Something I discovered about range and signal quality

All posts related to PCI MAX transmittors go here!

Moderators: Sir Nigel, Nina, pcs, 5r, phpBB2 - Administrators

Post Reply
nvrpunk
New registered user
New registered user
Posts: 2
Joined: Sat Jan 17, 2009 12:07 am

Something I discovered about range and signal quality

Post by nvrpunk »

So I have had my PCI Max 2007+ with the 15W FM exciter for about a week. Being that it's not a full time thing for me, I have just fiddled with trying to get the best reception possible all around.

Here are a few things I have come to realize:

1) Antenna Height is extremely important by an order of magnitude
2) Lowering the actual volume output on your sound card lowers the amount of interference and helps SWR
3) Putting a 15W transmitter's antenna directly on your metallic roof is a dumb idea (it's also not healthy)


While I was in a rush to setup, I tossed the antenna on the roof of my trailer just to test. At 15W's full, it would give me a headache... so I assume it's really unhealthy. Later I raised the antenna another 10' above my roof. This helped range and reception but I still had an issue of the reception going in and out depending on the make and model of vehicle I was driving. So I lowered the power, that did nothing to help the problem. Finally, today I lowered the sound card output to 75% volume, this helped amazingly. Suddenly areas where it would cut out were still getting reception. When it did break up, it was hardly noticeable.

So the lesson I have learned is the actual volume has a huge affect on how well the signal is received when obstacles are in the way etc.


If anyone wants to clarify and add technical details for the reasoning behind this, please do. I haven't invested a lot of time on learning exactly how SWR works or how to reduce the ratio etc. I know enough to understand it but not enough to fully explain in great detail.


Lastly, if anyone has Linux questions as to how to set up the card etc. Example, I use mpd with ncmpc on Linux and have it set to auto restart if power is lost and also use an UPS. I have considered using an ITX box with a solar panel and just setting up an outdoor automagical station that can run itself. However, I like managing my playlist :)
User avatar
pcs
Site master
Site master
Posts: 3132
Joined: Fri Jan 18, 2002 1:00 am
Location: Radio Land
Contact:

Post by pcs »

Dear forum poster,

I have to explain a few things:

1. Correct, antenna height is important
2. Wrong. You probably had your audio set way too high
and the result was limited range. You were over-modulating
severely, probably. Nearby receiver might be able to demodulate
such over-modulated signal, but as you move away the filters do
their job and what you'll hear will be distortion, lots of it.

So yes, if you're overdriving it with audio than setting it lower
does help. However, it has absolutely nothing to do with SWR.

3. I believe tinfoil hat is a solution here...

I don't know how you installed your antenna, but properly installed
antenna on a roof of a metal structure works just fine and gives
no headache. Do you get headache with your GSM next to your ear?
Fields your brain is exposed to are WAY larger in that case.

So either put a tinfoil hat on or think about other reasons for your
headache. For example, woman get one usually when you want to have
sex, usually no transmitter is involved :)

Yes, you can setup a small PC and network it. Put PCIMAX inside.
Than make it remotely manageable via VNC or remote desktop of
some kind. PC can be on the roof and network can be WLAN :)
Best regards,
Marko - PCS Electronics
--------------------------------------------------------
Turn your PC into a FM radio station!
http://www.pcs-electronics.com
fax +386 4 2316 128
Joeglennis
New registered user
New registered user
Posts: 19
Joined: Sun Mar 08, 2009 3:21 am

Wont go past the driveway

Post by Joeglennis »

I can get a signal in the house, but has static
I have the audio down on the pc
The 15W booster is up all the way, the antenna is over the house securly.
The light is on the PCS Max 2007 and in the pc securly
the programs are good
why wont it go past the house (signal) ??
Alot of $$$ invested into this device and i would like it to work right.
in another words, i can hear it on the house stereo but not in the car which is directly in front of the house and near the antenna.
what now???
Joe
User avatar
pcs
Site master
Site master
Posts: 3132
Joined: Fri Jan 18, 2002 1:00 am
Location: Radio Land
Contact:

Post by pcs »

I'd say you have a problem somewhere, maybe a badly installed connector on coax for example.
Maybe you can shoot some photos of various points of your system.
Best regards,
Marko - PCS Electronics
--------------------------------------------------------
Turn your PC into a FM radio station!
http://www.pcs-electronics.com
fax +386 4 2316 128
Post Reply