That's a good name.
I like it.
73 Jerry KM3K
Sent from my NOOK
Frank Precissi wrote:
On Mon, May 12, 2014 at 8:47 PM, Bill Turner wrote:
> I like that! Much more accurate. A roof keeps everything out while a
> window lets only certain things such as the desired signal in.
>
> Much more self
On Mon, May 12, 2014 at 8:47 PM, Bill Turner wrote:
> I like that! Much more accurate. A roof keeps everything out while a
> window lets only certain things such as the desired signal in.
>
> Much more self-explanatory.
>
Should rename them to skylight filters.. :) Holes in the roof to let stu
ORIGINAL MESSAGE: (may be snipped)
On 5/12/2014 4:15 PM, David Gilbert wrote:
So would you prefer to call it a "window?"
REPLY:
I like that! Much more accurate. A roof keeps everything out while a
window lets only certain things such as the desired signal in.
Much more self-expla
Actually, a roofing filter does exactly what it says. It protects
against ... i.e., does not allow to pass ... out-of-passband signals
from affecting the ADC or hardware AGC. It's a "roof" against unwanted
energy and a window for desired signals. So would you prefer to call it
a "window?
Think of your roof blocking the rain so the ceiling doesn't have to work so
hard.
It's not used for band-pass, it's to let the DSP work less.
Sent from my iPhone
...nr4c. bill
> On May 12, 2014, at 3:01 PM, Bill Turner wrote:
>
> ORIGINAL MESSAGE: (may be snipped)
>
>> On 5/12/20
Wasn't the chicken little sky is falling thing popular back when "roofing
filter" originated? We may be luckier than we know that it became known as a
roofing filter.
73 de Dennis KD7CAC
Scottsdale, AZ
On May 12, 2014, at 3:04 PM, David Gilbert wrote:
>
> Roof->upper ... higher ... o
ORIGINAL MESSAGE: (may be snipped)
On 5/12/2014 12:38 PM, Josh Fiden wrote:
"The term “roofing” stems from the fact that it protects the rest of
the radio following it from out of the passband signals."
REPLY:
A roof keeps what falls on it (rain, snow) out. It doesn't pass it
throug
Roof->upper ... higher ... overhead ... protective ...
There are several fairly intuitive possibilities, none of which are
worth getting confused about in the first place.
Dave AB7E
On 5/12/2014 12:01 PM, Bill Turner wrote:
I still don't get it. What does the word "roof" have
There you go!
Well said.
73 Jerry KM3K KX3#6088
Sent from my NOOK
Don Wilhelm wrote:
Bill,
Like a roof protects the contents of a building, a roofing filter
protects the electronics that follow it from overload.
73,
Don W3FPR
On 5/12/2014 3:01 PM, Bill Turner wrote:
>
>
> I still don't get
Bill,
Like a roof protects the contents of a building, a roofing filter
protects the electronics that follow it from overload.
73,
Don W3FPR
On 5/12/2014 3:01 PM, Bill Turner wrote:
I still don't get it. What does the word "roof" have to do with
bandpass? That's where the confusion comes
Bill,
Originally the superhet receivers converted from the signal frequency to
a lower fixed intermediate frequency in order to obtain sufficient
selectivity. IFs went as low as 85kHz until crystal filters became more
widespread. As designs changed ( changed not improved) it became usual
to
I have imperfect recollections that the source of the term "roofing
filter" came from the idea that the filter put a "roof" over your
receiver to prevent very strong, off-frequency signals from getting in.
You'll need to crank up your imagination here ... similar to the roof
of your house keep
From an older Inrad writeup (and consistent with Wayne's):
"The term “roofing” stems from the fact that it protects the rest of the
radio following it from out of the passband signals."
http://www.qth.com/inrad/roofing-filters.pdf
I like the term "preselector" from my 75S-1, but that doesn't
At least I do, Arie. Maybe those with fewer
"local" signals do not. Dunno.
Phil w7ox
On 5/12/14, 9:23 AM, Arie Kleingeld PA3A wrote:
Well,
You defenitely need those filters in the K3.
