Date   

Re: Wanted Tohtsu CX600NC relay

alwyn.seeds1
 

Dear All,

With the Amphenol relays, some models have good isolation; some not.

I burned out a stepped attenuator on 2m due to leakage on one of the types that look like the 316-10744-3, but with BNC connectors.

Regards,

Alwyn
_____________________________________________________

Alwyn Seeds, Director
114 Beaufort Street (Management) Company Ltd.,
114 Beaufort Street,
London,
SW3 6BU

114 Beaufort Street (Management) Company Ltd., Registered in England and Wales: No. 02797775 Registered Office Address: 114 Beaufort Street, London, SW3 6BU
______________________________________________________


Re: WR90-SMA transition update

David Redman
 

Neil,
Some nice machining , doesn't look to be anything wrong with your Bridgport miller

Dave G4IDR


Re: WR90-SMA transition update

Jacques PA3EVZ
 

Ok Neil,

Thanks for your fast response.
Waiting for that moment.

73, Jacques PA3EVZ
Op 10 sep. 2020, om 08:55, Neil Smith G4DBN <neil@...> schreef:

Hi Jacques, I’ll publish the drawings once I am sure the backshort distance is optimal.
Neil G4DBN

On 10 Sep 2020, at 06:50, Jacques PA3EVZ < Jacques.pa3evz@...> wrote:

Hello Alex,

Is there a drawing with dimensions,
I like it to machine it by my self.

Vy 73 Jacques PA3EVZ
Op 10 sep. 2020, om 07:28, Alex May M1BSX < alexmay@...> schreef:
A thing of beauty! :-)

Very intrigued as to how it was milled and whether you're using an empirical approach to determine the length of the "probe" ? 

73s Alex (M1BSX)


Alexander R. May
alexmay.net

On Thu, 10 Sep 2020, 00:01 Neil Smith G4DBN, < neil@...> wrote:

This pic is my first try at machining an SMA coax to WR90 waveguide transition.  Milled it from a lump of 1 3/4 inch aluminium square bar on my ancient Bridgeport.    It needs a bit of trimming to get it bang on frequency as I left the pin a little long. Now I'm waiting for a load of Radiall SMAs to arrive from Mouser.

Neil G4DBN

I modelled it in OpenEMS with a three-inch length of WR90 mated with the oval cavity. Return loss (black) and through loss (red) look promising, I need to check the real thing once I have the probe filed to resonance.

Fusion 360 CAD image





Re: WR90-SMA transition update

Robin Szemeti - G1YFG
 

Thanks for the detailed info, I am a big fan of WD40 for aluminium. It is useless as a lubricant in most situations, but as a cutting fluid for aluminium, it works quite well!

You clearly have the old Bridgeport running well. My CNC router does not have the stability to achieve anything like that sort of surface finish, sadly, even though it cuts aluminium quite nicely otherwise.


On Thu, 10 Sep 2020 at 07:54, Neil Smith G4DBN <neil@...> wrote:
I ran a load of simulations in OpenEMS, but I’ll file the probe to length and measure the actual length, then see how repeatable it is. Without a trimming screw, I’ll have to file them all to get them on frequency I’m sure.
I’ll publish the OpenEMS model when I publish the drawings
Neil G4DBN

On 10 Sep 2020, at 06:27, Alex May M1BSX <alexmay@...> wrote:

A thing of beauty! :-)

Very intrigued as to how it was milled and whether you're using an empirical approach to determine the length of the "probe" ? 

73s Alex (M1BSX)


Alexander R. May
alexmay.net

On Thu, 10 Sep 2020, 00:01 Neil Smith G4DBN, <neil@...> wrote:

This pic is my first try at machining an SMA coax to WR90 waveguide transition.  Milled it from a lump of 1 3/4 inch aluminium square bar on my ancient Bridgeport.    It needs a bit of trimming to get it bang on frequency as I left the pin a little long. Now I'm waiting for a load of Radiall SMAs to arrive from Mouser.

Neil G4DBN

I modelled it in OpenEMS with a three-inch length of WR90 mated with the oval cavity. Return loss (black) and through loss (red) look promising, I need to check the real thing once I have the probe filed to resonance.

