Date   

Re: making printed cicuit boards

Dave
 

Thanks Martin ,Your comment was really helpful. from Dave  G4GLT


From: M Vincent
To: ukmicrowaves@...
Sent: Tuesday, 7 December, 2010 16:28:40
Subject: Re: [ukmicrowaves] Re: making printed cicuit boards

 



Hi Dave
Nail Varnish (any colour !) is quite tough, but as Andy said, dalo etc are only really suitable for very simple layouts. In present climate, perhaps heat the solution a bit (warm oven ?), regularly stir gently and blowing bubbles down a straw all help speed up the process, and reduce 'creep' under the resist material.
73  Martyn G3UKV
 

----- Original Message -----
Sent: Tuesday, December 07, 2010 3:25 PM
Subject: [ukmicrowaves] Re: making printed cicuit boards

 

Hello guys, I have tried to make a printed circuit board yesterday using ferric chloride crystals mixed with water. The resist pen I bought from an electronics company as being for this sort of thing. Years ago when I did it I might have painted something on possibly. Suffice to say that I was very disappointed to see that a lot of the required track had been eaten away despite the pen. What can I put on that will truly resist the solution? Many thanks  Dave G4GLT  


From: g4bao
To: ukmicrowaves@...
Sent: Tuesday, 7 December, 2010 14:56:46
Subject: Re: [ukmicrowaves] Monday night activity

 

My antennas were iced up this morning as well. A good old Fenland
freezing fog that has persisted most of the day. Could have hung a few
baubles on them and saved money on a Christmas tree....

Anyway I did get on last night and worked a few people.

G4BEL JOØ2BI 55 55 3.4 GHz SSB 11 km
G4DDK JOØ2PA 59 59 23cm SSB 79 km
G4DDK JOØ2PA 54 55 3.4 GHz SSB 79 km
G4DDK JOØ2PA 57 57 70 cm. SSB 79 km
G8GXP IO93FQ 59 59 23 cm. SSB 196 km

I spent most of the time chatting on 23cms to G8GXP up in Wakefield at
nearly 200km.

Interestingly, the QSO quality knocked spots off 80 metres (where I
struggle to work G3PHO and G4DZU at a similar distance)! No QRM, very
little QSB and no ugly wires around your garden! Amazing what you can
work on 23cms with antennas the size of a decent freeview antenna, a
decent preamp and a bit of power both ends!

It's still my favourite band!

73
John

On 07/12/2010 13:32, Ray James wrote:
> I had intended to be active but an iced up antenna system put paid to that idea. Made for an interesting view this morning though.
>
> 73 Ray GM4CXM

--
G4BAO
Beacon keeper GB3CAM/24GHz
www.g4bao.com


Tonight - Microwave Activity Night, 12/13/2010, 8:00 pm

ukmicrowaves@...
 

Reminder from:   ukmicrowaves Yahoo! Group
 
Title:   Tonight - Microwave Activity Night
 
Date:   Monday December 13, 2010
Time:   8:00 pm - 9:00 pm
Repeats:   This event repeats every week.
Notes:   Monday nights are traditionally microwave activity nights. Why not try listening around at 20:00 local time? Better still, call CQ! Consider using KST to co-ordinate activities:

http://www.on4kst.com/chat/start.php
 
Copyright © 2010  Yahoo! Inc. All Rights Reserved | Terms of Service | Privacy Policy


looking for VHF 1 Watt+ broadband lab amplifier

g4bao
 

Hello Folks.
I'm on the lookout for a solid state, connectorised, Lab spec (i.e flat to 1 dB or less and linear, >20dB gain) broadband power amplifier that will produce a MINIMUM of 1 Watt (+30 dBm) P1dB continuous.

The sort of thing that Minicircuits do.

It must cover 50 - 150MHz and if it goes higher and lower, that's fine by me.

Will exchange a suitable amplifier for any one of the following;
  • Built and working G3WDG 1 Watt single GAsFET 10GHz PA module
  • DB6NT 30 Watt 1296MHz LDMOS PA module.
  • Unmodified AML PCs1900 Power Amplifier with W2AAU's CD of details of how to modify for 70Watts on 13cm.
  • Signal technology Corp.  STDB-2010-ILC  10-26.5GHz SMA-connectorised double balanced fundamental mixer.
Anything out there?

