Topics

Harmonics and Relay Replacement

iz oos
 

FYI, similar AXICOM relays are mounted on the RF sensed TX/RX switch (changeover) by Kanga. Attached you find the pic of one I assembled some time ago. As this provides RX protection, Kanga has evidently chosen the relays that offered a good compromise between cost and RF separation at HF.


Il 11/ott/2018 13:20, "iz oos" <and2oosiz2@...> ha scritto:

My guess is that your Panasonic are possessed by some SWR...


Il 11/ott/2018 13:01, "Raj vu2zap" <rajendrakumargg@...> ha scritto:
Kees,

My guess is that the contacts being underside are close to the ground plane of the board and that must be
helping decreasing the "coupling" of both sets of contacts.

Imagine a loop on one side of the relay and another on the other side.. perfect inductive coupling. The
Axicom has smaller loops compared to Virtual and others.

My Panasonic relays made the harmonics worse.. BUT the power out increased !!! about 20%.

It's possessed I tell you!

Raj

Panasonic relay DS2Y-S-DC12V



At 11/10/2018, you wrote:
>Those inductances all look right. Sure would like to know WHY the Axicom relays have better readings.





 

Relays are sealed, cant use SWR grease. I remember reading in QST some year April
about how SWR grease makes all the standing waves slip and fall off the antenna :-))

Most of my testing with harmonics were done on 7.2 or 14.2 Mhz. With Panasonic relays
the 2rd harmonic shot up by ~20db and the 5th dropped below the -43dbm green line.

As soon a I get back to the bench I am going to mill off the plastic around a Panasonic and
see what the construction is. Its height is a little less than the "Virtual" brand. This should
give us a better understanding or open a new can of worms!

This one of the best groups to learn from, thanks to you guys!

Raj


At 11/10/2018, you wrote:

My guess is that your Panasonic are possessed by some SWR...

Il 11/ott/2018 13:01, "Raj vu2zap" < rajendrakumargg@...> ha scritto:
Kees,

My guess is that the contacts being underside are close to the ground plane of the board and that must be
helping decreasing the "coupling" of both sets of contacts.

Imagine a loop on one side of the relay and another on the other side.. perfect inductive coupling. The
Axicom has smaller loops compared to Virtual and others.

My Panasonic relays made the harmonics worse.. BUT the power out increased !!! about 20%.

It's possessed I tell you!

Raj

Panasonic relay DS2Y-S-DC12V



At 11/10/2018, you wrote:
>Those inductances all look right. Sure would like to know WHY the Axicom relays have better readings.

Jim Sheldon
 

I agree with you Raj. Also, I believe it's because the Axicom relays were designed from the beginning to be used in RF applications where the ones originally used in the uBITX were and are not. The originals are power relays and no thought was given to RF isolation when they were manufactured. It's unfortunate but not all relays of this type are created equal and it is difficult to design RF carrying circuits using power relays when the internal capacitance and/or inductances are not known and not provided in the respective data sheets.

As to being "possessed", I know the 40 meter band on at least one of my uBITX boards IS possessed because the Axicom relays only marginally helped on 40. On all the other bands the 3rd harmonic was reduced significantly (at least 15 dBC) over the original relays.

Jim Sheldon - W0EB

------ Original Message ------
From: "Raj vu2zap" <@Raj>
To: BITX20@groups.io
Sent: 10/11/2018 6:01:37 AM
Subject: Re: [BITX20] Harmonics and Relay Replacement

Kees,

My guess is that the contacts being underside are close to the ground plane of the board and that must be
helping decreasing the "coupling" of both sets of contacts.

Imagine a loop on one side of the relay and another on the other side.. perfect inductive coupling. The
Axicom has smaller loops compared to Virtual and others.

My Panasonic relays made the harmonics worse.. BUT the power out increased !!! about 20%.

It's possessed I tell you!

Raj

Panasonic relay DS2Y-S-DC12V



At 11/10/2018, you wrote:
Those inductances all look right. Sure would like to know WHY the Axicom relays have better readings.


Gary Anderson
 

Hi Jim,
Just wanting to lob out an idea for consideration on your multiple uBITX board relay experiment, if it is still in progress.
Mounting the Axicom relays from the back side, where they are directly over a mostly ground plane.
Experiment split to see if it further improves / or addresses your 40m question.

Thanks for the work / effort.
Rgds,
Gary
AG5TX

Jim Sheldon
 

Hi Raj,
Funny, I have a DE-5000, LC-100A (real cheap one from eBay) and the AADE and they all agree within less than 1 percent. You might have a bad crystal oscillator on the uP in your AADE? Or maybe I just got lucky as I was given my AADE by a friend, several years ago. Not sure where he got it.