When signals are strong and the band is busy,
signals coming through the roofing filter (line
S9+20dB) is
ORIGINAL MESSAGE: (may be snipped)
On 5/12/2014 9:33 AM, Jerome Sodus wrote:
Hello Bill,
The term "roofing-filter" made sense back in the 1980's when I designed
roofing-filters at 70 MHz.
Bandwidths would be in tens of KHz.
The purpose then was to protect downstream circuitry by rejecti
I have two big time dxers/contesters near me - on 160 , one is -8 to -9 dBm
and the other is -10 to -11dBm . Folks , thats in the 50 to 100 mv area at
the poor K3 .(S9+60 to 70 area) Just for fun of it , I can easily see both
on my scope hung on my antenna.
With the 250 hz 8 pole - I could
>
> *From:* Greg [mailto:a...@cablespeed.com]
> *Sent:* Monday, May 12, 2014 12:52 PM
> *To:* Jack Brindle
> *Cc:* Jerome Sodus; elecraft@mailman.qth.net
>
> *Subject:* Re: [Elecraft] [K3] Roofing filters are misunderstood
>
>
>
> http://www.elecraft.com/K3/Ro
Thank-you, Greg.
Excellent.
Jerry KM3K
_
From: Greg [mailto:a...@cablespeed.com]
Sent: Monday, May 12, 2014 12:52 PM
To: Jack Brindle
Cc: Jerome Sodus; elecraft@mailman.qth.net
Subject: Re: [Elecraft] [K3] Roofing filters are misunderstood
http://www.elecraft.com/K3
Jerry,
Yes, the term has become corrupted and misunderstood over the years.
That *is* exactly what the K3 filters do (protect the downstream
circuits from strong out of passband signals), but is done using a much
more narrow bandwidth at the 1st IF.
If the operator never encounters signal le
sage-
> > From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of
> Bill
> > Turner
> > Sent: Monday, May 12, 2014 1:07 AM
> > To: elecraft@mailman.qth.net
> > Subject: Re: [Elecraft] [K3] Roofing filters are misunderstood
> >
> > ORI
has become corrupted over the years.
> 73 Jerry KM3K
>
>
> -Original Message-
> From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Bill
> Turner
> Sent: Monday, May 12, 2014 1:07 AM
> To: elecraft@mailman.qth.net
> Subject: Re: [Elecraft] [K3] R
net
Subject: Re: [Elecraft] [K3] Roofing filters are misunderstood
ORIGINAL MESSAGE: (may be snipped)
On 5/11/2014 7:25 PM, Fred Jensen wrote:
> I too think roofing filters are really not well understood.
REPLY:
A large part of the misunderstanding is due to the name. Whoever chose
Well,
You defenitely need those filters in the K3.
When signals are strong and the band is busy, signals coming through the
roofing filter (line S9+20dB) is said to pump the hardware AGC, even if
you have the DSP filtering set to a small BW. Anyway, you can certainly
hear that.
Try it on CW,
Good point. A true roofing filter would be in the antenna line.
Repeaters have "roofing" filters, typically in the form of an extremely high
Q resonant cavity.
Chas
- Original Message -
From: "David Cole"
To:
Sent: Monday, May 12, 2014 8:43 AM
Subject: Re: [El
On Sun, 2014-05-11 at 22:06 -0700, Bill Turner wrote:
"I have always thought that "roofing" was a marketing ploy to imbue it
with some kind of magical powers."
Bill,
"These aren't the filters you are looking for... Move along..."
Sorry, I just had too inject that at this point in the discussio
ORIGINAL MESSAGE: (may be snipped)
On 5/11/2014 7:25 PM, Fred Jensen wrote:
I too think roofing filters are really not well understood.
REPLY:
A large part of the misunderstanding is due to the name. Whoever chose
the name "roofing" did a great disservice. A better name would simply
I would take issue with your answer to #1. It really depends on your situation.
For most of the folks on this list your answer very well may be correct. In
areas where there is very high station density, it probably is not. Here in
Silicon Valley there are a LOT of very strong near-by signals. T
I can remember very loud stations 10 or 15 KHz away completely
desensing my receiver to the point that the station I was trying to
copy simply disappeared. When I switched to the K3 the difference
was astounding.
