Like Don, I have the 700-Hz filter and would never have heard of it
without Gary's announcements on the list. Considering some the other
dubious stuff that gets posted on the list, I'm happy to hear about
things that are actually of interest to me. It's not magical, but
when I found myself
I've also found the 700 Hz filter useful in VFO B for tuning through pileups,
or just scanning a band.
I think I can take the blame (or credit) for suggesting to Gary that his 700 Hz
filters would be useful for Field Day operations.
My son (AA0BP) and I have operated a number of years with
My filters are 6, 2.8, 2.1.1.0 and 0.4. 1.0 and
0.4 average to 0.7 so I think I have it covered ;-)
73, Phil w7ox
On 3/2/14, 11:05 PM, Bill Frantz wrote:
I am using:
13 KHz: 0 dB
2.7 KHz: 0 dB
2.1 KHz: 0 dB
250 Hz: 6 dB
When the 2.1 and 250 filters switch in, the
signal level in the
On 3/3/2014 7:18 AM, Charles Guenther wrote:
FD operators are not always good at zero beating, and we've found the wider
filters indispensable for hearing the off-frequency callers.
I've never used my K3 for Field Day; but I would sure use the 700 Hz filter.
I simply do not understand the
Jim,
It is obvious that you understand how the K3 works and that the use of a 700 Hz
filter doesn't match your operating style. It is just as obvious to me that
some other operators, also with very good understandings of the K3, find it
useful.
Can't we just chalk it up to personal
On 3/3/2014 9:08 AM, Will Ravenel wrote:
Can't we just chalk it up to personal preference without insulting those who
like to listen with a broader bandwidth than you but still would like the
protection a roofing filter provides against strong signals outside that
bandwidth?
Hi Will,
I'm
It has been suggested that a using a 400Hz filter for RTTY (or other digital
modes) puts the edges of the signal in the part of the passband with the worst
phase distortion. A 700Hz filter puts the signal in a better-behaved part of
the passband. The DSP filters have no phase distortion, of
On 3/3/2014 9:24 AM, Walter Underwood wrote:
It has been suggested that a using a 400Hz filter for RTTY (or other digital
modes) puts the edges of the signal in the part of the passband with the worst
phase distortion. A 700Hz filter puts the signal in a better-behaved part of
the passband.
I designed analog and digital filters for processing flight test vibration
measurements in the aerospace industry. I understand how cascaded filters
work, and the function of a roofing filter versus the DSP filtering in the K3.
I have owned and operated my K3 since mid 2008, and have turned
...@pwpconsult.com
To: Elecraft@mailman.qth.net
Subject: Re: [Elecraft] [K3] Perfect for Field Day SP ... Limited
Production 700 Hz 8-Pole Filters
I am using:
13 KHz: 0 dB
2.7 KHz: 0 dB
2.1 KHz: 0 dB
250 Hz: 6 dB
When the 2.1 and 250 filters switch in, the signal level in the
earphones doesn't seem
On 3/3/2014 12:24 PM, Walter Underwood wrote:
It has been suggested that a using a 400Hz filter for RTTY (or other
digital modes) puts the edges of the signal in the part of the
passband with the worst phase distortion. A 700Hz filter puts the
signal in a better-behaved part of the passband.
To: Elecraft@mailman.qth.net
Subject: Re: [Elecraft] [K3] Perfect for Field Day SP ... Limited
Production 700 Hz 8-Pole Filters
I am using:
13 KHz: 0 dB
2.7 KHz: 0 dB
2.1 KHz: 0 dB
250 Hz: 6 dB
When the 2.1 and 250 filters switch in, the signal level in the
earphones doesn't seem to change
Joe is right on.
Back when EME was real, i.e copied by ear, it wasn't unusual to copy signals
with a negative SNR.
A little story: I went to work for Hughes Aircraft here in Tucson when I was 25
years old. At the time I was given a hearing test as part of my physical exam.
(So they told
I have the 2.1 KHz (for SSB) and the 250Hz (for CW and digital)
filters. I used the frequencies marked on the filters for the K3
setup, so everything is quite standard. I notice as I am
narrowing the bandwidth in both CW and SSB, when the K3 switches
to a narrower filter, there is a noticeable
Hi Bill,
In the K3 Utility - Configuration tab - Configure Crystal Filters,
you will see that each filter has a Gain setting. You can change the
gain on a per-filter basis to maintain approximately the same overall
gain. Generally the smaller bandwidth filters require a few more dB
gain than
I am using:
13 KHz: 0 dB
2.7 KHz: 0 dB
2.1 KHz: 0 dB
250 Hz: 6 dB
When the 2.1 and 250 filters switch in, the signal level in the
earphones doesn't seem to change, but the noise level does
indicating an improvement in S/N. Perhaps they are sharpening
the cutoff of the DSP filter removing
This seems like an increasingly commercial trend cluttering up this list, with
dubious claims to boot.
I guess that I'm not a savvy operator since I use the discredited 400 Hz
filter and manage to get by.
Apparently, 700 Hz is a magical bandwidth, just as 43 feet is a magical length
for a
Agree re commercial messages of dubious merit. I
have a 400 and a 1000. Gee, that averages to 700
so I must be really clever :-)
Phil w7ox
On 3/1/14, 11:20 AM, Wes (N7WS) wrote:
This seems like an increasingly commercial trend
cluttering up this list, with dubious claims to
boot.
I guess
The advertisements for that particular brand of 700Hz filter are
passed through my junk filter or I wouldn't have seen it.
I'm surprised you didn't delete the entire advertisement. I guess
I'm going have to add the phrase limited production to my filters.
In the K3, as it comes from the factory
Eric has permitted such announcements, but limits them to one a month.
You will see offers to build a K2 that come in that same category.
Personal comment -- I particularly like the 700 Hz CW filter in my K3.
I got used to tuning the bands using a 700 Hz filter width in my K2, and
opted for
If you can, help me out here Don ...
These are roofing filters. From my perspective, which is likely wrong,
their job is to restrict the bandwidth presented to the 2nd mixer [and
downstream ADC]. They are of most value when you have very strong [i.e.
geographically close] signals adjacent
As usual, Fred has things pretty much right. Here in Silicon Valley narrow
roofing filters are needed to keep the local massive signals out of the
receiver. With the 500 Hz 5-pole filter I can operate within a few hundred
hertz of the big guys with very little problems. In fact it is pretty
Fred,
In general you are correct. However, there is one other effect that
the narrow roofing filters are not going to resolve - garbage from
your neighbors in the form of key clicks, transmitted phase noise and
IMD. I see it every time my neighbor (.66 mi) comes on a band with
his Icom POS
That's why on more than one occasion I've said that to evaluate a transceiver's
receiver performance, instead of a couple of HP8663 signal generators, two other
like transceiver transmitters should be used as the signal sources for the
measurements, until that is, our transceivers have the
Fred,
Everything you say is true, the DSP does set the final filter width, but
the hardware AGC can cause pumping in the presence of nearby strong signals.
Since my normal desired CW tuning width is in the vicinity of 700 Hz, I
bought and installed one of the 700 Hz filters. YMMV some say
Unless you have a panadapter, you'll never work weak stations, if you can't
hear them because they're outside your passband! (This is the beauty of 700
Hz!) In fact, many seasoned Elecraft K3 owners feel that using the radio's
400 Hz default (NORM) CW passband setting, is kind of like viewing
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