Date   

Re: Cumulative Report

Martyn G3UKV
 

Likewise enjoyable day for the Telford group on Brown Clee.
For once, everything went to plan and kept working. On 10G managed 25 QSOs, 12 on 5.7G but NIL (zilch, zero, 0 ) on 24G, although we had try 3 long haul attempts (G4EAT, G4NNS and G8CUB/P). Humidity was high, and tropo generally unsettled. At least we had GB3ZME on 24G to keep us company.
 
We seem to have cracked the /P hoodoo with 'KST (using Orange) which also worked 100% for us from Long Mynd on VHF NFD (where both T-Mobile and Vodaphone very wobbly). It gave us the best DX (F1PYB) on both 10G and 5.7G at the weekend. But even a modern notebook set to max. brightness is a pain out in the open air, as well as being a general distraction and complication. 2 metre talkback was far easier and almost all other QSOs relied on this preferred mode. There's nothing to beat a bit of audio feedback crossband to peak up a marginal signal, as well as an immediate audible response from a CQ etc. (we rest our case, m'lord....).
 
Thanks to all who were active on Sunday. Any chance from those of you north and west of Watford Gap Service Station of taking out 24G gear next month ? We'll be there.
 
73  Martyn G3UKV
 

----- Original Message -----
From: g3cwi
Sent: Monday, July 26, 2010 7:14 AM
Subject: [ukmicrowaves] Cumulative Report

 

Enjoyable day on 10GHz.

The Cloud IO83WE qualified in 45 minutes with one S2S and best DX 299km - thanks to G1MPW's CW skills. Four contacts total - hit and run SOTA activation.

Home for lunch (haggis and peas) and on to Rombolds Moor (Ilkley Moor) IO93CV. Qualified in 25 minutes (9 contacts) including a one-way with G8CUB/p. Average distances well over 100km.

SOTA people active; G4ERP, GW8OGI and G4BLH as well as myself.

73

Richard
G3CWI


Tonight - Microwave Activity Night, 7/26/2010, 8:00 pm

ukmicrowaves@...
 

Reminder from:   ukmicrowaves Yahoo! Group
 
Title:   Tonight - Microwave Activity Night
 
Date:   Monday July 26, 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


Re: Off Topic -- Warning re surplus Nokia Tetra base station Power amps on 70cms

Russ Stewart <g4pbp@...>
 

Christopher Bartram wrote:
Having designed TETRA PAs, I assume that these surplus amplifiers are designed to deliver 50 - 60W pep, and will produce >200W simply because they were run 'backed-off' in order to get good large signal linearity with a relatively poorly-performing lineariser. I should stress that I don't know these amplifiers, but the problems which Mark and Rob describe aren't black magic!

The issues which will arise from running the amplifiers at higher powers will (probably) be due to the choice of substrate for the microstripline output matching elements. If, as I suspect, the amplifiers are built on 0.62 or 0.31mm FR4 to save money, the major issue will be resistive heating due to dielectric losses, not dielectric breakdown. While you can't do a lot about the latter, the heating due to resistive losses in the substrate can be dealt with in the same way as you'd deal with losses in a resistor: heatsinking!
The power dissipated in a microstripline can be calculated, but as a rule of thumb, those in a 200W PA will probably only dissipate a few watts.
The characteristic impedance of a microstripline is relatively uneffected by heatsinking structures placed on top of the conductor. A U-shaped heatsink of, say, 0.25mm copper sheet soldered to the conductor will radiate the heat dissipated.

One tool which anyone designing, building or modifying a solid state power amplifier should possess is an infra-red thermometer. These are cheap and being non-contact, can be used to look at a the temperatures of PA components while it is running. Thermal design is often neglected in amateur designs.

Vy 73

Chris
GW4DGU


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

Yahoo! Groups Links




Hi Chris and I guess you are right on all counts.

I am actually using one these amps but envoked radical surgery to stop it burning up. It currently gives 280W o/p cold and drops to 240W when hot. It easily does 250W PEP !

The surgery involved firstly, cutting out the PA section from the main board and remounting it on the original heatsink. I left the bit of board which was the o/p line of the driver stage, (for matching purposes). I connected a piece of UT141-50 to this line and put a 10pf ceramic trimmer across the the coax / stripline transition to the gnd plane; this gave a 1:1 match when the o/p peaked (1st time ever :-)

At the output end I cut off the SWR monitor line part and stripped off the 50ohm track feeding it, right back to the Sageline combiner, just leaving a small pad which the Sageline is connected to. The used a piece of UT141-50 to bring out the RF. Without the line removal I could only get 230W cold.

