[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

Re: True FT-847 Minimum Power Output

At 11:59 PM 5/9/2006 +0000, Keith O'Brien wrote:
>With the happy announcement of one year anniversary of HamSat (VO-52), it 
>has reminded me of a question I have about my Yaesu FT-847. HamSat has such 
>a sensitive receiver that I very often find that I can hear myself 599 with 
>the FT-847 RF Power Level turned all the way down. But what I don't know is 
>just how much power that is.
>Has anyone ever measured what the minimum power output is of a FT-847 with a 
>accurate, calibrated wattmeter. Does the input DC voltage say between 12.6 
>and 13.6volts, have a bearing on it. I know the rig front panel meter shows 
>something on the order of 3 or 4 watts. My MFJ wattmeter I use can't be 
>relayed upon. From my past experience with Mighty Fine Junk power meters, 
>any resemblance between what it reads and what is actually there is strictly 
>coincidental. But that's another story.
>What ever the power level is, sometimes it still too much for HamSat. A 
>testament to how well that bird still hears after one year on orbit. Wonder 
>when we can expect the Dutch transponder to be switched back on so I can see 
>if it's just as sensitive as the VU.
>73 Keith


I have measured my FT-847 at minimum CW power on 144 MHz.  Using a Bird-43
meter with 5w element I see about 1.8w output.  It can vary about 0.2w from
measurement to measurement up to 2w.  I run my FT-847 at 14vdc so this may
be slightly higher than what you would see at 12.6 or 13.6 volts.  I know
that my maximum power is a few watts higher using the higher dc voltage
(55w CW into a load).  I do see more power output at 147 MHz than 144 MHz
so the radio apparently is tuned to the higher freq.  I sent the radio into
Yaesu in 1999 to have birdies removed and they tweaked the VHF and UHF
transmitter output for me (gained about 7w on each).
Ed - KL7UW 
BP40iq,  Nikiski, AK      http://www.qsl.net/al7eb
Amsat #3212
Modes: V - U - L - S
Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
Not an AMSAT member? Join now to support the amateur satellite program!
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org