This evening I've been trying to track down various noise sources that have been making reception on MF and the lower HF bands all but impossible in recent weeks. I'm pleased to report a couple of successes.
My first "trap" was the 12V Netgear AD6612 AC-DC adaptor that feeds my Virgin Media internet superhub. This little terror was producing an S6-8 noise floor on many of the lower ham bands. I tried ferrite chokes in the leads but to no avail. Fortunately I had an old Linksys 12V supply with the same sort of rating and 12V plug. Swapping the PSUs over and, guess what, the lower HF bands were much quieter once again.
At 470-500kHz though I still had an S8 noise floor, so there was another candidate noise generator around. Switching everything off in the house the noise floor dropped, so it was in the house. In the end I tracked this down to a Salus mains powered controller that receives wireless signals from the central heating roomstat. Turning this off and, guess what, 470-500kHz goes much quieter too! This unit is quite close to my antenna wire and must have a noisy SMPSU inside. Luckily we tend not to have the central heating on in the evening so all I have to do is turn off the Salus wall unit controlling the central heating boiler and I can, I think, go back to better reception on the MF bands in the evenings.
In 30 minutes I've reduced the noise floor in my home considerably from LF to at least 10MHz. This goes to prove that with a little bit of detective work we can do a lot to overcome many of the noise issues plaguing us these days. Both the Virgin Media superhub and the Salus unit are new (less than 6 months old) so this also explains why the noise issue was not such a problem last autumn and winter.
If you have a noise problem then I recommend you do some detective work and very good luck.
15 Nov 2012
Coils for projects
Many of the old TOKO range of coils are hard to find these days but an alternative source for many of these is now available from Spectrum Communications in the UK. See http://www.spectrumcomms.co.uk/Components.htm for more details. If you are a member of the GQRP Club, many of these are available through its excellent club sales. An example, the 45uH coil specified in my 472kHz transverter is available from the above suppliers.
Spectrum also sell a useful range of crystals as well as some of the harder to find, once common, MOSFETs.
Spectrum also sell a useful range of crystals as well as some of the harder to find, once common, MOSFETs.
14 Nov 2012
SHAMateur radio
Today the December 2012 RadCom dropped on my doormat. P16-17 contains a review of the Acom 1500 1500W linear amplifier for HF and 6m. Now, I am sure this is a very well engineered piece of kit, but at £2750 including VAT surely this is not for real amateur radio?
Anyone buying this has probably spent a few thousand on a big Yaecom black box multi-mode HF rig, another £400-500 on a beefy rotator, another few hundred on a mast and another few hundred on an HF beam to put on the top. Total bill for all this approaching £5000 if not more! They may be able to work some DX slightly more easily than me with a 5W or less radio and a small wire antenna strung up in the tree, but I bet they have less fun.
I have no objection per se to people spending the money they earn as they choose, but what I object to is this sort of expensive kit being projected as a necessity to enjoy our hobby.
To my mind this is SHAMateur radio, not amateur radio. It is a cheque book hobby far far removed from the hobby I wish to be associated with.
I wish our national magazine would publish more articles about REAL amateur radio, the sort that young kids and people on tight budgets can afford and enjoy. If the RSGB is short of material then it should ask the GQRP club for some ideas and circuits! Amateur radio is a very varied hobby and I do not want to be a killjoy, but anyone picking up RadCom would believe you need a very deep wallet to be able to enter the hobby. This simply is NOT the case. OK there is some good beginners content (for example the excellent series by Eamon Skilton) but not nearly enough.
One thing that IS good in this month's RadCom is the review of QRP Basics by G3RJV on p39. The first edition of this was a very good book that showed what amateur radio is really all about. I expect the new second edition will be even better. I commend it to you!
Are you a radio amateur or a radio shamateur?
Anyone buying this has probably spent a few thousand on a big Yaecom black box multi-mode HF rig, another £400-500 on a beefy rotator, another few hundred on a mast and another few hundred on an HF beam to put on the top. Total bill for all this approaching £5000 if not more! They may be able to work some DX slightly more easily than me with a 5W or less radio and a small wire antenna strung up in the tree, but I bet they have less fun.