Fusion 360 CAD image



<jdmjfhcdcmldgfop.png>


--
Robin Szemeti - G1YFG


Re: WR90-SMA transition update

Neil Smith G4DBN
 

Hi Jacques, I’ll publish the drawings once I am sure the backshort distance is optimal.
Neil G4DBN

On 10 Sep 2020, at 06:50, Jacques PA3EVZ <Jacques.pa3evz@...> wrote:

Hello Alex,

Is there a drawing with dimensions,
I like it to machine it by my self.

Vy 73 Jacques PA3EVZ
Op 10 sep. 2020, om 07:28, Alex May M1BSX <alexmay@...> schreef:
A thing of beauty! :-)

Very intrigued as to how it was milled and whether you're using an empirical approach to determine the length of the "probe" ? 

73s Alex (M1BSX)


Alexander R. May
alexmay.net

On Thu, 10 Sep 2020, 00:01 Neil Smith G4DBN, < neil@...> wrote:

This pic is my first try at machining an SMA coax to WR90 waveguide transition.  Milled it from a lump of 1 3/4 inch aluminium square bar on my ancient Bridgeport.    It needs a bit of trimming to get it bang on frequency as I left the pin a little long. Now I'm waiting for a load of Radiall SMAs to arrive from Mouser.

Neil G4DBN

I modelled it in OpenEMS with a three-inch length of WR90 mated with the oval cavity. Return loss (black) and through loss (red) look promising, I need to check the real thing once I have the probe filed to resonance.

Fusion 360 CAD image





Re: WR90-SMA transition update

Neil Smith G4DBN
 

I ran a load of simulations in OpenEMS, but I’ll file the probe to length and measure the actual length, then see how repeatable it is. Without a trimming screw, I’ll have to file them all to get them on frequency I’m sure.
I’ll publish the OpenEMS model when I publish the drawings
Neil G4DBN

On 10 Sep 2020, at 06:27, Alex May M1BSX <alexmay@...> wrote:

A thing of beauty! :-)

Very intrigued as to how it was milled and whether you're using an empirical approach to determine the length of the "probe" ? 

73s Alex (M1BSX)


Alexander R. May
alexmay.net

On Thu, 10 Sep 2020, 00:01 Neil Smith G4DBN, <neil@...> wrote:

This pic is my first try at machining an SMA coax to WR90 waveguide transition.  Milled it from a lump of 1 3/4 inch aluminium square bar on my ancient Bridgeport.    It needs a bit of trimming to get it bang on frequency as I left the pin a little long. Now I'm waiting for a load of Radiall SMAs to arrive from Mouser.

Neil G4DBN

I modelled it in OpenEMS with a three-inch length of WR90 mated with the oval cavity. Return loss (black) and through loss (red) look promising, I need to check the real thing once I have the probe filed to resonance.

Fusion 360 CAD image



<jdmjfhcdcmldgfop.png>


Re: WR90-SMA transition update

Neil Smith G4DBN
 

The flange face was fly-cut using a 7-insert 80mm end mill with a single polished carbide insert installed, 650 rpm, 35 mm/minute, 0.15 mm DOC finish pass, WD40 lube.  The insert has about 1 mm corner radius. Quick lap with Brasso to get a mirror finish so I can check for surface imperfections. Normally I would lap them on 2000 grit paper on a surface plate with WD40, like I do for the 122 GHz flanges, but the flycutter does a decent enough job to make that unnecessary at 10 GHz. Other surfaces are done with a 20 mm two-flute YG1 slot drill at 1200 rpm, 72 mm/min. That has sharp corners so there are some tool marks where the end of the cutter was used, but it does create a nice finish on the faces. Inside is done with an HSS-Co 8mm slot drill which is centre-cutting. I plunged a few holes to 0.5 mm short of full depth, then did a conventional milling cut to 0.2 mm from the dimension, then a climb cut for the finish. The cutter has two flutes and chatter was a problem at 24 mm deep, so I ran the finish cut at 500 rpm with a good splash of SAE 30 hydraulic oil mixed with WD40. I’m doing to try a 3-flute carbide end mill for the next ones to see if I can avoid some of the chatter in the corners which I got during roughing. It would be way easier doing a trochoidal cut on a CNC.

SMA position was done using an edge-finder from the flange face, 4.1mm centre hole reamed to size. I drilled through into the guide to tap the threaded M2.5 holes, but there is 6mm of metal that side, so I’ll try doing them 5.5mm and bind using a spiral-flute tap next time.

