Date   

Re: Source of feedthrough capacitors

DougF VK4OE
 

Greetings to all!

There are many relatively small ones waiting to be 'recovered' from each Elcom Synth, a previously valued microwave module which now seems to have fallen out of popular use (particularly in that their sources seem to have dried up).  I suspect that there are still many of these modules still sitting on readers' shelves, just waiting for a suitable project to come along!

Cheers and 73,

--Doug Friend, VK4OE

On 28/03/2021 10:21 pm, Mike GD6ICR wrote:
Anyone know of a source of small bolt in or solder in feed through capacitors. 3-4mm diameter max as I want to externalize some control pins on two transverters I have. All the ones Ive seen on Ebay/Banggood/Farnell etc all seem to be much larger 6mm size. Any advice/source appreciated.
Mike GD6ICR IO74PF73TW


Re: SDR UNO RSP 1 Problem

Dave (G1OGY)
 

>> I have a problem with my RSP 1 .

You need to take a look at ::

C:\Users\<Your-User-Name>\AppData\Roaming\SDRPlay\SDRuno.ini

It is a text file and will open in `Notepad`.
It may well be advisable to delete it; given you want an OOB experience.

Dave, G1OGY


On Sun, 28 Mar 2021 at 18:19, Adrian G4UVZ via groups.io <adrianwhatmore248=btinternet.com@groups.io> wrote:
Thanks Andrew ...Registry sounds dangerous ..with my limitted IT Skils!!   I foresee the blue screen of death on the horizon!

A


Re: Cleaning relay contacts

Andy G4JNT
 

I see an intelligent relay rejuvenation project in this.   Swap over the contacts repeatedly, with a constant current driven though each.   Monitor the voltage drop after each change to a make position and report the findings.



On Sun, 28 Mar 2021 at 19:42, Alan Melia via groups.io <Alan.Melia=btinternet.com@groups.io> wrote:
Mark beat me to it :-((  I was getting a number of Pye/Philips M290 relays going HR on receive contacts in the 1990s. This was not a coax relay but switching a few milliamps several times returned the receive sensitivity without needing to replace the relay (an RS stock item).   I believe it was a BT method in the days of Strowger.

Alan
G3NYK






Re: Cleaning relay contacts

Alan Melia
 

Mark beat me to it :-(( I was getting a number of Pye/Philips M290 relays going HR on receive contacts in the 1990s. This was not a coax relay but switching a few milliamps several times returned the receive sensitivity without needing to replace the relay (an RS stock item). I believe it was a BT method in the days of Strowger.

Alan
G3NYK


Re: Cleaning relay contacts

John Fell
 

Clamp gently in a vice onto the lid and whack the base with a small lump of wood - should break the epoxy seal and allow cover to come off .
Contacts can be seen and if appropriate cleaned with a contact strip - do not file !
Test results on a SAnn.
DC Wetting is useful , mainly on the RX contacts that are often NC for long periods and develop surface resistance .

73
JOhn
G0API

On Sun, 28 Mar 2021 at 16:56, Mike GD6ICR <gd6icr@...> wrote:
Been going through my sma relays and testing them on my primitive spectrum analyser has shown that I have quite a few lossy relay on TX as high as 4dB and quite a few showing around 1dB on RX side. I wonder if anyone can suggest a suitable contact cleaning method - one suggestion Ive had is connect 12v thru 500ohm resistors to NO and NC and leave them switching for about 5 minutes

Some of the relays of coarse can be dismantled and cleaned but most cannot - any comments please
--
Mike GD6ICR IO74PF73TW


Re: Cleaning relay contacts

Mike GD6ICR
 

Thanks Mark Im aiming in the switching DC on the contacts as per http://www.dl6nci.de/sma.htm Thanks to Dave RQI for this - its really good design especially 24/12v relays

Circuit building tomorrow
 

--
Mike GD6ICR IO74PF73TW


Re: SDR UNO RSP 1 Problem

Adrian G4UVZ
 

Thanks Andrew ...Registry sounds dangerous ..with my limitted IT Skils!!   I foresee the blue screen of death on the horizon!

