Date   

Re: Power rating of SMA relays

Grant Hodgson <grant@...>
 

Tim

Not sure about the Narda, but the datasheet for the Radiall is easy to find, this link should work :-

https://radiall-files.s3.amazonaws.com/tds/ramses/R570313000.pdf

- it says 240W average power.

regards

Grant G8UBN

Quoting tim.forrester@gmail.com:



I have an assortment of SMA relays made by Radiall and Narda

The Radiall units are rated 0-3GHz and part number R570313000 and the
Narda's are MS-SMA-020 FSCM99899

No matter how much I search I cannot seem to find out what their power
handling ratings are.

Any ideas ?

73 Tim G4WIM KT6UK


Links:
------
[1] mailto:tim.forrester@gmail.com?subject=Re%3A%20Power%20rating%20of%20SMA%20relays
[2] mailto:ukmicrowaves@yahoogroups.com?subject=Re%3A%20Power%20rating%20of%20SMA%20relays
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Re: Power rating of SMA relays

Roger Blackwell GM4PMK
 

On 30/09/2013 21:50, tim.forrester@... wrote:

I have an assortment of SMA relays made by Radiall and Narda


The Radiall units are rated 0-3GHz and part number R570313000 and the Narda's are MS-SMA-020 FSCM99899

A old Radiall catalogue I have, although it doesn't have the R570 ... series in it, does however  give a general power handling guide for their SMA relays as follows:
0.2GHz 100 W; 1 GHz 70 W; 10GHz 30W; 20 W 18GHz.

73
--

Roger Blackwell  GM4PMK

www.marsport.org.uk


Pneumatic masts

Michael Scott
 

Hi All
 
have decided to buy a pneumatic mast and had a look at the products from Clark and Total Mast Solutions at Newark last Friday. On balance, the Clark ones look to be slightly more sturdy, but wonder if anyone has experience of dealing with either company, and can make any recommendations.
 
Probably best to do it to me direct.
 
Many thanks in advance.
 
Mike, G3LYP


NEC NE72089 or NE72084

John Quarmby
 

I have had a request from a friend looking for a couple of NEC NE72089 or NE72084 to repair a piece of test gear. Anyone got one or two in their junk box that you might part with for a reasonable sum please?

73

John G3XDY


Re: Wanted: Male N chassis mount plug - preferably silver plated.

Dr. David Kirkby <drkirkby@...>
 

Yes thank you, someone donated me one!

Dave

On 30 September 2013 21:47, Grant Hodgson <grant@ghengineering.co.uk> wrote:
Dave

Did you get one?

regards
Grant G8UBN

On 23/09/2013 10:23, David Kirkby wrote:
Does anyone know of where I can get a *male* N plug that is chassis
mount. Something like this

http://uk.farnell.com/amphenol-connex/172118/rf-coaxial-n-plug-str-50-ohm-solder/dp/1791344

from Farnell, but I am not keen to pay £16 delivery charge as it is
only stocked in the USA and not the UK. I'm only looking for one.
Preferably one that is silver plated, so I can solder as close to the
centre as possible.

I want to make a test jig, to measure the DC resistance of some male
and female terminations using a DVM with 4-wire resistance
measurement.

Dave


------------------------------------

Yahoo! Groups Links



Réf. : 24GHz White Box modules

F1CHF
 

Yes 600/800 Mhz
see this F6DRO's article (page 4)
in french ... sorry
 
francois F1CHF
 
 
 
 
 
-------Message original-------
 
Date : 30/09/2013 20:51:13
Sujet : [ukmicrowaves] 24GHz White Box modules
 
 

Seem to have had a mental block...
 
I've done a fair bit  with these Alcatel units in the past, but can't remember what the original IF frequency range was.
Using them on 1296 or 432 is not optimum, and I'm guessing they were centred around 800MHz.- 900MHz
 
Does anyone know the correct IF ?
 
Had a brainwave of a good way to use these - will publish if it works out.
 
Andy
G4JNT
 

 


Power rating of SMA relays

G4WIM KT6UK
 

I have an assortment of SMA relays made by Radiall and Narda


The Radiall units are rated 0-3GHz and part number R570313000 and the Narda's are MS-SMA-020 FSCM99899

No matter how much I search I cannot seem to find out what their power handling ratings are.

Any ideas ?

73 Tim  G4WIM KT6UK


Re: Wanted: Male N chassis mount plug - preferably silver plated.

