Topics

Gamma-matching antenna tuner


hirosmb <hirosmb@...>
 

Hi, all.

 

I am getting interested in a Gamma-Matching antenna tuner (manual one) for suppressing spurious in order to observe Japans new spurious regulation.

 

BPF will be fine but I need to make number of coils, right?

 

Then, can anyone point me out where I find some schematics of the Gamma-Matching tuner, or kit of it is very much appreciated.

 

Thanks in advance.

 

// hiro, JJ1FXF


Timothy Fidler
 

Hiro,  suggest you look at  ARRL antenna HB . You should be able to find some PDF on line .....copyright breach and all. (this was supposed to be a  PM But what the Heck)

Gamma match generally used only on 2m and above. ONe side of your coax goes directly to the driven ele dipole side A.

Other side goes to  a rod that lines away from the side b but  paralled to  it. THis can be a  solid rod or of the same round stock as the driven element.

There are two PE or PP plastic elements holding the rod away from the B side driven element.  The rod can be slid back and forth along the B element  to get the best possible coupling.

THe exact stand off  distance and rod length  are a black art .  You never try to test or tune up this stuff except at low power or reduced V on finals.

THe coupling into the B side is capacitive and inductive  and distributed.  Hence black art.  It is hellish unlikely you will get this to work with anything other than a Yagi antenna.

Do you have a 1:1 balun in line as in current balun. If you have harmonics in your transmitted signal this will help the issue of return down the outside of your coax  and that will help keep any harmonics forced into the antenna where since they are not resonant , will be somewhat suppressed.   Voltage baluns can be work of the devil and for VHF accept nothing less than type 61 material in the balun core. Above 150 Mhz you cannot even have type 61 because it is getting very lossy but only your tests with a FSMeter will show what the difference is.

cheers New member -
A and B sides are whatever you define them to be - as above.

 

Timothy E. Fidler : Engineer BE Mech(1) Auckland , NDT specialist AINDT UT /RT3 , MT2 CB #2885, 
Telephone Whangarei   022  691 8405
e: Engstr@...



----- Original Message -----
From:
BITX20@groups.io

To:
<BITX20@groups.io>
Cc:

Sent:
Sun, 29 Jul 2018 23:57:39 -0700
Subject:
[BITX20] Gamma-matching antenna tuner


Hi, all.

 

I am getting interested in a Gamma-Matching antenna tuner (manual one) for suppressing spurious in order to observe Japans new spurious regulation.

 

BPF will be fine but I need to make number of coils, right?

 

Then, can anyone point me out where I find some schematics of the Gamma-Matching tuner, or kit of it is very much appreciated.

 

Thanks in advance.

 

// hiro, JJ1FXF


hirosmb <hirosmb@...>
 

Timothy,

Many thanks for your detailed explanation.

But I was wrong.

What I needed to know was “pi-match antenna tuner”.

Am I right that this type of antenna tuner suppress much spurious?

Again, thanks for your kind comments, Timothy.

// hiro, JJ1FXF



2018/07/30 16:52、Timothy Fidler <engstr@...>のメール:

Hiro,  suggest you look at  ARRL antenna HB . You should be able to find some PDF on line .....copyright breach and all. (this was supposed to be a  PM But what the Heck)

Gamma match generally used only on 2m and above. ONe side of your coax goes directly to the driven ele dipole side A.

Other side goes to  a rod that lines away from the side b but  paralled to  it. THis can be a  solid rod or of the same round stock as the driven element.

There are two PE or PP plastic elements holding the rod away from the B side driven element.  The rod can be slid back and forth along the B element  to get the best possible coupling.

THe exact stand off  distance and rod length  are a black art .  You never try to test or tune up this stuff except at low power or reduced V on finals.

THe coupling into the B side is capacitive and inductive  and distributed.  Hence black art.  It is hellish unlikely you will get this to work with anything other than a Yagi antenna.

Do you have a 1:1 balun in line as in current balun. If you have harmonics in your transmitted signal this will help the issue of return down the outside of your coax  and that will help keep any harmonics forced into the antenna where since they are not resonant , will be somewhat suppressed.   Voltage baluns can be work of the devil and for VHF accept nothing less than type 61 material in the balun core. Above 150 Mhz you cannot even have type 61 because it is getting very lossy but only your tests with a FSMeter will show what the difference is.

cheers New member -
A and B sides are whatever you define them to be - as above.