It was interesting to note that when I stripped off the stripline, the bit of board under where the o/p N-type spigot was soldered, was already black + burned even under the amps normal operating condition !

The o/p Sageline combiner is at or just over it's power limit at 280W and seems to be the primary heat source; you can't hold your finger on it after 5mins of carrier !!! So I blow the combiner and am currently testing use of a 20mm fin (copper strip) soldered to it's length in the air flow. I will know how well this works shortly .... need an IR camera for Christmas for all this PA work Hi. It would be easy to replace the Sageline with an external Wilkinson in UT141-75 as an alternative.

Finally and most importantly, as Mark found in his original mods, you must 'beef-up' the DC feed to each device and not rely on the via's and pc tracks than feed the DC pwr; this will result in a 'burn-up' and general mess.

If anyone needs it, I have photographs of the finished PA, these may already be on Mark's website.

All I need now is someone to work on 70cms :-(


regards de Russ G4PBP


Cumulative Report

g3cwi <richard@...>
 

Enjoyable day on 10GHz.

The Cloud IO83WE qualified in 45 minutes with one S2S and best DX 299km - thanks to G1MPW's CW skills. Four contacts total - hit and run SOTA activation.

Home for lunch (haggis and peas) and on to Rombolds Moor (Ilkley Moor) IO93CV. Qualified in 25 minutes (9 contacts) including a one-way with G8CUB/p. Average distances well over 100km.

SOTA people active; G4ERP, GW8OGI and G4BLH as well as myself.

73

Richard
G3CWI


Re: Off Topic -- Warning re surplus Nokia Tetra base station Power amps on 70cms

Christopher Bartram <cbartram@...>
 

Having designed TETRA PAs, I assume that these surplus amplifiers are designed
to deliver 50 - 60W pep, and will produce >200W simply because they were run
'backed-off' in order to get good large signal linearity with a relatively
poorly-performing lineariser.

I should stress that I don't know these amplifiers, but the problems which Mark
and Rob describe aren't black magic!

The issues which will arise from running the amplifiers at higher powers will
(probably) be due to the choice of substrate for the microstripline output
matching elements. If, as I suspect, the amplifiers are built on 0.62 or 0.31mm
FR4 to save money, the major issue will be resistive heating due to dielectric
losses, not dielectric breakdown. While you can't do a lot about the latter,
the heating due to resistive losses in the substrate can be dealt with in the
same way as you'd deal with losses in a resistor: heatsinking!

The power dissipated in a microstripline can be calculated, but as a rule of
thumb, those in a 200W PA will probably only dissipate a few watts.

The characteristic impedance of a microstripline is relatively uneffected by
heatsinking structures placed on top of the conductor. A U-shaped heatsink of,
say, 0.25mm copper sheet soldered to the conductor will radiate the heat
dissipated.

One tool which anyone designing, building or modifying a solid state power
amplifier should possess is an infra-red thermometer. These are cheap and being
non-contact, can be used to look at a the temperatures of PA components while
it is running. Thermal design is often neglected in amateur designs.

Vy 73

Chris
GW4DGU


Re: Off Topic -- Warning re surplus Nokia Tetra base station Power amps on 70cms

Rob, M0DTS
 

Thanks for pointing that out Mark...

Unfortunately when out portable today testing on 70cm Digital ATV i found another way of generating the same effect, very bad SWR....

Oh well.. will have to replace the o/p cct with some coax now!
I've had two years of good service at ~180W.

Maybe you should not have mentioned it...hi

73

Rob


Mark GM4ISM wrote:


Hi All
a little off topic, but may be of benefit to someone.
Some of you may have purchased ex Dolphin Tetra base station power amps for use on 70cms
I ran one recently on 70cm EME at about 225W op for a weekend and came close to destroying it. A fact i didn't notice until i looked inside recently.
I already spotted the fact the the DC feed for the PA devices was through small plated through holes, and not adequately rated for high power operation, I bypassed this on my amplifier and thought I was OK
Wrong
The output transmission line in the vicinity of the onboard directional coupler had heated up enough to start delaminating the board and the soldered joint to the output coupler was now a classic dry joint.
Much more operating time on this amplifier would have resulted in failure
I am starting to write up my findings, and those of Russ G4PBP on my web page with notes etc on using the amplifiers on 70cm, but this is a heads up to hopefully prevent anyone destroying one of these lovely amplifiers.
Mark GM4ISM
www.dc2light.co.uk <http://www.dc2light.co.uk>


Help - Anritsu MH672A TG User Manual

Dennis_G6YBC
 

Hi all,
 
Can anybody put me in the right direction of a user/service manual for this Tracking Generator.
 