I deburred the edges using a miniature Noga tool and a Noga hand countersink.  It really needs anodising or painting, but for a quick and dirty solution, it will do.

The OpenEMS model suggests that the bandwidth is good enough for the amateur band just using the standard 1.27 mm probe on the Radiall SMAs. I did consider making a bobbin or tapered probe, but I’ll see what bandwidth I get. The rounded corners appear to have little effect other than making the guide wavelength a bit longer, so the backshort distance needs to be a few percent more than with square corners.

Modelling it without the mating WR-90 section just needs the probe length to be trimmed a little, and changing the dimensions other than the backshort and probe length/diameter doesn’t show any dimensions being critical.

Once I’ve got this one trimmed to best match at 10368, I’ll check the match from 9 to 12 GHz and see if it looks anything like the simulation. I’ll publish the drawings once I’m happy the dimensions are optimal.

Neil G4DBN




On 10 Sep 2020, at 02:12, Robin Szemeti - G1YFG <robin@...> wrote:


Very nice surface finish ... lapped and hand polished?
On_._,_



--
Robin Szemeti - G1YFG
_._,_._,_


Re: WR90-SMA transition update

Jacques PA3EVZ
 

Hello Alex,

Is there a drawing with dimensions,
I like it to machine it by my self.

Vy 73 Jacques PA3EVZ
Op 10 sep. 2020, om 07:28, Alex May M1BSX <alexmay@...> schreef:

A thing of beauty! :-)

Very intrigued as to how it was milled and whether you're using an empirical approach to determine the length of the "probe" ? 

73s Alex (M1BSX)


Alexander R. May
alexmay.net

On Thu, 10 Sep 2020, 00:01 Neil Smith G4DBN, < neil@...> wrote:

This pic is my first try at machining an SMA coax to WR90 waveguide transition.  Milled it from a lump of 1 3/4 inch aluminium square bar on my ancient Bridgeport.    It needs a bit of trimming to get it bang on frequency as I left the pin a little long. Now I'm waiting for a load of Radiall SMAs to arrive from Mouser.

Neil G4DBN

I modelled it in OpenEMS with a three-inch length of WR90 mated with the oval cavity. Return loss (black) and through loss (red) look promising, I need to check the real thing once I have the probe filed to resonance.

Fusion 360 CAD image


Re: WR90-SMA transition update

Alex May M1BSX
 
Edited

A thing of beauty! :-)

Very intrigued as to how it was milled and whether you're using an empirical approach to determine the length of the "probe" ? 

73s Alex (M1BSX)


Alexander R. May
alexmay.net

On Thu, 10 Sep 2020, 00:01 Neil Smith G4DBN, <neil@...> wrote:

This pic is my first try at machining an SMA coax to WR90 waveguide transition.  Milled it from a lump of 1 3/4 inch aluminium square bar on my ancient Bridgeport.    It needs a bit of trimming to get it bang on frequency as I left the pin a little long. Now I'm waiting for a load of Radiall SMAs to arrive from Mouser.

Neil G4DBN

I modelled it in OpenEMS with a three-inch length of WR90 mated with the oval cavity. Return loss (black) and through loss (red) look promising, I need to check the real thing once I have the probe filed to resonance.

Fusion 360 CAD image


Re: WR90-SMA transition update

Robin Szemeti - G1YFG
 


Very nice surface finish ... lapped and hand polished?
On_._,_


--
Robin Szemeti - G1YFG


Re: WR90-SMA transition update

Gordon REASON
 
Edited

A very nice piece of work Neil .

On 10 September 2020 at 00:01 Neil Smith G4DBN <neil@...> wrote:

This pic is my first try at machining an SMA coax to WR90 waveguide transition.  Milled it from a lump of 1 3/4 inch aluminium square bar on my ancient Bridgeport.    It needs a bit of trimming to get it bang on frequency as I left the pin a little long. Now I'm waiting for a load of Radiall SMAs to arrive from Mouser.

Neil G4DBN

I modelled it in OpenEMS with a three-inch length of WR90 mated with the oval cavity. Return loss (black) and through loss (red) look promising, I need to check the real thing once I have the probe filed to resonance.

Fusion 360 CAD image


 


 


WR90-SMA transition update

Neil Smith G4DBN
 
Edited

This pic is my first try at machining an SMA coax to WR90 waveguide transition.  Milled it from a lump of 1 3/4 inch aluminium square bar on my ancient Bridgeport.    It needs a bit of trimming to get it bang on frequency as I left the pin a little long. Now I'm waiting for a load of Radiall SMAs to arrive from Mouser.