 

Timothy E. Fidler : Engineer BE Mech(1) Auckland , NDT specialist AINDT UT /RT3 , MT2 CB #2885, 
Telephone Whangarei   022  691 8405
e: Engstr@...



----- Original Message -----

To:
<BITX20@groups.io>
Cc:

Sent:
Sun, 29 Jul 2018 23:57:39 -0700
Subject:
[BITX20] Gamma-matching antenna tuner


Hi, all.

 

I am getting interested in a Gamma-Matching antenna tuner (manual one) for suppressing spurious in order to observe Japans new spurious regulation.

 

BPF will be fine but I need to make number of coils, right?

 

Then, can anyone point me out where I find some schematics of the Gamma-Matching tuner, or kit of it is very much appreciated.

 

Thanks in advance.

 

// hiro, JJ1FXF


ajparent1/KB1GMX <kb1gmx@...>
 

Hiro san,

A pi type tuner is generally in the same form as Low pass filters.  As such it can help with harmonics
but lower frequency spurious outputs it will be less helpful.

What you likely want is a transmitting band pass filter then an antenna matcher after that.
Two sites that may be more helpful.  

https://www.n1nc.org/Filters/

http://orarc.net/RF-Filters-2.pdf

Allison


Arv Evans
 

There are a great many articles available on-line for Gama Match Antenna.
Do a Google search for "gamma match antenna" to see what is available. 

Arv  K7HKL
_._


On Mon, Jul 30, 2018 at 2:08 AM Timothy Fidler <engstr@...> wrote:
Hiro,  suggest you look at  ARRL antenna HB . You should be able to find some PDF on line .....copyright breach and all. (this was supposed to be a  PM But what the Heck)

Gamma match generally used only on 2m and above. ONe side of your coax goes directly to the driven ele dipole side A.

Other side goes to  a rod that lines away from the side b but  paralled to  it. THis can be a  solid rod or of the same round stock as the driven element.

There are two PE or PP plastic elements holding the rod away from the B side driven element.  The rod can be slid back and forth along the B element  to get the best possible coupling.

THe exact stand off  distance and rod length  are a black art .  You never try to test or tune up this stuff except at low power or reduced V on finals.

THe coupling into the B side is capacitive and inductive  and distributed.  Hence black art.  It is hellish unlikely you will get this to work with anything other than a Yagi antenna.

Do you have a 1:1 balun in line as in current balun. If you have harmonics in your transmitted signal this will help the issue of return down the outside of your coax  and that will help keep any harmonics forced into the antenna where since they are not resonant , will be somewhat suppressed.   Voltage baluns can be work of the devil and for VHF accept nothing less than type 61 material in the balun core. Above 150 Mhz you cannot even have type 61 because it is getting very lossy but only your tests with a FSMeter will show what the difference is.

cheers New member -
A and B sides are whatever you define them to be - as above.

 

Timothy E. Fidler : Engineer BE Mech(1) Auckland , NDT specialist AINDT UT /RT3 , MT2 CB #2885, 
Telephone Whangarei   022  691 8405
e: Engstr@...



----- Original Message -----

To:
<BITX20@groups.io>
Cc:

Sent:
Sun, 29 Jul 2018 23:57:39 -0700
Subject:
[BITX20] Gamma-matching antenna tuner


Hi, all.

 

I am getting interested in a Gamma-Matching antenna tuner (manual one) for suppressing spurious in order to observe Japans new spurious regulation.

 

BPF will be fine but I need to make number of coils, right?

 

Then, can anyone point me out where I find some schematics of the Gamma-Matching tuner, or kit of it is very much appreciated.

 

Thanks in advance.

 

// hiro, JJ1FXF


Timothy Fidler
 

Arv seems he was rather confused. I  possibly should have spotted same before I wrote my detailed explanation. cheers


Christopher Miller
 

Would they not just need band pass filters for whatever the desired band is? I kind of see where you might be able to suppress spurious emissions in a tuner, but why? My limited understanding is that the ubitx has filters for hf bands 20 meters and lower. Do they not provide enough suppression?  If not a filter should be pretty straight forward to construct. No?


hirosmb <hirosmb@...>
 

Allison-san,

Thanks a lot for your info.

I am checking those presented URLs and a bit surprised with a huge filter using PC case. :)

In my understanding, because uBitx uses DDS and so is not likely to produce lower harmonics such as by frequency multiplier, but higher harmonics may occur in most cases.