Thanks for your possible help
 
Dennis G6YBC


Need HP 5340A for Spares ?

Dennis_G6YBC
 

Hi All,
 
Has anybody got a HP 5340A Frequency Counter for spares or repair they have lying around for doing nothing. I'm in need of bits to refurb mine.
 
Thank you for your possible help
 
Dennis G6YBC


Live Webstream of AMSAT-UK Space Colloquium

M5AKA
 

The 2010 International Space Colloquium, the 25th held by AMSAT-UK, is taking place on July 31 and August 1 at the Holiday Inn in Guildford, England. The event is open to all.

Among the speakers from around the world is the RSGB Microwave Manager Murray Niman G6JYB.

Sunday 1130-1200  Satelliite Bands - What's New - G6JYB     

Watch the Colloquium live during July 31-Aug 1 at
http://www.batc.tv/ - Click on Live Events

Weekend Programme
http://www.uk.amsat.org/content/view/713/284/

AMSAT-UK publish a colour A4 newsletter, OSCAR News, that is full of Amateur Satellite information.
Join online at https://secure.amsat.org.uk/subs_form/

73 Trevor M5AKA
Daily Amateur Radio Email/RSS News: http://www.southgatearc.org/
Email Your News To: editor at southgatearc.org
Or Upload Using Form At: http://www.southgatearc.org/news/your_news_1.htm
----


Re: Final Activity List for 5.7/10/24GHz Cumulative 25th July

g3cwi <richard@...>
 

Dear all

WX permitting, I will be QRV on 10GHz from two (or more) locations in IO83. 2m talkback only.

73

Richard
G3CWI


Re: Final Activity List for 5.7/10/24GHz Cumulative 25th July

Roger Ray
 

John,
I guess you didn't get my email.
I will be active as follows:

Callsign: G8CUB/P
Locator: Therfield IO92XA
Bands:
5.7GHz 2.5W
10GHz 1W
24GHz 0.75W
All on 0.8m dish 7m agl
Talkback: ON4KST and 144.175MHz
Times: 0900-1700

Also if all goes well Harold G3UYM/P will be on from the same site on 10GHz

73s
Roger

--- In ukmicrowaves@yahoogroups.com, "G3XDY" <g3xdy@...> wrote:

A limited response this month, perhaps everyone is on holiday?

Here are the plans received to date:

Callsign: G8AIM
Locator: IO92FH
Bands: 5.7GHz 10W 60cm dish
10GHz 200mW Procom dish
Talkback: 144-175 only
Probably on from Midday.

Callsign: G0JMI
Locator: IO91MD
Bands: 10GHz 10W 60cm dish to flyswatter
Talkback:144.175MHz
Times: 1000-2000 for several periods of an hour or so each.

Callsign: G4EAT
Locator: JO01hr
Bands: 5.7GHz 15W 60cms
10GHz 10W 60cms
24GHz 2.5W 60cms
Talkback 144.175/390MHz and ON4KST

Callsign: PA/ON7BV/P
Locator: JO11RM
Bands: 5.7GHz 10W 78cm dish
10GHz 4W 78cm dish
Talkback: 2m(50W and 9 elm yagi).
Possible also qrv on KST (if i can secure the second mast).

Callsigns: M0DTS/P and G0EHV/P
Locator: IO94LI
Bands: 3cm M0DTS QRO 10W.
G0EHV QRP < 1W.
Talkback on 144.175 MHz, 50W and 7 element.
KST possibly also (M0DTS)

Callsign: G8DTF/P
Locator: IO93AO
Bands: 10GHz 3W 85cm dish
Talkback: ON4KST and 144.175MHz
Times: 1000-1300 only.