73
John
-- 
G4BAO
Beacon keeper GB3CAM/24GHz
www.g4bao.com
 


Re: Nokia 'Tetra' amp, quick question

Russ Stewart <g4pbp@...>
 

On 12/12/2010 13:13, Christopher Bartram wrote:
 

Hello Martin

I don't know that amplifier in any detail, but in my own MOSFET SSPAs for 144,
432 and 1296 I switch-on the gate bias when I go into transmit. The 400W low-
noise 28V supplies are shared across the bands eg. each PSU typically supplies
both a 144 and 432MHz module. The 28V high current drain supply is present on
the amplifer modules in the rack (4 for 144, 4 plus driver for 432 and one
1296 module) whenever the rack is switched-on. This aspect of the PA has been
trouble-free for nearly a decade. I've not had any problems with noise on
receive and it's possible to operate the amplifier on both 144/432.
simultaneously.

It seems usual to design the standby switching of MOSFET PAs by varying the
gate voltage only.

Vy 73

Chris
GW4DGU




Hi Martin here is my '2P's-worth' :-)  Actually working on Nokias between QSO's !

In all my SSPA's I use a p-FET in series with the supply, (n-FET if you have the overhead), to disconnect the volts.I tie this FET triggering into the protection circuit as well as PTT.

Like others, I don't think it is necessary to dump the supply during RX but the switch is very useful in protection.
After all we don't turn off EHT in our thermionic PA's do we. On the PA's I have fiddled with lately, not found any noise problems due to leaving the supply connected, unlike some TWTA's.

regards de Russ .... G4PBP





Re: Nokia 'Tetra' amp, quick question

Christopher Bartram <cbartram@...>
 

Hello Martin

I don't know that amplifier in any detail, but in my own MOSFET SSPAs for 144,
432 and 1296 I switch-on the gate bias when I go into transmit. The 400W low-
noise 28V supplies are shared across the bands eg. each PSU typically supplies
both a 144 and 432MHz module. The 28V high current drain supply is present on
the amplifer modules in the rack (4 for 144, 4 plus driver for 432 and one
1296 module) whenever the rack is switched-on. This aspect of the PA has been
trouble-free for nearly a decade. I've not had any problems with noise on
receive and it's possible to operate the amplifier on both 144/432.
simultaneously.

It seems usual to design the standby switching of MOSFET PAs by varying the
gate voltage only.

Vy 73

Chris
GW4DGU


Re: Nokia 'Tetra' amp, quick question

bernie <bernie@...>
 

Eeek, read the f++++++g title! Apologies

Bernie


bernie wrote:

If it's the Philips one, then yes - that's how it is run in normal use.

Bernie G4HJW


Martin Andrew wrote:


Just a quick question on the Tetra amplifier.
Is it ok to leave the 28 volts (and maybe 12 volt) connected when the amplifier is in
standby, or is it preferable to switch either or both voltages off.
Have the first amplifier running fine, though did need to use different bias pots to those
recommended, second one being modified now.
Martin, GM6VXB

R <mailto:martin.andrew@...?subject=Re%3A%20Nokia%20%27Tetra%27%20amp%2C%20quick%20question>

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

Yahoo! Groups Links



Re: Nokia 'Tetra' amp, quick question

bernie <bernie@...>
 

If it's the Philips one, then yes - that's how it is run in normal use.

Bernie G4HJW


Martin Andrew wrote:


Just a quick question on the Tetra amplifier.
Is it ok to leave the 28 volts (and maybe 12 volt) connected when the amplifier is in
standby, or is it preferable to switch either or both voltages off.
Have the first amplifier running fine, though did need to use different bias pots to those
recommended, second one being modified now.
Martin, GM6VXB
R <mailto:martin.andrew@...?subject=Re%3A%20Nokia%20%27Tetra%27%20amp%2C%20quick%20question>


Nokia 'Tetra' amp, quick question

GM6VXB
 

Just a quick question on the Tetra amplifier.
Is it ok to leave the 28 volts (and maybe 12 volt) connected when the amplifier is in
standby, or is it preferable to switch either or both voltages off.
Have the first amplifier running fine, though did need to use different bias pots to those
recommended, second one being modified now.
 