Also I am afraid that the fixed BPF or LPF (such as until 30MHz) may not suppress the second harmonics (14MHz) when emitting 7MHz CW, but hoping that the pi-match antenna tuner may work for this case.

// hiro, JJ1FXF



2018/07/31 0:07、ajparent1/KB1GMX <kb1gmx@...>のメール:

Hiro san,

A pi type tuner is generally in the same form as Low pass filters.  As such it can help with harmonics
but lower frequency spurious outputs it will be less helpful.

What you likely want is a transmitting band pass filter then an antenna matcher after that.
Two sites that may be more helpful.  

https://www.n1nc.org/Filters/

http://orarc.net/RF-Filters-2.pdf

Allison


hirosmb <hirosmb@...>
 

Arv,

Thanks for your comment.

Yes, as Timothy said, I was completely confused that there would have been a gamma-match manual antenna tuner which could have been placed just after the RF output of rig.

All what I want is a manual antenna tuner which also works as a LPF, that is to say, a pi-match antenna tuner.

BR,

// hiro, JJ1FXF



2018/07/31 3:00、Arv Evans <arvid.evans@...>のメール:

There are a great many articles available on-line for Gama Match Antenna.
Do a Google search for "gamma match antenna" to see what is available. 

Arv  K7HKL
_._

On Mon, Jul 30, 2018 at 2:08 AM Timothy Fidler <engstr@...> wrote:
Hiro,  suggest you look at  ARRL antenna HB . You should be able to find some PDF on line .....copyright breach and all. (this was supposed to be a  PM But what the Heck)

Gamma match generally used only on 2m and above. ONe side of your coax goes directly to the driven ele dipole side A.

Other side goes to  a rod that lines away from the side b but  paralled to  it. THis can be a  solid rod or of the same round stock as the driven element.

There are two PE or PP plastic elements holding the rod away from the B side driven element.  The rod can be slid back and forth along the B element  to get the best possible coupling.

THe exact stand off  distance and rod length  are a black art .  You never try to test or tune up this stuff except at low power or reduced V on finals.

THe coupling into the B side is capacitive and inductive  and distributed.  Hence black art.  It is hellish unlikely you will get this to work with anything other than a Yagi antenna.

Do you have a 1:1 balun in line as in current balun. If you have harmonics in your transmitted signal this will help the issue of return down the outside of your coax  and that will help keep any harmonics forced into the antenna where since they are not resonant , will be somewhat suppressed.   Voltage baluns can be work of the devil and for VHF accept nothing less than type 61 material in the balun core. Above 150 Mhz you cannot even have type 61 because it is getting very lossy but only your tests with a FSMeter will show what the difference is.

cheers New member -
A and B sides are whatever you define them to be - as above.

 

Timothy E. Fidler : Engineer BE Mech(1) Auckland , NDT specialist AINDT UT /RT3 , MT2 CB #2885, 
Telephone Whangarei   022  691 8405
e: Engstr@...



----- Original Message -----

To:
<BITX20@groups.io>
Cc:

Sent:
Sun, 29 Jul 2018 23:57:39 -0700
Subject:
[BITX20] Gamma-matching antenna tuner


Hi, all.

 

I am getting interested in a Gamma-Matching antenna tuner (manual one) for suppressing spurious in order to observe Japans new spurious regulation.

 

BPF will be fine but I need to make number of coils, right?

 

Then, can anyone point me out where I find some schematics of the Gamma-Matching tuner, or kit of it is very much appreciated.

 

Thanks in advance.

 

// hiro, JJ1FXF


iz oos
 

I don't think you will be imprisoned for a long time because of the spurs and the harmonics of the Ubitx unless, as Allison pointed out elsewhere, you use the ssb mode above 20Mhz.


Il 31/lug/2018 00:20, "hirosmb" <hirosmb@...> ha scritto:
Allison-san,

Thanks a lot for your info.

I am checking those presented URLs and a bit surprised with a huge filter using PC case. :)

In my understanding, because uBitx uses DDS and so is not likely to produce lower harmonics such as by frequency multiplier, but higher harmonics may occur in most cases.

Also I am afraid that the fixed BPF or LPF (such as until 30MHz) may not suppress the second harmonics (14MHz) when emitting 7MHz CW, but hoping that the pi-match antenna tuner may work for this case.

