On 12/5/2021 8:38 PM, Dean L wrote:
Interesting.
How would you measure the impedance the sdr rx or even the K3, for that
matter adds to the circuit?
A vector impedance analyzer (VIA) or vector network analyzer (VNA) can
easily do that when properly calibrated. I used my VNWA-3E.
73, Jim
Good Evening,
Conditions were decent on both bands. QSB varied from moderate to
light, mostly it was rapid. Both of my antennas captured plenty of
noise. Normally they are different - one noisy, the other less so.
Winter may be a little early. Last night I had a hard frost which left
Interesting.
How would you measure the impedance the sdr rx or even the K3, for that
matter adds to the circuit?
I often wondered this when tuning a bandpass filter, to work with a
receiver, using a return loss bridge, how can you be sure the rx is
50ohm...?
73
Dean
On Sun, Dec 5, 2021, 6:27
Yeah, unless the splitter is active, the isolation is only going to be
as good as the source match (i.e. VSWR looking back toward the RF out
port of the K3). The devil is always in the details.
73, Mike W4EF...
On 12/5/2021 1:48 PM, Jim Brown wrote:
On 12/5/2021 1:18 PM, Joe Subich,
In a small zip bag was board with a 4 pin connector on each end. On
the back it is printed "Remove to instal KPA3".
Probably a "KPA Jumper Block" ... it is installed for low power
operation if the KPA3 is removed.
73,
... Joe, W4TV
On 2021-12-05 4:36 PM, Neil Foster wrote:
Recently I
Check your idling current.
73, Roy K6XK
On 12/5/2021 12:22 PM, Cono DelRosso wrote:
Hello,
I have a KPA1500 Over a year old, Came back from Elecraft on May 2021 for 12v
supply connector issue repair.
Does anyone have experience handling this particular hard fault "Low Gain
Ratio”
Now
On 12/5/2021 12:10 PM, Dave Erickson wrote:
Bob (and others),
The SDRPlay is capable of decoding and using the RF out directly.
There is no need for a splitter and it's resulting loss. There MAY be a
need for an inline ATT on the IF out to the SDRPlay but YMMV.
I have run mine this way
On 12/5/2021 1:18 PM, Joe Subich, W4TV wrote:
This only works 1) if the SDR impedance is consistently high from
100 KHz to 54 MHz and 2) the SDR has excess gain to compensate for
the loading from the K3 receiver.
However without a splitter, there is no protection for the K3 receiver
against
Recently I purchased a KPOD from a local SK's estate. In a small zip bag
was board with a 4 pin connector on each end. On the back it is printed
"Remove to instal KPA3". In searching the parts list it says the KPA3 is a
12V Sense Mod 1N4148. On the front next to the connectors are marked J67a
and
Another option, which I've used, is to connect the SDR to the IF OUT, using the
splitter in the P3, or directly to the IF OUT on the K3.
The available bandwidth is the 200 kHz (I think) at the IF, of course. N1MM
and DXLab have an option to specify the IF input instead of using the signal
This only works 1) if the SDR impedance is consistently high from
100 KHz to 54 MHz and 2) the SDR has excess gain to compensate for
the loading from the K3 receiver.
However without a splitter, there is no protection for the K3 receiver
against spurious signals generated by the SDR!
73,
I'm afraid you're right, Dave. I had the RX output into terminal 1 and
the line back in on terminal 2, because I figured the "common" terminal
should be the one going to the SDR. Great to get this straight, finally.
73, Pete N4ZR
Check out the new Reverse Beacon Network
web server at
Just a word of caution when doing this. If the SDR input Z is high
enough, then one needs to be mindful of the length of the cable running
from the "T" to the SDR antenna input. When the length of that cable
gets close to 1/4 wavelength (this is 3.2 to 4.4 ft at 50 MHz depending
on velocity
Are you hooking up the splitter correctly? RX ANT OUT from the radio
goes to the common terminal of the splitter, and one of the two
independent splitter outputs goes to RX ANT IN on the radio. The other
independent splitter output goes to the SDR. Sorry to bring up such a
simple
On 12/5/2021 9:35 AM, Dave wrote:
I have no idea about Minicircuits splitters,
Mini-Circuits makes a wide range of lab-quality devices. A study of
their catalog is informative. One type is a hybrid that provides about
20 dB of isolation between four outputs with about 6.6 dB of insertion
I don't know why I didn't think of that. Just tried it, and there is no
difference in S-meter reading , so it may/must be a splitter problem. I
tried it with another spltter, with and and without the SDR, and, again,
large drop. WTF???
73, Pete N4ZR
Check out the new Reverse Beacon Network
I use a pair of BNC to BNC cables, about 4" long, from the RX OUT and RX
IN to a "T" connector. The 3rd port of the "T" goes to the SDR. I find
that the SDR input impedance, is nowhere close to 50 ohms, is high
enough that it doesn't load the signal on the main RX. Again, no
splitter
Hello,
I have a KPA1500 Over a year old, Came back from Elecraft on May 2021 for 12v
supply connector issue repair.
Does anyone have experience handling this particular hard fault "Low Gain
Ratio”
Now I have low output 30w in only puts out 400watts
Cono, W2ZMZ
On 12/4/2021 2:41 PM, Bob KD7YZ wrote:
Hello Elecraft List
I recently got my K3 back from Elecraft. They'd upgraded it to K3s.
I used to be able to run a cable from the Rx in out area on the
right-upper-rear as I face it.
That gave me antenna without the threat of RF into my SDRPlay.
I
On 2021-12-05 12:35 PM, Dave wrote:
I have no idea about Minicircuits splitters, but my home made one had
a measured 3.1 dB loss at 29.7 MHz.
Only 0.1 dB is "loss" - an unamplified two way splitter will show at 3 dB
reduction in signal level from input to either of the output ports just
>I see about a 3 S-unit drop in signal
>level when routing through the splitter
Pete (N4ZR), what do you see with a straight cable linking in/out?
I have no idea about Minicircuits splitters, but my home made one had a
measured 3.1 dB loss at 29.7 MHz.
73 Dave G4AON
--
Sent from my iPhone SE
Through off-reflector correspondence, it appears Bob has a point. On my
K-3 (un-updated), I have a Mini-circuits splitter between the RX Out and
RX In jacks, feeding an Airspy HF+ to support the N1MM spectrum display
window. Using an XG-3, I see about a 3 S-unit drop in signal level when
Hello Richard Ferch:
Saturday, December 4, 2021, 8:38:26 PM, you chiseled out:
> To use the RxAnt In/Out BNC connectors in the KXV3, you need to select the
> RX Ant from the front panel RX Ant switch.
I have a Mini-Circuits splitter.
It comes off the Rx-Out of the K3s. The other two of the
Before making an active 4 port splitter, I used one made from a pair of
ferrite rings, the circuit and measured performance details are on my web
pages.
If anyone wants the circuit and construction details of my 4 port active
splitter, contact me off list.
https://www.qsl.net/g4aon/radio_mods/
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