The biggest surprise is how accurate the very inexpensive LC-100A has been. I think I paid $9.95 USD with free shipping for it.

Jim, W0EB

------ Original Message ------
From: "Raj vu2zap" <@Raj>
To: BITX20@groups.io
Sent: 10/11/2018 3:45:22 AM
Subject: Re: [BITX20] Harmonics and Relay Replacement

I don't trust my AADE meter below 1uH. I use a meter called DE 5000, it read commercial
sub uH inductors very accurately. The AADE meter was way off.

The DE meter can be set for 1,10,100 KHz measurement frequency. At 100K the meter
reads 1nH

Raj

https://www.amazon.com/Labs-DE-5000-Meter-Replaced-DE-6000/dp/B005EMT8PC
You will need the accesories TL-21 and 22 ..

At 11/10/2018, you wrote:
Kees,
In measuring a Virtual relay and an Axicom relay that I have here, both show approximately 20nH.


iz oos
 

About the possession I guess that a non filtered output shows a higher power, which is the sum of the fundamental, the spurs, harmonics and all the garbage left.


Il 11/ott/2018 14:37, "Raj vu2zap" <rajendrakumargg@...> ha scritto:
Relays are sealed, cant use SWR grease. I remember reading in QST some year April
about how SWR grease makes all the standing waves slip and fall off the antenna :-))

Most of my testing with harmonics were done on 7.2 or 14.2 Mhz. With Panasonic relays
the 2rd harmonic shot up by ~20db and the 5th dropped below the -43dbm green line.

As soon a I get back to the bench I am going to mill off the plastic around a Panasonic and
see what the construction is. Its height is a little less than the "Virtual" brand. This should
give us a better understanding or open a new can of worms!

This one of the best groups to learn from, thanks to you guys!

Raj

At 11/10/2018, you wrote:

My guess is that your Panasonic are possessed by some SWR...

Il 11/ott/2018 13:01, "Raj vu2zap" < rajendrakumargg@...> ha scritto:
Kees,

My guess is that the contacts being underside are close to the ground plane of the board and that must be
helping decreasing the "coupling" of both sets of contacts.

Imagine a loop on one side of the relay and another on the other side.. perfect inductive coupling. The
Axicom has smaller loops compared to Virtual and others.

My Panasonic relays made the harmonics worse.. BUT the power out increased !!! about 20%.

It's possessed I tell you!

Raj

Panasonic relay DS2Y-S-DC12V



At 11/10/2018, you wrote:
>Those inductances all look right. Sure would like to know WHY the Axicom relays have better readings.

Joe Puma
 

Amazon has the meter and accessories for $119.97. I’ll be picking up that meter off your recommendation.

Joe

On Oct 11, 2018, at 4:45 AM, Raj vu2zap <@Raj> wrote:

I don't trust my AADE meter below 1uH. I use a meter called DE 5000, it read commercial
sub uH inductors very accurately. The AADE meter was way off.

The DE meter can be set for 1,10,100 KHz measurement frequency. At 100K the meter
reads 1nH

Raj

https://www.amazon.com/Labs-DE-5000-Meter-Replaced-DE-6000/dp/B005EMT8PC
You will need the accesories TL-21 and 22 ..

At 11/10/2018, you wrote:
Kees,
In measuring a Virtual relay and an Axicom relay that I have here, both show approximately 20nH.


Kees T
 

Mike,
You asked about the two LPF filters. Here they are pictures and plots. The components used on the small board and the large board are the same and they are both at about 10MHz (same filter design as used on the uBITX but these use Mica caps and T-37 toroids. Using the existing capacitors and toroids off the uBITX board gives nearly the SAME results. The larger board is made from a proto board with squares on one side and a ground plane on the other. 

The last plot shows one of the QRP Labs boards at a slightly different frequency.

73 Kees K5BCQ
 
#1 shows the "Gold" LPF with quality short leads and the small LPF board with quality short leads.
#2 shows the "Gold" LPF plot
#3 shows the small LPF board plot. This is your NO5K built board with the same components and the one you have a picture of on your SA with MUCH better results ??
#4 is one of Hans' small QRP Labs boards (slightly different frequency.
 

Scott McDonald
 

Hi Jim, or Raj, or ….
 
I have trouble with reproducibility on lower numbers with my recently purchased LC200.
 
Butt when I see people that know what they are doing having good results, I'm inclined to ask whether there is anything special, or for that matter, just how are you measuring the lower value inductances, figuring based on past experience that I may not have yet acquired the "knack."
 
