Ive done something similar here by adding an MFJ 959C Preamp/Antenna
Tuner. It's a nice preamp with ability to bypass, a simple L tuner with
tunable inductance and C, a gain control for the preamp, by pass
switches for the tuner and/or preamp and 2 input switches and 2 output
switches. All for about 79 I think. In any case it's my preamp for the
Flags and Pennants as well as the noise antenna preamp for the MFJ
1025. I really don't use the ANC4 any more but occassionally will put
it out. I have noticed the tuned input helps peak the noise antenna -
very useful especially when you have a few and gives the added
flexibility for one more control to ride that noise up or down external
to the nuller. It is extra complexity and may sound silly but in a
local noise challenged suburban development, the choices are bleak. I
believe this MFJ product is rather unique on the market with all the
inputs/outputs and switching. I woudn't recommend it for contest
operation however given the limitations of the cheapie preamp circuit.
Pete W2PM
-----Original Message-----
From: Markus Hansen <mkve7ca@gmail.com>
To: topband@contesting.com
Sent: Mon, Dec 14, 2009 8:15 pm
Subject: Re: Topband: ANC-4 and MFJ-1026 Comparison
Tadek, SP7HT has asked me to share with the TOPBAND group his experience
with the ANC-4 and MFJ-1026. I quote below his email message:
"For years I am competing with local noises using ANC-4 (firstly) and
MFJ-1026 (last 10 months) for noise cancelling. I've modified the Front
End
of my old ANC-4 adding a tuned resonant circuit at the Input of Noise
Channel (low impedance Input to resonant circuit, next High impedance
paralell resonance circuit using ferrite core and RX tuning capacitor I
can
cover in 4 sub-bands from 1.74MHz to 30.1MHz and at the output low
impedance
to connect directly to ANC-4 noise antenna Input socket).
At the Output of that modification (outside ANC-4 case) I can adjust the
level of noise signal (470 Ohm potentiometer) connected to ANC-4. So, I
can
adjust NOISE GAIN in the middle position, when best cancelling can be
reached (in ANC-4).
Thanks to selective resonance circuit at the Input of Noise antenna I
can
avoid intermodulation products when propagation is in a great shape
(birdies
appeard every 5kHz or every 10kHz).
According to local noises in my location (a 5 floor block of flats, 19
neighbours in that house and about 300 neighbours in 100 metres circle
around my location) I can say (today) that modified ANC-4 is a better
tool
to fight with local noises noises on 80CW than newest version of
MFJ-1026.
73 Tadek SP7HT"
--
Markus Hansen
VE7CA, North Vancouver, BC CANADA
Web site: http://www.shelbrook.com/~ve7ca/
_______________________________________________
160 meters is a serious band, it should be treated with respect. - TF4M
_______________________________________________
160 meters is a serious band, it should be treated with respect. - TF4M
|