Callsigns : G6KIE/P + G1MPW/P
Locator : JO00AU
Bands : 10GHz ..60cm dishes ..1Watt
24GHz 30cm dishes 500mW
Talkback : 144.175 MHz + KST
Time : 0900GMT Onwards

Callsign: F1GHB/P
Locator : IN88IN - Le Menez Bre close to the city of Guingamp
Bands: 5.7 Ghz 9W 90 cm Prime Focus dish
10 GHz 4W 80 cm Offset dish
Talkback 144.175 MHz ( UK ) and 144.390 Mhz ( France ) - 100W 9 elts Tonna
No KST so please be present on 2m !
QRV If the weather is correct ( but looking at the forecast , this is not
the
case... ) :

Callsign: G3XDY
Locator: JO02OB
Bands: 5.7GHz 15W 60cm dish
10GHz 10W 60cm dish
Talkback: ON4KST and 144.175MHz
Times: 0900-2000 for several periods of an hour or so each

73

John G3XDY
UKuG Contest Adjudicator


Final Activity List for 5.7/10/24GHz Cumulative 25th July

John Quarmby
 

A limited response this month, perhaps everyone is on holiday?

Here are the plans received to date:

Callsign: G8AIM
Locator: IO92FH
Bands: 5.7GHz 10W 60cm dish
10GHz 200mW Procom dish
Talkback: 144-175 only
Probably on from Midday.

Callsign: G0JMI
Locator: IO91MD
Bands: 10GHz 10W 60cm dish to flyswatter
Talkback:144.175MHz
Times: 1000-2000 for several periods of an hour or so each.

Callsign: G4EAT
Locator: JO01hr
Bands: 5.7GHz 15W 60cms
10GHz 10W 60cms
24GHz 2.5W 60cms
Talkback 144.175/390MHz and ON4KST

Callsign: PA/ON7BV/P
Locator: JO11RM
Bands: 5.7GHz 10W 78cm dish
10GHz 4W 78cm dish
Talkback: 2m(50W and 9 elm yagi).
Possible also qrv on KST (if i can secure the second mast).

Callsigns: M0DTS/P and G0EHV/P
Locator: IO94LI
Bands: 3cm M0DTS QRO 10W.
G0EHV QRP < 1W.
Talkback on 144.175 MHz, 50W and 7 element.
KST possibly also (M0DTS)

Callsign: G8DTF/P
Locator: IO93AO
Bands: 10GHz 3W 85cm dish
Talkback: ON4KST and 144.175MHz
Times: 1000-1300 only.

Callsigns : G6KIE/P + G1MPW/P
Locator : JO00AU
Bands : 10GHz ..60cm dishes ..1Watt
24GHz 30cm dishes 500mW
Talkback : 144.175 MHz + KST
Time : 0900GMT Onwards

Callsign: F1GHB/P
Locator : IN88IN - Le Menez Bre close to the city of Guingamp
Bands: 5.7 Ghz 9W 90 cm Prime Focus dish
10 GHz 4W 80 cm Offset dish
Talkback 144.175 MHz ( UK ) and 144.390 Mhz ( France ) - 100W 9 elts Tonna
No KST so please be present on 2m !
QRV If the weather is correct ( but looking at the forecast , this is not the
case... ) :

Callsign: G3XDY
Locator: JO02OB
Bands: 5.7GHz 15W 60cm dish
10GHz 10W 60cm dish
Talkback: ON4KST and 144.175MHz
Times: 0900-2000 for several periods of an hour or so each

73

John G3XDY
UKuG Contest Adjudicator


Re: gps

richard <richard.bown@...>
 

On Fri, 23 Jul 2010 20:48:28 +0100
Andy Talbot <andy.g4jnt@googlemail.com> wrote:

Those chips have the same pinout as the industry standard 26LS31 / 32
family. Those are probably more readily available.
Yup 56p from RS

BTW, on another matter, how can some components be so incrediblycheap
!!!!!!!!!!!
Just ordered some 0805 1nF chip caps from Farnell at the rather silly price
of 0.4 pence each. Mind you, that is the 1000 off price. If I'd only
wanted the MOQ of 100, the price rises to a rip-off 0.7p each

No wonder PCB manufacturing companies like Number One Systems free-issue R's
and C's if you get then to assemble your boards.


Andy
www.g4jnt.com

--
Best wishes

Richard Bown G8JVM

###################################################################################
Registered Linux User 36561
OS: Mandriva 2010.1 Powerpack on an AMD Dual Athlon 64 +4400: 8 GB RAM DDR2
Ham Call: G8JVM , QRA IO82SP, Interests Microwave 1.3 GHz,2.3 GHz & 5.7GHz & 10
GHz
###################################################################################


Re: gps

Andy Talbot <andy.g4jnt@...>
 

Those chips have the same pinout as the industry standard 26LS31 / 32 family.   Those are probably more readily available.
 