Neil G4DBN

I modelled it in OpenEMS with a three-inch length of WR90 mated with the oval cavity. Return loss (black) and through loss (red) look promising, I need to check the real thing once I have the probe filed to resonance.

Fusion 360 CAD image


Re: Wanted Tohtsu CX600NC relay

DF6NA Rainer
 

Andy,    I think the CX3500 is a copy of the venerable Amphenol 316-10744 series, of which I was fortunate enough to rescue several from a defunct H.O. RF switching station many years ago.   One was 48v, the rest were 26v except one which was 12v !    These are just as good, if not better than the Tohtsu, in build quality at least.

 

What is rare, and I would love one for an application, is the same build but the common (centre) N connector coming out at 180 degrees so that the common can poke out of a plastic (mast head pre-amp) box for connection to the antenna.   Unfortunately the Tohtsu CX520 just does not cut it as far as isolation or power handling is concerned. I burnt one out with 23cm at 240w even when properly sequenced.

 

Regards Colin de G8LBS.

 

Sent from Mail for Windows 10

 

From: Richard GD8EXI
Sent: 08 September 2020 23:05
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Wanted Tohtsu CX600NC relay

 

Andy
    I have one which was retired from active service many years ago as the isolation was not good enough on 432MHz and above, destroying the preamp device. I might sell it but, what band is it for and how much isolation do you need. I can re measure it but from memory it was less than 40dB of isolation on 432 MHz and above, not enough if you are running 100watts plus.

A CX3500 is much better, if you need good isolation, as it has a double switch and the unused bar is grounded both ends. The isolation is so good it is difficult to measure, being in my experience greater than they 65dB they claim, more like 80dB even on 1296MHz.

Richard
GD8EXI


On 08/09/2020, 21:20, "Andy GD1MIP" <gd1mip@...> wrote:

Hi, I need a Tohtsu CX600NC 12v DC relay.

Before I buy new from a store does anyone have a spare they'd like to sell?

Thanks Andy GD1MIP

 



Re: Wanted Tohtsu CX600NC relay

alwyn.seeds1
 

Dear Richard,

I agree. The CX3500 gives very good isolation.

Power handling, however, is limited- looking at the data sheets, power rating has been reduced significantly over the years, particularly at high frequencies.

The EME-ers seem to have burned up quite a few.

My favourites are the Radiall Ramses series, quite frequently available new surplus and able to manage the full N-Type rating at UHF and above.

Regards,

Alwyn G8DOH
_____________________________________________________

Alwyn Seeds, Director
SynOptika Ltd.,
114 Beaufort Street,
London,
SW3 6BU,
England.


SynOptika Ltd., Registered in England and Wales: No. 04606737
Registered Office: 114 Beaufort Street, London, SW3 6BU, United Kingdom.
_____________________________________________________


Re: Wanted Tohtsu CX600NC relay

Colin Ranson
 

Same here no matter what I always, under advice from G3XDY/G4DDK and the VHF/UHF DX book, use an isolating relay...... however the tiny SMD relay in my HA8ET 70cm pre-amp has so far enabled the device to  survive, used last night in the 70cm  UKAC with 250w.

 

73’s

 

Colin de G8LBS.

 

Sent from Mail for Windows 10

 

From: ian hope (2E0IJH)
Sent: 09 September 2020 15:07
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Wanted Tohtsu CX600NC relay

 

I always use preamps that have internal bypass relays, even if they are only on the RX line and drop the power to those before switching the mast head relay, we use either cx520's or Cx600's depending on application, But as Ian says the older versions of both the cx600 and the cx520 had a different design.

 

Ian

M5IJH

 

 

Sent: Wednesday, September 09, 2020 at 2:47 PM
From: "Ian White" <gm3sek@...>
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Wanted Tohtsu CX600NC relay

By having the common port pointing the opposite way from the other two, the CX520D saves a lot of space inside a preamp box. I wish there was a wider choice of relays with that connector layout, and at a similar price point (which rules out the big, expensive EME relays) but I have never found even one alternative.