I have no objection per se to people spending the money they earn as they choose, but what I object to is this sort of expensive kit being projected as a necessity to enjoy our hobby.
To my mind this is SHAMateur radio, not amateur radio. It is a cheque book hobby far far removed from the hobby I wish to be associated with.
I wish our national magazine would publish more articles about REAL amateur radio, the sort that young kids and people on tight budgets can afford and enjoy. If the RSGB is short of material then it should ask the GQRP club for some ideas and circuits! Amateur radio is a very varied hobby and I do not want to be a killjoy, but anyone picking up RadCom would believe you need a very deep wallet to be able to enter the hobby. This simply is NOT the case. OK there is some good beginners content (for example the excellent series by Eamon Skilton) but not nearly enough.
One thing that IS good in this month's RadCom is the review of QRP Basics by G3RJV on p39. The first edition of this was a very good book that showed what amateur radio is really all about. I expect the new second edition will be even better. I commend it to you!Are you a radio amateur or a radio shamateur?
13 Nov 2012
Dell Inspiron 1545 power socket repair
My wife's laptop is a 3 year old Dell Inspiron 1545. Although otherwise a nice PC, this has a stupid design weakness: the power connector socket. This is on the side of the PC (back left) and it is almost impossible to use the machine and not snag the cord and socket regularly.
Consequently, over time, the SMA connector inside the PC has gone intermittent. The PC is covered by a 4 year hardware warranty and I hope that Dell will just fix this and not argue "wear and tear". I have had other PCs where the power socket is strain relieved within the housing and not had a problem.
One has just to look at the number of videos telling you how to fix this very issue to see it is a very common one. I like this video showing the repair in 3 minutes, although in reality it would take about 1 hour. In the limit I could do it myself, but let's see if Dell are in a good mood and are helpful first!
I do get really annoyed when a consumer product goes to market with such an elementary design weakness: this is the sort of rubbish that should have been spotted early in the design phase by design reviews looking for possible failure mechanisms. Dell should know better.
One has just to look at the number of videos telling you how to fix this very issue to see it is a very common one. I like this video showing the repair in 3 minutes, although in reality it would take about 1 hour. In the limit I could do it myself, but let's see if Dell are in a good mood and are helpful first!
I do get really annoyed when a consumer product goes to market with such an elementary design weakness: this is the sort of rubbish that should have been spotted early in the design phase by design reviews looking for possible failure mechanisms. Dell should know better.
Tenbox progress (10m QRP AM transceiver)
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| Tenbox breadboard RX -115dBm MDS |
The intended use of the Tenbox is local "across town" nattering when the band is quiet. The selectivity would NOT be suitable for DX use, although I'm sure it would pick up stateside 10m AM stations OK. I am always amazed by how well a simple super-regen RX works: they just fly for me and are always incredibly sensitive and non-critical. People who have not played with these do not know what they are missing. I highly recommend the RX in the Fredbox
Next stage is to breadboard up a simple AM modulator and TX strip. Again, I shall copy the basic Sixbox design but this time add a linear amp (a few 2N3904s in parallel as in the WISPY beacon) to get the carrier power to a useful level.
In summary, an interesting and productive hour or so after tea.
Weak signalling comparisons
Over the last few days I've been trying out my Lesser Chirpy 10m 80mW CW rig putting out CQ calls on 28.060 periodically and listening for replies and RBN reports. In three days I've only managed 2 RBN reports at around 3000km with it. So, this morning I fired up the hombrew WISPY WSPR beacon on 10m to see what happened. This runs about 6dB more power at around 200-250mW pep effective on the WSPR band. On the first transmission I got 3 reports immediately at 2200-3500km. With WSPR it is SO much easier.
Conclusions? Well if you just want to know what propagation is like then a small homebrew WSPR beacon is all you need. If you want the fun of the chase and the chance of a few QRP CW contacts with a human then the Lesser Chirpy rig is up for the challenge.
Life is too short to sit there endlessly calling CQ with the key though. So, I think Lesser Chirpy will be brought out when conditions and activity are good. Otherwise WISPY will whisper away quietly in the shack whilst I get on with designing interesting new little projects, HI.
