[G4DDK] PCB

[G4DDK via rec.radio.amateur.moderated Admin]

G4DDK- A radio blog

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PCB

Posted: 05 Feb 2013 02:46 PM PST
http://g4ddk.blogspot.com/2013/02/pcb.html

Prompted by a visit from G7OCD yesterday I decided to sort out my PCB
etching facilities.
For some months I have been unable to run my Mega triple tank etching
system because the clear etch crystal solution had crystalised out,
trapping the PCB holder and making it difficult to remove the tank lid to
pour in near-boiling water to dissolve the crystals in the solution. I
eventually had to cut the retainers from the lid, allowing me to remove it
and gain access!
With access I was able to (eventually) pour in the hot water and then
syphon out the spent solution. That didn't go too well as the syphon sucked
up crystals and stopped working. It didn't matter what I did, I couldn't
get it working again.
As I had to go to Rapid Electronics to get new crystals and other
components I added a new syphon to the growing list.
These come in pairs and even the first of these also gummed up. However,
the other syphon worked OK and the tank is now empty, ready for a new
etching solution to be added tomorrow.
I also bought new sensitised PCB material, universal solvent and some other
stuff. Now I can etch the new 4m transverter board and the two PA driver
boards.

Sam





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New 144MHz antenna

Posted: 27 Jan 2013 09:15 AM PST
http://g4ddk.blogspot.com/2013/01/new-144mhz-antenna.html

Last summer I erected a YU7EF dual band 4/6m five element yagi on my mast.
A few month's ago I asked Colin, G4ERO, if he would also make me a 5m boom
144MHz YU7EF yagi.

Yesterday I took delivery of the new yagi at the monthly Codger's breakfast
meeting, courtesy of G4BAO and his delivery system!

Taking advantage of the mild weather today, I assembled the yagi and put it
on my mast, ready for testing.





After normalising the cable I was able to check the match direct at the
yagi feedpoint, using my HP 8753C network analyser.

This showed the best match to be slightly low in frequency at 142.8MHz at
25dB, rising to 16dB ( about 1.3dB VSWR) at 144.3MHz.
I didn't have time today to play with the match, but suspect that the coax
balun is slightly too long.

Next time I have the mast down I will shorten the balun by a few mm and
check the match.

Listening around on 2n there wasn't much activity today, but the usual
beacons were all there and about their normal strength, although a longer
period of listening is required to see if their level is better or not.
My 'old' Cushcraft 145B2 ten element was quite good, but it is not an
optimised design, so I would expect marginally better performance on
terrestrial and a fighting chance at single yagi 144MHz EME.

73 de Sam





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Dubus Technik 12

Posted: 23 Jan 2013 05:02 AM PST
http://g4ddk.blogspot.com/2013/01/dubus-technik-12.html

Received my copy of DUBUS Technik 12 today.
Full of really good stuff including a reprint of my PGA Amp.
These were also on sale at Heelweg last Saturday.

Copies should be available from the UK DUBUS representative, GM4PMK.
Google on Roger's callsign for details.

I guess they will also be available elsewhere from the numerous DUBUS
country representatives.

Speaking of the PGA Amp, I now have a small number of low loss Arlon PCB
versions of the PGA Amp kit. See my web page.
This will be updated in a day or so to reflect the availability of
this 'other' PCB.



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Heelweg and Dwingeloo

Posted: 21 Jan 2013 12:12 PM PST
http://g4ddk.blogspot.com/2013/01/heelweg-and-dwingeloo.html

Safely back from The Netherlands.
We ( G4BAO, G4HUP and myself) had been concerned that the dreadful snowy
weather at the weekend might have meant calling off our annual visit to the
Heelweg Microwave meeting ( held in Westendorp!) on the 19th January this
year

As it happened it was probably a wise move to drive rather than taking a
plane as in previous years. The delays experienced on some airlines just
did not occur on the Stena ferry Line Harwich to Hook of Holland route and
although progress was slow across The Netherlands road network on Sunday (
I was interested to see that the Dutch are no better prepared for snow than
here in the UK), at least everything kept moving.

This is the first time we have taken the car, and it may not be the last.
It allowed us more freedom in our schedule and the opportunity to visit the
Dwingeloo dish in JO32. As this is a long way from our usual host's QTH,
there has not been enough time to visit previously.

Jan, PA3FXB, had invited us to visit many times over the last few years. At
last, and just after the dish was place back on the rotating plinth
following refurbishment, we were able to look over the site and admire the
handiwork of the original builders back in 1954/1956

This dish was used by Jan Oort of 'cloud' fame to map the galaxy HI line
for the first time and is one of the sites at which the ashes of famous
radio astronomer and radio amateur, Grote Reber, are intered.

The site is now well known as the location of the PI9CAM EME operation on
2m and 23,13 and 9cm

EME operation will not resume until later this year, and when it does I
would like to go back again.

