Roger,
Several articles have been written over the years (and postings made on
this reflector) about the usefulness of AM mode in tracking down noise
sources. Those HTs that offer aircraft band reception do use AM for that
range, and so are acceptable. The least effective mode is FM, because of
the use of limiters in the receive signal path. (The exception occurs when
tracking down RFI due to cable TV systems. If the system is analog and has
leaks in the 2m band, an FM HT is ideal for locating the source of the leak
by using the audio portion of the signal.)
As for the list of rigs, you may wish to add the Yaesu 817, which is the
QRP version of the 897, costs less, weighs less, and can be powered by AA
cells. I agree that rigs with SSB capability can be used, but AM mode does
work better with arcing sources.
73, Dale
WA9ENA
> [Original Message]
> From: Roger (K8RI) <k8ri@rogerhalstead.com>
> To: <rfi@contesting.com>
> Date: 1/23/2012 12:18:46
> Subject: Re: [RFI] Using VHF HT to "sniff-out" RFI
>
> On 1/23/2012 12:02 AM, Dirk Hacker wrote:
> > Hello all.....
> >
> > A handy tool to "sniff-out" noise and RFI is a VHF HT (handheld
xcvr)..with
> > small directional/yagi antena.
> >
> > Is a 2m FM HT suited enough for this purpose ?....
> > or is it the wrong tool for the job because you can hear noises best in
AM mode
> > ?
> "I think" the new breed of mobile rigs like the Yaesu 897D (and their
> QRP brethren) or Icom 7000 make great rigs for RFI hunting. Any mode
> and they'll cover almost DC to daylight.
> The Yaesu even has an optional battery pack although a bit pricey and
> those batteries don't last forever.
>
> Now days there are a LOT of those two rigs out there so there's likely
> to be some one with one handy to help out running down RFI. The rig on
> a shoulder strap, several feet of coax, and a sensing loop with a VHF,
> UHF Yagi for back up.
> >
> > Is it common practice to walk-around/use...
> > 1) a HT with AM mode that covers at least 136-150MHz (if not AM from
> > am-broadcast band up to VHF) ?
> Although some would argue I find SSB works just fine although both of
> the rigs mentioned I believe will run AM as well.
>
> 73
>
> Roger (K8RI)
>
>
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