Any advice, helpful hints on why my reception became more choppy after switching to an outside antenna. Currently have a BCD596HP, had the telescope antenna with decent results. After I put a 25MHz–1,300MHz VHF/UHF Discone Base Antenna on my roof my reception has degraded significantly. Several channels that were once clear now are not. Any input would be appreciated. Thanks!
Worse reception since hooking up my outside antenna
- Thread starter dazeddude
- Start date
What brand Discone? What type of coax did you use etc. Alot of variables to consider.
Are you monitoring a simulcast trunked radio system by any chance? If so, what you described is par for the course
Where did the reception degrade? On a trunked system, conventional freqs, across the board? If on a trunked system, is it a simulcast system? If so the outside antenna may be seeing more sites which the 536 might not do that well with.
Houston is a Simulcast system, putting up an outside antenna means you are probably receiving more than one tower at a time and getting distortion. The 596HP is not designed for simulcast systems like the SDS100/200 are. In simulcast systems less antenna is often better.
wiki.radioreference.com
Simulcast Distortion - The RadioReference Wiki
And lol, neither are the 436/536...
What is a BCD596HP?
Same thing happened to me on a simulcast system when I changed to an external antenna connected to my BCD536HP.
Same thing happened to me on a simulcast system when I changed to an external antenna connected to my BCD536HP.
wtp
Member
sales talk...25 to 1300, and so is a paperclip.
on the roof...OK was the cable new or used ?
could you have bent it too much and now the center contacts the shield ?
with every connector you loose a little signal strength.
and some cable can 'eat' signals, so you have less signal.
and the best is....to use the back of the set one .
on the roof...OK was the cable new or used ?
could you have bent it too much and now the center contacts the shield ?
with every connector you loose a little signal strength.
and some cable can 'eat' signals, so you have less signal.
and the best is....to use the back of the set one .
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Didn't catch that in my original post
Pretty sure you understand why so this is directed at the OP. When the scanner is inside your house with insulation in the walls and other stuff in the home that can bounce or reflect signals, the scanner gets whatever signal it can from wherever it can. Ever move near a window and reception gets better? Now stick the antenna on the roof and now it can see in all directions and it brings in much more signal. Not really good with simulcast systems.
wtp
Member
i have described simulcast as your radio listening in computer talk.
so it is looking for 11001010 is a certain amount of time.
but with a second tower and a little time shift it hears 1l1l0o0o1l0o1l0o and it makes no sense to the computer/radio receiver.
that little echo causes it to go silent.
the SDS series looks at the total signal and pick the signal it thinks is right.
it throws out the little echo.
my county changed to 700 Mhz P-25 phase 2 and some are on phase 1.
but my 396T, 396XT and 325P2 receive for 1/4 second and then nothing for 1/4 second at my house.
they are fine around almost all of my county, just not at home.
so we bought a SDS100, it receives fine, everywhere.
this is just for future reference, i would just go with the stock antenna.
that is MUCH cheaper.
so it is looking for 11001010 is a certain amount of time.
but with a second tower and a little time shift it hears 1l1l0o0o1l0o1l0o and it makes no sense to the computer/radio receiver.
that little echo causes it to go silent.
the SDS series looks at the total signal and pick the signal it thinks is right.
it throws out the little echo.
my county changed to 700 Mhz P-25 phase 2 and some are on phase 1.
but my 396T, 396XT and 325P2 receive for 1/4 second and then nothing for 1/4 second at my house.
they are fine around almost all of my county, just not at home.
so we bought a SDS100, it receives fine, everywhere.
this is just for future reference, i would just go with the stock antenna.
that is MUCH cheaper.
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Normally I hear 11001010, but at times, when my wife wants me to do things, I seem to hear 1l1l0o0o1l0o1l0o.
With my little Bearcat, I thought a discone on the roof would do better than the whip in the back of the scanner.
BOOM. no good. Noise and interfererance on all bands.
With this antenna, I needed a lot of added attenuation and aditional filters including FM trap, and band pass filter.
Not only was the stronger signals overloading the scanner front end, it caused birdies and all sorts of havock with reception.
Being 250 yards from a major repeater and cell sites didn't help much either.
Now once I got around all this, the discone did well with DX stuff. I get UHF and 700/800 Mhz sites 50 miles north that were just hearable with the whip.
What it ammounts to is a 'preselector' in front of the scanner.
That preselector helps my SDR setups a lot too.
Cheers
BOOM. no good. Noise and interfererance on all bands.
With this antenna, I needed a lot of added attenuation and aditional filters including FM trap, and band pass filter.
Not only was the stronger signals overloading the scanner front end, it caused birdies and all sorts of havock with reception.
Being 250 yards from a major repeater and cell sites didn't help much either.
Now once I got around all this, the discone did well with DX stuff. I get UHF and 700/800 Mhz sites 50 miles north that were just hearable with the whip.
What it ammounts to is a 'preselector' in front of the scanner.
That preselector helps my SDR setups a lot too.
Cheers
RFI-EMI-GUY
Member
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Mine seems to get overloaded by frequencies outside the 800 MHz public safety band, Like cellular. so I have a bandpass filter in front of it and it seems to be happier.
Thank to all for the suggestions. To answer a couple of questions, it is across most bands but mainly effecting the trunked, yes I know how they work and yes I know that the SDS100/200 are built for these types of systems. Might look into attenuation and additional filters like Merlin has or I guess I could make myself program the SDS100 I've had setting on my desk for 3 weeks and see how that works. Again thanks for the replies!
So if its affecting all bands then I would be looking at the coax and or connections. How many feet? What coax is it? How old is it? Did it come with connectors or did you have to do that?
Do this, it'll be a whole new world. I have an Omni X up about 20' connected to my SDS200 with good coax. In short, it kicks butt.
devicelab
Whacker Extraordinaire
This ^^^
I have to use a NOAA and FM notch filter for my discone antenna. Try the RTL-SDR FM notch filter: https://a.co/d/efwUTBm
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If you do not have a FM broadcast band filter in the line to the antenna, you should try adding one. Even if you do not think that is the problem (since a different band possibly), it often is. The new antenna may have increased the signal level in that band to the point that the radio has a problem. Note, that this problem does *not* appear as interference but rather as a weakening of reception.
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