BTW, on another matter, how can some components be so incrediblycheap !!!!!!!!!!!
Just ordered some 0805 1nF chip caps from Farnell at the rather silly price of 0.4 pence each.   Mind you, that is the 1000 off price.  If I'd only wanted the MOQ of 100, the price rises to a rip-off 0.7p each
 
No wonder PCB manufacturing companies like Number One Systems free-issue R's and C's if you get then to assemble your boards.
 

On 23 July 2010 12:44, Russ Stewart <g4pbp@...> wrote:
Andy Talbot wrote:
> That looks more like a poor GPS signal. If it can achieve a 2D fix,
> suggests its seeing something and getting a partial lock. The fact
> you're wandering, and have incorrect height are all the same issue as
> the 2D fix.
> Most Oncores (not Encore, that's Francais :-) do not do the time hold
> TRAIM mode, or at least not from the default turn on..
> If you manage to sort out the 3D fix, the old 500ns stability ones
> will still work OK with thE VE2ZAZ GPSDO (which I assume you'll be
> using) provided you set a long enough averaging time - and it should
> go without saying you have a good OCXO to start with. Locking
> bog-standard TCXOs to a jittery 1PPS is a non-starter.
> Have a word with Dave 'BIG. He may have some Palisades going still.
> They're far superior for controlling GPSDOs as the 1 PPS signal is
> especially stable, specifically for timing purposes.
>
> Andy
> www.g4jnt.com <http://www.g4jnt.com>
>
>
> On 23 July 2010 09:44, Russ Stewart <g4pbp@...
> g4pbp@...>> wrote:
>
>     DougF wrote:
>     >
>     > Hi there Russ!
>     > Have you downloaded and set up the relevant software from the
>     Motorola
>     > site? Is it the hardware that is giving you a challenge, or is
>     it the
>     > software? My experience (with two of these specific units) is
>     that it
>     > is quite straightforward....
>     > Best 73,
>     > --Doug, VK4OE.
>     > (uwaves@... uwaves@...>
>     uwaves%40bigpond.com uwaves%2540bigpond.com>>)
>     >
>     > Russ Stewart wrote:
>     > > Hi guys, trying to set up a Motorola Encore gps unit and
>     getting some
>     > > strange results. Can anyone help ?
>     > >
>     > > I think it will be a phone call, skype or qso job so please
>     contact me
>     > > direct and I will ring u back or something.
>     > >
>     > > regards de Russ ... g4pbp
>     >
>     >
>     Hi Doug, well it's hard to tell. I am trying to upgrade GB3CEM 10ghz
>     beacon with an RDDS source so looking to get a good 1pps source to
>     control a 10mhz ocxo.
>
>     The Encore module I have fails all the the self test parameters and
>     generally does not respond to issued commands like going into TRAIM
>     mode. The thing surveys and gets a 2D fix fine but gets my altitude
>     wrong and it thinks I am moving slowly, (not unusual Hi), when the
>     antenna is stationary of course. I can't identify which model I
>     have but
>     don't now think it's the model with a precision 1PPS option, so it's
>     probably not the correct one for the job (500ns timing stability).
>
>     I don't know much about GPS and don't particularly want to be an
>     expert
>     in the field Hi, I just need to know enough to set up a GPS to provide
>     good oscillator stabilisation. It's all taking too much time so may
>     ditch the project for the moment as I have too much else to do.
>     The main
>     problem is the current beacon LO is based on an ADRET synthesiser
>     and it
>     is really noisy and only 1km from this qth; I am considering
>     turning the
>     beacon off until I have time to do a proper job; then I can do weak
>     signal work in that direction again.
>
>     Thanks for your msg and I will look on the Motorola site and see if
>     there is any more appropriate software etc. (currently WinOncore12).
>
>     regards de Russ G4PBP
>
>
>
>
>     ------------------------------------
>
>     Yahoo! Groups Links
>
>
>     (Yahoo! ID required)
>
>     ukmicrowaves-fullfeatured@...
>     ukmicrowaves-fullfeatured@...>
>
>
>
>
Thanks Andy.