However, the problems with poor isolation and poor power handling are surprising. I used the same CX520D in the 70cm EME preamp for many years, handling 1kW CW and connected directly to the GaAsFET preamp, all with no damage. So does the performance really fall over a cliff between 432MHz and 1296MHz?

A possible explanation for poor isolation is that there have been at least two versions of that relay, sold under the same model number. In the modern ones, the isolated contacts are grounded onto gold-plated contacts that are screwed into the body. The older ones relied on grounding onto the body itself, which is a poorer contact and also less reliable... bearing in mind that the relay will be operated tens or hundreds of thousands of times, but preamp only has to be unlucky once.

Yet another thought is about the settings of the moving arms and the actuator plungers. These settings are quite critical to achieve the correct contact pressures, and the TohTsu relays aren't exactly built like Swiss watches.

As I said, I do wish there were other relays with that highly practical port layout and at a similar price point.

73 from Ian GM3SEK

 

 

On 09/09/2020 13:29, Colin Ranson wrote:

Andy,    I think the CX3500 is a copy of the venerable Amphenol 316-10744 series, of which I was fortunate enough to rescue several from a defunct H.O. RF switching station many years ago.   One was 48v, the rest were 26v except one which was 12v !    These are just as good, if not better than the Tohtsu, in build quality at least.

 

What is rare, and I would love one for an application, is the same build but the common (centre) N connector coming out at 180 degrees so that the common can poke out of a plastic (mast head pre-amp) box for connection to the antenna.   Unfortunately the Tohtsu CX520 just does not cut it as far as isolation or power handling is concerned. I burnt one out with 23cm at 240w even when properly sequenced.

 

Regards Colin de G8LBS.

 

Sent from Mail for Windows 10

 

From: Richard GD8EXI
Sent: 08 September 2020 23:05
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Wanted Tohtsu CX600NC relay

 

Andy
    I have one which was retired from active service many years ago as the isolation was not good enough on 432MHz and above, destroying the preamp device. I might sell it but, what band is it for and how much isolation do you need. I can re measure it but from memory it was less than 40dB of isolation on 432 MHz and above, not enough if you are running 100watts plus.

A CX3500 is much better, if you need good isolation, as it has a double switch and the unused bar is grounded both ends. The isolation is so good it is difficult to measure, being in my experience greater than they 65dB they claim, more like 80dB even on 1296MHz.

Richard
GD8EXI


On 08/09/2020, 21:20, "Andy GD1MIP" <gd1mip@...> wrote:

Hi, I need a Tohtsu CX600NC 12v DC relay.

Before I buy new from a store does anyone have a spare they'd like to sell?

Thanks Andy GD1MIP

 

 


Re: Wanted Tohtsu CX600NC relay

ian hope (2E0IJH)
 

I always use preamps that have internal bypass relays, even if they are only on the RX line and drop the power to those before switching the mast head relay, we use either cx520's or Cx600's depending on application, But as Ian says the older versions of both the cx600 and the cx520 had a different design.
 
Ian
M5IJH

 
 
Sent: Wednesday, September 09, 2020 at 2:47 PM
From: "Ian White" <gm3sek@...>
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Wanted Tohtsu CX600NC relay

By having the common port pointing the opposite way from the other two, the CX520D saves a lot of space inside a preamp box. I wish there was a wider choice of relays with that connector layout, and at a similar price point (which rules out the big, expensive EME relays) but I have never found even one alternative.

However, the problems with poor isolation and poor power handling are surprising. I used the same CX520D in the 70cm EME preamp for many years, handling 1kW CW and connected directly to the GaAsFET preamp, all with no damage. So does the performance really fall over a cliff between 432MHz and 1296MHz?

A possible explanation for poor isolation is that there have been at least two versions of that relay, sold under the same model number. In the modern ones, the isolated contacts are grounded onto gold-plated contacts that are screwed into the body. The older ones relied on grounding onto the body itself, which is a poorer contact and also less reliable... bearing in mind that the relay will be operated tens or hundreds of thousands of times, but preamp only has to be unlucky once.

Yet another thought is about the settings of the moving arms and the actuator plungers. These settings are quite critical to achieve the correct contact pressures, and the TohTsu relays aren't exactly built like Swiss watches.

As I said, I do wish there were other relays with that highly practical port layout and at a similar price point.