Martin, GM6VXB


47GHz?

Roger Ray
 

Ebay item 270632197102 Milli-metre transceiver. This looks to be on 37/38GHz. Not incredibly useful - except the output chip is an Agilent HMMC-5040 with potential gain at 47GHz (15dB when measured direct on the chip - according to Agilent) The output is direct into WR28. The driver to this is unknown. Maybe worth a punt, as gain at 47GHz is hard to come by / expensive.
Roger
ps no connection to seller in China!


Re: Seen in latest scatterpoint

Christopher Bartram <cbartram@...>
 

Hello Mike

I think there is a rule of thumb - which is don't. Unless of course you
have to and then as far apart as possible.
I agree with the rule of thumb! Careful simulation does provide a way of
minimising inter-antenna degradation, though.

I did manage to stack antennas for 6m up to 13cm in about 6ft of vertical
space but there was fairly severe degradation to the lower band antennas.
Stacking with an HF tri-bander offset by 90 degrees (so I could raise it)
in place of the 4/6m antenna was notably unsuccessful. The VHF booms
degraded the tri-bander pattern severely.
To put things in perspective, my 2/70/23 system occupied about 3.5m of ali.
scaffold tube above the top bearing of my tower, however, that included a
modified 6m boom G4CQM 2m antenna, a 432MHz antenna consisting of a pair of 4m
boom yagis of my own design, and a HB 4m boom 1296MHz yagi. The 70cm antennas
were spaced at about 1.3m, with the spacing being determined by the levels of
the first h-plane sidelobes. I'd be very sceptical about anyone stacking single
antennas for just those three bands in less than say 2.5m, and retaining good
multiband performance.

The best solution is probably to change ones' aspirations and only attempt
operate a few bands at a time. The UKAC has been a problem here - it needs
a keen club member to be on 6m-23cms. That is a lot of antenna changing or
a compromise stack.
Again, I agree. Many years ago, a particularly successful (HF CW) operator
suggested to me that you could only do really well on one band at a time. But
then, I've recently been idly playing with ideas for a 1.3 - 10.4GHz feed for
a 0.935f/D dish. That forces a couple of other sets of compromises!

Vy 73

Chris
GW4DGU


Re: Seen in latest scatterpoint

mike.willis@...
 

I think there is a rule of thumb - which is don't. Unless of course you have to and then as far apart as possible.

I did manage to stack antennas for 6m up to 13cm in about 6ft of vertical space but there was fairly severe degradation to the lower band antennas. Stacking with an HF tri-bander offset by 90 degrees (so I could raise it) in place of the 4/6m antenna was notably unsuccessful. The VHF booms degraded the tri-bander pattern severely.

The best solution is probably to change ones' aspirations and only attempt operate a few bands at a time. The UKAC has been a problem here - it needs a keen club member to be on 6m-23cms. That is a lot of antenna changing or a compromise stack.

Mike

--- In ukmicrowaves@..., Christopher Bartram <cbartram@...> wrote:

Hello Dom

Fellow American Kent Britain, WA5VJB, gave another entertaining talk, this
time re stacking dissimilar
antennas at HF and VHF, dispelling the myth that all our antenna farm has
to have a certain stacking distance
if severe interaction is to be avoided.
I don't see Scatterpoint at the moment, and unfortunately I wasn't able to get
to Martlesham, but I looked fairly thoroughly into the problems of stacking my
own antennas for 2/70/23 a few years ago. After running many, many simulations
of my entire proposed antenna system, I came to the conclusion that stacking
yagi antennas, with acceptable losses (I arbitarily chose 0.5dB degradation of
the performance of any band) is actually quite difficult, and each antenna
system - which means resimulating if spacings are varied - must be simulated
separately. That seemed particularly true for harmonically related bands.

I guess that it all depends on what's meant by 'severe interaction' but it's
notable that relatively few 'nested' 144/432MHz EME arrays have proven
particularly successful.

