Date   

Re: GB3FNM

Phil Guttridge G3TCU
 

Hi John,

I heard from Barry G4SJH Wednesday evening, that there was a power cut at the beacon site. I think some action is needed to get it going again.

73, Phil G3TCU.



On 01/05/2020 08:30, John Lemay via groups.io wrote:
Morning all

I've not heard the Farnham beacon on 13cms recently. Tropo conditions have
been awful lately but there's not even a hint of a signal on my waterfall,
which is odd.

Is it QRV ?

Last spotted on 22 April.

Thanks

John G4ZTR







Re: MGF 1200

Michael Scott
 

Hi John

Please can you fill in the order form on the UKuG website. Follow the link to the Chipbank.

73, Mike.

-----Original Message-----
From: John E. Beech
Sent: Thursday, April 30, 2020 7:19 PM
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] MGF 1200

Hi Mike,
I could do with two devices to repair my TVTR.

de John G8SEQ QTHR.


-------Original Message-------
From: Michael Scott via groups.io <g3lyp=btinternet.com@groups.io>
To: UKMicrowaves@groups.io <UKMicrowaves@groups.io>
Subject: Re: [UKMicrowaves] MGF 1200
Sent: Apr 30 '20 19:09

Hi Graham

Thanks for the reminder, yes the Chipbank has four MGF-1200s in
un-opened packs if anyone still needs them.

73, Mike, G3LYP

FROM: Graham - G3YJR
SENT: Thursday, April 30, 2020 5:40 PM
TO: UKMicrowaves@groups.io
SUBJECT: Re: [UKMicrowaves] MGF 1200

[Edited Message Follows] The ATF10136 is still working (ref above)

I may have dreamt this, but was there a mention in Scatterpoint of
some MGF1200s available as legacy devices in the Chip Bank?

73 Graham - G3YJR


GB3FNM

John Lemay
 

Morning all

I've not heard the Farnham beacon on 13cms recently. Tropo conditions have
been awful lately but there's not even a hint of a signal on my waterfall,
which is odd.

Is it QRV ?

Last spotted on 22 April.

Thanks

John G4ZTR


Re: DowKey Relay

Tom GM8MJV
 

Thanks All

Will have a go tomorrow - with luck will let me have 13cms and 9cms up the mast for Saturday.

Tom


--
73’s

Tom
GM8MJV (IO85)





On 30 Apr 2020, at 18:25, Robin Szemeti <robin@...> wrote:

I don't have details of this relay, however I have used others in the past with very similar configuration.

Almost certainly you will find a coil connected between 1+ and 1- .... and another coil between 2+ and 2- ... there may well be an internal diode, so respect the polarities shown.

Applying a voltage to coil 1 (+ve to the 1+ pin, -ve to the 1-) pin will pull the contacts over to the "1" position.

Similarly, applying a voltage to coil 2 will pull the contacts to the "2" position.


On Thu, 30 Apr 2020 at 17:57, Tom GM8MJV <tom@...> wrote:

Good Day

Anyone have any info on the DowKey 50140 / 401-136C / MS-13265  relay

It has a block of connectors - Identified  1 - C - 2  as the indicator pins.

I believe it is a latching relay - have a W6PQL board to handle the latching side used with other relays without any problem.

What I can't work out or seem to find details on is the connectors for switching:

There are 4 pins  labeled:     -1 +1 +2 -2  Vdc

Anyone help as to which pins actually do the business?

Thanks

Tom


--
73’s

Tom
GM8MJV (IO85)










--
Best regards,

Robin Szemeti

Redpoint Consulting Limited

E: robin@...
T: +44 (0) 1299 405028
M: +44 (0) 7971 883371

CONFIDENTIALITY NOTICE
The information contained in this e-mail is intended only for the
confidential use of the above named recipient. If you are not the
intended recipient or person responsible for delivering it to the
intended recipient, you have received this communication in error
and must not distribute or copy it.
Please accept the sender's apologies, notify the sender immediately
by return e-mail and delete this communication.

Thank you.


