Wednesday 31 December 2008
(Images to follow)
They will go into a single chassis along with other bands.
I bought a Delta 1010 LT which is a 10 input 10 output PCI sound card earlier in 2007 and will look at creating an all band SDR RX with it.
Wednesday 24 December 2008
As did all the shopping etc for xmas happy to put my feet up. And whilst doing that made up some new etch and used a new digital thermometer to check the bath is at 50 degrees C. The etch was really fast this time.
Just finished drying off the latest batch of PCB and what I especially like is no yellow/brown stains on everything. The solution turns a little blue/green, probably from the marker /cd pen I used. The boards are naturally yellow/green
These are top left; a N3ZI LCD display controller boards, top right; a Freakin' Beacon controller, bottom left; KD1JV (see earlier post) and botton right; one of the RD16HHF1 Mosfet PA boards (sea earlier post).
Whilst waiting for the etch I melted a little solder for a couple of N6BM projects, the Miniboots II PA and an LC Meter. The LC meter design is actually from MARC http://www.marc.org.au/index.html VK3BHR LC Meter Project - Mk.II but Wayne had reworked the PCB layout. I have a nice desktop calculator style case that one will go into.
Tuesday 23 December 2008
I am playing with output transformers so I have used either T106 or a pair of stacked BN43-202 or BN43-202 on the PCB hence the complicated component layout, but no extra tracks or holes. The T106 or BN43-302 or 202 were picked up from W8DIZ at FDIM but you can order online from him at http://www.kitsandparts.com
Expecting to get some time in the shack this Xmas I have pre made up these boards and a few others so I can make a fresh batch of etch and take that down with me.
The PCB will be about 2" square. Note there are NO LPF components fitted to this PCB they will be needed. The populated PCB will be fitted onto the lid of a Jack Daniels minature tin and I am using a 1U solid copper PC CPU heatsink and fan for cooling. The RD16HHF1 will be mounted under the board.
Thursday 11 December 2008
It took 1/2 day to cycle there, and after realising had forgotten the SLA battery... oops, fortunately found a cafe that had a box of rather old sun bleached packets of AA batteries I bought for £1.
Operation into a buddipole from FT817 with psk31 0.5W running using only the old batteries with a VERY OLD Dell laptop whilst the batteries lasted. It was light enough to operate inside the tent but brrrr... it was cold.
This was the same place where I operated from and sent a message to GQRP about the sea wall effect so thought I'd try it again.
Just checking where the tide is.
The bottom of the tent is a red fabric and there is plenty of room to sit and operate sitting up.
When the door is zipped up (There is a vent in two walls I can close from inside) the tent is wind and water proof.
Tuesday 9 December 2008
Hope to meet you on the bands.
Wednesday 26 November 2008
As my QTH is only c40 miles East of MKARS/Betchley Park I expect I might visit once operational.
I took all the parts out once arrived home, before dutifully putting it into one of the clear boxes I use for storing build projects in the shack. So far I can see I might experiment with a slightly larger case using an air spaced variable (another Leicester purchase) and a reduction drive for tuning or might try the varicap mod with a 10 turn pot (bought a whole box of various values both recycled and new at GQRP rally), definitely will add an in case battery holder which will also be used by rechargable batteries, a little L match ATU so self contained for /P http://m1kta-qrp.blogspot.com/2008/09/what-to-do-with-1-pole-12-way-switch.html, I find the W3EDP antenna works well for 80m and finally will have to paint it some luminous/gawdy colour scheme so a trip to B&Q to see what colour spray enamel paints are available is needed.
After spending last year in HB9 I discovered the benfit of using lock 'n' lock boxes for homebrew in cold & wet /P conditions so might investigate using one possibly as the enclosure not just transport in a rucksack/bicycle pannier.
Thursday 20 November 2008
Just picked up on the discussions about using the TA7358 as an alternative to the SE/NE602 as a mixer which I am all in favour of as the 602 are becoming very expensive.
Ordered a number from Peter at Jabdog and once they arrive will start to look at them in circuits.
One advanced option is here:
Cosy MUTO, JH5ESM (вольный перевод Валерия, RW3DKB)
Этот приемник - разработка для Технического Симпозиума ARRL 1999г в Кагава (Япония). Входная ИС используется для формирования внешних цепей FM-приемников и содержит каскады УВЧ/смеситель/гетеродин. Для питания достаточно 3 вольт - только 2 батарейки типа АА.
