I beg to differ :-) 250 Hz is too narrow for RTTY with 170 Hz Shift at 45Bd. Practice in commercial RF systems shows that the required baseband signal is 1.6 times the keying speed (45.45 Bd). This
Well I beg to differ )! I have used 250 Hz filters in my final IF for RTTY operation since 1985 or so in contests. I have used them with Icom 751, Icom 761, Icom 765, Kenwood 850, Yaesu FT-1000, Icom
[more deleted] I didn't say that 250Hz filters wont work at all :-) It's just that theory suggests that 250Hz could be too narrow. I know that real world filters never have 250 as exact cutoff edges
Hi, Ekki, By noisy signal, do you mean a badly modulated signal? If it is band noise or QRM, then using a wider filter should make the signal-to-noise ratio worse, not better? Also, does flutter also
Jay, Ekki, and all, I suspect you are both correct but I would also like to consult with the signal processing experts on the math. Ekki, can you steer me to some math sources on your BW calculations
I don't profess to know it all either, but I always thought that a 250 HZ filter would be more than adequate because the rtty signals were only 170 Hz shift :-) :-) :-) John - vk4cej math narrowest I
Sorry to hear that the 250 Hz filter is too narrow. I guess all those Q's I made with my FT-990 and 250 Hz filter are NG !! Seriously, I use the 250 Hz filter quite often, when I also add in the DSP-
Better yet, two filters separated by 170 HZ (a la DSP) !! 73, Dick, W1KSZ I don't profess to know it all either, but I always thought that a 250 HZ filter would be more than adequate because the rtty
It is my experience that both 250Hz and 500Hz filters both have their strengths. I generally run with 500 Hz filters unless the bands get too crowded. I like to hear what is close to me. Additionally
It is my experience that both 250Hz and 500Hz filters both have their strengths. I generally run with 500 Hz filters unless the bands get too crowded. I like to hear what is close to me. Additionally
Hey all. Filters 250 HZ filter is the best for rtty. That is to say if the filter has the it's bandwith at -3db at the 250 hz. 500hz filter is very good with it's bandwith at -12 db. so fellows we ca
Hi George, My back-of-envelope says about 260 Hz bandwidth. As a sanity check, I opened up Frerking ("Digital Signal Processing in Communication Systems"). He characterises the bandwidth in terms of
The old ST-6's and DT-600's would copy just one tone. I don't know about the new stuff tho. What is the width in MMTTY when the BP filter is on? I looked but couldn't find the setting. I know it sure
This is a multi-part message in MIME format. --=_NextPart_000_009C_01C13054.97478F40 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit 250 Hz filter might be expected to
Hello RTTY'ers, -- <jay@ieway.com> Radio) with the to some math correlation I "practical" Realy, Ekki remind us for good practical equation wellknown from early 1930's wich based on socalled "channel
_________________________________________________________ I think George may have the "best" answer of all. I suspect he is right that 250 Hz is a bit too narrow and I am sure 500 Hz is definitely to