Re: DowKey Relay

Nigel G8IFN
 

It may be a latching relay with self cut off. If so you wont need the W6PQL board.
See page 11 of http://f1chf.free.fr/fichiers/datasheet%20relais/DowKeyCatalogue.pdf
--
Nigel G8IFN


Re: MGF 1200

John E. Beech
 

Hi Mike,
I could do with two devices to repair my TVTR.

de John G8SEQ QTHR.

-------Original Message-------
From: Michael Scott via groups.io <g3lyp=btinternet.com@groups.io>
To: UKMicrowaves@groups.io <UKMicrowaves@groups.io>
Subject: Re: [UKMicrowaves] MGF 1200
Sent: Apr 30 '20 19:09

Hi Graham

Thanks for the reminder, yes the Chipbank has four MGF-1200s in
un-opened packs if anyone still needs them.

73, Mike, G3LYP

FROM: Graham - G3YJR
SENT: Thursday, April 30, 2020 5:40 PM
TO: UKMicrowaves@groups.io
SUBJECT: Re: [UKMicrowaves] MGF 1200

[Edited Message Follows] The ATF10136 is still working (ref above)

I may have dreamt this, but was there a mention in Scatterpoint of
some MGF1200s available as legacy devices in the Chip Bank?

73 Graham - G3YJR


Re: MGF 1200

Michael Scott
 

Hi Graham
 
Thanks for the reminder, yes the Chipbank has four MGF-1200s in un-opened packs if anyone still needs them.
 
73, Mike, G3LYP
 

From: Graham - G3YJR
Sent: Thursday, April 30, 2020 5:40 PM
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] MGF 1200
 

[Edited Message Follows]

The ATF10136 is still working (ref above)

I may have dreamt this, but was there a mention in Scatterpoint of some MGF1200s available as legacy devices in the Chip Bank?

73 Graham - G3YJR


Re: DowKey Relay

Robin Szemeti - G1YFG
 

I don't have details of this relay, however I have used others in the past with very similar configuration.

Almost certainly you will find a coil connected between 1+ and 1- .... and another coil between 2+ and 2- ... there may well be an internal diode, so respect the polarities shown.

Applying a voltage to coil 1 (+ve to the 1+ pin, -ve to the 1-) pin will pull the contacts over to the "1" position.

Similarly, applying a voltage to coil 2 will pull the contacts to the "2" position.


On Thu, 30 Apr 2020 at 17:57, Tom GM8MJV <tom@...> wrote:

Good Day

Anyone have any info on the DowKey 50140 / 401-136C / MS-13265  relay

It has a block of connectors - Identified  1 - C - 2  as the indicator pins.

I believe it is a latching relay - have a W6PQL board to handle the latching side used with other relays without any problem.

What I can't work out or seem to find details on is the connectors for switching:

There are 4 pins  labeled:     -1 +1 +2 -2  Vdc

Anyone help as to which pins actually do the business?

Thanks

Tom


--
73’s

Tom
GM8MJV (IO85)










--
Best regards,

Robin Szemeti

Redpoint Consulting Limited

E: robin@...
T: +44 (0) 1299 405028
M: +44 (0) 7971 883371

CONFIDENTIALITY NOTICE
The information contained in this e-mail is intended only for the
confidential use of the above named recipient. If you are not the
intended recipient or person responsible for delivering it to the
intended recipient, you have received this communication in error
and must not distribute or copy it.
Please accept the sender's apologies, notify the sender immediately
by return e-mail and delete this communication.

Thank you.


DowKey Relay

Tom GM8MJV
 

Good Day

Anyone have any info on the DowKey 50140 / 401-136C / MS-13265 relay

It has a block of connectors - Identified 1 - C - 2 as the indicator pins.

I believe it is a latching relay - have a W6PQL board to handle the latching side used with other relays without any problem.

What I can't work out or seem to find details on is the connectors for switching:

There are 4 pins labeled: -1 +1 +2 -2 Vdc

Anyone help as to which pins actually do the business?

Thanks

Tom


--
73’s

Tom
GM8MJV (IO85)


Re: Activity List for the UK Microwave Group Low Band Contest - 3rd May 2020

Graham - G3YJR
 

I will be entering the 70cm and 3cm Trophy contests on the Saturday from 1400 GMT, then Low bands on Sunday.

