TRX, why can't I program 800-801 MHZ?

Status
Not open for further replies.

RRR

What?
Premium Subscriber
Joined
Dec 6, 2005
Messages
1,772
My Whistler TRX-1 gives me an error message when I try to enter a freq. in the 800 - 801 MHZ range, of "invalid frequency"

Is this a bug? Uniden scanners receive in this range.

Help?
 

RRR

What?
Premium Subscriber
Joined
Dec 6, 2005
Messages
1,772
Absolutely ridiculous to exclude such a well used portion of the public safety P25 band like that. Hopefully this will be rectified in the near future. Love the scanner otherwise, but I am trying to monitor a local govt P25 system with a few freqs that fall out of the trx range, renderring it essentially useless on that system for the most part. Any rhyme or reason for this? Changes possibly forthcoming?
 

buddrousa

Member
Premium Subscriber
Joined
Jan 5, 2003
Messages
8,761
Location
NW Tenn
From all data I was able to look up the US 800 Band Plan Starts at 806.0125 this is a mobile transmit frequency (Trunking System Input) the Frequency paired (Trunking System Output) is 851.0125. I found this to by SY which is part of the 700 Public Safety Trunking Band
 
Last edited:

wa8pyr

Technischer Guru
Lead Database Admin
Joined
Sep 22, 2002
Messages
5,411
Location
Ohio
Absolutely ridiculous to exclude such a well used portion of the public safety P25 band like that. Hopefully this will be rectified in the near future. Love the scanner otherwise, but I am trying to monitor a local govt P25 system with a few freqs that fall out of the trx range, renderring it essentially useless on that system for the most part. Any rhyme or reason for this? Changes possibly forthcoming?
What are you trying to listen to? According to the official documentation, the TRX ranges are:

Spectrum Sweeper
25-54 MHz VHF Low Band
108-137 MHz VHF Aircraft Band
137-174 MHz VHF High Band
216-300 MHz 220 MHz Commercial/Amateur Band
300-406 MHz UHF Military Air Band
406-470 MHz UHF Band
470-512 MHz UHF-T Band
764-782 MHz 700 MHz Band
791-797 MHz 700 MHz Band
806-869 MHz 800 MHz Band
894-1300 MHz 900 MHz Band, 23 cm Amateur Band

This covers the base (and mobile simplex) side of the 700 MHz public safety band quite well; the mobile transmit frequencies are 30 MHz higher. Up to 763 MHz is part of the D Block and off-limits, while 763-764 would be a guard band requiring a special waiver and pretty stringent technical specs to use (in addition to an annual report to the FCC detailing how it's being used)

782-791 is not part of the public safety band (mostly C and D block cellular) so that's why it's blocked.

797-806 being blocked may be related to potential conflicts with images or birdies that pre-dates the availability of 700 MHz for anything but TV channels. I recall in the past that some scanners avoided certain 700 MHz ranges for this reason, and it may be a hardware consideration for the Whistler models.

800/801 would be mobile (repeater input) only, so I'm not sure what you would hear there that you wouldn't hear 30 MHz lower.
 

RFI-EMI-GUY

Member
Joined
Dec 22, 2013
Messages
4,319
I believe the frequencies just below 806 and 851 MHZ are set aside for air to ground telephone systems. The ECPA requires phone frequencies to be blocked in the US.

Sent from my SM-T350 using Tapatalk
 

RFI-EMI-GUY

Member
Joined
Dec 22, 2013
Messages
4,319
P25 simplex mobiles on 801... Mhz.
Can you point to an FCC licence with those frequencies? There shouldn't be any public safety mobiles operating there, simplex or not.

Sent from my SM-T350 using Tapatalk
 

Thunderknight

Member
Premium Subscriber
Joined
Jan 31, 2008
Messages
2,032
Location
Bletchley Park
P25 simplex mobiles on 801... Mhz.
Interesting...do you know what make/model of mobiles are running simplex on 801 MHz?

All of the mobiles I've run across will not receive 799-821 MHz. They will transmit there and TX/RX 764-776 and 851-869, but not receive 799-821 as it would complicate the RF design.
 

nd5y

Member
Joined
Dec 19, 2002
Messages
9,320
Location
Wichita Falls, TX

mikewazowski

Forums Manager/Global DB Admin
Staff member
Joined
Jun 26, 2001
Messages
11,873
Location
Central Ontario
That might be close to the input for the 700MHz repeaters but I doubt there's any mobiles operating simplex there. They'll all be in the repeater output band.
 

Jay911

.
Feed Provider
Joined
Feb 15, 2002
Messages
9,307
Location
Bragg Creek, Alberta
Likely the same reason 797-80x was "excluded" in the GRE versions of the radios back before Whistler bought it up - the architecture suffers from some kind of flaw that causes images from the 800 MHz range (generally 866-869) to be falsely represented in 796-805.
 

RRR

What?
Premium Subscriber
Joined
Dec 6, 2005
Messages
1,772
Again, there is a local P25 system that has the mobiles input in the 799-801.xxx MHz range, as is authorized under the current APCO format. They also will sometimes use a couple of these input freqs in this range for simplex comms. I can program my Unidens in this range, and they will pick them up, but my Whistler will not.

My question is not meant to steer debate if what I am seeing and hearing is real or correct or not, I am wanting to know why Whistler excluded this range, and if it can be added in with a future update.
 

SCPD

QRT
Joined
Feb 24, 2001
Messages
0
Location
Virginia
My beef is 255.255 MHZ cant be entered,its Satcom,the TRX1 corrects it to some other frequency.
 
Status
Not open for further replies.
Top