I believe that MFJ at least used to sell a fix for that - probably a high
pass filter.
Gene / W2LU
----- Original Message -----
From: "Grant Saviers" <grants2@pacbell.net>
To: "jim feldman" <mtnredhed@gmail.com>; <TowerTalk@contesting.com>
Sent: Monday, December 06, 2010 2:18 PM
Subject: Re: [TowerTalk] who's "right" (a tuner question)
> Your MFJ may not be "hosed" because it is sensitive to other frequency
> RF as it energy detects broad-banded. Mine is unusable on antennas
> because of a 50kw AM band tower about 1 mile away. OTOH my AIM4170
> handles the same situation with just an small noise blip which easily
> averages out.
>
> Grant KZ1W
>
> On 12/6/2010 10:30 AM, jim feldman wrote:
>> The cast of players: Kenwood TS-940, Heath SA 2060 ant. tuner, MFJ 259.
>> I
>> was trying to use the MFJ to create a table of settings for the tuner.
>> Just
>> wasn't working (never could find a SWR much lower than say 1.8:1). After
>> further reading, I tried the noise peaking method with C.out at max, C.in
>> at
>> about half and I dialed in L from the bottom. Once I had that (which got
>> me
>> surprisingly close), I turned the 940 power all the way down (around
>> 10w),
>> set the output to cw, hit transmit (after a quick ID) and dialed in a
>> near
>> 1:1 match in any band between 75-15. The TS-940 SWR readings were pretty
>> close to the meter on the tuner.
>>
>> So who's right and why? In one corner we have the transmitter and tuner.
>> Close enough I'd consider them the same. Should I prefer the tuner
>> reading?
>> In the other corner, we have the MFJ that wasn't even in the same
>> ballpark.
>> Is it hosed? I had it cabled to the tuner input for testing purposes.
>> Is
>> it because of the low output of the MFJ? I swapped around all cables
>> except
>> the output to the antenna. Put fresh cells in the MFJ.
>>
>> All connections were either RG8x (foil and braid) or RG213 except LMR400
>> out
>> to the trapped vertical antenna. Yes, I'm aware of the efficiency issues
>> here, but I'm on a small suburban lot with 35ft height restrictions and a
>> YL
>> who tolerates (just) my "metal pokey things" in her garden.
>>
>> thanks
>> jim (w6jmf)
>> _______________________________________________
>>
>>
>>
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