;) ;) Haven't the radio telescope guys
done this in GHz bands?
Grant KZ1W
On 3/13/2020 09:42, Jim Thomson wrote:
Date: Thu, 12 Mar 2020 20:25:16 -0700
From: Jim Brown
To: topband@contesting.com
Subject: Re: Topband: Hi Z amplifiers for 160m
_
Searchable Archives: http
On 3/13/2020 12:34 PM, Richard (Rick) Karlquist wrote:
On 3/12/2020 4:29 PM, Mikek wrote:
I'll stick my neck out and suggest Dallas Lankford's '2 FET amp'.
If anyone has an interest, I have some more files in my computer.
On 3/12/2020 4:29 PM, Mikek wrote:
I'll stick my neck out and suggest Dallas Lankford's '2 FET amp'.
If anyone has an interest, I have some more files in my computer.
https://www.okdxf.eu/lankford/Hi%20Z%20PPL%20Loop%20And%20Flag%20Arrays.pdf
I
Me neither.
On Fri, Mar 13, 2020, 12:22 PM Wes wrote:
> It's not clear to me.
>
> Wes N7WS
>
> On 3/13/2020 9:42 AM, Jim Thomson wrote:
> > ## Clearly whats required is a long overdue increase in TX
> power limits on 160 band...and also 80+40.
> > That or arrl legal remote
It's not clear to me.
Wes N7WS
On 3/13/2020 9:42 AM, Jim Thomson wrote:
## Clearly whats required is a long overdue increase in TX power
limits on 160 band...and also 80+40.
That or arrl legal remote RXs. pick one.
Jim VE7RF
_
Searchable
On Thu, Mar 12, 2020, 3:48 PM Michael Tope wrote:
> There are a lot of SMT to DIP adapter boards out there which would allow
> newer SMD op-amps to be used in older through-hole PWB layouts.
>
>
> https://www.digikey.com/product-detail/en/aries-electronics/LCQT-SOIC8-8/A880AR-ND/4754588
This
nn=verizon@contesting.com]
On Behalf Of Michael Tope
Sent: Friday, March 13, 2020 7:34 AM
To: topband@contesting.com
Subject: Re: Topband: Hi Z amplifiers for 160m (LONG)
I agree with your conclusions regarding the case of isotropic
atmospheric noise. This is the same reason that cold space looks like
Date: Thu, 12 Mar 2020 20:25:16 -0700
From: Jim Brown
To: topband@contesting.com
Subject: Re: Topband: Hi Z amplifiers for 160m
http://www.contesting.com/_topband - Topband Reflector
The document was published last year so we might assume the noise graph is
up to date. To put this in perspective,
To put the ITU-R P.372-14 claimed noise in perspective here's the
calculated antenna terminal voltage for a 100% efficient 1/4 wavelength
vertical in 500 Hz bandwidth. S-units are
s why having more amplified elements makes it more important to design
the antenna amplifiers for low circuit noise.
73, John W1FV
-Original Message-
From: Topband
[mailto:topband-bounces+john.kaufmann=verizon@contesting.com] On Behalf
Of Michael Tope
Sent: Thursday, March 12, 2020 4:
On 3/12/2020 7:44 PM, Dave Cuthbert wrote:
Feel free to review my method/math and make corrections as needed.
Didn't review your math, but the more important question is, "how old is
your noise data?" In my experience trying to work EU on Topband now as
compared to c.a. 2007-8 is vastly
*Amp/antenna noise *-- is the AD8045 noise low enough for a 3-meter
monopole? *0.26 uV amp noise vs. 0.16 uV man-made rural noise and 2.3 uV
city with a 3-meter monopole. *
Feel free to review my method/math and make corrections as needed.
*Rural Noise*, ITU-R P.372-14 (link below)
Working thru
Lankford's stuff works great.
I have used his antenna which does NOT use
a preamp.it's only suitable for situations
where match to the feedline isn't critical, but
it sure is great to not have any preamp outside.
de K8RYU
From: Topband on behalf
of Mikek
ow circuit noise.
73, John W1FV
-Original Message-
From: Topband
[mailto:topband-bounces+john.kaufmann=verizon@contesting.com] On Behalf
Of Michael Tope
Sent: Thursday, March 12, 2020 4:37 PM
To: topband@contesting.com
Subject: Re: Topband: Hi Z amplifiers for 160m
Hi
On 3/12/2020 4:13 AM, John Kaufmann via Topband wrote:
I think you are confusing voltage and power. For incoherent sources like
amplifier noise, the voltages of multiple incoherent sources add in a
root-sum-squared (RSS) fashion. The voltage of the sum of eight incoherent
sources is square
...@msn.com; topband@contesting.com
Subject: Re: Topband: Hi Z amplifiers for 160m
Lee,
I think you are confusing voltage and power. For incoherent sources like
amplifier noise, the voltages of multiple incoherent sources add in a
root-sum-squared (RSS) fashion. The voltage of the sum of eight
Hi Lee,
Yes, if you are combining coherent signals that are not in phase, then
the each of the voltage vectors is weighted by cos(phi-i) where phi-i is
the angle between the i-th voltage vector and the 1st vector. If phi=0,
then you have the case I described previously. I can see how this can
; topband@contesting.com
Subject: Re: Topband: Hi Z amplifiers for 160m
Lee,
I think you are confusing voltage and power. For incoherent sources like
amplifier noise, the voltages of multiple incoherent sources add in a
root-sum-squared (RSS) fashion. The voltage of the sum of eight incoherent
Chris,
Good choice.
