Scanner Antenna Question

Scanner Antenna Question

Post by Bob » Sun, 10 Oct 1999 04:00:00

I have a L-Bracket screwed into an aluminum overhang near a roof, with
RG-58A/U cable attached w/ BNC to a RS-2026.

I am getting very good reception on local police and high wattage repeaters
but anything long distance, even with a repeater has background noise to it.
I never had this problem before.  I am using a MAXRAD MMC-150 high gain
antenna. I live in northern NJ and I listen to CENCOM and MICCOM MICU
dispatch which is in the 150MHz range and also 40-47MHz range with the same
antenna ,as well as local police and NJ transit police.

My question is how do I elimate this background noise??  It sounds like a
hissing sound.

Any ideas or tips would be greatly appreciated.

Bob D

 
 
 

Scanner Antenna Question

Post by Glen » Sun, 10 Oct 1999 04:00:00


You say you never had this problem before so did you change anything?

 If you have changed nothing then start with the easy stuff first. The
hissing is possibly caused by a reduction in signal strength so it is no
longer full queiting. I would check connnectors, both ends. Is the outside
connector sealed? Could water have gotten into the coax?  Cable jacket not
broken or split?

Thats a start. RG-58 is not what I would recommend unless it is a real short
run.

Glenn


> I have a L-Bracket screwed into an aluminum overhang near a roof, with
> RG-58A/U cable attached w/ BNC to a RS-2026.

> I am getting very good reception on local police and high wattage
repeaters
> but anything long distance, even with a repeater has background noise to
it.
> I never had this problem before.  I am using a MAXRAD MMC-150 high gain
> antenna. I live in northern NJ and I listen to CENCOM and MICCOM MICU
> dispatch which is in the 150MHz range and also 40-47MHz range with the
same
> antenna ,as well as local police and NJ transit police.

> My question is how do I elimate this background noise??  It sounds like a
> hissing sound.

> Any ideas or tips would be greatly appreciated.

> Bob D

 
 
 

Scanner Antenna Question

Post by Bob » Mon, 11 Oct 1999 04:00:00

I have sealed the coax at the mount with silicone.  The only thing I did was
change location to a higher elevation.  I used 10/24 SS machine screws


> You say you never had this problem before so did you change anything?

>  If you have changed nothing then start with the easy stuff first. The
> hissing is possibly caused by a reduction in signal strength so it is no
> longer full queiting. I would check connnectors, both ends. Is the outside
> connector sealed? Could water have gotten into the coax?  Cable jacket not
> broken or split?

> Thats a start. RG-58 is not what I would recommend unless it is a real
short
> run.

> Glenn


> > I have a L-Bracket screwed into an aluminum overhang near a roof, with
> > RG-58A/U cable attached w/ BNC to a RS-2026.

> > I am getting very good reception on local police and high wattage
> repeaters
> > but anything long distance, even with a repeater has background noise to
> it.
> > I never had this problem before.  I am using a MAXRAD MMC-150 high gain
> > antenna. I live in northern NJ and I listen to CENCOM and MICCOM MICU
> > dispatch which is in the 150MHz range and also 40-47MHz range with the
> same
> > antenna ,as well as local police and NJ transit police.

> > My question is how do I elimate this background noise??  It sounds like
a
> > hissing sound.

> > Any ideas or tips would be greatly appreciated.

> > Bob D

 
 
 

Scanner Antenna Question

Post by Glen » Mon, 11 Oct 1999 04:00:00

Bob

I doubt the 10/24 SS machine screws make a difference unless you put them
through the coax. I do know that some brands of silicone sealant will
destroy your coax, it has something in it that is very corrosive. How long
ago did you seal them? How old is the coax? My other thought is though
higher is better your original location could have been a hot spot for
reception of the signals you listen to. You did move the antenna and some
there caused the change. BTW, what kind of antenna is it?

Glenn


> I have sealed the coax at the mount with silicone.  The only thing I did
was
> change location to a higher elevation.  I used 10/24 SS machine screws



> > You say you never had this problem before so did you change anything?

> >  If you have changed nothing then start with the easy stuff first. The
> > hissing is possibly caused by a reduction in signal strength so it is no
> > longer full queiting. I would check connnectors, both ends. Is the
outside
> > connector sealed? Could water have gotten into the coax?  Cable jacket
not
> > broken or split?

> > Thats a start. RG-58 is not what I would recommend unless it is a real
> short
> > run.

> > Glenn




- Show quoted text -

Quote:> > > I have a L-Bracket screwed into an aluminum overhang near a roof, with
> > > RG-58A/U cable attached w/ BNC to a RS-2026.

> > > I am getting very good reception on local police and high wattage
> > repeaters
> > > but anything long distance, even with a repeater has background noise
to
> > it.
> > > I never had this problem before.  I am using a MAXRAD MMC-150 high
gain
> > > antenna. I live in northern NJ and I listen to CENCOM and MICCOM MICU
> > > dispatch which is in the 150MHz range and also 40-47MHz range with the
> > same
> > > antenna ,as well as local police and NJ transit police.