UPDATE: After a few hours of 10m WSPR at 200mW I had a page of reports out to around 6500km. Back on 10m CW I tried a brief call with the FT817 at 5W and got a couple of USA spots on the RBN. A further 30 minutes of calling CQ with the 80mW transceiver and no reports or QSOs. Think I'll have to come back to 10m QRPp another day!
Conclusions? Well if you just want to know what propagation is like then a small homebrew WSPR beacon is all you need. If you want the fun of the chase and the chance of a few QRP CW contacts with a human then the Lesser Chirpy rig is up for the challenge.
Life is too short to sit there endlessly calling CQ with the key though. So, I think Lesser Chirpy will be brought out when conditions and activity are good. Otherwise WISPY will whisper away quietly in the shack whilst I get on with designing interesting new little projects, HI.
UPDATE: After a few hours of 10m WSPR at 200mW I had a page of reports out to around 6500km. Back on 10m CW I tried a brief call with the FT817 at 5W and got a couple of USA spots on the RBN. A further 30 minutes of calling CQ with the 80mW transceiver and no reports or QSOs. Think I'll have to come back to 10m QRPp another day!
AM broadcasts on Medium Wave
The BBC recently switched off some of its MW local radio AM outlets for some weeks to see if anyone was listening. Results suggest few people listen to their radios in the UK on Medium Wave any more. I know I am one of them, preferring to use Band 2 FM. We also have a DAB radio but it is pretty useless in the kitchen where FM is perfect. I think it is a signal strength issue.
So, will the BBC switch off all its MW output? Will anyone care? It may soon be that AM will be a dying mode unless we radio amateurs use it and show its strengths.
See www.theregister.co.uk/2012/11/08/dab_am_bbc/.
So, will the BBC switch off all its MW output? Will anyone care? It may soon be that AM will be a dying mode unless we radio amateurs use it and show its strengths.
See www.theregister.co.uk/2012/11/08/dab_am_bbc/.
12 Nov 2012
Microsoft Essentials virus protection
On our regular local Monday night 2m net on 144.575MHz (in the all mode section) - anyone is welcome to join us in the East Cambridgeshire area - the subject of PC virus protection came up tonight. Some months back someone told me about Microsoft Essentials which is a free virus protection package. I still use McAfee here and have another year to run on it, but wonder what people think about the free Microsoft package? Does it work well?
More DX on Lesser Chirpy
Another report via the Reverse Beacon Network from 5B4AGN in Cyprus this morning, but no QSOs and no further RBN spots. A brief outing this afternoon in which I'd hoped to get across the Atlantic proved to be a disappointment. There is always tomorrow....
The Argonaut VI is coming soon....
Just received this reply from Stan WD0BGS at Ten-Tec regarding the progress with the Argonaut VI. It sounds like they are now very close to releasing it.
The UK price tends to be close to the US price but in pounds. If importing from the USA directly we have to add Royal Mail handling charges (£8) and VAT at 20%. I gather import duty is not payable though. Against a 10 year old FT817 this looks like a lot of money.
"Hi Roger,Now, I have not done the sums yet, but $995 does not sound like a very competitive price for a radio that misses 2 HF bands out. The Argonaut has to be a seriously good radio when put next to the Elecraft KX3, but then Ten-Tec know this only too well. They must have decided this price is right and it will sell.
The Argonaut VI model 539 is in beta testing as we speak. Our first production has gone into the hands of many users to determine any slight improvements before the second production run begins next month. Our web site will be turned on and ready to place orders when all final numbers have been established and any firmware changes have finalized.The price of the Argo VI will be $995 and available around December/January time frame +/- The Argo VI will not be a kit and it will be a small 1-10 watt output multi-mode QRP transceiver. It will not contain 60 meters or 12 meters due to the design and size restrictions. Watch our web pages in December for release notes and a page about the Argonaut VI.Sincerely,Stan Brock, WD0BGS"
The UK price tends to be close to the US price but in pounds. If importing from the USA directly we have to add Royal Mail handling charges (£8) and VAT at 20%. I gather import duty is not payable though. Against a 10 year old FT817 this looks like a lot of money.
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