

                  voltage?� You might have a problem with the

receiver.

                  73's

                  --

                      Bryan Fields



                      727-409-1194�- Voice

                      727-214-2508�- Fax

                      [http://bryanfields.net](http://bryanfields.net)

                      App_rpt-users mailing list

                      App_rpt-users@ohnosec.org

                      [http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users](http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users)



                      To unsubscribe from this list please visit [](http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users)
                      and scroll down to the bottom of the page.

Enter your email address and press the
“Unsubscribe or edit options button”
You do not need a password to unsubscribe, you
can do it via email confirmation. If you have
trouble unsubscribing, please send a message
to the list detailing the problem.

–
Skyler Fennell
amsatnet.info

KD�WHB

electricity440@gmail.com

–
Skyler Fennell
amsatnet.info

KD�WHB




_______________________________________________
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-- Joe Leikhim
Leikhim and Associates
Communications Consultants
Oviedo, Florida
407-982-0446

Bryan@bryanfields.nethttp://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users

electricity440@gmail.comApp_rpt-users@ohnosec.orghttp://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-usershttp://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-usersJLeikhim@Leikhim.comWWW.LEIKHIM.COM

15

Here is the schematic of the hamtronics output:
amsatnet.info/r303out.png

Isn't R34 and C44 a lowpass??

I don't know what to make of your calibration errors as they don't seem to
correlate to a HF roll-off problem, but to answer your question, yes, it's
an RC low-pass filter, with a -3 dB corner at 2.4 kHz. You might want to
replace the 0.033 uF shunt cap with 0.01 uF to flatten out the high end of
the audio passband a bit.

        --- Jeff WN3A

···

---
This email has been checked for viruses by Avast antivirus software.

16

Replying to myself...

an RC low-pass filter, with a -3 dB corner at 2.4 kHz

After finding a better scan of the receiver schematic, what I thought was a
2k resistor as R34 is really 1k, so the corner is 4.8 kHz. Based on that, I
doubt even more the HF roll-off is the reason your calibration is failing.

          --- Jeff WN3A

···

---
This email has been checked for viruses by Avast antivirus software.

17

These are both very good points i didn't consider. I normally don't check my
reference oscillators in the hamtronics as they are using an external 10MHz
source.

You will want to check SINAD on it as well, if it's not making spec (and those
hamtronics are very sensitive), something else is wrong with it.

···

On 3/28/16 2:51 PM, Joe Leikhim wrote:

1) Make sure the receiver First Local Oscillator is adjusted correctly
on frequency. (Fo -10.700 MHz) Likewise the second LO should be at
around 10.2450 MHz. The second LO is not adjustable, so any minor error
would have to be made up with the TCXO U3. After this second step:

Then :

2) Make sure the general alignment is set properly, especially the
discriminator coil T2 which responds to 10.7000 MHz from a signal
generator, has an S curve response. In my experience with these sort of
Quadrature Detector chips, you can get a false sense of IF centering
where the noise component is suppressed. You might try adjusting for
maximum noise first without the 10.7000 MHz signal. Be careful you don't
jam the coil slug.

--
Bryan Fields

727-409-1194 - Voice
727-214-2508 - Fax
http://bryanfields.net

18

If you are using an external reference, you cannot make up for the 2nd LO error if it is wildly off. There is an easy SINAD related test in EIA-603 that is called Offset Acceptance Bandwidth that would indicate if the IF were off center. Things that could go wrong apart from simple misalignment of the Quad Detector coil could include the LO crystal being way off frequency, the IF filters being wrong BW or off spec pass frequency.

Given the symptoms, I am putting my money on a misadjusted quad coil.

Joe

···

On 3/28/2016 5:06 PM, Bryan Fields wrote:

On 3/28/16 2:51 PM, Joe Leikhim wrote:

1) Make sure the receiver First Local Oscillator is adjusted correctly
on frequency. (Fo -10.700 MHz) Likewise the second LO should be at
around 10.2450 MHz. The second LO is not adjustable, so any minor error
would have to be made up with the TCXO U3. After this second step:

Then :

2) Make sure the general alignment is set properly, especially the
discriminator coil T2 which responds to 10.7000 MHz from a signal
generator, has an S curve response. In my experience with these sort of
Quadrature Detector chips, you can get a false sense of IF centering
where the noise component is suppressed. You might try adjusting for
maximum noise first without the 10.7000 MHz signal. Be careful you don't
jam the coil slug.

These are both very good points i didn't consider. I normally don't check my
reference oscillators in the hamtronics as they are using an external 10MHz
source.

You will want to check SINAD on it as well, if it's not making spec (and those
hamtronics are very sensitive), something else is wrong with it.

--
Joe Leikhim

Leikhim and Associates

Communications Consultants

Oviedo, Florida

JLeikhim@Leikhim.com

407-982-0446

WWW.LEIKHIM.COM

19

I don’t have the test equipment to go through all of the dirty Local Oscilator, SINAD, etc., so I will have to wait on that a few weeks before the president of the club gets back in town.

WHEN I bypassed the capacitor and resistor ( 1k and .03µ) , the RTCM was able to calibrate squelch. The LED flashed several times and then was steady. Maybe the capacitor is the wrong value. There was no code on it, but based on the resistor code, the value was correct.

