开云体育

About to start my uBitX build... have the radio now, and acquiring some parts as well as scouring my junkbox?(which has been accumulating rather than shrinking!)

My goal is building a portable rig I can bring to do mountain-topping?on HF as well as a bunch of VHF bands.

Adding transverters...

I've mentioned the low-cost transverters?from Ukraine before (See eBay).? ?These units run from 20-30 bucks depending on the band, and will give you 5-8 watts output on each band (if you want to keep the spectrum clean.)? They can be driven with the drive before the uBitx?finals.

I'm actually going to stuff 4 extra bands in the box -- 50,144, 222 and 432.? ? The four boards cost around $120 with shipping.

Some of the challenges are switching all this.? ?Since we are talking 10m as the?

i-f,? I think I'm going to use cheap DPDT relays typically found in those Chinese relay boards (I bought 100 of them for a song many years ago).? I have some nice 12v SMA low-power relays, but not going to waist them on 10m!

In order to control transverter?I/O switching, I think I'll use a slave Nano via I2C.? I'll modify the KD8CEC sketches to have additional menu items to select the band; when 50, 144,222 or 432 is selected, I'll ensure the VFO displays the appropriate frequency (simply by adding the offset)? and, via the 2nd Nano, switch the UbitX finals off, and routes the low-level rf to the appropriate transverter.?

Sequencing...

With these transverters and the potential for external amplifiers, there is a need for

proper sequencing.? ?I'd also like it at HF as well (it can also be used to eliminate the pop when T/R switching between the uBitX?

I'll use the 2nd Nano to do this, using switching transistors and relays.? ?it will go something like this:

-PTT Closure

-Mute audio path via JFET switch

-Close transverter?T/R relay contacts

-Wait 20mS +/-

-Close external amp relay contacts

-Wait 20mS +/-

-Close UBitX Original PTT

When PTT opens, the process is done in reverse.

Jacks and buffers, and RX/Mic processing...

I want to use the UbitX for FT8 and other digital modes, probably with an external laptop.

Rather than messing around with the mic input or speaker out, I think I'll add an emitter follower or OpAmp on both the mic audio channel and the receiver audio, before the audio pot.? This way, I'll have fixed level line-in and line-out (via RCA jacks)

?I plan on using my Yamaha CM-500 headsets with the rig.? Should be a good match since these use an electret mic.? They are a bit big for portable use, but very comfortable.? ? In addition, I ordered an SSM2167 mic preamp/compressor board for $6 on ebay.? ?

Though my uBitX?has the new audio chip and is socketed, I'm going to replace the audio amp with the New England QRP Club's NESCAF project.? This is a switched capacitor filter-based CW filter board.?? The filter has two controls: 1. the center frequency control allows the user to raise or lower the received frequency (the CW note) in the bandpass filter. The pitch can be set to a default value anywhere between 450-1000 Hz. range. 2. the bandwidth control will vary the width of the received CW pitch from about 90 Hz to about 1500 Hz.? ?It has a built-in audio amp.? ?It's a bit pricey at $39, but I thought I'd support a local club effort.

The back panel will get pretty busy.? The new connector compliment will include the following additional items:

4 more BNCs for the four transverter?outputs.

5 more RCA jacks for HF/VHF/UHF amplifier keying

This reflector has been an awesome place for ideas!? Keep em flowing.

73, Gerry W1VE