Thanks, Scott ka9p
 
 

-----Original Message-----
From: Jim Sheldon <w0eb@...>
To: BITX20 <BITX20@groups.io>
Sent: Thu, Oct 11, 2018 9:37 am
Subject: Re: [BITX20] Harmonics and Relay Replacement

Hi Raj,
Funny, I have a DE-5000, LC-100A (real cheap one from eBay) and the AADE
and they all agree within less than 1 percent. You might have a bad
crystal oscillator on the uP in your AADE? Or maybe I just got lucky as
I was given my AADE by a friend, several years ago. Not sure where he
got it.

The biggest surprise is how accurate the very inexpensive LC-100A has
been. I think I paid $9.95 USD with free shipping for it.

Jim, W0EB

------ Original Message ------
From: "Raj vu2zap" <rajendrakumargg@...>
To: BITX20@groups.io
Sent: 10/11/2018 3:45:22 AM
Subject: Re: [BITX20] Harmonics and Relay Replacement

>I don't trust my AADE meter below 1uH. I use a meter called DE 5000, it
>read commercial
>sub uH inductors very accurately. The AADE meter was way off.
>
>The DE meter can be set for 1,10,100 KHz measurement frequency. At 100K
>the meter
>reads 1nH
>
>Raj
>
>https://www.amazon.com/Labs-DE-5000-Meter-Replaced-DE-6000/dp/B005EMT8PC
>You will need the accesories TL-21 and 22 ..
>
>At 11/10/2018, you wrote:
>>Kees,
>>In measuring a Virtual relay and an Axicom relay that I have here,
>>both show approximately 20nH.
>
>
>
>




Jim Sheldon
 

Scott,
Use the shortest leads possible, measure the inductance as quickly as you can after "Zeroing" your meter with the leads shorted.  That's the way I do it.  The inductance of the leads is a factor as well as the capacitance of your hand & fingers.  Zero it, connect the inductor and get your hands back.  Write down the reading as quick as you can.  I also turn the unit on and leave it on for at least 10-15 minutes before doing any measurements with it.  This applies to any LC meter, no matter the brand or the circuit it uses.

About the best advice I can give,  maybe Raj does it differently and he will chime in also.

Jim - W0EB

------ Original Message ------
From: "Scott McDonald via Groups.Io" <ka9p@...>
Sent: 10/11/2018 10:46:44 AM
Subject: Re: [BITX20] Harmonics and Relay Replacement

Hi Jim, or Raj, or ….
 
I have trouble with reproducibility on lower numbers with my recently purchased LC200.
 
Butt when I see people that know what they are doing having good results, I'm inclined to ask whether there is anything special, or for that matter, just how are you measuring the lower value inductances, figuring based on past experience that I may not have yet acquired the "knack."
 
Thanks, Scott ka9p
 
 
-----Original Message-----
From: Jim Sheldon <w0eb@...>
To: BITX20 <BITX20@groups.io>
Sent: Thu, Oct 11, 2018 9:37 am
Subject: Re: [BITX20] Harmonics and Relay Replacement

Hi Raj,
Funny, I have a DE-5000, LC-100A (real cheap one from eBay) and the AADE
and they all agree within less than 1 percent. You might have a bad
crystal oscillator on the uP in your AADE? Or maybe I just got lucky as
I was given my AADE by a friend, several years ago. Not sure where he
got it.

The biggest surprise is how accurate the very inexpensive LC-100A has
been. I think I paid $9.95 USD with free shipping for it.

Jim, W0EB

------ Original Message ------
From: "Raj vu2zap" <rajendrakumargg@...>
To: BITX20@groups.io
Sent: 10/11/2018 3:45:22 AM
Subject: Re: [BITX20] Harmonics and Relay Replacement

>I don't trust my AADE meter below 1uH. I use a meter called DE 5000, it
>read commercial
>sub uH inductors very accurately. The AADE meter was way off.
>
>The DE meter can be set for 1,10,100 KHz measurement frequency. At 100K
>the meter
>reads 1nH
>
>Raj
>
>https://www.amazon.com/Labs-DE-5000-Meter-Replaced-DE-6000/dp/B005EMT8PC
>You will need the accesories TL-21 and 22 ..
>
>At 11/10/2018, you wrote:
>>Kees,
>>In measuring a Virtual relay and an Axicom relay that I have here,
>>both show approximately 20nH.
>
>
>
>




Jim Sheldon
 

Thanks Gary!

I had not thought to try mounting them on the bottom of the board so there would be a ground plane shield between the relay and other wiring.  I just did that and ran the tests again.  Unfortunately they were NOT encouraging. 

