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
Lee,
Can you recommend an improved device to replace/upgrade the Analog Devices #
AD8055AN chip?
Any chance it would be a "drop-in replacement" ( pin-for-pin ) ?
I've got nine of the YCCC that I'd like to upgrade.
Or maybe I should just wait for Chris to complete his whole new design.
73
Lloyd -
>>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 limiter on the output so that it can be used by
"weak" SDR receivers such as the SDRPlay RSP series that cannot take
high RF
Well conditions were pretty good last night . . . but not many NA stations
active on CW . . .
Maybe we'll get more people on tonight.
(I personally usually pop on around 00.30Z . . . and again around 03.00Z)
73 Roger G3YRO
_
Searchable Archives:
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
Thank you very much, Lee. My last Mouser order arrived...today!
On the list for the next order. LOL
73 de Vince, VA3VF
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
>>>Recently I've been asked by a radio contest group to see if I can
redesign the YCCC Hi Z amplifier using modern components and using
similar mounting arrangements to our Loop Antenna Amplifier.
Hi Chris,
Any updates on the loop antenna amplifier revisions you were working on
a couple of
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
>>>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.
Vince, VA3VF
_
Searchable Archives:
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.
As well as being a radio amateur (G4HYG) I also run a small business
designing and making radio equipment (Cross Country Wireless).
Recently I've been asked by a radio contest group to see if I can
redesign the YCCC Hi Z amplifier using modern components and using
similar mounting
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