Next to the dish, on the Astron test range, we saw one ( or more) of the
low frequency LOFER array antennas. It is shown right in the very middle of
the photo and appears as a small black disc on the top of that short pole.






The Heelweg meeting was its usual excellent self with over 150 attendees,
lots of test gear in use and a small number of traders doing a good trade
in specialist parts for microwavers.

I would like to thank Jan, PA3FXB, for taking time to show us round the
Dwingeloo dish, and to the many organisers ( too many to mention) who
organise and run the Heelweg meeting.


Sam





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Heelweg plans

Posted: 17 Jan 2013 06:06 AM PST
http://g4ddk.blogspot.com/2013/01/heelweg-plans.html


Still packing stuff to take to the Dutch Heelweg Microwave meeting on
Saturday. However, the weather looks like it means to try and intervene.
Snow expected in East Anglia from lunchtime tomorrow. The forecasts are for
low amounts in this area so driving across to Harwich may not be too big a
problem. We'll see!
What awaits us on the otherside of the North Sea is possibly a bigger
concern.
I am looking forward to seeing the refurbished Dwingeloo dish on Sunday. I
hope we can make it.
More anon!

On another matter, I have been asked to produce the March Radcom VHF/UHF
column prior to the new, permanent, columnist taking over from the April
issue. I'm busy soliciting reports for the end of January deadline.
In particular I am interested in any reports, for any of the VHF bands,
from the Quantrids meteor shower. If you have a report you would like to
submit, preferably with a picture of your antenna system, I would be
pleased to receive it.




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PGA Amp updated documentation

Posted: 17 Jan 2013 05:49 AM PST
http://g4ddk.blogspot.com/2013/01/pga-amp-updated-documentation.html

I have updated the PGA Amp VHF preamplifier documentation on my web page,
www.g4ddk.com
In the PDF several minor schematic errors have been corrected and the type
of housing has been changed to show the preamp mounted into a smaller and
easier to work with tin plate box.
The documentation also now gives details of G4SWX's 130MHz HPF used, when
required, with the PGA Amp to give added protection against strong Band 2
FM transmissions.
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A happy new year?

Posted: 01 Jan 2013 12:51 PM PST
http://g4ddk.blogspot.com/2013/01/a-happy-new-year.html

Once again circumstances intervened. My good intentions to get on the new
472kHz band on 1st January were thwarted by a bereavment in the family on
New Year's Eve. The next week or so will be taken up by funeral
arrangements and further trips to GI.

On a more positive note, the hotel has been reserved near Heelweg, the
ferry has been booked and we are now all set for the Heelweg Microwave
meeting on the 19th January, followed by a trip to see the restored
Dwingaloo dish (PI9CAM) antenna on the 20th January.

John, Dave and I are looking forward to seeing our ( mainly) Dutch, Belgian
and German amateur friends once again. Expect to see a full report on the
Heelweg and Dwingaloo visits in Scatterpoint and, perhaps, Radcom.

Happy New Year






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472kHz

Posted: 29 Dec 2012 01:23 PM PST
http://g4ddk.blogspot.com/2012/12/472khz.html

Having registered for and downloaded my 472kHz band NoV I am currently
looking for parts to use on this MF band when it opens for 'service' on the
1January.
I had originally planned to use a G3XBM transmit converter with my FT817. I
have ordered a pack of ten 3.2MHz crystals on EBAY. However, they have not
yet appeared, probably due to the Christmas post backlog.

In the meantime I have been looking at alternative methods of accessing the
band, including transverting ( both transmit and receive) using my K3 which
will not receive directly on 472kHz due to not having the wideband RF
bandpass filter fitted. I am still considering this approach.

Meanwhile I have been fortunate to obtain a 50W RF output, Class B,
switching FET power amplifier. This was originally designed for use at
470kHz! Its high gain means it can be driven direcly from a mixer output.

It would have been fairly easy to make a switching MOSFET amplifier, but as
I am only dabbling at this stage and have lots of other projects on the go,
I wanted to minimise the amount of building I would need to do.




I am still learning a lot about antennas at MF and what may and may not
work.

Sam




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13cm back on

Posted: 16 Dec 2012 05:12 AM PST
http://g4ddk.blogspot.com/2012/12/13cm-back-on.html

I put the 13cm terrestrial system back on and can see 2dB of cold sky to
ground. That is about right for the system as it is currently configured.
Sadly, no sign of GB3ANT/B. I am beginning to suspect that the beacon may
well be a down a bit on normal. However, I will continue looking for it.
That's the 13cm 67 element yagi on the top of the mast.