The only improvement was the 40 meter third harmonic.  In all other cases, both the 2nd and 3rd harmonics were worse with the relays on the bottom rather than the top of the uBITX main board.  They did, however remain in spec with the worst case being the 3rd harmonic of 40 meters. This one was marginally better on the bottom but none of the others benefitted from the change.

Results with the relays on the bottom of the board vs on the top.  Same uBITX used for the original tests, I just carefully moved the relays to the bottom.  Not going to move them again, but will put the new relays back on top of the 2nd V4 board later today.

Jim Sheldon, W0EB

80 meters 
2nd harmonic  -62.1 dBC  vs -65.7 dBC - bottom worse
3rd harmonic -58.4 dBC vs -76.4 dBC  - bottom worse

30 meters - not tested today

40 meters 
2nd harmonic -56.2 dBC vs  -58.0 dBC - bottom worse
3rd harmonic -51.7 dBC vs -47.2 dBC - bottom better

20 meters
2nd harmonic - 57.5 dBC vs -65.2 dBC - bottom worse
3rd harmonic - -52.6 dBC vs -64.8 dBC - bottom worse

17 meters not tested yesterday so not tested with relays on top of the board.
2nd harmonic -53.1 dBC
3rd harmonic -61 dBC   


------ Original Message ------
From: "Gary Anderson" <gary.ag5tx@...>
Sent: 10/11/2018 9:34:14 AM
Subject: Re: [BITX20] Harmonics and Relay Replacement

Hi Jim,
Just wanting to lob out an idea for consideration on your multiple uBITX board relay experiment, if it is still in progress.
Mounting the Axicom relays from the back side, where they are directly over a mostly ground plane.
Experiment split to see if it further improves / or addresses your 40m question.

Thanks for the work / effort.
Rgds,
Gary
AG5TX

Scott McDonald
 

Thanks Jim that helps.  I may have been a bit optimistic about the test lead situation here.73 Scott


On Oct 11, 2018, at 12:02 PM, Jim Sheldon <w0eb@...> wrote:

Scott,
Use the shortest leads possible, measure the inductance as quickly as you can after "Zeroing" your meter with the leads shorted.  That's the way I do it.  The inductance of the leads is a factor as well as the capacitance of your hand & fingers.  Zero it, connect the inductor and get your hands back.  Write down the reading as quick as you can.  I also turn the unit on and leave it on for at least 10-15 minutes before doing any measurements with it.  This applies to any LC meter, no matter the brand or the circuit it uses.

About the best advice I can give,  maybe Raj does it differently and he will chime in also.

Jim - W0EB

------ Original Message ------
From: "Scott McDonald via Groups.Io" <ka9p@...>
Sent: 10/11/2018 10:46:44 AM
Subject: Re: [BITX20] Harmonics and Relay Replacement

Hi Jim, or Raj, or ….
 
I have trouble with reproducibility on lower numbers with my recently purchased LC200.
 
Butt when I see people that know what they are doing having good results, I'm inclined to ask whether there is anything special, or for that matter, just how are you measuring the lower value inductances, figuring based on past experience that I may not have yet acquired the "knack."
 
Thanks, Scott ka9p
 
 
-----Original Message-----
From: Jim Sheldon <w0eb@...>
To: BITX20 <BITX20@groups.io>
Sent: Thu, Oct 11, 2018 9:37 am
Subject: Re: [BITX20] Harmonics and Relay Replacement

Hi Raj,
Funny, I have a DE-5000, LC-100A (real cheap one from eBay) and the AADE
and they all agree within less than 1 percent. You might have a bad
crystal oscillator on the uP in your AADE? Or maybe I just got lucky as
I was given my AADE by a friend, several years ago. Not sure where he
got it.

The biggest surprise is how accurate the very inexpensive LC-100A has
been. I think I paid $9.95 USD with free shipping for it.

Jim, W0EB

------ Original Message ------
From: "Raj vu2zap" <rajendrakumargg@...>
To: BITX20@groups.io
Sent: 10/11/2018 3:45:22 AM
Subject: Re: [BITX20] Harmonics and Relay Replacement

>I don't trust my AADE meter below 1uH. I use a meter called DE 5000, it
>read commercial
>sub uH inductors very accurately. The AADE meter was way off.
>
>The DE meter can be set for 1,10,100 KHz measurement frequency. At 100K
>the meter
>reads 1nH
>
>Raj
>
>https://www.amazon.com/Labs-DE-5000-Meter-Replaced-DE-6000/dp/B005EMT8PC
>You will need the accesories TL-21 and 22 ..
>
>At 11/10/2018, you wrote:
>>Kees,
>>In measuring a Virtual relay and an Axicom relay that I have here,
>>both show approximately 20nH.
>
>
>
>




