SDRs and Tuning knobs

I am going to get an Elad Tmate-2 tuning accessory for my SDRPlay RSP2Pro. This device is a bit pricy, but it will make using the RSP2Pro much easier. Couple that with a good desktop running SDRUno, and I thing I will have a great receiver, when coupled to the mag loop set up I am designing (Mounted high, with a rotor for nulling and remote control).

 

When I get it, I will let everyone know how it works out.

 

73 de KD1IT

The QCX-30 Case

I ordered the recently announced QCX case for my QCX-30 rig by QRP-Labs. It is a very nice, simple, but well engineered case. Putting it together was a snap.

Here are some photos of it.

IMG 2718IMG 2719

IMG 2717

ZUMSpot

Yesterday, I received a ZUMSPot modem that plugs into a RaspberryPI. I opened to have it in a Raspberry PI3 B+, with integrated WiFi. After setting up PIStar on the unit, I started having conversations with people in England, Canada and the East coast of the United States. Basically, the ZUMSpot is a hotspot for Data/DMR/etc digital voice modes. It can connect to reflectors to allow you to see other people listed and make a call to them. Very cool. I am trying to get a friend in NH to get one, and get on it, so we can chat while the solar flux is at its lowest. HF hasn’t been too good lately.

 

Will say more on the ZUMSpot and MMVDM as I get more and more used to using it.

 

73

Got myself a new HT

The last time I bought a new HT, was in 1997. I bought an Icom T7H, back then.

 

I wanted to get a new HT that did DSTAR and APRS, etc. Well, that HT turned out to be the Kenwood TH D-74.

What a wonderful device. After getting used to the UX, it has been a joy to use. The fact that it covers 144/220/440 is a sweet aspect. It handles DSTAR, APRS and has a built in GPS. I got a good smoking deal on it from my local HRO in PDX. So far, I am overcome with joy. DSTAR is something to get used to, but once I got the hang of it, made a pretty quick QSO.

The only thing I want to do, to augment the radio, is to get a MMDVM access point to allow me to connect over the internet to a friends DSTAR repeater in NH. Then I can stay in touch.

I highly recommend this radio.

 

 

NewImage

uBITx Audio Amp woes

So, I got a new power supply at the Seaside Hamfest on the first week of June. I plugged my uBitX into it and a pop happened. Seems the audio amp chip popped its top. After asking a question on the uBitX FB group, Daniel King recommended a NJM2073D to replace it. Ordered about 5 of them, because you never know. Replaced it, this afternoon, and audio is back and they handle the 14 VDC the power supply was putting out. Apparently, there is a know issue with some of the stock audio amps in the uBITX and they seem to pop with more that 13 volts.

Restoring an Old Radio

This past week, I have recapped a Hallicrafters S-38B, 5 tube, all American classic. The 5 Tub all Americans are classic (National’s NC-60 Special is another version of such a radio). So far so good, it receives, but will need a tune up. So that is next on the list.

 

Here is the photo:

IMG 2532

MMDVM

So, I am interested in building a MMDVM (Multimode Digital Voice Modem) for hooking into DSTAR. So, I spent 8 hours working on a PI-Hat similar to the ZumSpot Pi Zero. Since ZumSpot seems to be dead, I decided to build my own. I finally have the schematic done, board placed and routed. Now, to get them built.

FWIW, I love the ST Micro STM32 MCUs. I use them in our professional work, through I am using a less powerful one on this design.

Here are photos of top and bottom:

 

MMDVM HS top

 

MMDVM HS bottom

uBITX finished

Last night I finished putting the uBITX together and testing it out. I did a 30 Meter CW contact (straight key) and listened up and down the bands. Nice little radio.

Here it is in completed form. The case was printed by Dave Schmidt, who has done these case for a number of BIT40X and uBITX folk.

 

IMG 2399

Now, what to do with the uBITX?

The uBITX comes with a 2 line display and an Arduino CPU. (not shown). I am designing a 5″ display, Cortex-A8 (minimum) CPU with the Si5351A Synthesizer chip, and will be writing the FW for it. Also, will be designing a circuit to tap off the IF and provide a band scope/waterfall on the 5″ display. In addition, will be designing an audio circuit so that the radio can be plugged into a computer to run digital modes. (Maybe include a decoder in the FW?). Maybe just put a bluetooth module and write a control protocol, and build an iOS app/macOS App to run the radio. Now, this sounds ambitious, and it is, but I really want to build the radio they way I want to. I will probably add a remote facility to control it via a network, or better the web (OpenWebRX?). I am hoping to be similar to the display in the second picture. If it turns out well, it could become a side business.  The display will look somewhat like this:

Screen Shot on 2018 02 18 at 15 08 47