Discussions for the qrss transceiver are based on an initial proposal which can be found here - http://g4oep.atspace.com/qrss/qrss.htm#Proposals for a...
Hi Folks, Just testing my posts reach our shiny new group :-) 73,s Des. ... Yahoo! Photos – NEW, now offering a quality print service from just 7p a photo. ...
Hi everyone, I have posted the complete set of articles from Rad-Com's Technical Topicics which describes a method of improving front end selectivity with the...
The Story so Far The question of the design for a simple qrss transceiver originated on the qrss net. http://mail.cnts.be/mailman/listinfo/knightsqrss_cnts.be...
I have had some difficulty getting reproducible results in my filter tests, but feel I am now getting it together. I have just uploaded my latest attempt to...
I am following with interest your tests. The idea to put a cristal filter in front of my DC RX seems good. I have here some 10140 xtals , I just tested a...
I have just completed a breadboard push-push doubler. This type of doubler has a low fundamental breakthrough, and I think it will be ok without additional...
Andy, Do you have a spectrum analyser? It would be very interesting to know the harmonic content of the resultant doubled oscillator output. The divided down...
Des, I am very excited by your results with the signal frequency crystal filter. I think it is a very clear demonstration of how much difference it makes, and...
... Hi Hans - this point had not escaped me ! I was asking about the 20.28MHz signal. We discussed at one point adding a filter to reduce any fundamental...
Hi Andy ... I am more than ready to bow to the superior expertise in this area of yourself or anyone else reading this: but instinctively I feel that it is...
From Andy- ... From Hans- ... We are thinking along the same lines Hans. I will put some thought into this - draw timing diagrams, etc, with different ...
I have posted a rigorous analysis of this question in the files area. The upshot is that only the fundamental breakthrough of the doubler need cause concern. ...
... Nice analysis. I agree with your conclusions (I think!). I agree that harmonics (even and odd) are Ok, but I think that they would be Ok only so long as...
How about this as an estimate of the 10.14MHz content of the doubler - My present qrss TX uses a single-transistor doubler to multiply the 5MHz output of my...
Andy I don't know what level of harmonic attenuation we should be aiming for but >50dB sounds pretty good. The only other reference I have to make a...
Here is another 2-crystal filter - A ladder type this time. This one has 1k Ohm terminations, and has 150pF capacitors in all three positions(shunting input &...
I have a confession to make. Whenever I need to make a small semiconductor PA I always have dreadful problems with instability, and achieving reasonable...
Hello all, seems as if I have managed now to join this Yahoo group :-) Will come back later after reading all the posted messages and files. Chris, DL6JAN...
I have just spotted that the 7474 is positive edge-triggered, so have ammended the spectral content doc accordingly. I have also added a few points to clarify...
In my files I have found a design by Drew Diamond for a 2W 7MHz tx line-up using a 602, 2 stages of driver, and a irf511 (similar to 510). See diamond.jpg....
I think the distinction needs to be drawn between a linear PA and a plain old CW PA. I have not succeeded in making a good linear. It usually either 1) burns...
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