New Antenna Question

[gtor72]

hi all. I have what might be a stupid question, but I will ask anyway.
I bought a Workman T734 discone antenna and now have it hooked up.
It works great on conventional frequencies, no more static signals are loud and clear.
My problem is I do not receive any traffic at all on the Michigan State Police frequencies.
I am using a pro96 scanner.
If I put my stock antenna on the scanner I do get traffic on the State Pd frequencies.
I used RG-6 cable to hook up the antenna.
Like i said conventional frequencies are way better than the old antenna I had, any ideas on why I cant receive anything on the Michigan state pd frequencies?
I am scanning in open mode.
thanks for any help you might provide. Mike

 

[ampulman]

hi all. I have what might be a stupid question, but I will ask anyway.
I bought a Workman T734 discone antenna and now have it hooked up.
It works great on conventional frequencies, no more static signals are loud and clear.
My problem is I do not receive any traffic at all on the Michigan State Police frequencies.
I am using a pro96 scanner.
If I put my stock antenna on the scanner I do get traffic on the State Pd frequencies.
I used RG-6 cable to hook up the antenna.
Like i said conventional frequencies are way better than the old antenna I had, any ideas on why I cant receive anything on the Michigan state pd frequencies?
I am scanning in open mode.
thanks for any help you might provide. Mike

Try turning attenuator on when monitoring that system.

Amp

 

[VE2ZTT]

Your Pro96 antenna input is 50 ohm ( look at your spec. )
So your antanna inpedance must be 50 ohm ( your discone is 50 ohm ) that is ok
But your RG6 is 75 ohm, causing a mismatch and a loss of +/- 15 @ 25 % reception
Use RG 58 cable (or any 50 ohm cable)

 

[gtor72]

thanks for the advice on the coax, after some research that is what i have found to be the problem, so I will get some better coax and give that a try.....thank you very much. Mike

 

[smason]

Your Pro96 antenna input is 50 ohm ( look at your spec. )
So your antanna inpedance must be 50 ohm ( your discone is 50 ohm ) that is ok
But your RG6 is 75 ohm, causing a mismatch and a loss of +/- 15 @ 25 % reception
Use RG 58 cable (or any 50 ohm cable)

Bah! I really have to disagree here. RG-6 will often out-perform RG-58, particularly at higher frequencies regardless of the minor impedance mis-match.

This has been discussed many times here (search on RG-6), and MANY of us are using RG-6, and it works VERY well because is is relatively low loss at 800MHZ compared to RG58.

Yes a low-loss 50 ohm cable (LMR400 etc) will beat RG-6 But RG-6 is a great performer if you're on a budget, as it's cheap and very readily available.

 

[JStemann]

agreed...

I'll admit it surprised me, but I did the math. 100' of (belden 8240) rg-58 vs. the (belden 8215) rg-6a @ 850mhz. Rg-6 shows ~9dB loss, rg-58 ~13 dB loss. That was the best of the rg-58's on the calc i used. The rg-58c was at >20 dB. I knew the bigger stuff(lmr 400, rg-8, heliax) was better, just never thought much of rg-6 coax('til now). Guess i have a use for the rg-6 I have left over.

jeff s.