Sam






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13cm update

Posted: 15 Dec 2012 02:23 PM PST
http://g4ddk.blogspot.com/2012/12/13cm-update.html

I investigated a fault on my 13cm masthead preamp some months ago. I didn't
find any fault, but the system sensitivity was definitely low. I put it all
back a few weeks ago, meaning to look at it again sometime. It still worked
( sort of) and that is better than not having any 13cm capability at all.

Normally I can hear GB3ANT/B , located near Norwich, all the time. Since
the summer reception of the beacon has been poor. G3LQR reports hearing
the beacon as normal so I have to assume the worst, hence the tests on the
masthead.

Today I decided to have another go. With the masthead preamp in the shack a
visual investigation revealed the preamp (VLNA13 - original Issue 1 board
but with the current build standard) input SMA connector was starting to
break away from the tinplate box. I had obviously missed this the first
time! The preamp still worked, but the noise match was totally shot.

I replaced the preamp input 2- hole female SMA connector with a four-hole
male SMA. With this arrangement I was able to connect the input of the VLNA
direct to a bulkhead SMA female-female connector.

Now, on test, the masthead preamp measures 0.5dB noise figure and 24dB
gain. As this is with a short SMA to SMA lead from the bulkhead Connector
to the relay receive port, N to SMA adapters on two ports and a home made
bias Tee to extract the 28v from the receive coax to the 12V regulator in
the box, I regard this as quite good and certainly far better than I
managed previously.
I hope to put the masthead box back on the tower tomorrow. It will be
interesting to see how well the system works now!

Sam






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EME doings

Posted: 12 Dec 2012 06:47 AM PST
http://g4ddk.blogspot.com/2012/12/eme-doings.html

A VLNA23 recently built-up for a well-known European EME operator.
I hope to see that he and his EME partner get even better results on 23cm
than they have done so far ( and they are pretty good!) with an older
design of preamplifier in use.



This one has an N type female output connector in place of the usual SMA
female connector.

The photo below shows independent results, measured by a well-respected
American amateur, of one of my VLNA23 preamps on test.

He is continuing with his tests, seeking to quantify results with a number
of input connector types and materials. With his permission, I will bring
you some results later.

Work continues to further improve the VLNA preamplifier range!

Sam






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Location:Falkenham Road,Kirton,United Kingdom

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Won't be QRV

Posted: 28 Nov 2012 01:34 PM PST
http://g4ddk.blogspot.com/2012/11/won-be-qrv.html

Unfortunately a family emergency means I won't now be QRV in the EME
contest at the weekend. I will be in GI until Sunday.

73 de Sam





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Location:Home

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Some results of tests with isolator and relays

Posted: 15 Dec 2012 02:04 PM PST
http://g4ddk.blogspot.com/2012/11/some-results-of-tests-with-isolator-and.html

Prior to putting my 23cm EME system back on-air I thought I would check out
some isolators and relays I had used previously.
I had thought about using the Totsu CX600N at the output of the TS2000X,
but the results show this is not a good idea. That relay is just OK at
432MHz, but definitely not at 1296MHz!
I have two identical 1200Mhz range isolators. The 'black' one shows the
best results at 1296MHz, so will be used for the TS2000X
transmitter 'protection'.
The isolator gives 0.33dB insertion loss ( forward) and 23.9dB reverse loss
with reverse return loss of 16.3dB
CX600N @1296MHz
Insertion loss common to NC with other port terminated in 50R
=0.14dB
Insertion loss common to NO ( relay operated) =0.19dB
Isolation common to NO 20.25dB
NC to NO isolation = 19.9dB
RLC electronics relay @1296MHz
Insertion loss common to NC or NO with other port terminated
=

More later.
Sam
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A purpose in life!

Posted: 25 Nov 2012 07:41 AM PST
http://g4ddk.blogspot.com/2012/11/my-current-thoughts-are-that-i-will.html

My current thoughts are that I will write about my EME actvities, in the
main, although there will be other stuff as well.
With the final part of the ARRL EME contest next weekend there is obviously
a lot of interest, judging from the number of requests I am getting for
preamps and spare parts for VLNA preamps!
I am going to try and get my own 23cm system up and running for next
weekend and will aim to have a few QSOs.
I was active on receive only in the 50-1296MHz section at the beginning of
this month. There were a lot of stations visible on my Spectravue screen.
Unfortunately MAP65 performed rather poorly and only the bigger stations
decoded. Changing to JT65C, decodes were close to 100% on all but the
weakest stations.
As far as I can tell, there has been no wind damage to the dish or mast (
luffed over from the previous wind storm, last week) from last night's
storm, at my QTH. Lots of branches down on surrounding country roads and
lanes.
73 de Sam




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Location:Falkenham Road,Kirton,United Kingdom

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A relaunch

Posted: 23 Nov 2012 09:49 AM PST
http://g4ddk.blogspot.com/2012/11/a-relaunch.html

After an almost two year hiatus I have decided to re-launch my blog. Now I
no longer write the GHz Bands column for Radcom I need a new canvas to lay
out my thoughts, current interests and project progress. Where better than
a blog? Facebook and Twitter are too limiting.