That is because the 756Pro is a completely brain dead design ... there
is only a
I too think roofing filters are really not well understood. For the
record, I have the stock SSB [2.7 KHz? I don't actually know] and the
500 Hz CW. In 99% of my operating situations, it doesn't matter which
one I use, I set the received BW with the DSP, and I'm a very happy ham.
I do have s
I completely agree with all of that except for the very last sentence.
Clearly you've never used a 756Pro (first version) in a major CW
contest. I can remember very loud stations 10 or 15 KHz away completely
desensing my receiver to the point that the station I was trying to copy
simply dis
What determines the bandwidth you hear at the loudspeaker? It's not your
roofing filter, despite a continuing notion that it is.
Dave Hachadorian's point in a post a few weeks ago was that you don't need a
1.8 kHz filter to get a 1.8 kHz bandwidth. You're free to set whatever
bandwidth you wan
If you do a lot of AM transmit you will have a cleaner signal with
the 6K filter.
Only marginally and only so far as it applies to synthesizer phase
noise more than +/- 3 KHz from the carrier. Even then, the K3 will be
much cleaner that the typical YaeComWood up-conversion transceiver with
th
I think Paul had gotten the information he was asking about from
others Bill and Don.
I don't see much use for the 6K filter since you can now use the
13K FM filter for AM transmit. If you do a lot of AM transmit
you will have a cleaner signal with the 6K filter. If you only
do AM receive, yo
Paul,
The roofing filters protect the A to D converter input from strong
adjacent signals, so choose your CW filter according to your operating
habits. If you do CW contesting or DXing in pileup situations, you will
want a narrow filter.
If you are using the K3 as an SWL receiver, you would
Paul Barlow-2 wrote
> Is the widest bandwidth available to the receiver the width of the widest
> roofing
> filter?
Correct. If you operate mostly CW, you may be wasting money getting wider
filters than the stock 2.7 kHz...you definitely need a 500 Hz or lower
filter for CW to prevent blocking in
Dear Elecrafters,
I've been using my K2 for a dozen years and I'm thinking I might go for a
K3. I have a question about RX filtering I'd like to get straight. Is the
widest bandwidth available to the receiver the width of the widest roofing
filter? I was wondering about getting the general coverag
Ray,
short answer: Use the SSB bw filter for JT65.
The sw looks at up to 4-KHz bw, if available, and the narrow band
feature of this mode is accomplished at the digital level in the sw
(inside the computer). Narrowing bw below this just limits the
number of signal the sw looks at. JT65 and
>
>From the operating you plan, and having operated many different K-3s,
for
>SSB & CW I would suggest:
>
>1. The standard 2.7 KHz filter for occasional SSB. As others have
>mentioned, the roofing filter is to protect the DSP.
>2. A 400 Hz, 8-pole (or 500 Hz-8 pole) filter for general CW operati
Excellent answer from Don, W3FPR.
I fit the mostly SSB type with sub-Rx, so I use diversity
reception. I chose for the main Rx:
13-KHz (for AM and FM)
2.8-KHz
400-Hz
The sub-Rx has just the 2.8-KHz filter
I chose the 8-pole for ease in set up for diversity Rx and for the
steeper skirts (whi
My 2 cents worth:
Since you are primarily a cw operator, you may now or in the future want
the roofing filter that is the ultimate in protecting the DSP in the
toughest possible conditions such as when you are running big antennas
in a contest on the lower bands. This would mean a very narrow r
Ivan, you wrote:
I am about to purchase a K3 (k). My main interest is certainly CW with
occasional
forays into SSB and even data, and I note the selection of roofing
filters available,
no doubt the 8-pole are somewhat better but what is the general
feeling regarding the
bandwidth(s) to be include
Unlike many other transceivers, ultimate selectivity in the K3 is not
determined by the crystal filter. Ultimate selectivity is determined
by the DSP whilst the roofing filter only impacts narrow band dynamic
range (the level of "close in" signals applied to the second mixer and
analog to digita
Hi Ivan,
250 Hz: CW and some data modes
1.8 KHz: Other data modes (MT63, WL2K) and SSB Narrow
2.8 KHz: Normal SSB
6.0 KHz: SWL (AM and DSB) and 80m AM nets
15.0 KHz: FM on 10m and 6m
The 250 Hz roofing filter works extremely well in crowded band
conditions on CW. It's also just about right for
I know many users are happy with the 700 Hz roofing filter you guys have had
custom-made. However, I am wondering just how helpful it actually is,
compared to other, more standard roofing filter BWs. If a 700 Hz bandwidth
is "ideal for scanning", just how is a roofing filter needed when scanning?
