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!
Wednesday, 8 October 2008
There is a nice program that will allow the updating of messages here:
I like to homebrew things and have a nice tin with slightly different dimensions to the original so have crafted a PCB mask using Express PCB and will etch a little later. Note the TO92 components are not necessarily the correct way around but then I don't use the silk screen anyway!
Please buy the kit from them, I will not share the Express PCB layouts without permission.
My layout purely for interest is here:
Final construction pictures will appear here:
In use with TX will appear here:
permanent antenna fixtures?
Before the end October I will be cabling for a new HF antenna I will
mount the antenna on a garage cable end where I used to have an
antenna and still have the mounting brackets and guy supports but I
moved the shack 2 years ago. The feeder length will be 65m-75m from
there to shack and I was thinking of using RG213 or seeing what other
options I might have, I don't have enough RG213 for a continuous run
so will have to either order a new 100m reel or make a junction
/inspection box in the line somewhere, which might be a bad idea. The
feeder will be in a buried plastic pipe as yet unused I put in when I
moved the shack 2 years ago There is about 200mm separation from a shielded
mains feed (another buried 50mm pipe) to the shack for maybe 80% of
the same run so I might have to add a choke at either end and mains
filtering to prevent break through. The pipe is 30mm OD/ 20mm I/D and for much of the length, it is in an almost straight run with no bends so I am sure there should not
be a problem with compression. At the same time I was thinking about
adding a shielded multicore control cable for a rotator, remote
antenna switch or AMU etc (e.g. G3ROO RAMU). I do not have problems
with water in either the mains or the antenna feed pipe as the pipe is
sealed and I inspect it regularly but I would be interested to hear
comments concerning behaviour of wet or submerged feeders with intact
Does anyone have an experience with any negative effects of 'pulling'
this cable through a conduit of this length and any hints what to
watch out for?
Tuesday, 7 October 2008
Last xmas during the GQRP xmas contest I operated cross band (3.5MHz/500kHz) manual CW with several that do hold NoV on 500kHz. Operation on 500kHz is a very narrow band and I found my FT817 could be used without any modification what so ever to RX the signals so I connected it to my 6BTV vertical adding a base loading coil 'bucket load' (Literally a bucket and c200m of multistranded wire wrapped around the bucket). Adding the base coil made the signals jump maybe 1-2 S points. I parked the RX on 502kHz and listened a lot.... after a time I heard some of those I saw post on the reflector so I thought here goes nothing... and emailed one or two and asked if interested in x band operating.
Operation this way the first time you do it is odd as you RX on 500kHz but tx on 80m frequencies. Still once you get the hang of it, it is pretty easy. Having a rig that operates split helps a lot but you can do it manually with two rigs.
Anyway suffice to say I manged a dozen or so contacts even with my completely awful cw and even posted on GQRP list after working Ian G3ROO this way. The LF activity seems to have increased of late as the nights draw in again.
Note that the humble softrock RX can be employed on 500kHz and I have a dedicated RX built just this way.
I also built a clone of M0MBU TX starting from the design in RSGB LF Today using MOSFETS, This is a picture of the final board, so don't get into problems I have not added the MOSFETS to it so cannot be used for TX. You can see the holes for the TO220 heat sink screws in the middle of the board. The whole board will be bolted to a heatsink. I modified the design to use a DDS based VFO not a 4MHz resonator (didn't have one at the time) and a divider network. The VFO feed comes in to the two holes on the bottom right, with the 4427 IC (8 pin DIL) just above. The DDS VFO uses a free AD9851 but with DIL dip switches not a PIC and rotary controller (originally an idea from Hans Summers http://www.hanssummers.com/radio/dds/index.htm). There are many different designs out there for LF capable DDS. I created the TX PCB layout with Express PCB and blue press n peel film and then etched it. The track side shows the wide spacing of the different parts. More as an exercise if could it be done that should it be done I took this and a few other project boards to FDIM show and tell. Most of the components were salvaged from an old APC UPS which was a wonderful source for the high value capacitors needed. I even include an LPF on the board (left hand side the paired up capacitors) as I wanted to use this /P from a beach with a kite antenna.... maybe one day.
