Tone modulation on Transmit. The test equipment was GPS locked.
After much contemplation and investigation and reading reviews on eham and other forums, I took a chance and ordered a Yaesu VX-7R from Gigaparts. The unit was to replace an FT-50R that was stolen from my car.
I programmed the local 444.175 MHz repeater, and joined a QSO, BUT was immediately told that the audio was barely audible. Having obtained a First Class FCC license in 1966, and been in on the design of several products at Motorola, including the 800 MHz "MX" series radio, and now do broadcast microwave consulting, I took the VX-7R into my shop, and fired it up.
The deviation was measured at +/- 2.35 KHz with a steady 400 Hz tone applied. The test cable was removed, and the deviation was measured under normal operating conditions, which for me, amounted to speaking into the small mic hole at a distance of approximately 4". This distance produced an average deviation of +/- 1.17 KHz (although the deviation was non-symmetrical and appeared distorted). The unit heated up rapidly, and as it did, the modulation would intermittently drop out.
I keyed the unit through a pad into a modulation analyzer, and measured the PL deviation (see picture below).
Tone modulation on Transmit. The test equipment was GPS locked.
A 400 Hz tone was applied, and the MAX DEV was reset with the tone applied, for a peak deviation of +/- 4.5 KHz. The recovered transmit audio was distorted at the original factory deviation setting, and retained the same percentage of distortion as the MAX DEV was re-adjusted for the proper level. This +/- 4.5 KHz deviation level, together with properly adjusted PL tone level (+/- 0.5 KHz), produce the proper deviation standard of +/- 5.0 KHz. (See distorted recovered transmit audio below)
VX-7R has distorted UHF transmit audio and is intermittent.
The same unit produced relatively clean audio on 2 meters.
VX-7R 2 meter transmit audio was relatively clean.
Even though the Yaesu Tech was informed that the unit was intermittent and produced distorted audio when working, they would not authorize Gigaparts to send a replacement radio, even though they were notified 3 days after I received this unit.
I was given the choice of having this unit returned to me, or sending it to Yaesu. I chose to send this defective unit to Yaesu.
I lucked out with my Yaesu FT-101 and FT-50R that was stolen, but this ends my dealings with Yaesu, especially since a hurricane is coming, and I have no handheld.
My Business website is www.TVtower.com
I finally was sent a replacement VX-7R, and this second unit worked flawlessly. After a couple years of service, my only complaint is that the silver paint on the upper corner of the case began to peel.
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