B
> For CW I think the choice is easy - head for the 500Hz filter.
>
> Regards
>
> John G4ZTR
>
> -Original Message-
> From: elecraft-boun...@mailman.qth.net
> [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of g3...@sky.com
> Sent: 06 August 2013 10:37
> To:
Ivan,
You are right to ask, the filters can drive the cost of the K3 spiraling
upward.
I will not answer simply, but rather give you some guidelines for selection.
Your choice of roofing filters will depend a lot on your operating
conditions and preferences.
Remember that the roofing filters
On Tuesday August 6, Ivan (G3IZD) wrote ...
"I am about to purchase a K3 ... what is the general feeling regarding
[filter] bandwidth(s) ..."
--
Hi Ivan,
In addition to the choices available from Elecraft and INRAD, WB2ART
and I also offer a 700 Hz (wide CW) alternative. IMHO 700 Hz fits r
Hi Ivan
I use Inrad
SSB Wide 2.8khz #716
SSB Narrow 1.5Khz #727
CW / Data 400hz #701
I find these filters outstanding in all conditions and I contest in SSB CW
RTTY and PSK31
Jim M0CKE
On 6 August 2013 10:50, James Balls wrote:
> Hi Ivan
>
> I use Inrad
> SSB Wide 2.8khz #716
> SSB Narrow 1.
ssage-
From: elecraft-boun...@mailman.qth.net
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of g3...@sky.com
Sent: 06 August 2013 10:37
To: elecraft@mailman.qth.net
Subject: [Elecraft] K3 Roofing filters
I am about to purchase a K3 (k). My main interest is certainly CW with
occasional f
I am about to purchase a K3 (k). My main interest is certainly CW with
occasional forays into SSB and even data, and I note the selection of roofing
filters available, no doubt the 8-pole are somewhat better but what is the
general feeling regarding the bandwidth(s) to be included.
Ivan G3IZD
_
Greetings, I've just received 2 emails asking for
my last 2 roofing filters.
So Alas...They are all gone.
Thanks for your responses.
VY73'
Steve W8CRH
SEMPER FI
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecr
_Love this reflector_I have two, K3-8 Pole
roofing filters spoken for, so that leaves only two
roofing filters left. Still available are the
KFL3A-2.1k and the KFL3A-6k filters.
$125.00 each shipped to your CONUS qth at my expense.
Wayne, Thanks so much for the preliminary KX3
manual...It
Both filters have been sold. Thanks for all the interest!
matt W6NIA
On Thu, 25 Nov 2010 10:08:22 -0800, you wrote:
>I have two 8-pole 1.0KHz filters for sale. Both were used in K3 #24
>for 1-2 years.
>
>$210 for both to same party, or $110 for a single. I'll pay for UPS
>Ground shipping in C
I have two 8-pole 1.0KHz filters for sale. Both were used in K3 #24
for 1-2 years.
$210 for both to same party, or $110 for a single. I'll pay for UPS
Ground shipping in CONUS.
Email: mzilmer(at)verizon(dot)net
Thanks and Happy Thanksgiving!
matt W6NIA
Dick Dievendorff wrote:
>
> I'll guess that 5 poles is often enough, 8 poles is almost always plenty
> and
> the benefit gained by going from 8 to 16 poles wouldn't often be very
> important.
>
Don't forget that the roofing filter is cascaded with the DSP filter, which
is typically equivalent
enough, 8 poles is almost always plenty and
the benefit gained by going from 8 to 16 poles wouldn't often be very
important.
