Ken Kopp K0PP wrote:
A couple of things to keep in mind ... RF flows on/near the surface of a
conductor, and the correct
length of an antenna made from insulated wire will
be slightly different than the formula-calculated length.
-
Can really good CW filters be made for VHF? By really good, I mean,
say, 400 Hz bandwidth, less than 6 dB loss, 6:60 dB shape factor less
than 3 to 1?
What about stability over the temperature range?
Going to be difficult.
From filter theory (see, e.g., Zverev) we know that the
Tektronix 465 series. 100 MHz, dual trace workhorse of the analog scopes
in the 1970's and should be readily available for a few hundred dollars.
Budget a decent set of 10X probes if not included.
Jack
Craig Rairdin wrote:
I'm browsing eBay for an oscilloscope suitable for troubleshooting
Hi Dick,
The variable crystal filters in the K2 are very good. In fact the best I
have ever used. As Don says, unless you have a bad component, crystal
filtering should be excellent down to about 250 Hz, and the DSP down to 100
Hz before you get a bit of attenuation of signal. You can even
There are some many practical problems with the holder capacitance,
stray capacitance and the like that would make such a filter challenging,
even if someone were to deliver a box of 45 MHz crystals with measured Qs
of 2 million to my doorstep. And if the box of crystals arrive, to obtain
Just a short reminder that if you are planning to purchase a Z90 or Z91
panadapter kit, the deadline to drop me an E-mail message is Friday,
August 18th.
A few days after the 18th, I will order enough of the expensive
volume-sensitive parts (enclosures, LCD, PCB) to meet the order
Yes, exactly. The minimum required Q scales proportionally to the
fractional bandwidth. Hence at a given frequency the required 400 Hz
filter demands resonator Q's 12.5 times higher than for a 5 KHz filter,
assuming a bunch of other factors remain constant. They don't, but this
is a good
If portability is not required, you might also want to look at the Tek
7000 series mainframes, and pick up a couple plugins. These tend to be a
little cheaper than the 465, and you can replace a plugin cheaply if it
goes bad. It also opens up the option of a spectrum analyzer plugin.
That
Jack Smith wrote:
Budget a decent set of 10X probes if not included.
I have a BK-1479A 30mhz scope.
I really am clueless in it's usage.
I plan to use it to help teach myself by trying some hf home brewing.
Could the group please point me to an online catalog number for an appropriate
probe
As Larry says, the major problem with the older scopes are that they use
custom ICs and mechanical components that are long out of production.
The attenuators on the 465 series are a weak point and are essentially
unrepairable and should be checked for proper operation before purchase.
I
For a 30 MHz o'scope, you can get by with a lot less probe than for,
e.g., a 400 MHz o'scope.
Assuming you don't want to purchase used Tek or HP probes via E-bay or
whatever, you could look at ProbeMaster http://www.probemaster.com/.
Take a look at their 3900-series probes. In your case, I
I was using a Tek TDS2014 for a while... FFT function was very useful to
calibrate filters, check CW and SSB bandwitdth, adjust SPOT tone, etc...
Also good for adjusting power output with a 10X probe with AC rms with
a directionnal coupler. Many things could be done
I recently change my
The hands-down nicest ones, ever, which are ironically
not more costly than low-grade hamfest specials, are
found here:
http://www.universal-radio.com/catalog/parts/4065.html
I daresay these connectors are worthy of Elecraft
official reference! Now, THAT is saying something!
Standard
In a message dated 8/12/06 8:03:20 AM Eastern Daylight Time,
[EMAIL PROTECTED] writes:
Hence, the resonator Q requirements for a 5 KHz filter at 40 MHz are not
grossly different than for a 500 Hz filter at 4 MHz, which is quite
achievable. But for a 400 Hz filter at 45 MHz, the required
Treid to post this before, did it not work?
http://www.universal-radio.com/catalog/parts/4065.html
This connector is the bees' knees, truly K2 grade.
Standard disclaimers.
__
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection
Jack Smith wrote:
Hence, the resonator Q requirements for a 5 KHz filter at 40 MHz are not
grossly different than for a 500 Hz filter at 4 MHz, which is quite
achievable. But for a 400 Hz filter at 45 MHz, the required resonator Q's
get into the million range.