When I said 2D fix I was inferring it had the lat/lon ok but not
altitude; It says it has a 3D fix on screen and I am getting up to 13
satellites / normally tracking 6-8 at good strength.

It does not look like my version is one of the posh versions like the
UT+ or M12 but it's not obvious from the type number (starts with R) and
no way of telling what unit I have.

The unit is in an MDSI S690 base unit for mobile mounting and the Oncore
board is plugged in on a header. Apparently a Trimble ACE also can be
plugged in.

I have Trimble Palisades but have been quoted the end of August for the
bus interface chips (Marks circuit). Hence the interest in getting the
Oncore working.

I don't understand why the Oncore fails the self test and why it won't
go into TRAIM. Don't know much about GPS so struggling.

Anyway thanks for the comments .... Russ .... G4PBP



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Re: Activity list for 5.7/10/24GHz Cumulative - Sunday 25th July

f1ghb
 

John ,

If the weather is correct ( but looking at the forecast , this is not the case... ) :

F1GHB/P
Loc : IN88IN - Le Menez Bre close to the city of Guingamp
5.7 Ghz 9W 90 cm Prime Focus dish
10 GHz 4W 80 cm Offset dish
Talkback 144.175 MHz ( UK ) and 144.390 Mhz ( France ) - 100W 9 elts Tonna
No KST so please be present on 2m !
09:00 - 15:00 GMT ( if activity on 2m... )

73s Eric

----- Original Message -----
From: "G3XDY" <g3xdy@btinternet.com>
To: <ukmicrowaves@yahoogroups.com>
Sent: Monday, July 19, 2010 4:05 PM
Subject: [ukmicrowaves] Activity list for 5.7/10/24GHz Cumulative - Sunday 25th July



The third of the series of 5.7/10/24GHz Cumulatives takes place next
Sunday, 25th July, from 0900 - 2000 GMT. Hopefully the weather will be kind,
and maybe oblige with some rainscatter but not right over head.

Please let me know your activity plans and I will compile an email list to
go out next Saturday morning.

I will be active as follows:

Callsign: G3XDY
Locator: JO02OB
Bands: 5.7GHz 15W 60cm dish
10GHz 10W 60cm dish
Talkback: ON4KST and 144.175MHz
Times: 0900-2000 for several periods of an hour or so each.

73

John G3XDY
UKuG Contest Adjudicator



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

Yahoo! Groups Links




Re: GPS antenna

SAM JEWELL
 

I'l have you know I've been a regular on 4m this year and 6m last year!

73 de Sam

----- Original Message ----
From: Conrad Farlow <conrad@g0ruz.com>
To: ukmicrowaves@yahoogroups.com
Sent: Friday, 23 July, 2010 15:20:54
Subject: Re: [ukmicrowaves] GPS antenna

50 MHz Sam? I must have been off that day, slumming it were we?

73

Conrad G0RUZ

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

G0RUZ's new web pages <http://g0ruz.com/new/>



Sam wrote:


Thanks for the great advert, Andy!

I have no recollection of what one that was, but I'm sure it wasn't
'made' by me!
Maybe one of the low cost Trimble units?
If so, mine is still in use. I should say, the second one is. The
first one didn't like 100W of 50MHz 6 foot away from it. It just gave
up after giving several years of faultless service!

73 de Sam




On 23 Jul 2010, at 12:43, Andy Talbot <andy.g4jnt@googlemail.com
<mailto:andy.g4jnt@googlemail.com>> wrote:

Those littlective antennas are usually more than adequate - I have
many, most in constant use BUT if it is an old one that can work
from only 5V, and your modern GPS is supplying 3.3V it may not work
too well.

Also, I've seen two instances of active GPS antenna going unstable
and oscillatiing. Of course, with a high Q ceramic patch this is
spot-on 1575MHz and not only fails to Rx very well, but also jams
nearby GPS receivers too. One occurrance of this was at work (when
I used to do that :-) I dismantled the antenna to find out why, only
to find the grounding of the patch was inherently poor. Contacted
the manufacturers who were rather embarassed, said a whole batch had
been made incorrectly, and we (HM Government) had purchased most of
that very same batch. All had to be replaced. Fortunately they
hadn't at that point gone into service out in the field, otherwise
things could have got "very interesting" if GPS was failing all over
the place for no apparant reason.

