CDM 1250 UHF SWAr Severe Issue

[ButlerAlerts]

CDM 1250 UHF SWR Severe Issue

Ok, so I got my CDM 1250 in the mail yesterday, with the Astron power Supply and Hood with Desk Mic. I have been receiving EXTREMELY high SWR, to where it goes off my meter. I have tried it on my A99 at 38 Feet, my TRAM at about 10-12 Feet, and my new RadioShack UHF Scanner antenna, sat about 16-18 feet. I have tried it on 2 different RadioShack Coax's, while connected to my RadioShack SWR/Power Meter, and replaced the jumper cable to the Meter to Radio. I even tried 2 different RadioShack Mini-UHF to PL-259 adapters. Also even tried on Low and High Power Settings. I am using this on 470.000 MHz. If you have any questions, please comment below. ALL suggestions is helpful! Thanks

 

[KG4INW]

Are those antennas resonant on 470? Isn't an A99 a CB antenna (HF/27 MHz)? Anyways, is your RS meter capable of handling UHF? I thought most of what they sold were for CB and below.

 

[KevinC]

I'm pretty sure your Radio Shack SWR meter is only rated for the CB range, so it won't be anywhere near accurate at 470 MHz.

 

[SteveC0625]

I'm pretty sure your Radio Shack SWR meter is only rated for the CB range, so it won't be anywhere near accurate at 470 MHz.

+1

Radio Shack SWR meters are strictly for 27 mhz.

 

[ButlerAlerts]

Thanks guys, never thought about the Range in meters. Reading RadioShacks website, it says 3-30 Mhz. So do you think if I have the UHF Antenna directly to my CDM 1250, it has a good SWR. I just dont want to damage my radio or antenna. thanks again!

 

[jim202]

Thanks guys, never thought about the Range in meters. Reading RadioShacks website, it says 3-30 Mhz. So do you think if I have the UHF Antenna directly to my CDM 1250, it has a good SWR. I just dont want to damage my radio or antenna. thanks again!

I strongly doubt that your going to damage any antenna with what you have.

Your problem is that the meter your using is worse than junk at the 470 MHz range. I am surprised that it even moves the meter pointer. Find an SWR meter that is rated for the 470 MHz segment before you make any judgements on what is going on. Maybe you can make friends with one of the ham radio operators in your town. Borrow his meter.

 

[ButlerAlerts]

Oh, lol, it moved, as fast as lightning. It works for power, but maybe I can borrow a fellow fire departments meter if they have one.

 

[Skypilot007]

You really should check SWR if you can especially if the antenna and feed line are questionable. Is the tram antenna a UHF specific antenna? Reason I ask is I have one of those ebay specials trimmed for the GMRS band but the SWR is acceptable on 440 MHz also. Out of the bag it was pretty close but I'm a stickler for lowest SWR I can get. It performs well for a $50 antenna.

 

[ButlerAlerts]

I wished, lol. No, CB, I had a nice CB Base station and went to UHF

 

[N4KVE]

I hope you're not trying to use a CB antenna for 470 mhz.
QUOTE "When your 16 year old neighbor buys an old Navaho base station and asks you (the local CB guru of the block) what would be a good, cheap, starter antenna for him, you suggest the A99." QUOTE

 

[ButlerAlerts]

I was using 2 differnt ones, but since it was so staticy and unstable, I went with a Hi-VHF and UHF Dual band antenna.

 

[RadioDaze]

Is anyone going to ask "the big question"?

 

[evfd1625]

Wirelessly posted (Mozilla/5.0 (Linux; U; Android 4.1.1; en-us; HTC6435LVW 4G Build/JRO03C) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30)

The... "Do you have an appropriate license for the frequency used?" Question? Lol

 

[evfd1625]

Wirelessly posted (Mozilla/5.0 (Linux; U; Android 4.1.1; en-us; HTC6435LVW 4G Build/JRO03C) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30)

The... "Do you have an appropriate license for the frequency used?" Question? Lol

 

[ButlerAlerts]

Yes I do! WQRF973

 

[evfd1625]

Wirelessly posted (Mozilla/5.0 (Linux; U; Android 4.1.1; en-us; HTC6435LVW 4G Build/JRO03C) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30)

There are so many people that think it is their place to enforce the license thing on people that could even just be asking a hypothetical question.

 

[cmdrwill]

WQRF973, as most of thought, this IS only a GMRS license.

Maybe you meant 467 mHz as that is the mobile transmit for GMRS repeater channels.

 

[ButlerAlerts]

Yes, I will be using 462.XXXX, but im testing it on 470.000 with a local fellow before I pay to get it programmed.

 

[tech020]

Unless you are transmitting into a dummy load, you are not authorized to transmit on 470.0000mhz. A FCC type person could easily make life uncomfortable or expensive for you. They do enforce and are always looking for someone to make an example of.

 

[kayfox]

There are a couple of other issues I see here:

1. Isn't GMRS limited to 2 watts for transmitters other than a repeater?
2. I don't think the CDM1250 is type accepted for GMRS.