Рис. 1 показывает оригинальную схематику приемника.
Рис.1 Оригинальная схематика приемника.
Микросхема TA7358AP содержит в себе все входные каскады для FM приемника в одном корпусе. Ножки с 1 по 3 - это цепи каскада УВЧ, с 4 по 6 - это цепи двойного балансного смесителя Гилберта (Gilbert DBM cell) и с 7 по 9 - выводы транзистора гетеродина.
Полный диапазон приемника оценен как 90dB. Дополнительный звуковой усилитель потребовался для получения громкоговорящего приема.
Возникают паразитные звуковые эффекты, когда Вы делаете громче регулятор громкости. Это вызвано обратной связью через линию питания. Для их устранения необходимо модернизировать схему. В частности ввести в нее развязывающие цепочки по питанию каскадов.
Переделанная схема представлена на Рис.2.
Если напряжение постоянного тока через резистор 1 кОм больше чем 0.6 V, его номинал должен быть уменьшен, чтобы избежать запирания внутренних диодов в TA7358.
Thursday 23 October 2008
Found a centre at GQRP rally last w/e, go to http://www.amtoolsuk.com/ANTENNAPLATECP1PAGE.html for the details and read the drilling instructions.
The centre unit is designed for 20mm conduit so for the cobweb 10m-20m you need poles 6' 6" long the poles I have are 4m poles from sky blue. The centre 2 sections are exactly 20mm at the base so I will use the centre two sections only. So will 'store the base and whip sections for something else. You could use thick walled 20mm conduit tubing, with some 'sag'.
The great thing about the centre plate is the option of use of the 4 pole 90 degree options for all sorts of antennas. Not just a cobweb, I can see a wire beam as per spider beam should be possible as well.
Wednesday 22 October 2008
Anyway thinking time I need to add WARC bands 17m and 12m to it.
Saw the add on kits at Dayton FDIM but serious costs involved so this is how I will do it (direct copy from AD5TH):
1. 25ft - Multi strand insulated copper wire (just wired up green house so spare lengths)
2. 2 - ring terminals (crimp or solder)
3. 4 - plexiglass spreader arms (home brew)
One of the home brew "spreader" arms
Clive (M5CHH) had given me a small piece of plexiglass a while back. You need a piece 14 inch x 8 inch and about 1/4 inch thick. The alternative is you could use ply wood and paint or varnish it.
1. Cut plexiglass into 14 inch long by 2 inch wide strips (use band saw or score and snap)
2. Drill a single 1 1/4" hole in center on each strip. Drill very carefully.
3. Drill a single 1/8 " hole on center 1 inch from each end of strip. 2 holes per strip (1 on each end)
1. From 25 ft of wire cut 2 lengths 14ft (17M) and 10 ft (12M)
2. Strip one end of each and attach crimp or soldered ring terminal
1. Disassemble your Hustler antenna and place a plexiglass spreader over the main tube at the very bottom right above the base and then place a spreader on top of the 10M trap and another on top of the 15M trap. The fourth and final spreader is installed at the bottom of the 20M trap supported by a plastic tie around the antenna tube directly beneath the spreader. Reassemble the antenna and test for proper operation on original 10/15/20/40/80M bands
2. Attach both 12M and 17M wire ring terminals to the main feedpoint.
3. Thread the 12M and 17M wires through the 1/8 inch hole in each spreader. The spreader on top of the 10M trap needs to be slid up the main antenna tube about half way towards the 15M trap and held with a plastic tie. This locates the spreader properly to intersect the upper portion of the 12M vertical radiator
4. Temporarily secure the other end of each wire with a plastic tie or folding the wire over it's top most spreader.
5. Check the VSWR and trim to resonance for 12M and 17M. Secure wires to spreaders with plastic ties.
6. Typically after 12M and 17M are tuned you'll need to re-tune one or two of the other bands of the Hustler BTV
AD5TH 5-BTV 10M and 20M needed a retune. 15M 40M and 80M VSWR was unchanged after the modification.