It wasn't just crystal filters that improved. The older methods of
computing component values (Image Parameter) was replaced by modern
network theory in the 1950's and '60's and LC filters became a lot
better performing as a result.
I don't see the widespread cheap availability of crystals
OK, I'm back for more help. I've been building a KPA 100 and I'm at
the part where you are supposed to first test the transmitter by
transmitting into a dummy load and listening on another receiver.
Now the other other receiver I have is a Yaesu VX-7R handy-talkie.
Now I've tuned them both
An AM receiver will not give you any tone when receiving a CW signal.
A CW signal is the same thing as an unmodulated AM carrier. The best
you'll be able to hear would be a 'quiet' spot when tuning across the
signal.
Mark
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To hear a beat note when sending CW, your VX-7R will have to be in SSB
or CW mode. When set for AM reception what you are hearing is normal.
Jack
Michael Cook wrote:
OK, I'm back for more help. I've been building a KPA 100 and I'm at
the part where you are supposed to first test the
Jack Smith wrote:
To hear a beat note when sending CW, your VX-7R will have to be in SSB
or CW mode. When set for AM reception what you are hearing is normal.
Jack
Michael Cook wrote:
OK, I'm back for more help. I've been building a KPA 100 and I'm at
the part where you are supposed to
Alas, the VX-7R does not support CW or SSB modes.
- Original Message -
From: [EMAIL PROTECTED] [EMAIL PROTECTED]
To: Jack Smith [EMAIL PROTECTED]
Cc: elecraft@mailman.qth.net elecraft@mailman.qth.net; Michael Cook [EMAIL
PROTECTED]
Sent: Sat Aug 12 17:05:30 2006
Subject: Re: [Elecraft]
Think of it this way:
KAT1 - AT inside a K1
KNB1 - NB inside a K1
KNB2 - NB inside a K2
KDSP2 - DSP inside a K2
KSB2 - SB inside a K2
ad infinitum
de Joe, aa4nn
I wish Elecraft had chosen a little more logical system of model numbers
for their accessories, one that began with the
Search for a broadcast strong station first, then bring the
transmit-freq near that broadcastfreq, perhaps you can hear a beatnote.
73
Arie PA3A
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In a message dated 8/12/06 12:40:53 PM Eastern Daylight Time,
[EMAIL PROTECTED] writes:
It wasn't just crystal filters that improved. The older methods of
computing component values (Image Parameter) was replaced by modern
network theory in the 1950's and '60's and LC filters became a lot
Think of it this way:
KAT1 - AT inside a K1
KNB1 - NB inside a K1
KNB2 - NB inside a K2
KDSP2 - DSP inside a K2
KSB2 - SB inside a K2
OK then, so what is a KAT100?? (Rhetorical question only)
Mike / KK5f
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Post to:
Sam:
I found a reasonably user-friendly introduction to the care and feeding
of oscilloscopes at http://www.hobbyprojects.com/oscilloscope_tutorial.html
This may get you to the point where the Tektronix and Agilent literature
will be more useful.
Jack K8ZOA
www.cliftonlaboratories.com
Bob W7AVK wrote:
Jack - Have been reading the mail and enjoyed the discussion. Might
also point out a reason for the mechanical filter in the 390A was
Collins had the patent and Art was pushing their use. I worked for
Art a few years later and he was still activity pushing the filters
for
Just got my K-2 S/N 04401 finished with MUCH help from Steve Banks K0PQ (2
broken transistors, 1 backward diode on SSB board, many cold solder joints,
etc.) and Gary. I got my Tech 2 years ago, but hope to get past the 5 wpm
hurdle with the help of the FISTS disk and about 1 week intense
In a message dated 8/12/06 8:46:40 PM Eastern Daylight Time,
[EMAIL PROTECTED] writes:
It's interesting that Collins added the mechanical filter to the R390
(thus producing the R390A) as part of a 1955 cost reduction study. The
study report is floating around the Internet and I took a
Good Evening,
Another hectic week but the project has been tested successfully. Now
for the SBIR round 2 grant :) If that comes through we'll be very happy.
This week I had to get up at 3 AM three days in a row. Saturday I slept
until noon and then started my chores. I still feel
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