Eric and the list, The testing you have described is called "Noise Power Testing" and the figure of merit is the NP Ratio or NPR. This type of testing is many decades old and has been used in the com
Here are some keying test results done with real radios and an HP spectrum analyzer. The radios were set up at full output power and were keyed at 40 WPM. The spectrum analyzer was setup with a narro
This is precisely the reason why strong signals sound clicky in the 1000MP and probably other radios. Signals outside the crystal filter passband but inside the roofing filter passband are not subje
Lets look at this another way. Sometimes some analysis can put limits on what we should measure in the lab. This is a guide line to see if we are making the measurement correctly or if the equipment
Whoops, looks like I forgot to send this. It got put in the wrong box. The 141T is quite able to see not only the envelope of the keying sidebands, but the actual sidebands themselves. I've repeated
Agilent has done a marvelous job of animating the spectra of a square wave with various numbers of harmonics included at this site. http://www.educatorscorner.com/experiments/spectral/SpecAn2.shtml Y
Thanks to Tom for working on the keying waveform issue and finding a good point to do a mod in the radio. I set up my 1000MP for keying waveshape measurements to examine the effect of Toms. mod. Here
The readily available band pass filters will not help between modes on one band. When we did W1AW/7 at W7RMs, I built a tuneable 40 meter filter using a two large toroids wound with heavy wire. They
I think Ron has found an oversight in the 1000MP firmware. What the list doesn't know is that Ron has no filters installed in the 455 kHz 500 or 250 slots. I simulated his set up here and it seems th
Many years ago I read an article in the Journal of the Franklin Inst (I think) about some research that was done on the ability to recognize tones below 0 dB S/N ratio. It seems that the brain can se
either. I else's the In the beginning , transmitting and receiving bandwidths were limited by antenna resonances only and were many MHz wide. The TRF and vacuum tube transmitters changed this to hun
I don't remember if W6VSS won or not, but I do remember that station knocking me off a few times into Europe on 40. I was running 2 elements at 95' on a hilltop in NJ with a KW driving it. George w2
percentage LC filters are not much help when operating in a single sub-band due to the small percentage frequency differences. However, it is no problem for crystal filters. They can be inserted in t
The main limitation when trying to receive on the same band with another transmitter operating is the wideband transmitted noise it creates. This noise is a combination of phase noise from the synthe
percentage LC filters are not much help when operating in a single sub-band due to the small percentage frequency differences. However, it is no problem for crystal filters. They can be inserted in t
The main limitation when trying to receive on the same band with another transmitter operating is the wideband transmitted noise it creates. This noise is a combination of phase noise from the synthe
Jim has an excellant idea and it surely will help increase participation. Eliminating the zero pointers would also help. Since the CQ contests use the CQ Zones as multipliers, why not use the Zones t
Here are some measured numbers for those of us that like to see data. Mechanical filters have bandwidths specified at -3 dB and crystal filters are specified at -6 dB. To make the comparison, both ty
Kirk, I don't know anything about the LTA decoder, but I designed the Top Ten units. You must be using the "SD" model if you are sending +12 to the relays. There are also "sink" outputs on pins 1 thr
IC-756 PERFORMANCE TESTS S/N 01020 3/8/97 K6AW and W6OTC were nice enough to lend me an IC-756 to run some lab tests on. K6AW has covered the operator impressions and features very well in a prior no