7. These photos are from AD5TH. I will add mine shortly.
1. I keep meaning to purchase/make a tilt over mount for my 6-BTV, AD5TH said this would have really helped throughout the procedure. It is more cumbersome to complete this modification without the aid of a tilt over mount. An alternative is to enlist the assistance of a helper and a ladder.
As I am doing an antenna 'shoot off' especially as I bought a centre for the HEx beam/cobweb at GQRP rally this will be my 'reference antenna'.
The orginal AD5TH website seems to have gone. These were the original instructions:
25ft - #12 insulated copper wire - (about $4)
ring terminals (crimp or solder) - (about $1)
plexiglass spreader arms (home brew) - (about $5)
Home brew "spreader" drawing
Required stock 14 inch x 8 inch 1/4 inch thick plexiglass (about $5 cost)
Cut plexiglass into 14 inch long by 2 inch wide strips (use band saw or score and snap)
Drill a single 1&1/4 inch hole in center on each strip. Use 1 1/4 inch hole saw. Drill very carefully.
Drill a single 1/8 inch hole on center 1 inch from each end of strip. 2 holes per strip (1 on each end)
From 25 ft of #12 wire cut 2 lengths 14ft (17M) and 10 ft (12M)
Strip one end of each and attach crimp or soldered ring terminal
Disassemble your Hustler antenna and place a plexiglass spreader over the main tube at the very bottom right above the base and then place a spreader on top of the 10M trap and another on top of the 15M trap. The fourth and final spreader is installed at the bottom of the 20M trap supported by a plastic tie around the antenna tube directly beneath the spreader. Reassemble the antenna and test for proper operation on original 10/15/20/40/80M bands if 5-BTV. Likewise if 4-BTV or 6-BTV check on all original bands for proper operation after reassembly.
Attach both 12M and 17M wire ring terminals to the main feedpoint.
Thread the 12M and 17M wires through the 1/8 inch hole in each spreader. The spreader on top of the 10M trap needs to be slid up the main antenna tube about half way towards the 15M trap and held with a plastic tie. This locates the spreader properly to intersect the upper portion of the12M vertical radiator
Temporarily secure the other end of each wire with a plastic tie or folding the wire over it's top most spreader.
Check the VSWR and trim to resonance for 12M and 17M. Secure wires to spreaders with plastic ties.
Typically after 12M and 17M are tuned you'll need to re-tune one or two of the other bands of the Hustler BTV. On my 5-BTV 10M and 20M needed a retune. 15M 40M and 80M VSWR was unchanged after the modification.
I have a tilt-over mount on my 5-BTV so this really helped throughout the procedure. It is more cumbersome to complete this modification without the aid of a tilt over mount. An alternative is to enlist the assistance of a helper.
The wire lengths cited in the instructions are longer than needed by design so simply prudent trimming and testing will achieve resonance. It took me only 3 trim and test cycles to get both 12M and 17M flat.
If your Hustler is ground mounted without any buried radials it is highly recommended that you add at least 25 or 30 ground radials at least 15 ft in length each. Radials in soil need not be "tuned" as "in-the-air" radials must be.
Today I completed retuning 20M and 10M. Now ALL 7 bands are under 1.3:1. 20M was stubborn and needed to be shortened but was already shortened to the max. I raised the 20M capacitive hat about 1 1/2 " which predictably raised the resonant frequency. I was then able to routinely lengthen the 20M adjustment and the match fell right in.
QRPp Cat in QSO with M1KTA at GQRP hotel
Jan (G0BBL), Alan (M0PUB) and Klaus
The top table... Ken, Graham, Dick Pascoe, Tony, George...
Nick and XYL in front (M0NJP/ON4NIC), Clive (M5CHH) on right, Me (M1KTA) on left
Back in the shack I have started to look at different coil formers for use in homebrew so will add them to the ones I already have.
From left to right they are straws from Burger King, Starbucks, Costa Coffee and wooden stirrers from Little Chef. The largest is the Starbucks clear straw.
More info to be updated after testing.
Tuesday 21 October 2008
Thursday 16 October 2008
I am one of those giving a talk this year.
The agenda email from Graham....
Here is a list of the speakers and their subjects at Rishworth this coming Saturday:
11.00 : Software Defined Radio For Home Construction
Alan M0PUB and Jan G0BBL will present recent developments from the popular Softrock kits to the new QRP2008 transceiver Project. They will also cover the trend towards "Direct to All Digital".
