July 4: Time for radio

Todays USA holiday was used as a chance to catch up on some radio projects.

First I tried out the 6GHz TWT and power supplies which failed during last weekends activities. Miraculously both now worked, one pair produced 27W the other, a bit more temperamental,  only 15W so they were put aside for operations this weekend

While having coffee at around 1700z heard the WF9XRU beacon from Virginia on 70.005 at 529.Antenna is Dipole at 20' feeding a microwave modules converter into the K3

Next the KX3 was interfaced to the Ipad to use the ISDR app as a panadaptor. An IMIC is connected to the IPAD through the Apple USB "camera adaptor". A 3.5mm stereo to 2.5mm cable was made to connect the IMIC to  I/Q output of the KX3.  Note the demodulated audio comes out of the "out" connector of the IMIC, NOT the Ipads speaker, so this was fed to some amplified speakers I have that are normally used for the HPSDR. It worked well but it took me ages to find how to set the vertical signal axis. I eventually found the answer on the ISDR yahoo group. This setting is not controlled from within the ISDR programme but is set from within the "settings" "ISDR" of the Ipad itself. Initially I had to reverse the I/Q settings in ISDR but eventually I crossed over the tip and sleeve connections on the 3.5mm connector and set the menu entry to "normal". The following is a screen capture of 20m from the Ipad

Next it was time to make some audio cables to allow the KX3 to be used on digital modes. Unlike the K3 the KX3 does not have isolated audio inputs and outputs which in the past I have found essential to avoid ground loops. Luckily I had previously made a box containing 2 audio transformers to isolate the audio paths for my now sold FT847. receive and transmit audio paths so matching cables just had to be made. The audio comes out of the KX3 from the 3 pole 3.5mm speaker connector. The transmit audio input to the KX3 and the PTT signal  were input to the KX3 via the 4 pole 3.5mm MIC connector using a resistive divider. the speaker output Voltage from the computer is far too high for the KX3 mic input. To try it out I used JT-65HF to have a few QSOs with success. It also drives the new version of Argo used as a QRSS grabber fine.

Finally I installed the Hetrodyne App for the HPSDR on my ipad.This provides a panadaptor display and can decode various modes (USB, LSB,CW etc). The LAN port of the Metis card is connected to a Netgear WNCE2001 configured as an access point which the Ipad can see from anywhere in the house. Now I am glad I upgraded to a 802.11n WIFI router. The following is a screen capture from the Ipad

Visit to Hamcom 2012

Just returned from the annual Hamcom Hamfest which was held in Plano, Texas.  As usual it was hot and clashed with the ARRL 50MHz to Light Contest

Elecraft were in attendance showing the recently released KX3 transceiver. They were currently still sending out kit radios ordered on the day that orders started being taken. Unfortunately mine was ordered on the 2nd day!

One interesting demonstration was using the I/Q data supplied by the KX3 to drive an IPAD to produce a panadaptor display using the ISDR app. As the 3.5mm audio input to an IPAD is mono and the I/Q requires a stereo input it cannot be used. This was overcome by using the I-MIC interface connected to the IPADs 30 pin connector via the IPADs USB camera adaptor

Unfortunately the ISDR software doesnt track the mode and frequency that the KX3 is tuned to.  However there is an app called HAMLOG which can track the frequency, but it currently doesnt interface to ISDR. The issue of how to connect the RS232 output from the KX3 to the IPAD which doesnt have an RS232 connector is solved by a device called a Pigtail available from Pignology LLC. This is an RS232 to WIFI converter which allows the IPAD to see the KX3 device. All I need now is the KX3 to arrive to try it out!

I also got to see the new Elecraft KAT500 500W Auto ATU which was smaller than I visualised. It only has the same footprint as the K3. It will be available from August.

I did finally give in and ordered the RemoterigII pair to allow me to remotely control one K3 with another K3 over the Internet without a computer. Sufficient RJ45 cables were found at the Hamfest to make the necessary interface cables.

To help the construction of a 472kHz bandpass filter for my 10MHz to 472kHz Transverter the opportunity was taken to stock up on a range of silver mica capacitors  on one of the outside stalls. The only other purchases were a speaker/mic for my IPAQ and an active GPS antenna for $5 each