Perhaps one note of caution. With a BJT input like this the input current
noise may be more dominant, unless the input impedance is kept low.
Would be great to see the final design.
GL and 73,
George,
AA7JV
On Thu, 12 Mar 2020 10:10:44 +
Chris Moulding wrote:
*JFET op amp vs bipolar op amps, *LTSpice simulations connected to a 3
meter monopole
A bipolar op amp doesn't always give the lowest noise with a short monopole
at 1.8 MHz because the op amp current noise creates noise voltage across
the antenna capacitive reactance. Additonally, op amps can be
noise power.
73, John W1FV
-Original Message-
From: Lee STRAHAN
To: topband@contesting.com
Sent: Wed, Mar 11, 2020 10:22 pm
Subject: Re: Topband: Hi Z amplifiers for 160m
Hello John and all,
Concerning the adding the noise in a typical array. If the noise was coherent
or exactly
Thanks again for all the comments. Very interesting especially the
reasoning behind the designs.
The device I've picked for my design is the LTC6228. This is a new
device by Analog Devices that only came out late last year. The voltage
noise is 0.88 uV/sqrt Hz and the current noise is 3
Mike and all,
Well stated Mike. It's been a long time since we have conversed. The
modifier to this is when the signals coming into the combiner are no longer in
phase or coherent. This as a result of delay lines and time of signal arrival
at the many elements. Most often in our small
On 3/11/2020 9:39 PM, Michael Tope wrote:
The signal components add coherently at the combiner output yielding a
total signal voltage of 14.14 Volts rms. The noise voltages are
incoherent, so they add as root-sum-square at the output of the
combiner. This yields a total noise voltage of
What matters is the signal-to-noise ratio (SNR). Take the canonical
example of an ideal 2-port Wilkinson power combiner with in-phase
coherent signals of 10 Vrms applied to each input along with 1 Vrms
random thermal noise from the respective element amplifiers applied to
each input (i.e. each
Here is an example at Digikey:
ACX1545-ND
Expensive, but...
73,
George
On Wed, 11 Mar 2020 13:33:08 -0400
DXer wrote:
>>>Use an F connector (a high quality one that can be torqued.)
Can you point to a place that sells them. I became a 'fan' of F termination,
but have recently had
Hello John and all,
Concerning the adding the noise in a typical array. If the noise was
coherent or exactly the same signal from each element/amp the summed noise
would indeed be 8 times. However circuit noise is always random and incoherent
which causes the summation to be a single
As the designer of the YCCC high impedance feedpoint amplifier, let me
address some issues related to the design of the YCCC amplifier as well as
feedpoint amplifiers in general. If you don't want to read a lot of
technical gobbledygook, please disregard this message.
The YCCC uses an AD8055 RF
.
73
Lloyd - N9LB
-Original Message-
From: Topband [mailto:topband-bounces+lloydberg=tds@contesting.com] On
Behalf Of Lee STRAHAN
Sent: Wednesday, March 11, 2020 12:17 PM
To: topband@contesting.com
Subject: Re: Topband: Hi Z amplifiers for 160m
Greetings all,
George has some very
Thanks for all the very helpful replies and suggestions.
I'll change the BNC connector to a 4 hole F connector with 75 ohm output.
The design already has a 20 kA gas discharge tube and DC biased diode
limiter for lightning and surge protection. It also has an optional (by
internal link) diode
Mouser 601- 25-7630 or 601-25-7660
[Lee K7TJR]
>>>Use an F connector (a high quality one that can be torqued.)
Can you point to a place that sells them. I became a 'fan' of F termination,
but have recently had second thoughts because of the bulkhead connector's
quality.
Thanks and 73.
On 3/11/2020 6:28 AM, GEORGE WALLNER wrote:
Assuming a trans-impedance amplifier, "unity gain" is enough (with
reasonable size elements). Noise and IP3 are far more important.
Lightning and surge immunity are also important. Also, isolate the amp
from common mode noise travelling on the
Greetings all,
George has some very pertinent points here and only on one point I will
disagree. What a Hi-Z amplifier needs to do is dependent on your aspirations of
the size and quantity of elements you decide to use. The combiner losses will
dictate what you must do at the element end of
Chris,
I just finished making my own set of amplifiers derived from the YCCC design
but using SMD components. I used an AD8045 (SOIC-8 size) instead of the 8055
and added a voltage regulator.
They have replaced a set of the original Hi-Z amps (the ones in the black
mini-boxes with metal
Chris,
Assuming a trans-impedance amplifier, "unity gain" is enough (with
reasonable size elements). Noise and IP3 are far more important. Lightning
and surge immunity are also important. Also, isolate the amp from common
mode noise travelling on the feed-line. Filter the power supply well.
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