// hiro, JJ1FXF



2018/07/31 0:07、ajparent1/KB1GMX <kb1gmx@...>のメール:

Hiro san,

A pi type tuner is generally in the same form as Low pass filters.  As such it can help with harmonics
but lower frequency spurious outputs it will be less helpful.

What you likely want is a transmitting band pass filter then an antenna matcher after that.
Two sites that may be more helpful.  

https://www.n1nc.org/Filters/

http://orarc.net/RF-Filters-2.pdf

Allison


ajparent1/KB1GMX <kb1gmx@...>
 

Hiro san,

The NCO (form of synthesis) is very clean save for harmonics due to square waveform.

However there are three oscillators and mixers and the resulting combines can and do
create spurs.

Allison


hirosmb <hirosmb@...>
 

“Not for a long time in prison” is a Good news, Iz. :)

Yes, I like 15m, too.

// hiro, JJ1FXF



2018/07/31 7:41、iz oos <and2oosiz2@...>のメール:

I don't think you will be imprisoned for a long time because of the spurs and the harmonics of the Ubitx unless, as Allison pointed out elsewhere, you use the ssb mode above 20Mhz.


Il 31/lug/2018 00:20, "hirosmb" <hirosmb@...> ha scritto:
Allison-san,

Thanks a lot for your info.

I am checking those presented URLs and a bit surprised with a huge filter using PC case. :)

In my understanding, because uBitx uses DDS and so is not likely to produce lower harmonics such as by frequency multiplier, but higher harmonics may occur in most cases.

Also I am afraid that the fixed BPF or LPF (such as until 30MHz) may not suppress the second harmonics (14MHz) when emitting 7MHz CW, but hoping that the pi-match antenna tuner may work for this case.

// hiro, JJ1FXF



2018/07/31 0:07、ajparent1/KB1GMX <kb1gmx@...>のメール:

Hiro san,

A pi type tuner is generally in the same form as Low pass filters.  As such it can help with harmonics
but lower frequency spurious outputs it will be less helpful.

What you likely want is a transmitting band pass filter then an antenna matcher after that.
Two sites that may be more helpful.  

https://www.n1nc.org/Filters/

http://orarc.net/RF-Filters-2.pdf

Allison


hirosmb <hirosmb@...>
 

You are right, Allison-san.

There should be a possibility of lower spurs on uBitx.

Thank you for letting me know it.

// hiro, JJ1FXF



2018/07/31 7:50、ajparent1/KB1GMX <kb1gmx@...>のメール:

Hiro san,

The NCO (form of synthesis) is very clean save for harmonics due to square waveform.

However there are three oscillators and mixers and the resulting combines can and do
create spurs.

Allison


hirosmb <hirosmb@...>
 

Christopher,

I saw somewhere that spurious emission is at the level of -45dB toward the fundamental frequency.

However, Japan’s latest spurious regulation requires more than -50dB and so I started thinking about pi-match tuner or BPF.

This doesn’t mean that uBitx doesn’t suppress good enough spur but it just means that Japan’s regulation is a little tight, I suppose.

// hiro, JJ1FXF



2018/07/31 5:14、Christopher Miller <djmalak2k6@...>のメール:

Would they not just need band pass filters for whatever the desired band is? I kind of see where you might be able to suppress spurious emissions in a tuner, but why? My limited understanding is that the ubitx has filters for hf bands 20 meters and lower. Do they not provide enough suppression?  If not a filter should be pretty straight forward to construct. No?


hirosmb <hirosmb@...>
 

Ah, correction:

I saw somewhere that spurious emission OF UBITX is at the level of -45dB toward the fundamental frequency.

// hiro



2018/07/31 12:04、hirosmb <hirosmb@...>のメール:

Christopher,

I saw somewhere that spurious emission is at the level of -45dB toward the fundamental frequency.

However, Japan’s latest spurious regulation requires more than -50dB and so I started thinking about pi-match tuner or BPF.

This doesn’t mean that uBitx doesn’t suppress good enough spur but it just means that Japan’s regulation is a little tight, I suppose.

// hiro, JJ1FXF



2018/07/31 5:14、Christopher Miller <djmalak2k6@...>のメール:

Would they not just need band pass filters for whatever the desired band is? I kind of see where you might be able to suppress spurious emissions in a tuner, but why? My limited understanding is that the ubitx has filters for hf bands 20 meters and lower. Do they not provide enough suppression?  If not a filter should be pretty straight forward to construct. No?