I doubt very much if there are any simple 'rules of thumb' for stacking yagi
antennas for different bands.

Vy 73

Chris
GW4DGU


GB3CSB off for upgrade

David GM6BIG <freevil@...>
 

Hi All,

Just to let you know, I have taken GB3CSB off the air today.
This is to add 13cm and 9cm, along with a new PA for 23cm.

Some preparation will also be made in anticipation of some other bands being added later on.

73 David GM6BIG


Re: Seen in latest scatterpoint

Peter Day <microwaves@...>
 

On 09/12/2010 10:35, DEHAYS Dominique wrote:
Hello

---------------------------------------snip----------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Fellow American Kent Britain, WA5VJB, gave another entertaining
talk, this time re stacking dissimilar antennas at HF and VHF,
dispelling the myth that all our antenna farm has to have a certain
stacking distance if severe interaction is to be avoided.

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

Interesting subject. Anything written somewhere?

73 Dom/F6DRO


try emailing Kent at: wa5vjb@...


Re: Scatterpoint Nov-Dec 2010 edition

Peter Day <microwaves@...>
 

On 09/12/2010 05:57, David Jones wrote:
I've tried to get into the Scatterpoint Yahoo site, but Yahoo says
Scatterpoint does not exist.

Can somebody post me a url please? The one from the latest scatterpoint
does not work.

Hi David...

I've just checked and it works for me provided I type it into the box on the browser. However if you copy and paste from the Scatterpoint pdf file it apparently puts a space after group/ and then it won't work! I should have made sure the whole URL was on one line and not split across two. Sorry about that! Fortunately severak readers have found that out as there were 10 emaiuls from Yahoo tonight asking me to OK their registrations.

http://uk.groups.yahoo.com/group/scatterpoint/

and

http://uk.groups.yahoo.com/group/scatterpoint/files


The first one should take you to the join page. The second one has the files on it


Hope it works for you now.

73


Peter


Re: Seen in latest scatterpoint

Christopher Bartram <cbartram@...>
 

Hello Dom

Fellow American Kent Britain, WA5VJB, gave another entertaining talk, this
time re stacking dissimilar
antennas at HF and VHF, dispelling the myth that all our antenna farm has
to have a certain stacking distance
if severe interaction is to be avoided.
I don't see Scatterpoint at the moment, and unfortunately I wasn't able to get
to Martlesham, but I looked fairly thoroughly into the problems of stacking my
own antennas for 2/70/23 a few years ago. After running many, many simulations
of my entire proposed antenna system, I came to the conclusion that stacking
yagi antennas, with acceptable losses (I arbitarily chose 0.5dB degradation of
the performance of any band) is actually quite difficult, and each antenna
system - which means resimulating if spacings are varied - must be simulated
separately. That seemed particularly true for harmonically related bands.

I guess that it all depends on what's meant by 'severe interaction' but it's
notable that relatively few 'nested' 144/432MHz EME arrays have proven
particularly successful.

I doubt very much if there are any simple 'rules of thumb' for stacking yagi
antennas for different bands.

Vy 73

Chris
GW4DGU


Seen in latest scatterpoint

F6DRO
 

Hello

---------------------------------------snip----------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Fellow American Kent Britain, WA5VJB, gave another entertaining talk, this
time re stacking dissimilar
antennas at HF and VHF, dispelling the myth that all our antenna farm has
to have a certain stacking distance
if severe interaction is to be avoided.

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

Interesting subject. Anything written somewhere?

73
Dom/F6DRO


Re: Scatterpoint Nov-Dec 2010 edition

bernie <bernie@...>
 

It works here, David.

G4HJW

David Jones wrote:


I've tried to get into the Scatterpoint Yahoo site, but Yahoo says
Scatterpoint does not exist.

Can somebody post me a url please? The one from the latest scatterpoint
does not work.

Thank you,

David.

On Wed, 2010-12-08 at 21:19 +0000, Peter Day wrote:
To all paid up members of the UK Microwave Group..

The latest edition of our newsletter Scatterpoint has been just emailed
to those on the email lists and also uploaded to the Scatterpoint Yahoo
Group site for download by UKuG members who have registered there.
Please note this is NOT a public domain site!