Callsign: G3YJR
Locator:  IO93FJ
Bands:   70cm 25 W 19el yagi
             3cm   3W 80cm dish
             23cm  8W 1 x 44 el Wimo
             13cm, 2300 (NoV) and 2320MHz  25W 40 el Wimo
            
Talkback:   via ON4KST, Zello (possibly - I've never used Zello)
Times: Various throughout

Keep well! 73 Graham


Re: MGF 1200

Graham - G3YJR
 
Edited

The ATF10136 is still working (ref above)

I may have dreamt this, but was there a mention in Scatterpoint of some MGF1200s available as legacy devices in the Chip Bank?

73 Graham - G3YJR


Re: Activity List for the UK Microwave Group Low Band Contest - 3rd May 2020

Andy GD1MIP
 

I will be on 23cm only, airing my newly built amp.

Callsign: GD1MIP
Locator: IO74ti
Bands: 1296MHz 100W 44 ele
            
Times: Throughout
Talkback: ON4KST, direct CQs on 1296MHz


Re: Mixer Diode Bias

Chris Bartram G4DGU
 


On 30/04/2020 12:23, Chris Bartram wrote:

Hello Andy,

I'm pretty sure that the constant voltage case is correct. It's an interesting question, though. Biassing the diode to the point of conduction would generate what might be described as a 'class-B' switching waveform which, at least at first consideration, would tend to improve conversion loss in the third-order (Fsig -2Fxlo) conversion process, and to reduce the drive-level sensistivity. 

Temperature compensated bias supplies are easy nowadays. Forget trying to use a diode as a sensor, and get one of the now very accurate thermometer chips and use that with an opamp to scale the output voltage. I've done that in (work) LDMOS and HEMT amplifiers in recent years with excellent results.

73

Chris G4DGU


On 30/04/2020 11:14, Andy G4JNT wrote:
I'm looking to use an HP33801A mixer diode in a harmonic mixer arrangement to make a tracking generator for my HP8569B SpecAn.    The mixer diode came from an old, dismantled Ailtech SpecAn of the same vintage as the HP.   (Next month's RadCom DNotes carries some info about that).   The Tracking generator will be virtually the inverse of the SpecAn. input circuitry,  with the IF port of the mixer fed with a signal at 321.4MHz; the IF used in the HP6569B

The limited data I have on that mixer diode  - little more than a one-page summary - states that bias is typically 0.4V for harmonic mixer operation - which seems an odd way of specifying it.    I'd have thought a constant current would be the correct arrangement.   A DVM diode test (~ 200uA) shows a Vf of 0.42V. so 0.4V at the same temperature, would give virtually zero current, but increased sensitivity to RF drive.

SO, does anyone know if correct bias arrangement is a fixed voltage from a low Z source, which I guess would have to be properly temperature compensated,  or a constant current?  I hope it's the latter as that's just a resistor, but intuition says not.

Only ever met one case where forward junctions are biassed from a low-resistance temperature compensated voltage source, and that's class-B bipolar power amplifiers.   Does optimum use of this mixer diode rely on the same bias arrangement ?


Re: Mixer Diode Bias

Glyn M0XGT
 

I’ve seen reference to the HP33901A used as a harmonic mixer in this configuration: input combiner, diode, and bias-tee to define the DC coupled path and bias state independently from the RF one.  Very easy to setup and experiment with using connectorised components.  

Glyn M0XGT


Re: Mixer Diode Bias

Andy G4JNT
 

An isolator covering the exact frequency band needed was one of the components recovered from the Ailtech.
Beginning to think that was more and more a cheap copy of the HP
 


On Thu, 30 Apr 2020 at 11:57, PAUL NICKALLS via groups.io <paulnick=btinternet.com@groups.io> wrote:
Hi Andy,

I Have a long term project TG and have found Peripheral Mode Isolators for isolating the tracking output from the HP8566.  There are a few on Ebay.  Reading other peoples experiences this isolation is quite important.