For the shack a PCB box containing a 7 pole LPF for 500kHz was also constructed complete with SO239 connectors the design came from http://www.g0mrf.freeserve.co.uk/lpf.htm I think, not checked log, that G0MRF was one of those xband QSO.
To obtain an NoV for 500kHz it is important that you show you can meansure the field strength of the antenna (this site is for LF generally http://www.strobbe.eu/on7yd/136ant/#ERP) so I also started to build a field strength meter following a design by Dick, PA0SE
http://www.wireless.org.uk/pa0se.htm using a cheap digital meter. I bought a box of 10 of them for £2 and I have employed a few about the shack, one as an RF probe another pair monitor the V and I of a HB power supply. I have a wide band FSM using an AD8307 as well so might see if I can add a band pass at the front as well.
Lastly you have to demonstrate that you can measure frequency and I have a PIC based frequency meter that I know will work down to 100kHz ready for use. I calibrated it against a 1Mhz crystal oscillator but I probably have to do better than this.
All of this was a while back now and I was not successful with my NoV application earlier this year for some reason, I didn't get a reply even, but then the 3B8 trip and other activities took over. I will reapply shortly and now the ERP level is 1W which is 10 times what it was at 100mW last year. I might try a qQRP station on 137KHz for fun, SPRAT 123 featured a 137kHz qQRP circuit in a build contest by John G8SEQ
I might even add a small PA to c5W as I note I have some IRF630 salvaged from that same APCUPS mentioned above. For a 137kHz antenna a fishing pole supported wire and base load will be employed. or I might try Finbar GI4DPE (another x band qso) design for a spiral (1/4 wave?) at 8m AGL.
Just today I noted that this was a suggested possible tuner on the LF group lists:
And as I have an almost identical setup I used for a tuner initially I will be using this for my 160m 1/4 wave antenna. The coil on mine is wound over a paxolin(?) former with added tap points, the capacitor on mine is almost identical with 4 x 250pF sections. When in place will add details of my 500kHz station.
Back 22nd January 2008 posted to GQRP:
Re: [GQRP] 500kHz QRP crossband QSOs
Hi Roger (G3XBM),Whilst waiting for my own NoV to arrive I am listening out on 500kHz and like you managing a few x band qso on 80m.Inspired by your comments on GQRP last year and the RSGB conference talks on LF my initial RX were FT897 or FT817 with no modifications. (Advise at the conference was to consider 80m if cross band QSO required).I have an SDR RX on 500kHz based on a softrock I modified with a reused a 4MHzxtal from a PIC project and the divide by 8 option on the board (For those that may ask Tony Parks, KB9YIG will sell a softrock lite V6.2 for just $11 sent to EU and the modifictions can be done for pennies. The 500khz band is just 3khz wide so the whole band activity can be seen on the SDR display, infact I see 480- about 527 kHz! I used axial inductors (a bit fatter than 1/2 W resistors) fora new front input filter. The L are 10uH and 100uH. I used Rocky RX software.If you have a 80m CW setup and can RX on 500kHz as Roger says have a listen in the evenings as some of the operators, there are only about 40 in UK that have an NoV (several are GQRP members) often call for a x band qso on 80m (stating the qsx frequency ) I know many were interested to hear my signal reports as a'new kid on the block' so to speak 500kHz wise.I managed a qso with GI4DPE (Finbar) him on 501.33khz and me on 3533khz. (Finbar has managed a transatlantic qso on 500kHz), amazing when you consider his ERP was 100mW. Similarly with G3ZWH and G3ROO the same night. So far heard/worked themand G3KEV, G3GMH, G3XIZ and GOMRF, cw is the primary mode although hearing some RTTY as well as seeing QRSS in waterfall. I have been surprised at how quiet the band is noise wise compared to 160m or 80m (or it is around me).The signals are easy to copy and maybe just me but the cw is nice and slow.73 Dom M1KTA
Do I need or want a better antenna at the home QTH? Every time seem to operate from home for contest etc it involves putting up a dipole as the vertical (Hustler 6BTV) works FB but just doesn't seem as useful for inter G working on 80m and seems limited to working EU stations only. As soon as a dipole or G5RV goes up the US opens up and there is more DX heard.