13.00 : "Alpine style" DXpeditions VE3-7/, HB9/, HB0/ and 3B8/Dominic Baines, M1KTA
"Alpine Style" is a reference to mountaineering, back in early 20th Century the big mountains of the world were conquered by huge expeditions over many months with huge teams. Climbers now carry everything they needed"Alpine Style" and move self contained using whatever they had with them or found.
14.00 : Antenna for Limited SpacesColin Turner, G3VTT
Colin writes the popular SPRAT feature AAA (Antennas, Awards, and Anecdotes)and offers practical ideas for the operator who has to cope with limitedspace for antennas.
15.00 : Life is Too Short for QRO
George Dobbs, G3RJVA little QRP philosophy and a few practical ideas. George is standing infor Rob Mannion of PW, who sadly cannot join us but sends everyone hisgreetings.
16.00: Open Technical Forum with David Stockton, GM4ZNX
A regular at the convention, David applies his flexible technical mind tosubjects suggested by your questions. You ask the questions and David provides his explanations. David enjoys active questioning from the audience, at all levels, so do not be afraid to ask him to pitch his explanations to your level.
See you all there?
Monday 13 October 2008
It takes longer to tell about how to use this than to actually perform measurements. Once you have been through the process a couple of times, it only takes a couple of minutes to fully investigate a meters characteristics.
Place the unknown meter between C and D, The orientation needs to be so that positive voltage applied makes the meter move, most normal meters that means the positive lead connects to C. I have a couple of centre zero meters as well so the connection could be either way. With the battery connected select full scale on the switch position.
Rotate R1 for maximum resistance. Many pots have maximum resistance (which will be minimum current) when the control is fully CCW, but the direction of travel is arbitrary and unimportant. The important thing is to be sure it is set for minimum current to start the test.
If you have it set your DVM to read 200 mA, or more, then insert it into the circuit with positive lead to B and negative lead to A. Always start with a high current setting on your DVM and work down.
You may see absolutely nothing on the meter, adjust R1 (reducing it) to obtain a full scale reading on the unknown meter by reducing the resistance. If a full-scale reading cannot be obtained with R1 set for minimum resistance, the unknown meter is beyond the current supply capabilities of the batteries. In such an event, disconnect the DVM quickly to prevent draining your batteries. This condition is probably due to an internal shunt in the unknown meter. This can be overcome as will be explained, later.
As I was wanting to use mine as an audio level S meter for the Norcal-20 O built (maybe a good idea?) I wanted a meter with FSD of between 100uA and 500uA. The first meter I tested has a full deflection current of 200 uA.
Now re-adjust R1 for a full scale reading.
Change the S1 to Half Scale and adjust R2 for a half scale reading.
YOU NOW KNOW THE INTERNAL RESISTANCE OF YOUR (formerly) UNKNOWN METER.
Given that you are salvaging a meter, the next stage should not be a problem, surgery is required. That is, you must open the meter and remove the built-in shunt, then proceed as you would with a "normal" meter. The internal components are mechanically very delicate, similar to the insides of a mechanical watch. So, if you have the patience and dedication required to disassemble the meter, remove the shunt, re-assemble the meter and perform the Meter Master investigation as described above, you can salvage most any meter. Some are very easy to get into some seem to be sealed within plastic, your milage may vary and may not always be successful, but it will be a satisfying end if you are so inclined. If not, its best to simply toss the meter into the nearest trash can and forget about it.
Friday 10 October 2008
Thursday 9 October 2008
On power on the meter, with no RF connections states F:1.4W R:1.4W SWR:9.9 and the analogue meter reads hard over FSD. Or the R (reverse) jumps about and so does the SWR and the meter bounces to FSD (see the video clip).
I first thought it might have been the battery so I changed that but no change in behaviour.
I put it down to making a basic error somewhere and thought nothing more of it and thought would return to look at this later when another on the QRP-L list posted a similar problem. So thought perhaps wasn't just me.
As I built it, you can see there isn't much to it, but see if you can spot the problem before you look at the solution lower down the post?
The problem was D3 and D4.
I should have read the schematic and used the brain cells!