The other one that took-off occasionally came from Sam G4DDK at RAL a
few years ago. It was a black round thingy about 40mm in
diameter. OK if mounted on a metal groundplane - like it supposed
to be - but on a wooden or plastic surface sometimes would break
into oscillation. I only spotted this once when the 500kHz beacon Tx
using this antenna showed loss of GPS lock , and also my VE2ZAZ
GPSDO that runs 24/7 dropped out. The black antenna had been OK for
several months, but just decided to break into sprogs that day.

So, after that long spiel, check your GPS antenna.

Andy
www.g4jnt.com <http://www.g4jnt.com>


On 23 July 2010 11:55, eai3ld <eai3ld@yahoo.com
<mailto:eai3ld@yahoo.com>> wrote:



Folks,

I am using one of the Jupiter GPS boards with the 10kHz output
for my 10 MHz frequency reference a la G3RUH.
The antenna is one of those small 4 by 5 cms black boxes with an
inbuilt preamp.
When I run the system outdoors it will lock within 1 minute or so but
when the sky is partly blocked by a building or alike, it takes a
long time to receive enough satellites to get in a "lock" state.
Sometimes there will be no lock at all. Even clouds seem to
attenuate reception. My handheld navigation system, which has of
course a more modern DSP, locks within 30 seconds, so there is
obviously a lack of sensitivity in the system.

Can anyone point me to an antenna solution that is a bit more
effective (homemade would do)?

Any hint would be appreciated.

Daniel
DL3IAE



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

Yahoo! Groups Links


Re: Activity list for 5.7/10/24GHz Cumulative - Sunday 25th July

Robert Price <g8dtf@...>
 

Hi

I will be active as follows:

Callsign: G8DTF/P
Locator: IO93AO
Bands:  10GHz      3W    85cm dish
Talkback: ON4KST and 144.175MHz
Times: 1000-1300 only.

73
Bob
G8DTF

----- Original Message ----
From: G3XDY <g3xdy@btinternet.com>
To: ukmicrowaves@yahoogroups.com
Sent: Mon, 19 July, 2010 15:05:18
Subject: [ukmicrowaves] Activity list for 5.7/10/24GHz Cumulative - Sunday 25th
July

The third of the series  of 5.7/10/24GHz Cumulatives takes place next
Sunday, 25th July, from 0900 - 2000 GMT. Hopefully the weather will be kind,
and maybe oblige with some rainscatter but not right over head.

Please let me know your activity plans and I will compile an email list to
go out next Saturday morning.

I will be active as follows:

Callsign: G3XDY
Locator: JO02OB
Bands:    5.7GHz    15W    60cm dish
                10GHz      10W    60cm dish
Talkback: ON4KST and 144.175MHz
Times: 0900-2000 for several periods of an hour or so each.

73

John G3XDY
UKuG Contest Adjudicator



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

Yahoo! Groups Links


Re: GPS antenna

Conrad Farlow <conrad@...>
 

50 MHz Sam? I must have been off that day, slumming it were we?

73

Conrad G0RUZ

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

G0RUZ's new web pages <http://g0ruz.com/new/>



Sam wrote:



Thanks for the great advert, Andy!

I have no recollection of what one that was, but I'm sure it wasn't 'made' by me!
Maybe one of the low cost Trimble units?
If so, mine is still in use. I should say, the second one is. The first one didn't like 100W of 50MHz 6 foot away from it. It just gave up after giving several years of faultless service!

73 de Sam




On 23 Jul 2010, at 12:43, Andy Talbot <andy.g4jnt@googlemail.com <mailto:andy.g4jnt@googlemail.com>> wrote:

Those littlective antennas are usually more than adequate - I have many, most in constant use BUT if it is an old one that can work from only 5V, and your modern GPS is supplying 3.3V it may not work too well.
Also, I've seen two instances of active GPS antenna going unstable and oscillatiing. Of course, with a high Q ceramic patch this is spot-on 1575MHz and not only fails to Rx very well, but also jams nearby GPS receivers too. One occurrance of this was at work (when I used to do that :-) I dismantled the antenna to find out why, only to find the grounding of the patch was inherently poor. Contacted the manufacturers who were rather embarassed, said a whole batch had been made incorrectly, and we (HM Government) had purchased most of that very same batch. All had to be replaced. Fortunately they hadn't at that point gone into service out in the field, otherwise things could have got "very interesting" if GPS was failing all over the place for no apparant reason.
The other one that took-off occasionally came from Sam G4DDK at RAL a few years ago. It was a black round thingy about 40mm in diameter. OK if mounted on a metal groundplane - like it supposed to be - but on a wooden or plastic surface sometimes would break into oscillation. I only spotted this once when the 500kHz beacon Tx using this antenna showed loss of GPS lock , and also my VE2ZAZ GPSDO that runs 24/7 dropped out. The black antenna had been OK for several months, but just decided to break into sprogs that day.
So, after that long spiel, check your GPS antenna.

