[Yaesu] Ft1kMP loss of receive gain

[Tyler Stewart]

Is it frequency dependent?  A good check is find the points where it rolls
over to the next bandpass filter and see if the sensitivity drop
appreciably.  All my problems have been confined to the HPF and RF units.

I assume you have tweaked the RF Gain in the hidden menu?  I usually have
mine set to around 14, but it is somewhat radio dependent.

You can bypass the HPF board to eliminate it by using the RX In port instead
of the antenna jack.

Do you have the service manual?

Ty K3MM


-----Original Message-----
From: yaesu-bounces at contesting.com [mailto:yaesu-bounces at contesting.com] On
Behalf Of G3SJJ
Sent: Saturday, December 16, 2006 9:41 AM
To: yaesu at contesting.com
Subject: Re: [Yaesu] Ft1kMP loss of receive gain

Thanks Ty. Well the problem does seem to be further along. I have determined
that the sub-rx is mores sensitive than the main rx but several s-units, so
the fault looks to be in the main rx IF chain. It is not the roofing filter
either.

Chris G3SJJ


-----Original Message-----
From: Tyler Stewart [mailto:k3mm at verizon.net] 
Sent: 16 December 2006 05:52
To: 'G3SJJ'; yaesu at contesting.com
Subject: RE: [Yaesu] Ft1kMP loss of receive gain


Over the years, I've had several of the small coils in both the LP/HP and
bandpass filters go bad...I'm sure due to excess RF.  They seem pretty
fragile.  Since I started using RX limiters in the RX line, I havent had any
more trouble.

Ty K3MM
 

-----Original Message-----
From: yaesu-bounces at contesting.com [mailto:yaesu-bounces at contesting.com] On
Behalf Of G3SJJ
Sent: Monday, December 11, 2006 4:48 AM
To: yaesu at 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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