[TenTec] Omni VII first impressions....odd things i.e. SWRvalues

[Bob McGraw - K4TAX]

Mike:

OK good to know that the rig is not folding back due to erroneous SWR values 
indicated internally.  Likely it is a defective otherwise intermittent diode 
in the SWR bridge circuit.  This would likely be D3 which is a BAT41 device. 
Again, I'd suspect either a board replacement from Tentec or a trip for the 
radio back to Sevierville is in order.  My preference, the latter.

As to actual power output, the spec is 100 watts +/- 1 dB which would 
indicate a high, nominal 100 watts, to be about 125 watts and a low, nominal 
100 watts to be about 76 watts.  Now, if due to Vcc drop on the power cable, 
series fuse, internal wiring, PC board traces and such the nominal power 
value is 90 watts then the up and down values would be 113 and 71 
respectively.  And it could be greater if the nominal value were 80 watts, 
otherwise, 100 watts at the upper end of the spec and as low as 63 watts. 
Of course all of these are calculated values and do not take into 
consideration typical power meter tolerances of +/- 10%.  One other post 
indicated his measured output power to be 99 down to 65 watts.  This numbers 
looks to be "in spec" as well.

In checking mine this evening, it is running 90 watts, diminishing somewhat 
downward as band/frequency increase with 12M & 10M being the lowest at 75 
watts.  I didn't have a slug at the house to measure the 6 meter output.  At 
the same time, I could see the Vcc from the power supply decrease about 1/2 
needle width, whatever that amounts to.  The DVM was not at the desk so I 
couldn't confirm the actual Vcc at the radio.  Perhaps this week I'll put 
the radio on the bench with the adjustable supply and see what happens at 
14.0 volts at the radio under transmit load.  I suspect that the power will 
be very close to 100 watts on all bands.

Thanks for sharing your findings.  Doesn't sound to serious to me.

73
Bob, K4TAX



----- Original Message ----- 
From: "Mike Bryce" <prosolar at sssnet.com>
To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
Sent: Saturday, December 22, 2007 5:45 PM
Subject: Re: [TenTec] Omni VII first impressions....odd things i.e. 
SWRvalues


> bob....
>
> the output power on the bird shows forward power like it should, but
> it is lower than what I would expect for a $3K rig.
>
> But the output did NOT vary with the swr.. like it should if the swr
> went up to 9 to 1
>
>
>
>
> Mike, WB8VGE
> SunLight Energy Systems
> The Heathkit Shop
> http://www.theheathkitshop.com/
> J e e p
> o|||||||o
> Note: No trees were killed in the sending of this message, but a
> large number of electrons were terribly inconvenienced
>
>
> On Dec 22, 2007, at 5:53 PM, Bob McGraw - K4TAX wrote:
>
> Mike:
>
>
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