Grant Hodgson <grant@...>
 

Dave

Did you get one?

regards
Grant G8UBN

On 23/09/2013 10:23, David Kirkby wrote:
Does anyone know of where I can get a *male* N plug that is chassis
mount. Something like this

http://uk.farnell.com/amphenol-connex/172118/rf-coaxial-n-plug-str-50-ohm-solder/dp/1791344

from Farnell, but I am not keen to pay 16 delivery charge as it is
only stocked in the USA and not the UK. I'm only looking for one.
Preferably one that is silver plated, so I can solder as close to the
centre as possible.

I want to make a test jig, to measure the DC resistance of some male
and female terminations using a DVM with 4-wire resistance
measurement.

Dave


24GHz White Box modules

Andy G4JNT
 

Seem to have had a mental block...
 
I've done a fair bit  with these Alcatel units in the past, but can't remember what the original IF frequency range was.
Using them on 1296 or 432 is not optimum, and I'm guessing they were centred around 800MHz.- 900MHz
 
Does anyone know the correct IF ?
 
Had a brainwave of a good way to use these - will publish if it works out.
 
Andy
G4JNT
 


Re: IF Interface to FT-817 - having linearity problems

Richard Ferryman
 

Quick update Sam.  Lifted the transmit path input diode and replaced with 1nF cap.  Now have perfect drive and RX still OK.

Dick G4BBH 



---In ukmicrowaves@..., <ukmicrowaves@...> wrote:

Folks,
This seems like an ideal time to comment on something I've mentioned previously.
When a circuit is published in a book it tends to reappear ad infinitum, in that form, even if there had been corrections in the meantime. There have been many examples in RSGB books over the years.
I am assuming the circuit Dick refers to is the interface to the 23cm transverter.
In that circuit the transmit path input diode can safely be removed and replaced by a 1nF capacitor. The diode bias resistor needs to be removed, of course, as it is no longer required.
The only downside is that some receive signal is shunted. The input switching can then handle a much bigger signal without distortion, otherwise the IF drive should be limited to a few tens of mW.


73 de Sam



Sent tomorrow from my time machine

g4ddk.com
g4ddk.blogspot.com


Re: IF Interface to FT-817 - having linearity problems

Christopher Bartram <cbartram@...>
 

Can I just put-in an entirely shameless plug for my SAT144P371 switchable power attenuator. This is designed to operate with the FT817 amongst a large number of other transceivers, and can be used - as indeed can all of my microwave system components - independently from other units in my range.

The SAT144 uses a combination of P-I-N diode and pHEMT switches, and has an internal adjustable power attenuator.

The SAT432P371 is available for people who want to use a 432MHz IF. 28 and 50MHz versions are also planned.

Further information is at <www.chris-bartram.co.uk>

Vy 73

Chris
GW4DGU


Re: Free PIN Switching Diodes

Michael Scott
 

Hi Andy et al
 
Just a reminder that the Chipbank has a number of PIN diodes including a recently received reel of BAR50-02V single diodes which have not yet been added to the catalogue but will be in the next update. They are good to 6GHz for switching.
 
73, Mike, G3LYP 

----- Original Message -----
Sent: Monday, September 30, 2013 10:07 AM
Subject: [ukmicrowaves] Free PIN Switching Diodes

 

(Well, for an SASE anyway)
 
A recent discussion on the UKMicrowaves Group recently reminded me I still have probably more than 500   DC2850E PIN switching diodes.   These were rescued from a skip (literally) after the cancellation of a large mil-comms order back in 1990 or thereabouts.   The PIN diodes were made by Marconi Electronic Devices (now there's a name from history) and each individual diode comes in its own sealed envelope.  
 
Designed for RF low to medium  power switching, these diodes have an on resistance of 0.8 ohms at 5mA forward current making them ideal for switching the output of HF through VHF (don't know about UHF) at moderate power  They are of ancient design, being glass encapsulated wire ended and are therefore a bit delicate, particularly when bending the wires close to the device body. 
They're rather large by modern standards;  the glass body is 4mm long, and allowing another 1mm on each wire for bend radius means PCB pads need to be at least 7 to 8mm apart.   
 
Over the years I've used them to switch the power steps in the 5MHz beacons GB3 RAL, WES and ORK, as other low level switches for various purposes, as an IF switch in several transverter interfaces from  HF through to  144MHz and as T/R switching for 10 - 20 Watts at 144MHz and 70MHz This latter application is probably close to their original design purpose. 
 
If you send me an SASE I will give free up to a maximum of 10 per individual.    Anyone wanting more that that, please explain why  - and to sell on Ebay is not a good excuse :-)    Postal address is QTHR and on QRZ.com - and has been for the last 25 years
 
They don't need a jiffy bag, a decent quality normal letter type envelope is OK.   Tiny lightweight things, already in a protective paper envelope.
And after reading the follow-up to Peter's recent offering, overseas customers, please follow the same procedures as Peter recommended. 
 