73 from Ian GM3SEK

 

 

On 09/09/2020 13:29, Colin Ranson wrote:

Andy,    I think the CX3500 is a copy of the venerable Amphenol 316-10744 series, of which I was fortunate enough to rescue several from a defunct H.O. RF switching station many years ago.   One was 48v, the rest were 26v except one which was 12v !    These are just as good, if not better than the Tohtsu, in build quality at least.

 

What is rare, and I would love one for an application, is the same build but the common (centre) N connector coming out at 180 degrees so that the common can poke out of a plastic (mast head pre-amp) box for connection to the antenna.   Unfortunately the Tohtsu CX520 just does not cut it as far as isolation or power handling is concerned. I burnt one out with 23cm at 240w even when properly sequenced.

 

Regards Colin de G8LBS.

 

Sent from Mail for Windows 10

 

From: Richard GD8EXI
Sent: 08 September 2020 23:05
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Wanted Tohtsu CX600NC relay

 

Andy
    I have one which was retired from active service many years ago as the isolation was not good enough on 432MHz and above, destroying the preamp device. I might sell it but, what band is it for and how much isolation do you need. I can re measure it but from memory it was less than 40dB of isolation on 432 MHz and above, not enough if you are running 100watts plus.

A CX3500 is much better, if you need good isolation, as it has a double switch and the unused bar is grounded both ends. The isolation is so good it is difficult to measure, being in my experience greater than they 65dB they claim, more like 80dB even on 1296MHz.

Richard
GD8EXI


On 08/09/2020, 21:20, "Andy GD1MIP" <gd1mip@...> wrote:

Hi, I need a Tohtsu CX600NC 12v DC relay.

Before I buy new from a store does anyone have a spare they'd like to sell?

Thanks Andy GD1MIP

 


Re: Wanted Tohtsu CX600NC relay

Ian White
 

By having the common port pointing the opposite way from the other two, the CX520D saves a lot of space inside a preamp box. I wish there was a wider choice of relays with that connector layout, and at a similar price point (which rules out the big, expensive EME relays) but I have never found even one alternative.

However, the problems with poor isolation and poor power handling are surprising. I used the same CX520D in the 70cm EME preamp for many years, handling 1kW CW and connected directly to the GaAsFET preamp, all with no damage. So does the performance really fall over a cliff between 432MHz and 1296MHz?

A possible explanation for poor isolation is that there have been at least two versions of that relay, sold under the same model number. In the modern ones, the isolated contacts are grounded onto gold-plated contacts that are screwed into the body. The older ones relied on grounding onto the body itself, which is a poorer contact and also less reliable... bearing in mind that the relay will be operated tens or hundreds of thousands of times, but preamp only has to be unlucky once.

Yet another thought is about the settings of the moving arms and the actuator plungers. These settings are quite critical to achieve the correct contact pressures, and the TohTsu relays aren't exactly built like Swiss watches.

As I said, I do wish there were other relays with that highly practical port layout and at a similar price point.

73 from Ian GM3SEK



On 09/09/2020 13:29, Colin Ranson wrote:

Andy,    I think the CX3500 is a copy of the venerable Amphenol 316-10744 series, of which I was fortunate enough to rescue several from a defunct H.O. RF switching station many years ago.   One was 48v, the rest were 26v except one which was 12v !    These are just as good, if not better than the Tohtsu, in build quality at least.

 

What is rare, and I would love one for an application, is the same build but the common (centre) N connector coming out at 180 degrees so that the common can poke out of a plastic (mast head pre-amp) box for connection to the antenna.   Unfortunately the Tohtsu CX520 just does not cut it as far as isolation or power handling is concerned. I burnt one out with 23cm at 240w even when properly sequenced.

 

Regards Colin de G8LBS.

 

Sent from Mail for Windows 10

 

From: Richard GD8EXI
Sent: 08 September 2020 23:05
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Wanted Tohtsu CX600NC relay

 

Andy
    I have one which was retired from active service many years ago as the isolation was not good enough on 432MHz and above, destroying the preamp device. I might sell it but, what band is it for and how much isolation do you need. I can re measure it but from memory it was less than 40dB of isolation on 432 MHz and above, not enough if you are running 100watts plus.

A CX3500 is much better, if you need good isolation, as it has a double switch and the unused bar is grounded both ends. The isolation is so good it is difficult to measure, being in my experience greater than they 65dB they claim, more like 80dB even on 1296MHz.