> > > My question is how do I elimate this background noise??  It sounds
like
> a
> > > hissing sound.

> > > Any ideas or tips would be greatly appreciated.

> > > Bob D

 
 
 

Scanner Antenna Question

Post by Bob » Mon, 11 Oct 1999 04:00:00

coax is 6 months old.  I used black silicone, I use the same stuff for
sealing drilled holes in metal for lightbars.  The coax was sealed maybe
week and a 1/2 ago.  I sealed it where the coax is sottered to the M-Mount.
The antenna is a Maxrad MMC-150 and I switched to a MHB-5800, and I still
get the same results.

Bob

> Bob

> I doubt the 10/24 SS machine screws make a difference unless you put them
> through the coax. I do know that some brands of silicone sealant will
> destroy your coax, it has something in it that is very corrosive. How long
> ago did you seal them? How old is the coax? My other thought is though
> higher is better your original location could have been a hot spot for
> reception of the signals you listen to. You did move the antenna and some
> there caused the change. BTW, what kind of antenna is it?

> Glenn


> > I have sealed the coax at the mount with silicone.  The only thing I did
> was
> > change location to a higher elevation.  I used 10/24 SS machine screws



> > > You say you never had this problem before so did you change anything?

> > >  If you have changed nothing then start with the easy stuff first. The
> > > hissing is possibly caused by a reduction in signal strength so it is
no
> > > longer full queiting. I would check connnectors, both ends. Is the
> outside
> > > connector sealed? Could water have gotten into the coax?  Cable jacket
> not
> > > broken or split?

> > > Thats a start. RG-58 is not what I would recommend unless it is a real
> > short
> > > run.

> > > Glenn



> > > > I have a L-Bracket screwed into an aluminum overhang near a roof,
with
> > > > RG-58A/U cable attached w/ BNC to a RS-2026.

> > > > I am getting very good reception on local police and high wattage
> > > repeaters
> > > > but anything long distance, even with a repeater has background
noise
> to
> > > it.
> > > > I never had this problem before.  I am using a MAXRAD MMC-150 high
> gain
> > > > antenna. I live in northern NJ and I listen to CENCOM and MICCOM
MICU
> > > > dispatch which is in the 150MHz range and also 40-47MHz range with
the
> > > same
> > > > antenna ,as well as local police and NJ transit police.

> > > > My question is how do I elimate this background noise??  It sounds
> like
> > a
> > > > hissing sound.

> > > > Any ideas or tips would be greatly appreciated.

> > > > Bob D

 
 
 

Scanner Antenna Question

Post by Glen » Tue, 12 Oct 1999 04:00:00

Yea, that is what I am thinking also Tom. I did a news search and the
comments lean toward silicone with acetic acid is a no no. Also it is said
that some stay conductive while it cures. According to the postings it can
take a couple weeks, guess it would depend on the thickness of the
application.

Bob, Go get a hunk of RG-6 and give it a try. Bet it raises a smile. Hell if
you don't like it Tom says he will buy it from you.  :-)

OTOH, if you have an ohm meter check between the coax center and shield.
Should be open.

Glenn




> >coax is 6 months old.  I used black silicone, I use the same stuff for
> >sealing drilled holes in metal for lightbars.  The coax was sealed maybe
> >week and a 1/2 ago.  I sealed it where the coax is sottered to the
M-Mount.
> >The antenna is a Maxrad MMC-150 and I switched to a MHB-5800, and I still
> >get the same results.

> >Bob

> If you used the Black Silicon that I'm thinking of "RTV, Permatex,
> ect" I found out (through this ng) that it's not only VERY corrosive
> but also has some conductivity. Thus a slight short
> ////////\\\\\\\\\\\\//////////\\\\\\\

> De N3WTF, Tom Markert Trooper, PA
> To respond please remove the NOSPAM from my address.

 
 
 

Scanner Antenna Question

Post by Tom Markert N3W » Wed, 13 Oct 1999 04:00:00


>coax is 6 months old.  I used black silicone, I use the same stuff for
>sealing drilled holes in metal for lightbars.  The coax was sealed maybe
>week and a 1/2 ago.  I sealed it where the coax is sottered to the M-Mount.
>The antenna is a Maxrad MMC-150 and I switched to a MHB-5800, and I still
>get the same results.

>Bob

If you used the Black Silicon that I'm thinking of "RTV, Permatex,
ect" I found out (through this ng) that it's not only VERY corrosive
but also has some conductivity. Thus a slight short
////////\\\\\\\\\\\\//////////\\\\\\\

De N3WTF, Tom Markert Trooper, PA
To respond please remove the NOSPAM from my address.