Dick, K6KR
-Original Message-
From: elecraft-boun...@mailman.qth.net
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Walter V. Gilles
Sent: Tuesday, June
Walter V. Gilles wrote:
>
>
> Is it possible, albeit perhaps not terribly beneficial at first glance, to
> put another 0.40 roofer in the next downstream slot from my current 0.40
> roofer? Would the F/W even accept that setup? If it would allow that
> configuration, would the F/W just selec
Greetings,
One more question on roofing filters, specifically about using identical BW
filters in adjacent slots. Lots of roofing filter blurbs on the reflector, but
I could not find anything specific to this question.
In reading the owners manual, it states that roofing filters are to be pl
I don't recall anyone answering the original question of why "roofing
filters" The term has been used in the UK for many many years. Imagine
you are in a well designed tent and it is capable of keeping you warm and
dry in "normal" weather conditions but during a cloud burst water may start
to en
73,
... Joe, W4TV
> -Original Message-
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On Behalf Of David Lankshear
> Sent: Monday, December 10, 2007 6:24 PM
> To: elecraft@mailman.qth.net
> Subject: [Elecraft] K3 Roofing Filters - Zerobeat
>
>
> 270 x
270 x 2 = 540, so the difference is 356Hz. ;-)
73, Season's Greetings all. DaveL G3TJP
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[EMAIL PROTECTED] wrote:
Use the shape factor to predict the 60 db down response or band width.
example = the 200 Hz filter has 4 to 1 so ... multiply
with a calculator the 6 db response by 4 and that would equal 224 X 4 =
896 Hz and the 8 pole 250 Hz has a 2 X 1 so it is 270 X
Use the shape factor to predict the 60 db down response or band width.
example = the 200 Hz filter has 4 to 1 so ... multiply with
a calculator the 6 db response by 4 and that would equal 224 X 4 = 896 Hz
and the 8 pole 250 Hz has a 2 X 1 so it is 270 X 2 = 740 !
so the 8 pole
Lyle Johnson wrote:
Can I use all 5 available roofing filter slots and also have the
KBPF3 General Coverage Rx filter module installed without losing
any of the slots for the roofing filters?
Yes. The KBPF3 is an array of pre-mixer bandpass filters rather than
a post-mixer roofing filter, so
Larry Maguire wrote:
I plan to order my K3 probably in January '08.
Can I use all 5 available roofing filter slots- in my case the FM, AM, 2.8,
2.1 and 1.0 roofing filters- and also have the KBPF3 General Coverage Rx
filter module installed without losing any of the slots for the roofing
filt
Can I use all 5 available roofing filter slots and also have the
KBPF3 General Coverage Rx filter module installed without losing
any of the slots for the roofing filters?
Yes. The KBPF3 is an array of pre-mixer bandpass filters rather than a
post-mixer roofing filter, so it does not count as
I plan to order my K3 probably in January '08.
Can I use all 5 available roofing filter slots- in my case the FM, AM, 2.8,
2.1 and 1.0 roofing filters- and also have the KBPF3 General Coverage Rx
filter module installed without losing any of the slots for the roofing
filters? I will not be ord
craft@mailman.qth.net
> Subject: Re: [Elecraft] K3 roofing filters: Important
> ordering information
>
> Does that mean that if we substitute the 2.8kHz 8 pole filter for the
> 2.7kHz 5 pole then we'll get a slightly cleaner transmit signal, too?
>
> 73, doug
>
>From
Does that mean that if we substitute the 2.8kHz 8 pole filter for the
2.7kHz 5 pole then we'll get a slightly cleaner transmit signal, too?
73, doug
From: wayne burdick <[EMAIL PROTECTED]>
Date: Tue, 1 May 2007 10:21:38 -0700
If you wish to transmit in wide-band modes (AM, ESSB, FM), yo
If you wish to transmit in wide-band modes (AM, ESSB, FM), you'll need
to have the corresponding wide filter bandwidths installed in the main
receiver. This is because the transmitter and main receiver share the
same circuitry. By "wide", I mean:
AM or ESSBKFL3A-6.0 (6 kHz)
FM
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