Adapter vs jumper

Scanners, antennas, coax, filters, amplifiers, demodulators...you get the idea. Scanning equipment questions, answers, and discussion belongs here!

Post Reply
Message
Author
User avatar
schwab
Posts: 523
Joined: 13 Apr 2010 11:16
Location: Rollinsford, NH

Adapter vs jumper

#1 Post by schwab » 13 May 2018 20:53

I have a Uniden BCD396XT in my car, and I currently have a UHF-to-SMA adapter like this:
https://www.talleycom.com/viewProduct?r ... gK9ZPD_BwE
connecting the coax to the radio. Would it be beneficial to replace it with a UHF-to-SMA jumper, like this?:
http://www.americanradiosupply.com/10-l ... gK8ofD_BwE
More loss/less loss? I am also a bit concerned with strain on the SMA connection on the radio. Thanks folks.

User avatar
W1KNE
Posts: 3959
Joined: 19 Aug 2005 12:00
Location: Taunton, MA
Contact:

Re: Adapter vs jumper

#2 Post by W1KNE » 14 May 2018 01:06

You're going to have more loss on that PL259 connector than the jumper. That tiny jumper's loss will be almost unnoticeable for standard scanner band reception. Definitely in a mobile environment, the loss is minimal versus the stress of a big connecting adapter on the scanner. If it were my choice, I'd replace that PL259 with a less lossy BNC connector, and I'd still use a jumper.

And I'd steer clear of that big adapter.

User avatar
trp
Posts: 430
Joined: 30 Mar 2010 19:44

Re: Adapter vs jumper

#3 Post by trp » 14 May 2018 01:08

schwab wrote:
13 May 2018 20:53
I have a Uniden BCD396XT in my car, and I currently have a UHF-to-SMA adapter like this:
https://www.talleycom.com/viewProduct?r ... gK9ZPD_BwE
connecting the coax to the radio. Would it be beneficial to replace it with a UHF-to-SMA jumper, like this?:
http://www.americanradiosupply.com/10-l ... gK8ofD_BwE
More loss/less loss? I am also a bit concerned with strain on the SMA connection on the radio. Thanks folks.
A UHF connector (PL-259/SO-239) is only rated for frequencies up to 300 MHz. If you are monitoring frequencies above 300 MHz and you want optimal performance, you should avoid the use of a UHF connector anywhere in your antenna feed line. Much better connectors to use for frequencies above 300 MHz include F connectors (rated to 1 GHz/1,000 MHz), BNC connectors (rated to 4 GHz/4,000 MHz), N connectors (rated to 11 GHz/11,000 MHz) and SMA connectors (rated to 18 GHZ/18,000 MHz). Here's a link to a handy chart from Amphenol which lists the rated frequency limits of the various RF antenna connectors: https://www.amphenolrf.com/frequency-range-chart/

If I were in your situation I would change the PL-259 on the end of your antenna coax to a BNC male connector. I would then use a short pigtail jumper that would have a BNC female on one end and an SMA connector on the other end to connect to your BCD396XT. That would take the strain off of your SMA connector on your radio and possibly avoid a costly repair in the future. It would also allow you to directly connect your antenna to any other scanners that have BNC antenna connectors without having to use any adapter or pigtail on the end of your coax.

I use a 19" BNC-to-SMA pigtail with a gold-plated 90-degree elbow with my BCD396XT and it keeps the strain off of my radio's SMA connector. If you have any interest in the same cable/adapters that I use, I currently have 2 brand-new complete pigtail/adapter sets listed in the SNE classifieds: viewtopic.php?f=54&t=39204 (PM me if you want the missing pictures as they disappeared when SNE converted over to the new website.)

NOTE: For those readers who subscribe to The Spectrum Monitor magazine, there is a very good article in the current May 2018 issue entitled "Goes Inta / Goes Outta" which details the pros/cons/limits of the various RF antenna connectors. The article can be found on pages 52-54. If you want to purchase the current May 2018 issue for $3.00 or subscribe to the magazine, here's the link: https://www.thespectrummonitor.com/
trp
RCA 16S400, Regency HX1500, PRO-2006, PRO-197, TRX-2, BC950XLT, BCD996XT, BCD396XT, SDS100, Motorola Minitor II, Antenna Specialists MON731

User avatar
schwab
Posts: 523
Joined: 13 Apr 2010 11:16
Location: Rollinsford, NH

Re: Adapter vs jumper

#4 Post by schwab » 15 May 2018 18:43

Thanks for the input gents.

Post Reply