RF Cafe

This looks to be a very useful resource for both professional and amateur RF designers with lots of useful links, software and calculators available. See http://www.rfcafe.com/

Iceland to get 500kHz band for 1 year

Hams in Iceland have been given access, by special permits, to the 493-510kHz band until the end of the year with a power limit if 100W.

2010 ARRL International DX Contest

Conditions on 15m were good enough for some solid CW QSOs across the pond this afternoon. Worked stations in New Hampshire, Connecticut and Virginia when running 5W QRP. I did also check up on 10m but didn't hear any stations when I listened between 1600-1720z.

Communications below 9kHz

This has just been posted on the LF reflector by DO1KHS. I wonder how many other people have experimented with communications at radio frequencies below 10kHz? If so, do share your experiences here. See also my website on the subject at http://sites.google.com/site/g3xbmqrp/Home/10khz

Hello,

Some years before, some experimental licences for ham radio below 9 kHz were issued in germany. Meanwhile this frequency range is free as the Bundesnetzagentur has confirmed last year.

Transmitter is an Präcitronic GF62 Level Generator actually at 8,79 kHz. PA is an old homebrew NF-Amplifier with 2x 2N3055 and about 40 Watt at 4 Ohm into a 100V ELA transformer. Antenna is a T-Antenne of 10m with 20m top capacity and poor ground.

Receiver is a portable sferics RX that I built some years before (AATIS). Unfortunately its whip antenne is highly influenced by trees and houses.

The fact that I can hear (!) my beacon in normal CW up to 100m in an city environment with a highly unmatched antenna makes me believe, that in a better environment and with a matched antenne and with help of ARGO one can make tests over longer distances. But even from my QTH in the city the ODX ;-)) surely can be improved.

The mean problem now ist how to match the antenna . . . - or using ground antennas vor TX, RX or both.

vy73 Horst

10m - signs of life

OD5NH has been a decent signal on 10m SSB this morning. Have not managed to work him (yet) but did get a "QRZ the x-ray?" with 5W SSB to the 500kHz vertical. 12m is also open with EA8CQW on CW. You really do sense that the higher HF bands are coming back to life again after a long period of hibernation - great!

Lightbeam communications

Before I became a radio ham, a friend and I had our first phone wireless QSO using a small torch bulb modulated with a couple of germanium transistors. The DX was across the road, about 20m at most. At the far end the receiver was based on an OC71 with its black coating scraped off, which made quite an effective photo transistor. These days there are much better ways. For some examples, see some of the fascinating links at  http://www.carolinaflashers.org/ . One of these days I must revisit optical communications. The picture on the right is from http://www.laud.no/ww2/lispr/index.htm and shows a WW2 lightbeam communications device used by the German Army.

More 500kHz reports

This evening, 2 new stations reported my 1mW ERP 500kHz WSPR signal: PA1GSJ at 274kms and G0API at 232kms. A few days ago I was copied by G1IRG at 74kms. This brings the total number of unique WSPR reports to 79 and 81 total unique reports including CW contacts.

Dell Heaven!

Well, I have to say I was impressed with Dell today. Having suffered a series of blue screen disasters in the last month or so and having tried various things to fix it (roll backs, defrags, de-installs of software, etc) without success, it was time to contact the technical support help desk. The last I did this some years ago it took me several days to get through. Today I was connected to the Indian help-desk in 5 minutes or so and over the phone they checked the HW was OK. The software guy came on line next to instruct me how to load a clean Windows 7 installation. BTW, they rang me back, so Dell paid for the call after the first 30 minutes. An hour later and I have what seems like a brand new, stable Windows 7 installation. They charge for software support (NOT covered by the 4yr at-home warranty) but I was glad to get my wife's machine working again so quickly.  It is nice to be able to say something very good about Dell and the service from their lads in Bangalore.

Dell Hell

I have just wasted a day of my life ....

My wife's 8 month old Dell Inspiron laptop running Win7 keeps coming up with the blue screen of death (again) and no matter what I try (system restores to various dates) nothing fixes it. I have a 4 year HW warranty  but this does not cover software issues and I suspect this is software. I'm unable to do a full restore to the factory image as no backup is included on the hard drive.  I'm no PC expert and get totally frustrated by this sort of issue and the fact that Dell help is so poor: you just go around in circles.

My little Asus EEE, that I am using now to type this, has NEVER failed, ever.

Fivehead 20m QRP SSB transceiver kit

A friend of mine, Ted G4NUA, is busy building one of the Walford kits called the Fivehead. He is doing the 20m SSB version which puts out around 1.5W pep when completed. So far he has got the RX part working (see picture of the build so far), which shares a lot of the IF with the TX part. The PCB is not silk screened making construction a bit more tricky than for an Elecraft kit. This is presumably to reduce the kit cost. When finished it should make a credible QRP rig for 20m, although 1.5W on SSB is a bit lower than I'd like. There is an option for a 10W PA add-on if Ted struggles to get contacts.