Paul G8AQA

On 30/04/2020 11:14, Andy G4JNT wrote:
I'm looking to use an HP33801A mixer diode in a harmonic mixer arrangement to make a tracking generator for my HP8569B SpecAn.    The mixer diode came from an old, dismantled Ailtech SpecAn of the same vintage as the HP.   (Next month's RadCom DNotes carries some info about that).   The Tracking generator will be virtually the inverse of the SpecAn. input circuitry,  with the IF port of the mixer fed with a signal at 321.4MHz; the IF used in the HP6569B

The limited data I have on that mixer diode  - little more than a one-page summary - states that bias is typically 0.4V for harmonic mixer operation - which seems an odd way of specifying it.    I'd have thought a constant current would be the correct arrangement.   A DVM diode test (~ 200uA) shows a Vf of 0.42V. so 0.4V at the same temperature, would give virtually zero current, but increased sensitivity to RF drive.

SO, does anyone know if correct bias arrangement is a fixed voltage from a low Z source, which I guess would have to be properly temperature compensated,  or a constant current?  I hope it's the latter as that's just a resistor, but intuition says not.

Only ever met one case where forward junctions are biassed from a low-resistance temperature compensated voltage source, and that's class-B bipolar power amplifiers.   Does optimum use of this mixer diode rely on the same bias arrangement ?



Re: Mixer Diode Bias

John E. Beech
 

Hi Andy,
At Parmeko we had some kit operating just below 1GHz. That used DC bias on a Schottky diode (BAT86) to improve sensitivity. All we did was connect a high value resistor from the + 12 v rail to the diode to give a forward bias current of about 100 uA, if that's of any use to you.
(The BAT86 will go to at least 3GHz I used a pair back to back as a harmonic mixer to extend the range of a SpecAn to 3GHz when I was working on 2.45 GHz oscillators.)

de John G8SEQ

-------Original Message-------
From: Andy G4JNT <andy.g4jnt@gmail.com>
To: UK Microwaves groups.io <ukmicrowaves@groups.io>
Subject: [UKMicrowaves] Mixer Diode Bias
Sent: Apr 30 '20 11:14

I'm looking to use an HP33801A mixer diode in a harmonic mixer
arrangement to make a tracking generator for my HP8569B SpecAn. The
mixer diode came from an old, dismantled Ailtech SpecAn of the same
vintage as the HP. (Next month's RadCom DNotes carries some info about
that). The Tracking generator will be virtually the inverse of the
SpecAn. input circuitry, with the IF port of the mixer fed with a
signal at 321.4MHz; the IF used in the HP6569B

The limited data I have on that mixer diode - little more than a
one-page summary - states that bias is typically 0.4V for harmonic
mixer operation - which seems an odd way of specifying it. I'd have
thought a constant current would be the correct arrangement. A DVM
diode test (~ 200uA) shows a Vf of 0.42V. so 0.4V at the same
temperature, would give virtually zero current, but increased
sensitivity to RF drive.

SO, does anyone know if correct bias arrangement is a fixed voltage
from a low Z source, which I guess would have to be properly
temperature compensated, or a constant current? I hope it's the latter
as that's just a resistor, but intuition says not.

Only ever met one case where forward junctions are biassed from a
low-resistance temperature compensated voltage source, and that's
class-B bipolar power amplifiers. Does optimum use of this mixer diode
rely on the same bias arrangement ?

Andy
www.g4jnt.com


Re: Mixer Diode Bias

Paul G8AQA
 

Hi Andy,

I Have a long term project TG and have found Peripheral Mode Isolators for isolating the tracking output from the HP8566.  There are a few on Ebay.  Reading other peoples experiences this isolation is quite important.

Paul G8AQA

On 30/04/2020 11:14, Andy G4JNT wrote:
I'm looking to use an HP33801A mixer diode in a harmonic mixer arrangement to make a tracking generator for my HP8569B SpecAn.    The mixer diode came from an old, dismantled Ailtech SpecAn of the same vintage as the HP.   (Next month's RadCom DNotes carries some info about that).   The Tracking generator will be virtually the inverse of the SpecAn. input circuitry,  with the IF port of the mixer fed with a signal at 321.4MHz; the IF used in the HP6569B

The limited data I have on that mixer diode  - little more than a one-page summary - states that bias is typically 0.4V for harmonic mixer operation - which seems an odd way of specifying it.    I'd have thought a constant current would be the correct arrangement.   A DVM diode test (~ 200uA) shows a Vf of 0.42V. so 0.4V at the same temperature, would give virtually zero current, but increased sensitivity to RF drive.

