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?
----- Original Message -----
From: "G3SJJ" <firstname.lastname@example.org>
Cc: <email@example.com>; <firstname.lastname@example.org>
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
>> 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
>> 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
>> 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
>> it, but George of Inrad has written a book on how to tackle the problem
>> interstation interference. That is one of many things on my wish list.
>> 73, Mike K9MI
>> ---- Original Message -----
>> From: "dsthill" <email@example.com>
>> To: <firstname.lastname@example.org>; <email@example.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
>>> common mistake I think to not use them in some situations. I think
>>> a multi-transmitter setup, it's very important that each rig has
>>> 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
>>> but it was the labour that was "expensive" - $200+ for labout against $5
>>> Hope it's not that bad!!!
>>> Dean - 8P6SH
>>> -----Original Message-----
>>> From: firstname.lastname@example.org [mailto:email@example.com]
>>> Behalf Of G3SJJ
>>> Sent: December 11, 2006 5:48 AM
>>> To: firstname.lastname@example.org
>>> 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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