Topband: "Thinking out loud" - Something else to Think About (REV)

Crystal filters are nonlinear passive devices by nature of the characteristics of the crystal(s).  The motional characteristic of a quartz crystal is a function of the level of the signal applied to it, known as drive level dependence or (DLD) in engineering terms.  Crystal filters can

Topband: "Thinking out loud" - Something else to Think About

Crystal filters are nonlinear passive devices by natureof the characteristics of the crystal(s).  The motional characteristic ofa quartz crystal is a function of the level of the signal applied to it, knownas drive level dependence or (DLD) in engineering terms.  Crystal filters can

Re: Topband: "Thinking out loud"

ssage- >> From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Matt >> Murphy >> Sent: Thursday, December 22, 2016 11:19 PM >> To: k...@myfairpoint.net >> Cc: Topband <topband@contesting.com> >> Subject: Re: Topband: "Thinking out loud&qu

Re: Topband: "Thinking out loud"

ontesting.com> Subject: Re: Topband: "Thinking out loud" This appears to be the 4O3A unit. I hadn't realized these existed, so I'm glad you posted the question: http://www.4o3a.com/index.php/products/ham-radio-gear/crystal-front-end-unit / On Thu, Dec 22, 2016 at 3:47 PM, K1FZ-Bruce &l

Re: Topband: "Thinking out loud"

, 2016 11:19 PM To: k...@myfairpoint.net Cc: Topband <topband@contesting.com> Subject: Re: Topband: "Thinking out loud" This appears to be the 4O3A unit. I hadn't realized these existed, so I'm glad you posted the question: http://www.4o3a.com/index.php/products/ham-radio-gear/c

Re: Topband: "Thinking out loud"

band Sent: Thursday, December 22, 2016 3:41 PM Subject: Topband: "Thinking out loud"   We know that limiting the noise pick up from more directions of an antenna we can usually hear better. We also know  if we limit the noise from a receiver IF we can hear less noise, and better yet, if we

Re: Topband: "Thinking out loud"

The SNR is set at the antenna. There is a persistent desire to move the selectivity closer to the antenna, however With modern "bullet-proof" front ends, filtering can be delayed and done at i-f. In fact, with H-mode mixer front ends, the IMD in the following filter can be more of a

Re: Topband: "Thinking out loud"

73, Stew K3ND > > From: K1FZ-Bruce <k...@myfairpoint.net> > To: Topband <topband@contesting.com> > Sent: Thursday, December 22, 2016 3:41 PM > Subject: Topband: "Thinking out loud" > > > > We know that limiting the noise pick up from more dir

Re: Topband: "Thinking out loud"

mber that they worked very well. I never saw one for 160. 73, Stew K3ND From: K1FZ-Bruce <k...@myfairpoint.net> To: Topband <topband@contesting.com> Sent: Thursday, December 22, 2016 3:41 PM Subject: Topband: "Thinking out loud"   We know that limiting the noise pi

Re: Topband: "Thinking out loud"

-Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of K1FZ-Bruce Sent: Thursday, December 22, 2016 3:42 PM To: Topband <topband@contesting.com> Subject: Topband: "Thinking out loud" We know that limiting the noise pick up from more directions

Re: Topband: "Thinking out loud"

Hi, I wonder if you could cover the whole band or just the part that interest *you*. I have a radio now that uses an xtal filter with about a 7 kHz bandwidth on the 20 meter band. Probably those filters can be made wider with perhaps less filtering action - tradeoffs ya know. The idea isn't

Topband: "Thinking out loud"

Thanks Mirko and Matt,   This is not on the market yet, but should do a lot for noise on 160 meters.     Bet a tube transmitter had  naysayers. Need  a spark to transmit. hi.   73 Bruce-k1fz   On Thu, 22 Dec 2016 16:18:56 -0600, Matt Murphy wrote: This appears to be the 4O3A unit. I

Re: Topband: "Thinking out loud"

This appears to be the 4O3A unit. I hadn't realized these existed, so I'm glad you posted the question: http://www.4o3a.com/index.php/products/ham-radio-gear/crystal-front-end-unit/ On Thu, Dec 22, 2016 at 3:47 PM, K1FZ-Bruce wrote: > > Thanks Mirko, > > > Very Good

Topband: "Thinking out loud"

Thanks Mirko,   Very Good information.   What is needed is to reduce noise more (lower) than signals. 73 Bruce-k1fz   On Thu, 22 Dec 2016 22:36:30 +0100, S57AD wrote: As far as I recall, Inrad sells front-end xtal filters. Some 25 years ago when I lived in Belgrade, at YU1EXY we had

Re: Topband: "Thinking out loud"

Thanks Mirko,   Very Good information.   What is needed is to reduce noise lower than signals. 73 Bruce-k1fz   On Thu, 22 Dec 2016 22:36:30 +0100, S57AD wrote: As far as I recall, Inrad sells front-end xtal filters. Some 25 years ago when I lived in Belgrade, at YU1EXY we had two

Re: Topband: "Thinking out loud"

As far as I recall, Inrad sells front-end xtal filters. Some 25 years ago when I lived in Belgrade, at YU1EXY we had two six-pole filters for SSB part of 40M band but I can't recall and difference with or without those filters. Beside those two xtal filters we used 8 pole Cohn LC filter with

Re: Topband: "Thinking out loud"

  160 meters is above the broadcast band. 3rd order should be above 160, not lower. lattice filters, many near 9 MHZ. for single sideband transceivers,  are used successfully. Could take out more noise, than adding.   All the arguments against this could also be used against roofing filters.

Re: Topband: "Thinking out loud"

Tim,   My single crystal was in the 1950's.   A crystal lattice could take in much of the 160 meter band and be pratical.   Thanks for your input.   73 Bruce On Thu, 22 Dec 2016 15:49:12 -0500, Tim Shoppa wrote: Bruce -  It has long been rumored that the big EU multi-multis have a

Re: Topband: "Thinking out loud"

Crystal filters are known to have a 3rd order intercept point. Depending on how many AM BCB stations impinge on your filter, you could get intermods. Switching in an attenuator ahead of the filter should help, if you can stand the increase in noise figure. Rick N6RK On 12/22/2016 12:41 PM,

Topband: "Thinking out loud"

  We know that limiting the noise pick up from more directions of an antenna we can usually hear better. We also know  if we limit the noise from a receiver IF we can hear less noise, and better yet, if we have a roofing filter earlier in the receiver we can eliminate even more noise  in