SO, does anyone know if correct bias arrangement is a fixed voltage from a low Z source, which I guess would have to be properly temperature compensated,  or a constant current?  I hope it's the latter as that's just a resistor, but intuition says not.

Only ever met one case where forward junctions are biassed from a low-resistance temperature compensated voltage source, and that's class-B bipolar power amplifiers.   Does optimum use of this mixer diode rely on the same bias arrangement ?



Mixer Diode Bias

Andy G4JNT
 

I'm looking to use an HP33801A mixer diode in a harmonic mixer arrangement to make a tracking generator for my HP8569B SpecAn.    The mixer diode came from an old, dismantled Ailtech SpecAn of the same vintage as the HP.   (Next month's RadCom DNotes carries some info about that).   The Tracking generator will be virtually the inverse of the SpecAn. input circuitry,  with the IF port of the mixer fed with a signal at 321.4MHz; the IF used in the HP6569B

The limited data I have on that mixer diode  - little more than a one-page summary - states that bias is typically 0.4V for harmonic mixer operation - which seems an odd way of specifying it.    I'd have thought a constant current would be the correct arrangement.   A DVM diode test (~ 200uA) shows a Vf of 0.42V. so 0.4V at the same temperature, would give virtually zero current, but increased sensitivity to RF drive.

SO, does anyone know if correct bias arrangement is a fixed voltage from a low Z source, which I guess would have to be properly temperature compensated,  or a constant current?  I hope it's the latter as that's just a resistor, but intuition says not.

Only ever met one case where forward junctions are biassed from a low-resistance temperature compensated voltage source, and that's class-B bipolar power amplifiers.   Does optimum use of this mixer diode rely on the same bias arrangement ?


Re: Activity List for the UK Microwave Group Low Band Contest - 3rd May 2020

Phil Guttridge G3TCU
 

Hi John,

The Combe Gibberlets remain spread across the south of England, so I'll be on my single band from home again!



Callsign: G3TCU
Locator: IO91QE
Bands: 1296MHz 250W 44 ele
             
Talkback: Direct CQ, ON4KST
Times: Various throughout, on KST when in the shack.


73, Phil G3TCU









On 25/04/2020 10:23, John Quarmby via groups.io wrote:
The third session of the UKuG Low Band contest on 1296,2300,2320, and 3400MHz will take place next Sunday 3rd May from 0900-1500 BST (0800-1400 GMT) which aligns with the latter part of the RSGB and IARU Region 1 coordinated contests. Only single operator fixed station entries will be accepted. The rules are here:

https://microwave.rsgbcc.org/cgi-bin/contest_rules.pl?year=2020&contest=lb_contest

Activity for the April event was good, and this time there will be more European activity, although aircraft scatter will no doubt be more challenging due to the scarcity of planes. Serial numbers do not need to start at 001, so you can enter if also taking part in the RSGB 24hr event.

Please send your activity plans and I will compile and circulate a list next Saturday morning. if you can follow this format it speeds up editing the list:

Callsign: G3XDY
Locator: JO02OB
Bands: 1296MHz 400W 4 x23ele
             2300/2320MHz 200W 0.8m dish
             3400MHz 20W 0.8m dish
Times: Throughout
Talkback: ON4KST, direct CQs on 1296MHz

73

John G3XDY
UKuG Contest Manager




Re: Activity List for the UK Microwave Group Low Band Contest - 3rd May 2020

Dave G1EHF
 

Depending on the weather, I'll put up another temporary mast in the back garden and concentrate on 2320/2300:

Callsign: G1EHF
Locator: IO91LH
Bands: 2300/2320MHz 60W, 0.8m mesh dish
Times: Throughout
Talkback: ON4KST + occasional direct CQ

73, Dave G1EHF

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