I maybe way off but I think someone posted this type of problem a while back
and it turned out to be a defective Inrad roofing filter. Roofing filter
was removed and things returned to normal.
Any chance that might be the problem here?
Cecil....
----- Original Message -----
From: "G3SJJ" <g3sjj@btinternet.com>
Cc: <yaesu-bounces@contesting.com>; <yaesu@contesting.com>
Sent: Monday, December 11, 2006 10:26 AM
Subject: Re: [Yaesu] Ft1kMP loss of receive gain
> Thanks Mike. We had plenty of separation and bandpass filters.
>
> The suspicion is that the radio hasn't been smoked as a result of the
> contest, but there is definitely a receive fault. I am trying to
> determine where to look.
>
> Listening to broadband white noise on 160m from local high voltage
> power lines, the Main Rx S-meter registers s1, where as Sub Rx registers
> s6-7, which is more like what I am used to. Looking at the cct diag, the
> paths are common until a hybrid coupler and then the main Rx signal goes
> into the 1st mixer. so the problem may be around here. I wondered if
> anyone has experienced this before.
>
> Chris G3SJJ
>
>
> Mike K9MI wrote:
>> Since the ARRL has the new "F" class (operating from an EOC) we have been
>> operating from our EOC where the antennas for the 2 rigs we use are
>> within
>> about 40ft, and at the same height. Testing shows that around 3 watts is
>> seen on the wattmeter, using one antenna hooked to a dummy load and watt
>> meter. We use coaxial stubs and now you can see a very very small
>> movement
>> on the watt meter. So, we use the stubs every year, although the bandpass
>> filter I'm sure would be better, more elegant way to approach the
>> problem.
>> Ice and Dunestar make these and Dunestar has an "all band" box, but I'm
>> thinking it is around $600. We're just using 100 watts. I have not
>> purchased
>> it, but George of Inrad has written a book on how to tackle the problem
>> of
>> interstation interference. That is one of many things on my wish list.
>>
>> 73, Mike K9MI
>>
>> ---- Original Message -----
>> From: "dsthill" <dsthill@cbcbarbados.bb>
>> To: <yaesu-bounces@contesting.com>; <yaesu@contesting.com>
>> Sent: Monday, December 11, 2006 15 28
>> Subject: Re: [Yaesu] Ft1kMP loss of receive gain
>>
>>
>>
>>> Hi Chris
>>>
>>> As someone who zapped an FT1kmpMK5 about a year ago, I think it's easier
>>> than you think. I hope you were using bandpass filters on this rig. It's
>>> a
>>> common mistake I think to not use them in some situations. I think
>>> though
>>> in
>>> a multi-transmitter setup, it's very important that each rig has
>>> necessary
>>> filters.
>>>
>>> I've actually measured 1 to 5 watts at the end of some of my coax cables
>>> when transmitting on another antenna.
>>>
>>> When I did my repair, it was just a single diode or a pair that were
>>> bad,
>>> but it was the labour that was "expensive" - $200+ for labout against $5
>>> for
>>> parts!!!!
>>>
>>> Hope it's not that bad!!!
>>>
>>>
>>> Dean - 8P6SH
>>>
>>>
>>>
>>> -----Original Message-----
>>> From: yaesu-bounces@contesting.com [mailto:yaesu-bounces@contesting.com]
>>> On
>>> Behalf Of G3SJJ
>>> Sent: December 11, 2006 5:48 AM
>>> To: yaesu@contesting.com
>>> Subject: [Yaesu] Ft1kMP loss of receive gain
>>>
>>> I am noticing a receive loss of around 10-12 dB. I have checked Antenna
>>> B and receive antenna inputs. They are the same.
>>>
>>> What I do notice is around 2-4 s units difference in indicated signal
>>> strength between main and sub Rx, which would indicate the problem is
>>> after the 1st mixer.
>>>
>>> We recently used the radio as a spotter in CQWW CW at G5W . Whilst it is
>>> unlikely, we could have zapped the front end somewhere.
>>>
>>> Anyone got any thoughts?
>>>
>>> Chris G3SJJ
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>>>
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>>>
>>
>>
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