[R-390] R-390a Image problem?

[Bob Camp]

Hi

I'd check the grounds as Jon suggested. The R390 can pick up "stuff"  
from the power line pretty easily. The AC line filter works both ways  
with a loose ground ...

Next up would be to start swapping front end tubes. You may find that  
you simply have a defective tube. You may also find that somebody  
"improved" the design by putting in a tube that didn't belong there.

Bob

On Oct 19, 2007, at 8:58 PM, Tony Casorso wrote:

> Hi Bob, I'm using the balanced input. I bought a twinax to BNC  
> adapter so one side of the balanced input is grounded.
>
> Same antenna doesn't bother the R-392.
>
> Tony
>
>
> ----- Original Message ----- From: "Bob Camp" <ham at cq.nu>
> To: "Tony Casorso" <canthony15 at msn.com>
> Cc: <R-390 at mailman.qth.net>
> Sent: Friday, October 19, 2007 6:52 PM
> Subject: Re: [R-390] R-390a Image problem?
>
>
>> Hi
>>
>> Which antenna input are you running into? The situation you  
>> describe would be pretty typical if you run a long antenna into  
>> the  "unbalanced" input.
>>
>> Bob
>>
>>
>> On Oct 19, 2007, at 8:31 PM, Tony Casorso wrote:
>>
>>> Hi everyone. This is my first post to the list although I've been  
>>> following it for a long time now. A few months back I bought a  
>>> 67  EAC R-390a. The only problem I had was an open Z-503 AGC  
>>> coil. I  replaced that and did an alignment and the radio seemed  
>>> to be  working real well. Sensitivity was very good on all bands.  
>>> Recently  I've noticed broadcast stations coming through in the  
>>> 3Mhz band. A  local station on 1650KHz is about 40db at 3300KHz  
>>> on the R-390a. I  don't hear it on my R-392. Even moving the  
>>> 2-4MHz RF slug rack by  hand, I still hear the station (although  
>>> it does get a bit  quieter). There are several other stations  
>>> coming through as well  on other frequencies. I didn't notice  
>>> anything odd when I aligned  it, everything seemed to peak like  
>>> it should. Looking around at  other frequencies with my signal  
>>> generator, I started noticing all  kinds of harmonic responses,  
>>> but that is probably (at least to some degree) just my signal  
>>> generator (a Boonton 102C). I'm pretty sure something is wrong  
>>> here but I'm scratching my head trying to think  of a good  
>>> explanation. If the BC station harmonic was that bad, I'd  hear  
>>> it in my other radios I would think.
>>>
>>> Ideas anyone? How do I track this one down?
>>>
>>> Thanks,
>>>
>>> Tony
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>