A


Re: SDR UNO RSP 1 Problem

Andrew G8TZJ
 

Many programs store their data in the registry. Its quite likely the RSP 1 also does. So the only way is to look through the registry with regedit.exe (search for key words) and delete as necessary. BEWARE! Editing the wrong thing in the registry could lead to nasty things happening. Make a backup of the registry first and then its fingers crossed.

73 Andrew G8TZJ


Re: Cleaning relay contacts

Mark GM4ISM
 

Mike

Hot switching a small  DC current  really does work in many cases.

 You generate micro-arcs at the contact surface  which disrupt the  oxide layer and promote  a lower contact resistance

 Some system designs  allow a few 10ms of mA DC to switch alongside the RF  in service to whet  the contact at each switching event

I used to use special very slightly abrasive paper pulled between contacts on old (large) PO relays It was routine maintenance but even that  did damage the contact surface and it  was a constant battle

Mechanical  'cleaning' of delicate contact surfaces as in most RF relays is a recipe for disaster.

Mark GM4ISM

 

On 28/03/2021 16:56, Mike GD6ICR wrote:
Been going through my sma relays and testing them on my primitive spectrum analyser has shown that I have quite a few lossy relay on TX as high as 4dB and quite a few showing around 1dB on RX side. I wonder if anyone can suggest a suitable contact cleaning method - one suggestion Ive had is connect 12v thru 500ohm resistors to NO and NC and leave them switching for about 5 minutes

Some of the relays of coarse can be dismantled and cleaned but most cannot - any comments please
--
Mike GD6ICR IO74PF73TW

Virus-free. www.avg.com


Re: Cleaning relay contacts

Dave - G4RQI
 

Hello

Unless someone says otherwise you might try this http://www.dl6nci.de/sma.htm

David - G4RQI


From: UKMicrowaves@groups.io <UKMicrowaves@groups.io> on behalf of Mike GD6ICR <gd6icr@...>
Sent: Sunday, March 28, 2021 4:56:02 PM
To: UKMicrowaves@groups.io <UKMicrowaves@groups.io>
Subject: [UKMicrowaves] Cleaning relay contacts
 
Been going through my sma relays and testing them on my primitive spectrum analyser has shown that I have quite a few lossy relay on TX as high as 4dB and quite a few showing around 1dB on RX side. I wonder if anyone can suggest a suitable contact cleaning method - one suggestion Ive had is connect 12v thru 500ohm resistors to NO and NC and leave them switching for about 5 minutes

Some of the relays of coarse can be dismantled and cleaned but most cannot - any comments please
--
Mike GD6ICR IO74PF73TW


Re: Cleaning relay contacts

Andy G4JNT
 

I cured a few of mine by just operating them a few times



On Sun, 28 Mar 2021 at 16:56, Mike GD6ICR <gd6icr@...> wrote:
Been going through my sma relays and testing them on my primitive spectrum analyser has shown that I have quite a few lossy relay on TX as high as 4dB and quite a few showing around 1dB on RX side. I wonder if anyone can suggest a suitable contact cleaning method - one suggestion Ive had is connect 12v thru 500ohm resistors to NO and NC and leave them switching for about 5 minutes

Some of the relays of coarse can be dismantled and cleaned but most cannot - any comments please
--
Mike GD6ICR IO74PF73TW


Cleaning relay contacts

Mike GD6ICR
 

Been going through my sma relays and testing them on my primitive spectrum analyser has shown that I have quite a few lossy relay on TX as high as 4dB and quite a few showing around 1dB on RX side. I wonder if anyone can suggest a suitable contact cleaning method - one suggestion Ive had is connect 12v thru 500ohm resistors to NO and NC and leave them switching for about 5 minutes

Some of the relays of coarse can be dismantled and cleaned but most cannot - any comments please
--
Mike GD6ICR IO74PF73TW


Frequency West / Continental Microwave PLL 10m GHz Multiplier

Adrian G4UVZ
 

There is a well know law of electronics that if you have a fiull set of spares for an item it is very unlikely to go wrong!

During the rebuild of GB3KBQ, due to the generocity of individuals on this forum, I was able to build an 'almost'  spare driver unit for the beacon.

What I am missing, to complete a spare unit, is the 108 MHz - 10GHz multiplier. This is a Continental Microwave / Frequency- West Microwave PLL multiplier 'Brick'

These were commonly available at round tables and rallies a few years ago.