Some of you reading this will not get your copy this time because you
have not renewed your subs, in spite of several reminder emails from
the
membership secretary ! :-(

The paper version went to the printers on Monday morning and, all being
well, should be in the hands of subscribers before the end of the week.
However please allow extra time for this to happen as there maybe
delays
in the Christmas postal deliveries.

Paper readers will notice two glaring errors: Page 4 first paragraph
should read 2012, not 2010 for the EME Conference to be held in the UK
and the next to last page should say page 23 at the bottom, not page
21! :-)

These errors were only noticed yesterday when it was too late to change
them at the printers. The electronic versions have been corrected.

Peter G3PHO

Scatterpoint Editor



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

Yahoo! Groups Links



Re: Scatterpoint Nov-Dec 2010 edition

David Jones <david.g6feo@...>
 

I've tried to get into the Scatterpoint Yahoo site, but Yahoo says
Scatterpoint does not exist.

Can somebody post me a url please? The one from the latest scatterpoint
does not work.

Thank you,

David.

On Wed, 2010-12-08 at 21:19 +0000, Peter Day wrote:
To all paid up members of the UK Microwave Group..

The latest edition of our newsletter Scatterpoint has been just emailed
to those on the email lists and also uploaded to the Scatterpoint Yahoo
Group site for download by UKuG members who have registered there.
Please note this is NOT a public domain site!

Some of you reading this will not get your copy this time because you
have not renewed your subs, in spite of several reminder emails from the
membership secretary ! :-(

The paper version went to the printers on Monday morning and, all being
well, should be in the hands of subscribers before the end of the week.
However please allow extra time for this to happen as there maybe delays
in the Christmas postal deliveries.

Paper readers will notice two glaring errors: Page 4 first paragraph
should read 2012, not 2010 for the EME Conference to be held in the UK
and the next to last page should say page 23 at the bottom, not page 21! :-)

These errors were only noticed yesterday when it was too late to change
them at the printers. The electronic versions have been corrected.

Peter G3PHO

Scatterpoint Editor



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

Yahoo! Groups Links



Re: making printed circuit boards H2O2

Michael Scott
 

Many thanks for the info David.
 
Mike

----- Original Message -----
From: g0mrf@...
Sent: Wednesday, December 08, 2010 7:11 PM
Subject: [ukmicrowaves] making printed circuit boards H2O2

 

In a message dated 08/12/2010 10:08:51 GMT Standard Time, g3lyp@... writes:
Hi David
 
Is it the 10 vol stuff you used to be able to buy from Boots or do you have access to the 100 vol stuff which is quite corrosive I think, and would ring alarm bells if one tried to buy it these days?
 
On another topic, a few days ago I asked you, via this reflector, what sort of IR thermometer you used for surface mount soldering, but the message didn't appear so must have been lost in cyberspace!
Hello Mike.
 
Sorry the message was lost.
 
I did a reply for Andy giving the proportions as best I can remember, but the H2O2 is about 40 volume, perhaps a little less.  It can be purchased as 'developer' from Hair stylist suppliers. However, I do have access to 100 volume but sadly no higher. - I've always fancied trying to build a monopropellent thruster to demonstrate at the AMSAT colloquium. 100 vol with silver disc catylists work well enough for a demo, but for real applications 68% is the critical concentration. Beyond that, the conversion process generates Oxygen as expected but also superheated steam at temps up to 600 degrees.
 
The IR thermometer was purchased from RS components who were doing a special on them a couple of months ago.
The stock number is 411-122.  The datasheet will be at rswww.com
It can be calibrated for various colours. That particular product also has a socket on the front to connect an external Type K thermocouple.
With a bit of research you can probably find them much cheaper from other suppliers. (It's almost certainly a relabelled product from another company)
 
Thanks
 
David
 
 


Re: Monday night activity

Peter Day <microwaves@...>
 

On 07/12/2010 22:29, Sam Jewell wrote:

Try working ZL on 80m without an ionosphere. The moon is as natural a
reflector as the ionosphere!


In fact the moon must be much more reliable and predictable than the F
layers ... no problem with "moonspots" affecting propagation :-)


Peter