Date   

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
--
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus


GB3CSB on 10GHz

Mark GM4ISM
 

Thanks to Dave GM6BIG, the rebuilt GB3CSB 10GHz beacon is back on and working well.

Reports welcome!


Mark GM4ISM


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https://www.avg.com


Re: Farnham and Mow Cop SDRs

Colin G4EML
 

Try looking for SEE later in the day when the temperature has reduced. It has an intermittent fault at the moment where the power drops when the ambient temp is above about 20 degrees. 

Colin G4EML. 


On 8 Sep 2020, at 14:41, Adrian G4UVZ via groups.io <adrianwhatmore248@...> wrote:

Sound now working on Mowcop...but no sign of SEE or anything else on Farnham?

Any ideas if it is working?


Re: Farnham and Mow Cop SDRs

G1DFL
 

GB3SEE 10GHz at Reigate is there, just weak into Farnham SDR this afternoon. It's been orange (poorly?) on Beaconspot for a while, does drop off the SDR during hot weather. 

Looking forward to GB3GCT the new 10GHz beacon when its operational from Greenham Common. That will be a better direction for me.

Regards..Pete
G1DFL


On Tue, 8 Sep 2020 at 14:41, Adrian G4UVZ via groups.io
<adrianwhatmore248@...> wrote:
Sound now working on Mowcop...but no sign of SEE or anything else on Farnham?

Any ideas if it is working?


Re: Farnham and Mow Cop SDRs

Adrian G4UVZ
 

Sound now working on Mowcop...but no sign of SEE or anything else on Farnham?

Any ideas if it is working?


Re: FS: coax to waveguide transitions

Alex May M1BSX
 

Hi Wilko,

Thanks a lot for this link - could be useful! :-)

73s Alex


On Tue, 8 Sep 2020, 08:31 Wilko, <wkb@...> wrote:
hi,

I seem to remember people were/are looking for waveguide to coax transitions.  I just stumbled on this
one:  

https://www.zendamateur-marktplaats.nl/antennestoebehoren/golfpijp/wr90-sma-adapter-incl-meetrapport-wr112-n-8056.html

I am not associated with the seller, just thought it might be useful to someone.

73 Wilko
PA1WBU


FS: coax to waveguide transitions

Wilko
 

hi,

I seem to remember people were/are looking for waveguide to coax transitions.  I just stumbled on this
one:  

https://www.zendamateur-marktplaats.nl/antennestoebehoren/golfpijp/wr90-sma-adapter-incl-meetrapport-wr112-n-8056.html

I am not associated with the seller, just thought it might be useful to someone.

73 Wilko
PA1WBU


Re: Farnham and Mow Cop SDRs

Neil Smith G4DBN
 
Edited

I can hear myself fine on Mow Cop this evening, propagation is pretty much back to normal, with OSW arriving here at -15dB in JT4G.  No sign of GB3KBQ, but CAM is about S3 and I'm hearing PKT pretty well, despite it being enfeebled at present. 

Mow Cop receive level fro my signal is usually 6dB over noise across the Peak District/Staffordshire Moorlands from down here near sea level.

I was about the same strength on Mow Cop as OSW was, at least until a plane at 2500 ft on the approach to Manchester produced a nice fat AS reflection.

Neil G4DBN

On 07/09/2020 18:10, Mark GØNMY wrote:

I have been logged onto mowcop sdr the last three nights Fri Sat Sunday and it hasnt lost OSW beacon, LEX image came up after midnight on Sat and Sun. but is down in the noise now.

OSW is S7 on the SDR meter.

One tip, you may already know this but, on the Waterfall settings

Under view select weak sigs it helps show up weaker signals.

If you already knew this then carry on, as you were hee hee

 p.

View/Reply Online (#58271) | Reply To Group | Reply To Sender | Mute This Topic | New Topic

Your Subscription | Contact Group Owner | Unsubscribe [neil@...]

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-- 
Neil
http://g4dbn.uk


Re: Farnham and Mow Cop SDRs

Mark GØNMY
 

Yes the two artifacts are birdies of some kind I dont know if they are internal or externally generated.

Shame about html5 not working, I use FireFox browser and have no issues, once I select html5 but I think it is selected by default as Java suxs

 

Hope that helps a little.

73 Mark G0NMY


Re: Farnham and Mow Cop SDRs

Adrian G4UVZ
 

On Mon, Sep 7, 2020 at 10:10 AM, Mark GØNMY wrote:

 

Under view select weak sigs it helps show up weaker signals.

If you already knew this then carry on, as you were hee hee

Thanks very much for the info ..I wasn't aware of the weak sig option..I can now see the Oswestry beacon..I assume that the 2 other signal pretty much symetrical on the centre line are funies. Unfortunately I can't hear any idents as I gave up a long time ago trying to get Java to work on my PC and the HTML sound doesn't seem to work either!..unless I am not clicking something I should!

 

 

 


From: Adrian G4UVZ <adrianwhatmore248@...>

 
 
 
Reply to Group Discard Private


Re: Farnham and Mow Cop SDRs

Mark GØNMY
 

I have been logged onto mowcop sdr the last three nights Fri Sat Sunday and it hasnt lost OSW beacon, LEX image came up after midnight on Sat and Sun. but is down in the noise now.

OSW is S7 on the SDR meter.

One tip, you may already know this but, on the Waterfall settings

Under view select weak sigs it helps show up weaker signals.

If you already knew this then carry on, as you were hee hee

 

 

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