An article in a series documenting measurements on an IC-7410.
This focuses on receiver Noise Figure.
Month: March 2014
IC-7410 tests – 02 – digital audio output
An article in a series documenting measurements on an IC-7410.
This focuses on digital audio output level encoding headroom.
IC-7410 tests – 01 – linearity
An article in a series documenting measurements on an IC-7410.
Using an attenuator for NoiseLo/NoiseHi in NFM
A common method of making Noise Figure measurements of a receiver is to use a noise generator of known noise power. The output power of the DUT is measured with the generator off (NoiseLo) and on (NoiseHi), a Y factor calculated, and from that Noise Figure is calculated.
Continue reading Using an attenuator for NoiseLo/NoiseHi in NFM
Slot car controller connectors – AU
I ‘needed’ to explore modern controller technology for slot cars.
It is a very long time since I played with slot cars, more the technology (rewinding motors) than the racing, but as a 13 year old, I did a share of that too.
G5RV woes – W6OGC
G5RV antenna figure prominently in many online forums.
At (eHam 2014) W6OGC describes his G5RV antenna system.
102′ center feed point at 32′ drooping off on each side to 12-15′, 31′ of 450 ohm twin lead, fed with ~130′ or so of RG-8X through a 1:1 current balun at the base of the mast, aligned roughly N-S. On no band is it resonant nor has SWRs less than 3 or so to 1…
Though a G5RV is commonly thought as a ‘no tune’ antenna, just make it to the dimensions in the book, the above shows a possible outcome.
Simple Morse beacon keyer updated 2014/03/01
Above is a clip from W4HBK’s 40m grabber today, the signal is VK2OMD running 5W QRSS6 over a 14,700km path. We can infer (Duffy 2012b) from the 15dB S/N in that capture in 0.25Hz noise bandwidth, that in an 800Hz CW filter for say -5dB S/N (threshold of copy) we need 15dB more signal, or 160W for reliable copy. (Less power may be adequate for very short QSOs at the peak of fade cycles.)
Continue reading Simple Morse beacon keyer updated 2014/03/01