22 Apr 2012 - Rear view of Front Panel at 4:30 pm on Day 1 (page 23 of assembly manual).
Unboxing video at http://www.youtube.com/watch?v=jdJzRTR7DDU
Compare to radio building in 1946
Front view of Front Panel completed by 6:00 pm on Day 1 (page 25 of assembly manual)
Rear of RF Board by 11:00 pm on Day 1.
Front of RF Board by 11:00 pm on Day 1 (page 30 of assembly manual). About 7 hours total assembly time at this point.
Close-up view of lower right quadrant of RF board. The dime is for size comparison.
Close-up view of center of completed front panel
One of the kit's 0.01 μF monolithic capacitors. Having built a Heathkit HW-101 in the 1970's and most recently a Heathkit SB-1000 amplifier in the 1990's, this was my first kit that required using a magnifying lens to identify the component values. Confirming the value of each of these little components and finding its mounting holes on the printed circuit board reminded me of the times I've played the old "Where's Waldo?" game over and over!
3 May 2012 - I spent 2 more hours building the Elecraft XV144 tonight and reached the end of page 34 of the assembly manual. The IF bandpass inductor L17 was not installed as it was defective and awaiting replacement. This is my RF board after 9 hours total assembly time.
L17, one of the IF bandpass filter inductors, was defective. The ferrite tuning slug was bound so tightly that it cracked while attempting to loosen it.
Another view of the IF bandpass filter inductor L17
5 May 2012 - I worked 3 more hours today and finished to page 43 of the assembly manual. I am awaiting the replacement L17 so I can mount this board to the bottom cover and complete the assembly. 12 hours assembly time at this point.
Here is a close up of T1. For those who suffer inductophobia, you can buy one of these pre-wound by AA3WF for $19.00. I can't imagine someone hesitating to wind this transformer after having accomplished all the detailed building to this point.
Here is a close up of the $50 XVOVN crystal oven option.
7 May 2012 - The replacement L17 arrived today. I was impressed with Elecraft service's prompt response to my request! Here is the completed Elecraft XV144 transverter with the top cover removed after 13 hours total assembly time from start to finish.
Here is the front panel of the completed XV144 transverter kit.
A view of the rear panel.
I placed an N male to BNC female adapter on the antenna connector as I use BNC coaxial cable jumpers in my station.
Transmitter Output Power as measured into a non-reactive 50 ohm dummy load after alignment per the instruction manual. The Input Attenuation Adjustment, R22, was set for 20 watts maximum output with the Flex 1500 set to 100% drive level from 144-146 MHz. R22 may be adjusted for 20 watts output on other frequencies.
Together with the crystal oven option, a SilenX Ixtrema Pro 40mm x 10mm 14dBA 5 cfm fan secured with double-sided foam tape over the vent holes in the top cover stabilized the temperature and frequency control of the Elecraft XV144 transverter sufficiently for WSPR operation on 144.490500 MHz.
Exposed temperature sensitive components in the Elecraft XV144 transverter 116 MHz Local Oscillator: slug tuned L19 at 10 o'clock from Isotemp crystal oven; Q1, C12 (behind Q1), C14 and L4 (at 3 o'clock next to crystal oven)
A wad of cotton is in place around all the exposed temperature sensitive components of the Elecraft XV144 transverter 116 MHz Local Oscillator.
Sterling Coffey NØSSC demonstrated this frequency stabilization technique on http://www.youtube.com/watch?v=wXkhsfEDIok
A 1,5 cm high by 5 cm dia. styrofoam cover for the Elecraft XV144 local oscillator circuit was cut from the bottom of a disposable cup.
The styrofoam cover was placed snugly over the cotton ball surrounding the Elecraft XV144 Local oscillator components. The purpose was to pack the cotton tightly around the components and to prevent air circulation around them.
Elecraft XV144 frequency stability test. At first, a loose wad of cotton was around the local oscillator components.
At 0400 UTC on 24 June, a styrofoam cover was placed over the cotton and local oscillator components.
The diurnal frequency variation corresponds with room temperature that varies between 73° F and 78° F.
The smaller oscillations represent short term thermal cycling.
The graph shows no apparent effect on the day-night frequency variation, but the smaller oscillations are denser and suggest improved short term stability.
8 May 2012 - I finally applied power and aligned the transverter. Here are the Flex-1500 and Elecraft XV144 in operation.
The XV144 was later moved away from the Flex-1500 as its radiated heat adversely affected the frequency stability of the transverter for WSPR operation.
Video of transmission at http://www.youtube.com/watch?v=7Pf84lb8iX0 and reception at http://www.youtube.com/watch?v=DNjbPv_0bBY
My Transverter Setup in PowerSDR (Alt-X) for the Elecraft XV144. The LO Error will vary for your setup and adjusts the Flex 1500 frequency readout to a known standard on 2 meters. Not having a precision signal generator, this is how I calibrated the XV144 Local Oscillator. First I calibrated the Flex 1500 precisely to WWV, then tuned my other 10 meter transmitter precisely to 29.000 MHz as measured on the Flex 1500 receiver. While transmitting a CW signal on 29 MHz (very low power is sufficient) I coarsely tuned the Flex receiver to its 5th harmonic on 145.000 MHz with L19, then fine tuned for zero beat with the LO Error adjustment. I set the RX Gain to the nominal 25 dB conversion gain as stated in the XV144 specifications. This gave a near S1 meter reading on receiver background noise. The XV144 receives and transmits according to specifications within 144-146 MHz range. It does work beyond that range (and on MARS frequencies) with some reduction in transmitter power and receiver sensitivity.
