Topics

Airspy HF+/Spectrum Display/Receive Antenna

Pete Smith
 

I would like to be able to use a receiving antenna on my K3 while also using the spectrum display of N1MM+.  I assume from the manual's discussion of using the HF+ that it *must* be used on the Ant Out/Ant In loop of my K3.  That suggests that I either have to choose one or the other or cascade splitters and accept the 6+ dB of loss.  Am I missing something?

-- 

73, Pete N4ZR
Check out the Reverse Beacon Network 
at <http://reversebeacon.net>, now 
spotting RTTY activity worldwide. 
For spots, please use your favorite 
"retail" DX cluster.

Rick Tavan
 

You can drive the HF+ from the IF Out port of the K3, leaving the RX IN connection available for an actual RX antenna. I tried this successfully but eventually reverted to the RX Ant loop. You don't suffer the 3 dB sharing loss but I think you have to specify different IF offsets when you change modes. I'm not using an actual RX antenna. I suppose you could use both an HF+ connected to RX Ant OUT and an actual RX antenna connected to RX Ant IN but I haven't tried it.

73,

/Rick N6XI


On Fri, Oct 25, 2019 at 8:00 AM Pete Smith <n4zr@...> wrote:

I would like to be able to use a receiving antenna on my K3 while also using the spectrum display of N1MM+.  I assume from the manual's discussion of using the HF+ that it *must* be used on the Ant Out/Ant In loop of my K3.  That suggests that I either have to choose one or the other or cascade splitters and accept the 6+ dB of loss.  Am I missing something?

-- 

73, Pete N4ZR
Check out the Reverse Beacon Network 
at <http://reversebeacon.net>, now 
spotting RTTY activity worldwide. 
For spots, please use your favorite 
"retail" DX cluster.



--
--

Rick Tavan
Truckee and Saratoga, CA

Joe Subich, W4TV
 

That suggests that I either have to choose one or the other or
cascade splitters and accept the 6+ dB of loss. Am I missing something?
1) A 2 port splitter is 3 dB not six.

2) there should be no need to cascade spliters:

ANT OUT --> Splitter --> RX ANT Switch -> ANT IN
| |
| +--< RX ANT 1
HF+ Ant In <----+ +--< RX ANT ..
+--< RX ANT N

Note: the spectrum display is always connected to the TX antenna.
RX Antenna switch can be 2 ... n position with position 1 being
the transmit antenna, positions 2-n representing the number of
physical antenna inputs (loop, K9AY, Beverage, BSEF, etc.).

More complex switching can be utilized to provide separate antenna
feeds to the K3 RX ANT IN (Main RX) an AUX jack (Sub RX) for
diversity with separate RX Antennas if one has a K3/K3S with
second receiver.

73,

... Joe, W4TV


On 2019-10-25 10:59 AM, Pete Smith wrote:
I would like to be able to use a receiving antenna on my K3 while also using the spectrum display of N1MM+.  I assume from the manual's discussion of using the HF+ that it *must* be used on the Ant Out/Ant In loop of my K3.  That suggests that I either have to choose one or the other or cascade splitters and accept the 6+ dB of loss.  Am I missing something?
--
73, Pete N4ZR
Check out the Reverse Beacon Network
at<http://reversebeacon.net>, now
spotting RTTY activity worldwide.
For spots, please use your favorite
"retail" DX cluster.