You may find a shortform data sheet on the web, but all it'll be is something like the one page I have and more-or-less summarised here:
  Vb(min) 35V 
  Vf(max) 1.0V
  Rs(max) 0.8 ohms at If 5mA, 40MHz
  Cd max  1.2pF at Vrr 20V
  Tr 5ns
 
There then follows a curve of slope resistance against forward current, with X,Y points   (mA, ohms) :
(0.01, 35)  (0.03, 18)  (0.1, 6.5)  (0.3, 2.5)  (1, 1.3)  (3,0.85)  (10, 0.7)  (30, 0.5)    You can join-up the dots !
 
I have no more data and think I've given enough information here to prevent the need for any email follow up and especially Group email clogging!
 
Andy
G4JNT
 
ps. 
If you feel generous, donations to the South Coast Beacon and Repeater group  http://www.scrbg.org/donate/   
The beacons are going though  a major mechanical overhaul with all wire guy and haul ropes being replaced - which all costs money
 


Re: IF Interface to FT-817 - having linearity problems

Richard Ferryman
 

Thanks for that tip Sam.  Will try a capacitor today.  Easier than having to etch and build yet another board.  On the receive path I can lose a little as my system gives optimum signal/noise wirh about 9dB attenuation between the mixer and FT-817.

Dick G4BBH



---In ukmicrowaves@..., <ukmicrowaves@...> wrote:

Folks,
This seems like an ideal time to comment on something I've mentioned previously.
When a circuit is published in a book it tends to reappear ad infinitum, in that form, even if there had been corrections in the meantime. There have been many examples in RSGB books over the years.
I am assuming the circuit Dick refers to is the interface to the 23cm transverter.
In that circuit the transmit path input diode can safely be removed and replaced by a 1nF capacitor. The diode bias resistor needs to be removed, of course, as it is no longer required.
The only downside is that some receive signal is shunted. The input switching can then handle a much bigger signal without distortion, otherwise the IF drive should be limited to a few tens of mW.


73 de Sam



Sent tomorrow from my time machine

g4ddk.com
g4ddk.blogspot.com


Free PIN Switching Diodes

Andy G4JNT
 

(Well, for an SASE anyway)
 
A recent discussion on the UKMicrowaves Group recently reminded me I still have probably more than 500   DC2850E PIN switching diodes.   These were rescued from a skip (literally) after the cancellation of a large mil-comms order back in 1990 or thereabouts.   The PIN diodes were made by Marconi Electronic Devices (now there's a name from history) and each individual diode comes in its own sealed envelope.  
 
Designed for RF low to medium  power switching, these diodes have an on resistance of 0.8 ohms at 5mA forward current making them ideal for switching the output of HF through VHF (don't know about UHF) at moderate power  They are of ancient design, being glass encapsulated wire ended and are therefore a bit delicate, particularly when bending the wires close to the device body. 
They're rather large by modern standards;  the glass body is 4mm long, and allowing another 1mm on each wire for bend radius means PCB pads need to be at least 7 to 8mm apart.   
 
Over the years I've used them to switch the power steps in the 5MHz beacons GB3 RAL, WES and ORK, as other low level switches for various purposes, as an IF switch in several transverter interfaces from  HF through to  144MHz and as T/R switching for 10 - 20 Watts at 144MHz and 70MHz This latter application is probably close to their original design purpose. 
 
If you send me an SASE I will give free up to a maximum of 10 per individual.    Anyone wanting more that that, please explain why  - and to sell on Ebay is not a good excuse :-)    Postal address is QTHR and on QRZ.com - and has been for the last 25 years
 
They don't need a jiffy bag, a decent quality normal letter type envelope is OK.   Tiny lightweight things, already in a protective paper envelope.
And after reading the follow-up to Peter's recent offering, overseas customers, please follow the same procedures as Peter recommended. 
 
You may find a shortform data sheet on the web, but all it'll be is something like the one page I have and more-or-less summarised here:
  Vb(min) 35V 
  Vf(max) 1.0V
  Rs(max) 0.8 ohms at If 5mA, 40MHz
  Cd max  1.2pF at Vrr 20V
  Tr 5ns
 
There then follows a curve of slope resistance against forward current, with X,Y points   (mA, ohms) :
(0.01, 35)  (0.03, 18)  (0.1, 6.5)  (0.3, 2.5)  (1, 1.3)  (3,0.85)  (10, 0.7)  (30, 0.5)    You can join-up the dots !
 
I have no more data and think I've given enough information here to prevent the need for any email follow up and especially Group email clogging!
 