Andy
www.g4jnt.com <http://www.g4jnt.com>


On 23 July 2010 11:55, eai3ld <eai3ld@yahoo.com <mailto:eai3ld@yahoo.com>> wrote:


Folks,

I am using one of the Jupiter GPS boards with the 10kHz output
for my 10 MHz frequency reference a la G3RUH.
The antenna is one of those small 4 by 5 cms black boxes with an
inbuilt preamp.
When I run the system outdoors it will lock within 1 minute or so but
when the sky is partly blocked by a building or alike, it takes a
long time to receive enough satellites to get in a "lock" state.
Sometimes there will be no lock at all. Even clouds seem to
attenuate reception. My handheld navigation system, which has of
course a more modern DSP, locks within 30 seconds, so there is
obviously a lack of sensitivity in the system.

Can anyone point me to an antenna solution that is a bit more
effective (homemade would do)?

Any hint would be appreciated.

Daniel
DL3IAE



Re: Activity list for 5.7/10/24GHz Cumulative - Sunday 25th July

Eddie G0EHV
 

M0DTS and G0EHV will be /P on 3cms from IO94LI.

M0DTS QRO 10W.
G0EHV QRP < 1W.

Talkback on 144.175 MHz, 50W and 7 element.
KST possibly also (M0DTS)

Regards,
Eddie


Re: GPS antenna

SAM JEWELL
 

Thanks for the great advert, Andy!

I have no recollection of what one that was, but I'm sure it wasn't 'made' by me!
Maybe one of the low cost Trimble units?
If so, mine is still in use. I should say, the second one is. The first one didn't like 100W of 50MHz  6 foot away from it. It just gave up after giving several years of faultless service!

73 de Sam




On 23 Jul 2010, at 12:43, Andy Talbot <andy.g4jnt@...> wrote:

Those littlective antennas are usually more than adequate - I have many, most in constant use  BUT if it is an old one that can work from only 5V,   and your modern GPS is supplying 3.3V it may not work too well.
 
Also, I've seen two instances of active GPS antenna going unstable and oscillatiing.  Of course, with a high Q ceramic patch this is spot-on  1575MHz and not only fails to Rx very well, but also jams nearby GPS receivers too.   One occurrance of this was at work (when I used to do that :-)  I dismantled the antenna to find out why, only to find the grounding of the patch was inherently poor.  Contacted the manufacturers who were rather embarassed, said a whole batch had been made incorrectly, and we (HM Government) had purchased most of that very same batch.   All had to be replaced.  Fortunately they hadn't at that point gone into service out in the field, otherwise things could have got "very interesting" if GPS was failing all over the place for no apparant reason.
 
The other one that took-off occasionally came from Sam G4DDK at RAL a few years ago.    It was a black round thingy about 40mm in diameter.    OK if mounted on a metal groundplane - like it supposed to be -  but on a wooden or plastic surface sometimes would break into oscillation.  I only spotted this once when the 500kHz beacon Tx using this antenna showed loss of GPS lock ,  and also my VE2ZAZ GPSDO that runs 24/7 dropped out.   The black antenna had been OK for several months, but just decided to break into sprogs that day.
 
So, after that long spiel, check your GPS antenna.
On 23 July 2010 11:55, eai3ld <eai3ld@...> wrote:
 

Folks,

I am using one of the Jupiter GPS boards with the 10kHz output for my 10 MHz frequency reference a la G3RUH.
The antenna is one of those small 4 by 5 cms black boxes with an inbuilt preamp.
When I run the system outdoors it will lock within 1 minute or so but
when the sky is partly blocked by a building or alike, it takes a long time to receive enough satellites to get in a "lock" state. Sometimes there will be no lock at all. Even clouds seem to attenuate reception. My handheld navigation system, which has of course a more modern DSP, locks within 30 seconds, so there is obviously a lack of sensitivity in the system.

Can anyone point me to an antenna solution that is a bit more effective (homemade would do)?

Any hint would be appreciated.

Daniel
DL3IAE