73

Skyler

···

On Mon, Mar 28, 2016 at 4:08 PM, Joe Leikhim rhyolite@leikhim.com wrote:

On 3/28/16 2:51 PM, Joe Leikhim wrote:

  1. Make sure the receiver First Local Oscillator is adjusted correctly

on frequency. (Fo -10.700 MHz) Likewise the second LO should be at

around 10.2450 MHz. The second LO is not adjustable, so any minor error

would have to be made up with the TCXO U3. After this second step:

Then :

  1. Make sure the general alignment is set properly, especially the

discriminator coil T2 which responds to 10.7000 MHz from a signal

generator, has an S curve response. In my experience with these sort of

Quadrature Detector chips, you can get a false sense of IF centering

where the noise component is suppressed. You might try adjusting for

maximum noise first without the 10.7000 MHz signal. Be careful you don’t

jam the coil slug.
These are both very good points i didn’t consider. I normally don’t check my

reference oscillators in the hamtronics as they are using an external 10MHz

source.

You will want to check SINAD on it as well, if it’s not making spec (and those

hamtronics are very sensitive), something else is wrong with it.

If you are using an external reference, you cannot make up for the 2nd LO error if it is wildly off. There is an easy SINAD related test in EIA-603 that is called Offset Acceptance Bandwidth that would indicate if the IF were off center. Things that could go wrong apart from simple misalignment of the Quad Detector coil could include the LO crystal being way off frequency, the IF filters being wrong BW or off spec pass frequency.

Given the symptoms, I am putting my money on a misadjusted quad coil.

Joe

On 3/28/2016 5:06 PM, Bryan Fields wrote:

–

Joe Leikhim

Leikhim and Associates

Communications Consultants

Oviedo, Florida

JLeikhim@Leikhim.com

407-982-0446

WWW.LEIKHIM.COM

App_rpt-users mailing list

App_rpt-users@ohnosec.org

http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users

To unsubscribe from this list please visit http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users and scroll down to the bottom of the page. Enter your email address and press the “Unsubscribe or edit options button”

You do not need a password to unsubscribe, you can do it via email confirmation. If you have trouble unsubscribing, please send a message to the list detailing the problem.

–

Skyler Fennell
amsatnet.info

KDØWHB

electricity440@gmail.com

20

Were these receivers factory built and tuned or did individual club
members build them? Either way, you might try others from the lot.
If you have only a rudimentary signal generator and / or frequency
counter, perhaps I can walk you through some “field expedient” steps
over the phone.

···

On 3/30/2016 12:01 PM, Skyler F wrote:

    I don't have the test equipment to go through all

of the dirty Local Oscilator, SINAD, etc., so I will have to
wait on that a few weeks before the president of the club gets
back in town.

      WHEN I bypassed the capacitor and resistor ( 1k and .03µ) ,

the RTCM was able to calibrate squelch. The LED flashed
several times and then was steady. Maybe the capacitor is the
wrong value. There was no code on it, but based on the
resistor code, the value was correct.

73

Skyler

      On Mon, Mar 28, 2016 at 4:08 PM, Joe

Leikhim rhyolite@leikhim.com
wrote:

On 3/28/16 2:51 PM, Joe Leikhim wrote:

              1) Make sure the receiver First Local Oscillator is

adjusted correctly

              on frequency. (Fo -10.700 MHz) Likewise the second LO

should be at

              around 10.2450 MHz. The second LO is not adjustable,

so any minor error

              would have to be made up with the TCXO U3. After this

second step:

              Then :



              2) Make sure the general alignment is set properly,

especially the

              discriminator coil T2 which responds to 10.7000 MHz

from a signal

              generator, has an S curve response.  In my experience

with these sort of

              Quadrature  Detector chips, you can get a false sense

of IF centering

              where the noise component is suppressed. You might try

adjusting for

              maximum noise first without the 10.7000 MHz signal. Be

careful you don’t

              jam the coil slug.

            These are both very good points i didn't consider.  I

normally don’t check my

            reference oscillators in the hamtronics as they are

using an external 10MHz

            source.



            You will want to check SINAD on it as well, if it's not

making spec (and those

            hamtronics are very sensitive), something else is wrong

with it.

        If you are

using an external reference, you cannot make up for the 2nd
LO error if it is wildly off. There is an easy SINAD related
test in EIA-603 that is called Offset Acceptance Bandwidth
that would indicate if the IF were off center. Things that
could go wrong apart from simple misalignment of the Quad
Detector coil could include the LO crystal being way off
frequency, the IF filters being wrong BW or off spec pass
frequency.

        Given the symptoms, I am putting my money on a misadjusted

quad coil.

            Joe



          On 3/28/2016 5:06 PM, Bryan Fields wrote:


          --


          Joe Leikhim





          Leikhim and Associates



          Communications Consultants



          Oviedo, Florida

            App_rpt-users mailing list

            App_rpt-users@ohnosec.org

            [http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users](http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users)



            To unsubscribe from this list please visit [](http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users)
            and scroll down to the bottom of the page. Enter your

email address and press the “Unsubscribe or edit options
button”
You do not need a password to unsubscribe, you can do it
via email confirmation. If you have trouble
unsubscribing, please send a message to the list
detailing the problem.

–
Skyler Fennell
amsatnet.info

KDØWHB


-- Joe Leikhim
Leikhim and Associates
Communications Consultants
Oviedo, Florida
407-982-0446

JLeikhim@Leikhim.com

407-982-0446

WWW.LEIKHIM.COM

http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users
electricity440@gmail.comJLeikhim@Leikhim.comWWW.LEIKHIM.COM