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Location:Home

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Bangor

Posted: 28 Dec 2010 02:20 PM PST
http://g4ddk.blogspot.com/2010/12/bangor.html


Well, we arrived safely in Bangor, GI.
After our Monday ferry was cancelled we were re-booked on the slower
Ulysses super ferry. This is variously reported as the largest ferry in the
world and the largest on the Irish Sea routes.
Anyway, we arrived at Holyhead about 4 hours before our ferry was due to
sail. Try as we could, they would not allow us on the 12:00 fast ferry. I
guess it was full, but I still think it was unfair not to have been offered
the option of the fast ferry since that is what we paid for. I shall be
sending a stiff e-mail to the booking company! This has lost us a whole day
and over £150 in unplanned costs.....

More pleasantly, fuel is really cheap in Eire. Around £1:00/ litre for
diesel. Needless to say, we topped up before crossing the border into
Northern Ireland. This must be the only border in Europe where you can
drive across the border, changing the speed readout from MPH to KPH or vice
versa, as you go!

I'm relieved to see there is no water shortage problems here in Bangor,
unlike large parts of the Province. It is getting serious in some areas,
from what we see on TV!

The car temperature gauge was reading 10C as we arrived in Bangor. That
must be the warmest it has been for months.

More tomorrow.





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Location:Northern Ireland

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North Wales

Posted: 28 Dec 2010 01:44 AM PST
http://g4ddk.blogspot.com/2010/12/north-wales.html

Now in Bangor. A pretty smooth drive up except for the M6 which was very
slow from around Stafford to Sandbach. It was just the volume of traffic
that slowed it, together with spray from the persistent light rain.

Of course it is raining more heavily this morning, in Bangor.

We are off to catch the ferry at 14:10, so a little bit of time to check
out Brunel's Britannia bridge on the way over!

There was some sort of emergency in the Straits last night with the Air Sea
Rescue helicopter out looking for the source of an emergency call from
close to the bridge. The bridge is about 1/2 mile from this hotel, but no
noises to awaken us......

More words from the ' other side'.

Sam




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Location:Falkenham Rd,,United Kingdom

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New Year

Posted: 26 Dec 2010 03:21 PM PST
http://g4ddk.blogspot.com/2010/12/new-year.html

Tomorrow we head off to Bangor, Northern Ireland. But, since Irish Ferries
informed us this morning that they have cancelled the 17:15 Holyhead to
Dublin ferry tomorrow, we have had to re-book onto the 14:10 on Tuesday.
This is a bigger, slower ferry than the cat we were booked on.
As a result of the change in crossing we have decided to travel as far as
Bangor, North Wales tomorrow. So then, Monday night in Bangor and then
Tuesday night in Bangor! Just different countries....

More from Bangor!

Sam




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Location:Falkenham Rd,,United Kingdom

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Home

Posted: 19 Oct 2010 02:16 PM PDT
http://g4ddk.blogspot.com/2010/10/home.html


A good flight from Vancouver to the UK, only marred by the fact that my car
battery was flat when I retrieved my car from LHR Long Term car park. The
guys there soon sorted that out with jumper leads.
I could see no obvious reason for the flat battery. Nothing was left on?

I was far too tired to get on for the UKAC this evening.

I'm not sure when I will blog again, but I have been contemplating making
this a regular place for thoughts on my radio activities.

Thanks again to everyone who read the blog over the last 12 days. I hope
you enjoyed the 'trip' as much as we did.




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Location:Felixstowe

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Finale

Posted: 18 Oct 2010 11:37 AM PDT
http://g4ddk.blogspot.com/2010/10/finale.html

About to go QRT from Vancouver.
I will update the blog when I get home. Thanks to everyone who read my
words. From the comments received, it appears we had at least a few people
along with us on the trip.

Those whales......wow! They made the whole trip worthwhile.

Sam and Shirley on Granville Island and about to check out and lose
WiF...........






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Location:Vancouver

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Granville Island

Posted: 19 Oct 2010 02:19 PM PDT
http://g4ddk.blogspot.com/2010/10/granville-island.html

I swear I didn't know!
Leaving our room last evening, I happened to look over the glass balcony
outside the room. Not 8 foot from our room door.......a Micro Brewery.
Yes, just 8 foot from the top of one of about 15 fermenting tanks.
It appears that this hotel is also the location of the island's Dockside
Brewery!

Sam




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Location:Vancouver

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To show there is some radio content...

Posted: 18 Oct 2010 02:29 AM PDT
http://g4ddk.blogspot.com/2010/10/to-show-there-is-some-radio-content.html




Mast on Mount Seymour



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Location:Granville Island