The PowerSDR Antenna Selection Form is set in Expert Mode here for Separate Transmit and Receive RF Connections to the transverter.
A Mirage B2518G Linear Amplifier with a SilenX EFX-12-15T cooling fan.
The oversize heat sink temperature did not exceed 101° F during a 2 minute WSPR transmission at 50 watts output power.
A Turnigy 130A Watt meter and power analyzer gives an accurate indication that DC voltage, current and power are within safe levels.
This 18 inch Sensible Storage 91818 chrome wire shelving unit provides space and excellent ventilation for the additional station equipment.
Today I reversed the two fans secured with double sided foam tape to the top and bottom covers of the Elecraft XV144 so that air blows down through the top vents and is sucked down and out the bottom vent holes adjacent to the power amplifier module. This should better prevent the diffusion of hot air from the amplifier module to the local oscillator components. Here is the SilenX Effizio-14-12 140mm Quiet Fan secured over the vent holes under the transverter.
The SilenX Ixtrema Pro 40mm x 10mm 14dBA 5 cfm fan is secured with double-sided foam tape and blows air down through the vent holes in the top cover of the Elecraft XV144 transverter.
20 May 2013 - Effect of reversing the ventilating fans on the Elecraft XV144 transverter. The WSPR Spot Database shows a decrease from -3 Hz to -2 Hz in the mean frequency drift during each 2 minute WSPR transmission.
22 May 2013 - I removed the right panel of the Elecraft XV144 to gain access to the underside of the local oscillator circuit. Although the white styrofoam and cotton insulation surround the local oscillator components atop the printed circuit board, the underside of the printed circuit board is exposed to heat radiated by the bottom panel that serves as the heat sink for the power amplifier module.
Thermal insulating sheets were cut from a recyclable styrofoam food container. These sheets measured 3 inches by 6 inches and together measured 0.15 inch thick.
The styrofoam thermal insulating sheets were carefully and snugly wedged into the space between the local oscillator circuitry and the bottom panel.
Here the styrofoam sheets are in position before I replaced the right panel of the Elecraft XV144 transverter. Now thermal insulation encases all sides of the 116 MHz local oscillator except for residual lateral thermal conduction through the printed circuit board.
29 June 2013 - GPS active antenna has a clear view of the sky, magnetically secured to a steel lumber H3 Hurricane Tie plate on an awning upright.
29 June 2013 - N6GN engineered this GPS disciplined frequency reference for selected stations in our West Coast VHF/UHF WSPR Study Group. It provides a 10 MHz reference as well as a GPS disciplined substitute for the master oscillator or local oscillator of various commercial transceivers or transverters. The discussion thread can be read at https://groups.google.com/forum/#%21topic/2-meter-wspr/-hDK071K1iM
I connected a length of RG-174/U 50 ohm miniature coaxial cable to unused J8 for 116 MHz reference signal from the GPS10V.
Elecraft XV144 Transverter modification for GPS frequency reference. The 47Ω resistor suppresses the 116 MHz crystal oscillations and Q1 functions to amplify the external 116 MHz reference signal.
Here is the unmodified local oscillator circuit of the Elecraft XV144 transverter.
The Elecraft XV144 transverter GPS reference modification. The .01 μF capacitor and 47 Ω resistor are soldered across R5 and the RG-174/U cable connected across the 47 Ω resistor.
Prior to 30 June 2013, the Elecraft XV144's internal local oscillator with crystal oven option and additional ventilation and temperature insulation exhibited significant frequency drift during each 2 minute WSPR transmission. This frequency drift was eliminated with the GPS10 frequency reference.
The Elecraft XV144's internal local oscillator with crystal oven option and additional ventilation and temperature insulation exhibited significant frequency instability with ambiental temperature changes. This frequency instability was eliminated with the GPS10 frequency reference.
WaveNode modulation display during 144 MHz WSPR transmission. This is a signal tone 1500 Hz on upper sideband.
The ripple is caused by heterodyne beats with the suppressed lower sideband and carrier.
WaveNode signal spectrum display during 144 MHz WSPR transmission.
The peaks at 1500 Hz and 3000 Hz are caused by heterodyne beats with the suppressed lower sideband and carrier.
WaveNode Modulation QuickView display during 144 MHz WSPR transmission.
The peaks at 1500 Hz and 3000 Hz are caused by heterodyne beats with the suppressed lower sideband and carrier.
Spectrum analysis of 55 watt 2 meter WSPR signal from FlexRadio 1500, Elecraft XV144 Transverter and Mirage B2518G Linear Amplifier.
The WSPR transmission is the large peak on the right at 144.4905 MHz.
The central peak is the suppressed carrier and the left peak is the suppressed lower sideband.
The unwanted signals would appear to be suppressed about 40 dB from the upper sideband WSPR signal.
This is a SDRSharp software screen capture with an uncalibrated $20 RTL-SDR USB DVB-T dongle receiver with sample rate 0.25 MSPS, both RTL and Tuner AGC off, and RF Gain set to 9 dB.
FlexRadio 1500 specifications are: SSB Carrier Suppression : At least 55 dB below peak output.
Undesired Sideband Suppression : At least 55 dB below peak output.
Spectrum analysis of 5.1 watt 2 meter WSPR signal from FlexRadio 1500, Elecraft XV144 Transverter without the Linear Amplifier.
All signals would appear to have decreased about 10 dB at this lower power level.