Richard
GD8EXI


On 08/09/2020, 21:20, "Andy GD1MIP" <gd1mip@...> wrote:

Hi, I need a Tohtsu CX600NC 12v DC relay.

Before I buy new from a store does anyone have a spare they'd like to sell?

Thanks Andy GD1MIP

 


Re: Wanted Tohtsu CX600NC relay

Colin Ranson
 

Andy,    I think the CX3500 is a copy of the venerable Amphenol 316-10744 series, of which I was fortunate enough to rescue several from a defunct H.O. RF switching station many years ago.   One was 48v, the rest were 26v except one which was 12v !    These are just as good, if not better than the Tohtsu, in build quality at least.

 

What is rare, and I would love one for an application, is the same build but the common (centre) N connector coming out at 180 degrees so that the common can poke out of a plastic (mast head pre-amp) box for connection to the antenna.   Unfortunately the Tohtsu CX520 just does not cut it as far as isolation or power handling is concerned. I burnt one out with 23cm at 240w even when properly sequenced.

 

Regards Colin de G8LBS.

 

Sent from Mail for Windows 10

 

From: Richard GD8EXI
Sent: 08 September 2020 23:05
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Wanted Tohtsu CX600NC relay

 

Andy
    I have one which was retired from active service many years ago as the isolation was not good enough on 432MHz and above, destroying the preamp device. I might sell it but, what band is it for and how much isolation do you need. I can re measure it but from memory it was less than 40dB of isolation on 432 MHz and above, not enough if you are running 100watts plus.

A CX3500 is much better, if you need good isolation, as it has a double switch and the unused bar is grounded both ends. The isolation is so good it is difficult to measure, being in my experience greater than they 65dB they claim, more like 80dB even on 1296MHz.

Richard
GD8EXI


On 08/09/2020, 21:20, "Andy GD1MIP" <gd1mip@...> wrote:

Hi, I need a Tohtsu CX600NC 12v DC relay.

Before I buy new from a store does anyone have a spare they'd like to sell?

Thanks Andy GD1MIP

 


Re: Wanted Tohtsu CX600NC relay

Richard GD8EXI
 

Andy
    I have one which was retired from active service many years ago as the isolation was not good enough on 432MHz and above, destroying the preamp device. I might sell it but, what band is it for and how much isolation do you need. I can re measure it but from memory it was less than 40dB of isolation on 432 MHz and above, not enough if you are running 100watts plus.

A CX3500 is much better, if you need good isolation, as it has a double switch and the unused bar is grounded both ends. The isolation is so good it is difficult to measure, being in my experience greater than they 65dB they claim, more like 80dB even on 1296MHz.

Richard
GD8EXI


On 08/09/2020, 21:20, "Andy GD1MIP" <gd1mip@...> wrote:

Hi, I need a Tohtsu CX600NC 12v DC relay.

Before I buy new from a store does anyone have a spare they'd like to sell?

Thanks Andy GD1MIP


Re: [UKBeacons] GB3CSB -- 10G ON Air -- Update 05

David GM6BIG
 

Hi All,

New LO chain built and fitted to the 10GHz part of GB3CSB to replace the original failed unit.

Thanks to Mark GM4ISM and Alan GM0USI for checking all was well off air when the equipment was restored to service this evening.

For the moment, 10G power remains the same as before.

If anyone would like to donate a suitable 10G PA (24/7 running) of a few watts or more please get in touch by email, gm6big@gmail.com
The existing PA is just over 1W, and solid as a rock, but a little more poke to the antenna would be better.....



With great timing, the annual electric bill is due soon to Walter GM8IIH, the very helpful site owner.
If anyone would like to donate, please send to my Paypal account at...

aware@freeuk.com

(Do not email me using that address though)
Please include a message with your call so I know who your are.

Thanks again to those who have already sent me some help...!

Cheers, David

On 11/08/2020 10:41, David GM6BIG via groups.io wrote:
Hi All,
The temporary exciter for CSB has been removed and the original repaired (and upgraded) driver now returned to service.
So now back to its usual self.
GPS locked, JT4 etc.
With one exception,  the 10GHz is OFF.
At some point since installing the temporary exciter the 10GHz part has failed.
Nothing obviously wrong with the 10GHz assembly, so until its on the bench and I find what is wrong with it, I cant predict how long it will be off air for.
Perhaps an opportunity to replace the 10G PA with a more powerful one !
Cheers, DAvid
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