Andy
G4JNT
 
ps. 
If you feel generous, donations to the South Coast Beacon and Repeater group  http://www.scrbg.org/donate/   
The beacons are going though  a major mechanical overhaul with all wire guy and haul ropes being replaced - which all costs money
 


Re: IF Interface to FT-817 - having linearity problems

SAM JEWELL
 

Folks,
This seems like an ideal time to comment on something I've mentioned previously.
When a circuit is published in a book it tends to reappear ad infinitum, in that form, even if there had been corrections in the meantime. There have been many examples in RSGB books over the years.
I am assuming the circuit Dick refers to is the interface to the 23cm transverter.
In that circuit the transmit path input diode can safely be removed and replaced by a 1nF capacitor. The diode bias resistor needs to be removed, of course, as it is no longer required.
The only downside is that some receive signal is shunted. The input switching can then handle a much bigger signal without distortion, otherwise the IF drive should be limited to a few tens of mW.


73 de Sam



Sent tomorrow from my time machine

g4ddk.com
g4ddk.blogspot.com


Re: GM Roundtable

Ian White
 

Richard wrote:

Is there any chance the organisers of the Scottish round table could
reconsider the dates, foe next year.
The reason is very simple due to the celebration of the only man to
enter
parliament with true intent, G. Fawkes.
Anyone traveling up with partners who have pets, either leave them
alone,
put them in a cattery/kennel, or if lucky have someone to look after
them.
However all the bangs from fireworks at the weekend closest to November
5, scare pets and its better to stay with them.
For me, dont know about anyone else, the last weekend in October would
be better. That week difference also gives a little bit more daylight
for the
drive home, especially if ts before the clocks go back to GMT.

--
When organising the first GMRT, two years ago, we did consider the
weekend in October.

However, that would now create a direct clash with the BATC Convention,
and would also place the GMRT at the end of an extremely busy month for
microwavers including the October contest, the RSGB Convention and
Microwave Update. Those competing events obviously wouldn't affect
everyone attending the GMRT; but they *would* have a significant effect
on some of the speakers we would like to invite.

Also the local bonfire night is different: the night when Burntisland
tries to live up to its name is always November 5th itself.

But having said all that, I have no doubt that next year's organising
committee will try to bear all possible considerations in mind, in an
effort to choose the right date for as many people as possible.


So this is a good opportunity to remind everyone:

The 2013 GM Round Table will take place on Saturday 2nd November at the
Museum of Communication, Burntisland, Fife (just over the bridges from
Edinburgh).

http://www.rayjames.biz/microwavert/

The GMRT is always a good event, well worth making a weekend of it...
and the Museum of Communication is a truly unique venue, well worth a
visit in its own right.


73 from Ian GM3SEK


Re: IF Interface to FT-817 - having linearity problems

R Hopkins
 

Hi Dick

I use a FT817 to drive my 10GHz transverter. When I was designing my transverter this was one of the
things that occupied my mind for some time. My solution was to switch in an attenuator (using a
relay) on transmit (about 20dB if my memory serves). I also provided a variable negative supply in
the transverter so that I could control the ALC in the '817 to give me the exact amount of drive. I
realise that your mail was about speed of switching which in my case wasn't too important. I have a
PIC micro that controls the synthesiser to look after my LO but it also controls the tx/rx timing/
switching. The '817 has every connection on the back to achieve this. I also have an interlock that
dumps the RF from the '817 into a 50 Ohm load if I forget to put the plug into the accessory socket.

If you need fast switching for some sort of data mode or whatever this would probably be not what
you are looking for.

Good luck

Roger GW4NOS


Re: IF Interface to FT-817 - having linearity problems

Andy G4JNT
 

Its a very big coincidence, but I'm actually designing an IF interface for the FT817 / transverters at this very moment.  PIN switching obviously, and also including a variable resistance PIN for feedback with smooth electronic IF drive control over a few dB for fine optimising Tx drive level.  That means two different types of PIN will be needed.  One optimised for RF switching, the other for variable attenuation
 
Looking throgh the RS catalogue, they do quite a range of PIN diodes, and I notice they do one type BAP70 - this is too just close to the BAT70 you mentioned to be a coincidence.   ONE letter different in type number.
 And it only costs 12.2p each (but mininimum order 20 off)  http://uk.rs-online.com/web/p/pin-diodes/6261835/
 
and...  looking at the data sheet - its perfect for my variable attenuator function.with 40 ohms at 1mA Ifwd.   100R at 350uA
Less useful as a switch, as 20mA gives 3 ohms - and a switch really ought to be better than that.    Anyway, I have several hundred PINs designed for RF switching, wire ended glass body, very old and obsolete and mil-spec,  but they're tooo god not to use.

