Expert: Cezar L. Palconet - 6/16/2010

Question
QUESTION: I have recently purchased a Clearstream2 50+ mile peak range, gain of 1.2 dBi, with that a Apex (DT250) digital TV converter box w/analog pass-trough.  On my computer I have a UM175 mobile broadband usb modem service with US Cellular.  Like my cell phone the signal strength comes and goes and is usually 1 to a week 1 1/2 bars.  But when my neighbor parks his truck next to his drive I have a 2 to 3 bar signal. (he has the new radio that is out).  I have asked at Radio shack, Best buy, I have also sent the question to Antennas direct.  Is there a way to use one antenna to get the required signals?  Have extremely fixed income and trying to make do.

ANSWER: Hi Cindy

Your question is a bit confusing, are you using the same antenna for your TV and CDMA system?

If that is about the case, it is best that you use separate antennas.
But I like to assume the other way, however, if you are having weak signal when there are no trucks parked and a strong signal when a truck is parked, then you are definitely suffering from insufficient signal, probably your location is in the fringe of the service area, CDMA (as your service is) is fairly robust when it comes to signal multipathing, nevertheless CDMA is not immune to the laws of physics.

I would suggest that you put a directional antenna for your modem, in case where it is not possible for an external antenna, the only choice would be to find a suitable location inside your house to improve the signal, possibly in the second floor.

it is also possible for you, to get some sort of a square metal can, that you can experimentally move around your modem and see if the signal improves, the reason for this is that the metal can, can influence the directionality of your modems reception and transmission, that it will improve the signal strength and quality, very much the same way as the truck influences the signal.


best regards and good luck.

---------- FOLLOW-UP ----------

QUESTION: Actually I was asking if it was possible to use one antenna for 2 purposes.  The one I have is a HD and DTV.  I just wanted to know if it could also enhace my Cell receptions.  I think I understand, my TV antenna is blind to all other signals except for TV broadcasts, inorder to enhace it's performance?

ANSWER: Hi, Cindy

Yes I miss read the heading of your question, Sorry about that.

It is possible to use one antenna for both services, first if the antenna was specifically designed to serve both signal types, I have seen many antennas serving multiple frequency bands and it is fine.
However it is always better practice to have separate antennas for each service, to avoid directionality issues.

Usually in far fringe locations, service providers, install directional or sectoral antenna types, this is where directionality issues stem.
One possible problem is when one, either the TV broadcast station location or the CDMA base station is out of the signal path from the other, this means that one of the signals will not be optimized, either the TV or the CDMA will suffer, but with separate antennas, this would not be a problem.

If you decide to go for a single antenna,I would suggest that you optimize your reception for the CDMA and give second priority to your TV signal, the reason for this is that CDMA systems with strong signal quality will have a higher bandwidth capacity, than a lesser signal quality, and your TV broadcast will always have a stronger transmitting power compared to a power limited CDMA system.

Second, your CDMA system is transmitting as well as receiving, while in a TV broadcast, you would only be receiving.

best regards,
good luck





---------- FOLLOW-UP ----------

QUESTION: Thank you, with this type of antenna in mind what would I need to get the signal to my CDMA?  Everyone else I have asked has either not answered the first question or simply said I don't know.  And if they could not answer the first, they would definitely have a problem with this one.  Thank you so much.

Answer
Hi, Cindy

What type of antenna do you have in mind?
Excuse me, but I cannot guess what type of antenna you have decided upon, the one that combine your TV and CDMA or the individual antenna for each.

I think the best option for you would be to use separate antennas for each, since this will allow you greater latitude on the efficiency of a particular antenna.

Example you can get a high gain directional fixed station antenna for your CDMA, and point it directly to the CDMA base station, this configuration would allow you to have higher speed and bandwidth, this is a very significant improvement from what you are experiencing right now.

and your TV can be another type of high gain directional antenna which is pointed to the broadcasting station.

the logic for this is that you would have the flexibility of choosing the best suitable antenna for each particular system.

commonly, most antennas that are supplied as multiple frequency antennas are a compromise for efficiency for each end of the service band, except of course for those extremely high end specialized antennas that would cost several thousand dollars.

best regards
Good luck.