The recent windy WX in UK had seen a tree limb came down at the bottom of the garden and it bent literally the vertical over at 60 degrees about 5ft AGL and also took out the dipole support. A new length of Ali tube was obtained and antenna is back up again but thought time to consider the options.
Current thoughts are:
(http://www.g3tpw.co.uk/ and http://homepage.ntlworld.com/andymuza/G7VOT/Cobweb/Cobweb.html)
Nice small footprint and will fit on gable end of garage or side of house easily!
Downside is long feeder.
Gain but bigger footprint. c5m radius
Will fit on side of house but not easily!
Downside is also long feeder.
Simple Dipole for 80m or a fan dipole.
However run into the "wires down the garden XYL and neighbour problems".
Copper Pipe, got some 22mm pipe and 90 degree couplers and end stops or 1/2" heliax (LDF-450) Mag loop.
I have a small vaccum capacitor bought at Friedrichsafen 2007 and a gear box of Mecano Gears and inners from a small hand drill. See this site for one option http://www.qsl.net/hb9mtn/hb9mtn_magnet_80.html
Maybe could build this and put in attic?
Do nothing and stick with vertical and temporary dipoles (maybe end result depending on planning) and add a sloping wire from house to the shack with a tall support at the shack end, would result in about a 50m run which is enough for a 160m 1/4 wave. like this:
The ground system could/would need to be be improved as well so I picked up a few extra ground spikes that were on sale at B&Q.
So bought a couple dozen 5m telescoping fishing poles and will start a 'shoot off' as I will construct the cobweb and hexbeams for all bands 10m through 20m. And a mag loop for 40m and 80m. For 160m I will look at the sloper and any other antenna designs I have seen.
I might end up having to stick with the vertical and a dipole but this might be fun.
As I progress will post the results and which tuners worked best if needed.
My rear garden is larger than most at > 50m long but narrow 15m, It runs N-S with shack at South, house at North. I have 2 large 60ft+ poplar trees next door to the East. No cannot use them I asked but it is tempting to fire a line over them but when windy the tops whip about a lot so any antenna would be shredded or drag the shack with it!
All activity will be QRP only.
Back in May 2008 I spent a week with Ken Evans and Ted Bruce (and a few other amateurs) at FDIM/Dayton 2008 and they mentioned the NoGaWatt meter so I thought I'd have to try it.
This is a fine example from N5FC and shows how small and neat these really are:
The project docs are here:
At the 2007 GQRP rally Henning Mikklesen OZ4XF gave me a pair of dual meters which are high quality dual channel VU meters surplus from some B&O project that never happened. The scale is 250uA FSD and a little more that the NoGaWatt project so I will adjust things a little.
I used a couple of Ge diodes bought from Harrisons (Local repeater group rally at Bottisham, wx was cold and wet that day and did the round trip 20+ miles by bicycle with xyl!) and two 47 ohm (matched from a big batch) 10W resistors that measured 49.2(ish) ohms. I also have a load of 51 ohm resistors and I have another version using a load in series/parallel combinations to obtain 50 ohm. I switched the trim pots for minature rotary pots after proving the construction worked as I wanted to be able to adjust the scales.
In HB style I have used Double sided PCB to fabricate a sloping front box, I was going to try and use the humble backed bean tin (http://www.hanssummers.com/electronics/equipment/bcdfreq/beans.jpg) but didn't have enough as the green bins were just collected and xyl threw out my stash of tins. The meter being almost 4 1/2" across meant this was never going to be an Altoid project.
I initially wound the FT50-43 with 24SWG wire but will replace the single turn with a length of RG174.
I have a load of 50 ohm 100W chip resistors so adding on as a dummy load. Put 4 out just to see if would fit as also available in smaller 10W variety also TO220 so would put them on back with a switch of the VSWR meter and have a dummy load too.
Pics of my construction follow:
I am also playing (right word?) with PIC variations and I have some 2x40 (yes 40) character displays from Diz W8DIZ and I have an initial PIC VSWR working that shows the fwd/rev and VSWR as figures on the left and moving bar graphs. When complete and stable I'll add the details. I am using a 16F874A (same as 16F877A but 1/2 memory).