Andy
G4JNT

On 29 September 2013 22:10, <g4bbh@...> wrote:
 

Thanks Andy.  I will look at an alternative.  The text associated with the circuit I was plagiarising did refer to it as a PIN but data sheet says Schottky!!!  It certainly creates a lovely 'hedgehog' effect on the SA well over 10dB below what I get from the relay system.

Dick G4BBH




---In ukmicrowaves@..., <ukmicrowaves@...> wrote:

I don't how significant, but the BAS70 is not a PIN diode.  Its a Schottky.
 
Is it being used for RF switching ?
 
A proper PIN really would be a better choice
 
Andy
G4JNT

 
On 29 September 2013 18:10, <g4bbh@...> wrote:
 

My transverter has a single mixer for TX and RX and brings mixer IF port out directly on an SMA for connection the the rig.  My FT-817 outputs a pretty clean 27dBm and I need around 0dBM into the mixer for optimum  results.   I used to use a relay and SMA attenuators to get the correct TX drive and near straight through on RX which gave perfect linear drive but slow switching.  I recently decided to change to using PIN diodes (BAS70-05) instead of the relay and copied the circuit used in the 'DDK 23cm transverter as per the International Microwave Handbook, 2nd Edition..  This works but  whatever I do I don't seem to be able to overcome excesive distortion even at -10dBm to the mixer.   I wonder if someone has any suggestions as to where I am going wrong or knows of a foolproof (and linear) interface for the job.  Needless to say I am not very experienced with PIN diode switching!
Dick G4BBH




Re: IO91RF in Low Microwave Bands 6-Oct

Phil Guttridge G3TCU
 

The group of us who often activate IO91RF in the Low Microwave Bands sessions will be on next Sunday.
(G1EHF, G4SJH, G3TCT, G3TCU, G3WBQ) we'll post the details asap.
We couldn't make the June session as we nearly all had other commitments.

There will have to be lots of good Dx QSOs to justify the early start!

73, Phil.

 

On 28/09/2013 14:29, Ralph Bird wrote:
 

If I get shot down, I will deploy a parachute!.
 
Seriously:
I am increasingly more and more alarmed at
the numbers who indicate that they are to be
active for the contests.
 
Investment apart, the time I put to these events
is increasingly becoming counter productive.
 
I know there are a few who choose not to indicate
their intentions via this reflector, but one cannot
deny that numbers are dropping off.
 
I am active every day. sickness and Christmas day
being the only exceptions.  I know that is my choice but
'Surely',  when you see the numbers active on the
reflector,  some of you could boost the
activity,  even if its only for an hour or two.
 
Like it or not, I still say that if I did not have that
window into France. This station would have been
sold off after 50 years being an active radio amateur,
starting as VQ8BY in 1963 while in Mauritius with the R.N.
to buy a Leica M9 and get a life.
 
Please, please switch on your gear, maybe you may
even enjoy it. Also answer the often debated topic on here
of   "Activity on the bands"., simple!.
 
73 Ralph
G4ALY
 


Re: IF Interface to FT-817 - having linearity problems

Richard Ferryman
 

Thanks Andy.  I will look at an alternative.  The text associated with the circuit I was plagiarising did refer to it as a PIN but data sheet says Schottky!!!  It certainly creates a lovely 'hedgehog' effect on the SA well over 10dB below what I get from the relay system.

Dick G4BBH




---In ukmicrowaves@..., <ukmicrowaves@...> wrote:

I don't how significant, but the BAS70 is not a PIN diode.  Its a Schottky.
 
Is it being used for RF switching ?
 
A proper PIN really would be a better choice
 
Andy
G4JNT

 

On 29 September 2013 18:10, <g4bbh@...> wrote:
 

My transverter has a single mixer for TX and RX and brings mixer IF port out directly on an SMA for connection the the rig.  My FT-817 outputs a pretty clean 27dBm and I need around 0dBM into the mixer for optimum  results.   I used to use a relay and SMA attenuators to get the correct TX drive and near straight through on RX which gave perfect linear drive but slow switching.  I recently decided to change to using PIN diodes (BAS70-05) instead of the relay and copied the circuit used in the 'DDK 23cm transverter as per the International Microwave Handbook, 2nd Edition..  This works but  whatever I do I don't seem to be able to overcome excesive distortion even at -10dBm to the mixer.   I wonder if someone has any suggestions as to where I am going wrong or knows of a foolproof (and linear) interface for the job.  Needless to say I am not very experienced with PIN diode switching!
Dick G4BBH