If you have such an item gathering dust and surplus to your requirements ..I can find a good home it!

Adrian G4UVZ  Beacon Keeper GB3KBQ 10,368.870 MHz IO80LX


Re: Source of feedthrough capacitors

John Lambo
 

https://rfshop.co.uk/feedthru-tusonix-compatible-8-32-unc-thread-1500pf-ft-1500 but postage is £6.. #8-32 UNC is for a 4.2 mm hole

CPC have some that are 5.5mm #12-28 UNF

Franco Rota has some 2.9mm ones, but carriage is ludicrous unless you have other stuff to order https://www.rf-microwave.com/en/corry-micronics/ft24-01-102p/ultra-miniature-feed-through-capacitor/cp-d26

Neil G4DBN







Re: Source of feedthrough capacitors

Neil Smith G4DBN
 

https://rfshop.co.uk/feedthru-tusonix-compatible-8-32-unc-thread-1500pf-ft-1500 but postage is £6.. #8-32 UNC is for a 4.2 mm hole

CPC have some that are 5.5mm #12-28 UNF

Franco Rota has some 2.9mm ones, but carriage is ludicrous unless you have other stuff to order https://www.rf-microwave.com/en/corry-micronics/ft24-01-102p/ultra-miniature-feed-through-capacitor/cp-d26

Neil G4DBN


Re: Source of feedthrough capacitors

Keith Le Boutillier
 

Hi Mike

 

 

Try

 

https://www.sv1afn.com/en/product-category-4/

 

73 Keith

 

From: UKMicrowaves@groups.io <UKMicrowaves@groups.io> On Behalf Of Mike GD6ICR
Sent: 28 March 2021 13:21
To: UKMicrowaves@groups.io
Subject: [UKMicrowaves] Source of feedthrough capacitors

 

Anyone know of a source of small bolt in ir solder in feed through capacitors. 3-4mm diameter max as I want to externalize some control pins on two transverters I have. All the ones Ive seen on Ebay/Banggood/Farnell etc all seem to be much larger 6mm size. Any advice/source appreciated.
--
Mike GD6ICR IO74PF73TW


Source of feedthrough capacitors

Mike GD6ICR
 

Anyone know of a source of small bolt in ir solder in feed through capacitors. 3-4mm diameter max as I want to externalize some control pins on two transverters I have. All the ones Ive seen on Ebay/Banggood/Farnell etc all seem to be much larger 6mm size. Any advice/source appreciated.
--
Mike GD6ICR IO74PF73TW


Re: Off Topic computer/Rig interface?

Clive Jenner
 

Hi Andy, thanks for your comment, it is the Panasonic AQV252G as you say quite chunky.

Ensures you don't need to use an external device to beef up the connection to external relays!

73 Clive GW0PPO


Re: Meteor of Plane on 2.3Ghz

Neil Smith G4DBN
 

I'd guess a plane under 3000 m somewhere between Newton Stewart and Cumnock, travelling east-west.  If it was very high, it might be outside your antenna lobes, and if it was travelling at a small angle to the path from you to CSB, you wouldn't see much doppler.

If you are 200km from the beacon for instance, and there is a plane travelling at 90 degrees to the path, and 1 km  away from it, for each metre the plane travels towards the path, the distance from you via the plane to the beacon is dropping by a tiny bit over 2cm.

If the plane is doing 500 knots, that is about 250 metres per second, so the path length is changing by 5 metres per second.

For small angles, the geometry means that the rate of change of the path is pretty much linear with distance, so at 2km away, it is about 10 m/sec and 3 km is it 15 m/sec.

At 2.3 GHz, a path length change of 10 m/sec gives a doppler shift of 2.3e9 x 10 / 3e8, which is around 77 Hz

So at 3 km away, the doppler shift is 115 Hz, and at 1km, 38 Hz.  The doppler is changing by 38 Hz per km.

Now the plane is doing 1km in four seconds, the rate of change of doppler is 38/4 = 9.5 Hz per second.

Over the 20 seconds or so of the reflection, the first trace will start at 10 seconds away from the track, at around +100 Hz. It will drop linearly to zero as the plane crosses the line of sight, then as the path is getting longer, it will continue to drop at the same rate, until the reflection is lost at +10 seconds.  If the trace lasts 20 seconds and the plane is going at 500 kts at 90 degrees to the path then, you shoudl see a total of almost 200 Hz change in frequency.

