[TenTec] Scout 555: power goes down as frequency goes up

[dukeshifi]

I think I have a pair. NOS USA made.

Gary

> On Jun 12, 2019, at 5:12 AM, Carlos <carlos.peco at gmail.com> wrote:
> 
> Well, mistery solved.
> 
> One of the two drivers (2SC2166) is crook. At least they are cheaper than
> the MRF455 finals.
> 
> A popular auction site is plagued with counterfeits, it is too risky to buy
> there (I was badly burnt with 4 x VRF2933 recently). Any good source out
> there ? Buying RF devices from China is like going on a picnic to a
> minefield.
> 
> 
> 73,
> Carlos VK1EA
> 
> 
> 
> On Saturday, June 1, 2019, Carlos <carlos.peco at gmail.com> wrote:
>> Hi Gary,
>> 
>> I measured the power generated in "tune" mode. I did not have a
> microphone or a key with me, but the low power issue appears in both SSB
> voice or with a key.
>> 
>> QRG    PWR    I at 12.5VDC
>> 
>> 3700   10W   5.4A
>> 7200    9W   5.2A
>> 14200   8W   5.0A
>> 21400  0.5W  1.8A
>> 28200  0.25W 1.5A
>> 28700  0.2W  1.5A
>> 
>> I don't know if this is one of the Scouts with the FET driver. Going for
> a trip tomorrow, I hope to check it next weekend.
>> 
>> I bought the radio from ebay Australia, it was a total scam. It took me a
> while to fix all the issues, I even had to fit a new PTO shaft (the radio
> had been dropped by someone and it was bent).
>> 
>> 73,
>> Carlos VK1EA
>> 
>> 
>> 
>> 
>> On Saturday, June 1, 2019, MadScientist <dukeshifi at comcast.net> wrote:
>>> Does your Scout have the FET driver transistors or the bipolar?
>>> 
>>> Can you measure current drawn by the radio when transmitting?
>>> 
>>> If so, check to see if the current draw on the weak bands is the same or
> higher than on the strong bands.
>>> 
>>> As it happens, the signal going through the driver stage can get
> distorted (harmonic distortion) and these harmonics go into the final  but
> not out the low pass filter, so all that lost signal is lost as heat in the
> final and LPF.
>>> 
>>> Gary
>>> 
>>> Sent from my iPad
>>> 
>>>> On May 31, 2019, at 10:29 PM, Carlos <carlos.peco at gmail.com> wrote:
>>>> 
>>>> Hi,
>>>> 
>>>> I'm very fortunate having several Ten-Tec radios. I use one for several
>>>> weeks, then I put it aside, and use the next one for some more weeks.
>>>> 
>>>> So I have this Scout that I have only used in 80/40, where it puts full
>>>> power (slightly more in 80 meters). But I also have modules for 20/15/10
>>>> and the other day I decided to check their health.
>>>> 
>>>> Well, everything seems to be OK in RX but, to my dismay, output power
> drops
>>>> as you go up in frequency, up to the point of putting less than 5W in 10
>>>> meters.
>>>> 
>>>> Before I start investigating, maybe someone knows of a common issue
> that I
>>>> should be looking at in the first place?
>>>> 
>>>> Many thanks in advance,
>>>> Carlos VK1EA
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>>> 
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