Mon DU1FV

 notes from auction site ic-706 Product Description It is in working condition. The transmission output on each amateur band was measured using our uncalibrated power meter. 1.9MHz band: 85W, 3.5MHz band: 100W, 7MHz band: 95W, 10MHz band: 90W 14MHz band: 94W, 18MHz band: 94W, 21MHz band: 88W, 24MHz band: 85W 28MHz band: 85W, 50MHz band: 58W, 144MHz band: 11W It was. [Photo 9] The cooling fan operation was also confirmed. (Normal: Low speed, When transmitting at a speed other than 144MHz: High speed) There are no strange noises. There was no noticeable difference in reception compared to other amateur radios. However, due to the inherent performance of this model, the reception sensitivity in the 144MHz band is poorer than other models. We carry out the following repairs: This is a problem specific to this model, but it is caused by insufficient support on the female side of the power connector. PA unit L21, L31, and Q5 were pushed off by the housing and fell off. L21 and L31 were t...

 My First Software Defined Radio at less than P5k I bought this on a whim, and when I got it, I kicked myself for not ordering it sooner! Some tech details from the Readme:   For SSB reception, the a digital SDR phasing stage is used; this means that a Tayloe Quadrature Samplimg detector supplies individual I and Q outputs, directly fed into the ATMEGA328P ADC inputs for signal processing. The ATMEGA328P (over-)samples the ADC input at a 62kHz sample-rate, an decimates this high-samplerate to a lower samplerate, performs a phase-shift by means of a Hilbert-transform, summing the result to obtain side-band rejection; it subsequently applies a low-pass filtering, AGC and noise-reduction functions. The ADC inputs are low-pass filtered (-40dB/decade roll-off at 1.5kHz cut-off) to prevent aliasing and input are biased with a 1.1V analog reference voltage to obtain additional sensitivity and dynamic range. With the 10-bit ADCs and a 4x over-sampling rate, a theoretical dynamic range...

  "Bago ako naging ham operator, tambay lang ako sa kanto." This roughly translates to "Before I became a ham, I used to hang around a lot at the street corner." Sometime back in the early 70s, somebody decided to put up a Radio TV repair shop at the main corner of our barrio. The shop would play Beatles vinyls often and soon I go to sitting on the long bench at the shop's entrance watching people go by and enjoying the good music off two baffles hanging on walls of both sides of the shop. In the 60s and earlier, a favorite pastime was to sit at the corner "lamyaan", an elevated wooden platform positioned at strategic corners of the barrio where men would sit around and share stories after a hard morning's work in the rice fields and river vegetable plots (called "tumana"). The PInoy word "tambay" is from the english "stand by". So indeed I was a "tambay sa kanto" I got to know the owner well. He was traine...

  Erwin Hackl OE5VLL said "How it came about: Due to a momentary idea, I bought a defective FT757GX2 on ebay. In addition, there was the statement "Frequencies are displayed, noise comes from the loudspeaker, no test option". Of course, you can get such a device much cheaper than a fully functional one, but it needs to be repaired and I wanted to accept this challenge. First function tests: A first simple reception test showed that the device apparently works, but a station that was well received on a comparison device could not be heard on the 757. It soon turned out that the receiving frequency deviated from the displayed frequency by a few kHz. This made it clear that the crystals that determine the frequency were already showing major deviations due to their age of around 30 years. For common crystal oscillator circuits, this means that the series capacitance must be reduced (parallel to the tuning capacitor). Frequency processing: If you start to “crank” the frequen...