If the plane is going at a different speed, the shift scales in proportion.  If the plane is not perpendicular to the path, then the rate of change is reduced according to the angle, until it drops to zero where the plane is low and in line with the path.  I won't bore you with the trigonometry.

Looking at your trace, the shift is a total of about 100 Hz, but I can't see the time scale.  If that is a duration of 10s, then the plane was pretty much at 90 degrees to the path. If it was 20 seconds, then the plane was maybe at 40 degrees to the path.

If you run Airscout, you can check exactly which planes are causing the reflection and check the rate of change of frequency against the speed and heading relative to the line of sight.

You may find an asymmetry, where there is more reflection before or after the plane crosses the zero point.  That is usually because of the reflection coming from a grazing incidence reflection which is less efficient as the angle changes very slightly.  After a while, you'll develop a sixth sense about which type of planes work best, and what heights and relative headings give the longest and most consistent reflections.  Fast digimodes like JT9E-fast work best for this sort of thing, or very short SSB/CW overs, maybe 5 or 10 seconds tx/rx, with you and a QSO partner choosing first or second period.  Huge fun when there is no tropo about!

Neil G4DBN

On 28/03/2021 08:44, Mike GD6ICR wrote:
Many thanks Neil I’m going to see if I can look back to that time period ans see what planes were about. Quite a Doppler shift on it as well

Mike

On Sat, Mar 27, 2021 at 05:05 PM, Neil Smith G4DBN wrote:
Definitely a plane Mike, meteor returns above 70cm are almost
nonexistent.  You can verify by running Airscout software to see what
planes are causing the reflections.

If you calculate the rate of change of frequency, you can work out the
geometry for how fast the path length via the plane is changing, and if
you know the track of the plane, you can calculate the speed, or
vice-versa.

Neil G4DBN

On 27/03/2021 16:43, Mike GD6ICR wrote:

[Edited Message Follows]

The pic below is one of monitoring of GB3CSB Please note the Doppler
shifted signal on the lower part of the beacon reception
 


Re: Off Topic computer/Rig interface?

Andy G4JNT
 

Just looked-up the opto used in that.  It's quite a chunky beast,  capable of switching   60V at 2.5A.
Not cheap either.  Over £5 each



On Sun, 28 Mar 2021 at 12:37, Andy Talbot <andy.g4jnt@...> wrote:
Don't need a manual. you can work it out from the diagram.  Taking the connections as shown in your diagram, starting from the top left:

Pins 1/2 , connect to your receiver either headphone socket or line out.

Pins 3/4  connect to PC line input (ideally) or mic input though a separate resistive divider of about 100:1 if that's all you have for audio input to the PC

Pins 5, I'll come to later .....

Pins 6/7 Tx audio drive to your transceiver.  By the look of the PTT path,  you can work out pin 7 is therefore ground of the rig.  Pin 6 the hot side of the audio with the 10k resistor.   Line input to the ideally, if you have the option, otherwise mic in, again via an attenuator 100:1 or so

Pins 8/9.   8 is ground as ;labelled.  Audio OUT from PC soundcard, usually headphones, but you may have a line-out option

There's audio VOX on there, that's the purpose of the two transistors, which drives an opto isolator - the IC.  Link the two pins on the bottom labelled PTT enable.   That's presumably some sort of safety Tx inhibit if you want it.

PTT drive to your rig is Pin 5, the output of the opto isolator, and it pulls down to pin 7  which will therefore need to be the ground side of the audio drive to the rig.

Apply 12V as labelled an that's it.   A fully isolated soundcard interface.

Mind you. if you have line in and out on the radio, transformer+opto isolation hasn't got much to offer in the way of stopping spurii from the PC





On Sun, 28 Mar 2021 at 12:04, Clive Jenner <clivejenner@...> wrote:
Hi folks, long shot I know but here are some very knowledgable people on here. I want to resurrect a computer/rig interface. I have reverse engineered the schematic for it but I have no info on connecting the board up. I have attached an image of the board and my scruffy attempt at the schematic. If you recognise the board and have a copy of the user guide I would appreciate a copy. Thanks in advance and 73 Clive GW0PPO

2381 - 2400 of 64095