Re: [Elecraft] Rx-In/Out used for exteranl SDR Device

2021-12-05 Thread Jim Brown
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

[Elecraft] Elecraft CW Net Report

2021-12-05 Thread kevin
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

Re: [Elecraft] Rx-In/Out used for exteranl SDR Device

2021-12-05 Thread Dean L
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

Re: [Elecraft] Rx-In/Out used for exteranl SDR Device

2021-12-05 Thread Michael Tope
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,

Re: [Elecraft] ID a small board

2021-12-05 Thread Joe Subich, W4TV
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

Re: [Elecraft] "Low Gain Ratio" Hard Fault

2021-12-05 Thread Roy
 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

Re: [Elecraft] Rx-In/Out used for exteranl SDR Device?

2021-12-05 Thread Dave Erickson
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

Re: [Elecraft] Rx-In/Out used for exteranl SDR Device

2021-12-05 Thread Jim Brown
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

[Elecraft] ID a small board

2021-12-05 Thread Neil Foster
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

Re: [Elecraft] Rx-In/Out used for external SDR Device

2021-12-05 Thread Jim McDonald
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

Re: [Elecraft] Rx-In/Out used for exteranl SDR Device

2021-12-05 Thread Joe Subich, W4TV
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,

Re: [Elecraft] Rx-In/Out used for exteranl SDR Device?

2021-12-05 Thread Pete Smith N4ZR
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

Re: [Elecraft] Rx-In/Out used for exteranl SDR Device

2021-12-05 Thread Michael Tope
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

Re: [Elecraft] Rx-In/Out used for exteranl SDR Device?

2021-12-05 Thread David Hachadorian
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

Re: [Elecraft] Rx-In/Out used for exteranl SDR Device?

2021-12-05 Thread Jim Brown
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

Re: [Elecraft] Rx-In/Out used for exteranl SDR Device?

2021-12-05 Thread Pete Smith N4ZR
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

[Elecraft] Rx-In/Out used for exteranl SDR Device

2021-12-05 Thread Bob McGraw
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

[Elecraft] "Low Gain Ratio" Hard Fault

2021-12-05 Thread Cono DelRosso
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

Re: [Elecraft] Rx-In/Out used for exteranl SDR Device?

2021-12-05 Thread Dave Erickson
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

Re: [Elecraft] Rx-In/Out used for exteranl SDR Device?

2021-12-05 Thread Joe Subich, W4TV
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

Re: [Elecraft] Rx-In/Out used for exteranl SDR Device?

2021-12-05 Thread Dave
>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

Re: [Elecraft] Rx-In/Out used for exteranl SDR Device?

2021-12-05 Thread Pete Smith N4ZR
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

Re: [Elecraft] Rx-In/Out used for exteranl SDR Device?

2021-12-05 Thread Bob KD7YZ
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

Re: [Elecraft] Rx-In/Out used for exteranl SDR Device?

2021-12-05 Thread Dave
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/