MVS Sarma
 

I had an old Panasonic DS2E relay. Here are top and side exploded photos. Sorry for lack of clarity

The contacts can be seen mounted on either side of the relay. The armature moves sideways pulling one and pushing another contact.
regards
sarma
 vu3zmv

MVS Sarma
 

Regarding Filters and axicom realy towards band switching  , i saw an useful link.
 http://www.i1wqrlinkradio.com/antype/ch97/chiave50.htm

Perhaps it helps.
regards
sarma
 vu3zmv

iz oos
 

Interesting link by this Italian guy, surely not a macaroni one hihi, he also says to add a capacitor across (?) the coil.


Il 12/ott/2018 12:49, "Mvs Sarma" <mvssarma@...> ha scritto:
Regarding Filters and axicom realy towards band switching  , i saw an useful link.
 http://www.i1wqrlinkradio.com/antype/ch97/chiave50.htm

Perhaps it helps.
regards
sarma
 vu3zmv

Joe Puma
 

This is a cool find. Nice read. 



On Oct 12, 2018, at 6:49 AM, Mvs Sarma <mvssarma@...> wrote:

Regarding Filters and axicom realy towards band switching  , i saw an useful link.
 http://www.i1wqrlinkradio.com/antype/ch97/chiave50.htm

Perhaps it helps.
regards
sarma
 vu3zmv

Kees T
 

Thanks for those pictures, Sarma. To me, that seems to indicate even closer coupling from the relay armature to the coil. Bad for RF.

73 Kees K5BCQ

Gary Anderson
 

Good Morning Jim,
Thanks for entertaining the idea.  Your shared data maybe useful as you have shown same board and relay with different measured results.
For that particular board and the measurement data you gathered, I would say the results ARE encouraging from this viewpoint:
You have 4.5 dBc more margin to FCC spec on your worst case data point (40m 3rd harmonic) with the supplied data set.



Comments:
I have no measurement error / uncertainty reference or relevant personal judgement / experience to truly offer.
But, I would think it more difficult to accurately measure the case of more suppression, and so the uncertainty here would be higher.
Note that the 2nd and 3rd harmonics are swapping (80m Top and 17m Bot)

Regards,
Gary
AG5TX

Kees T
 

Great find, Sarma, as the world continues to look into this problem.

I'll run a test later today with the 1mH inductor isolation of the relay coils and then see the effect of adding a 10nF capacitor across the coil. May be dependent on how the relay contact wiring is configured and what is on each armature. I wouldn't think there is a radiated problem between relays as he implies .....conducted, yes.

73 Kees K5BCQ 

Jim Sheldon
 

I have another V4 board that I'm going to build up, but I'm waiting on a special 3.2" Color TFT touch screen display (NOT a Nextion) for use with the Trimuvirate Skonk Worx "BITeensio" controller board.  We have 2.8 and 5" displays running nicely with released software and instructions for them.  The 5" draws too much current so the next is a compromise down to the 3.2" and that will probably be our last display iteration unless something really innovative comes out that's larger and keeps the current draw under 200 mA so we don't have to add heavy duty 3.3V regulators on the BITeensio.

I've already replaced the relays on the 3rd board with Axions (mounted on top) and I have one more set of the Axion relays on hand.  I may just make up a test bed using a V3 board I have left over and keep it open frame with DIP sockets for the relays to make it easier to change them if something better than the Axion comes along.  

One thing the Axions seemed to help with was reduce radiated pickup of digital noise from the controller card & wiring.  It may be because I replace all 5 relays, or may be because I got better solder joints (non lead-free solder) when I replaced the relays.

Jim -- W0EB

------ Original Message ------
From: "Gary Anderson" <gary.ag5tx@...>
Sent: 10/12/2018 9:45:08 AM
Subject: Re: [BITX20] Harmonics and Relay Replacement

Good Morning Jim,
Thanks for entertaining the idea.  Your shared data maybe useful as you have shown same board and relay with different measured results.
For that particular board and the measurement data you gathered, I would say the results ARE encouraging from this viewpoint:
You have 4.5 dBc more margin to FCC spec on your worst case data point (40m 3rd harmonic) with the supplied data set.



Comments:
I have no measurement error / uncertainty reference or relevant personal judgement / experience to truly offer.
But, I would think it more difficult to accurately measure the case of more suppression, and so the uncertainty here would be higher.
Note that the 2nd and 3rd harmonics are swapping (80m Top and 17m Bot)

Regards,
Gary
AG5TX