Railfan Technology > Kenwood TH-K20A for RR narrow band use

I have been looking at the Kenwood TH-K20A to use for narrow band rail scanning.
Have not seen any info on this model in here. I understand that it is narrow band
capable on the receive side as well. Is the Yaesu FT-250 narrow band capable on the receive
side also? Any info would be greatly appreciated. Thanks.

Yaesu FT270 with MFJ 1717S antenna

csx950 Wrote:
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> I have been looking at the Kenwood TH-K20A to use
> for narrow band rail scanning.
> Have not seen any info on this model in here. I
> understand that it is narrow band
> capable on the receive side as well. Is the Yaesu
> FT-250 narrow band capable on the receive
> side also? Any info would be greatly appreciated.
> Thanks.

No, the FT-250 is not narrow-band on the receive side. As to the TH-K20A, I have not seen or used one personally. They are pretty well rated over at http://www.eham.net .

See my comments in the post here: http://www.trainorders.com/discussion/read.php?9,2909362

Thanks for the info.

Earlier this year I called Kenwood to try to find out if the TH-K20A did narrowband receive. I talked to sales and a couple of techs and none of them could ever tell me if it is or not.
John

JS_IN_KY Wrote:
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> Earlier this year I called Kenwood to try to find
> out if the TH-K20A did narrowband receive. I
> talked to sales and a couple of techs and none of
> them could ever tell me if it is or not.
> John

From what I've read in both Kenwood advertising and the TH-K20A manual (available online), the radio is a fully narrow-band configurable radio on both receive and transmit. The same with the TM-281A mobile. I have experience with both Kenwood and Yaesu amatuer products. Both make some very good quality radios. For me, the Yaesu's are usually a bit more straightforward to program and operate, with both brands having radios that are very selective and sensitive. As noted, though, the Yaesu's are not narrow-band receive radios--so, if a person is looking to buy a new radio, I would recommend the Kenwood TH-K20A handheld or the TM-281A mobile over the Yaesus now.

Again, none of the amatuer radios and scanners will receive NXDN digital signals if and when the railroads deploy that. My gut feeling is that the railroads will go narrow-band analog first (they all have to be there by 1/1/2013), then to NXDN unencrypted digital next, with encrypted digital probably never coming into wide use on anything but company-specific local channels. The necessity of inter-operability of radios on locomotives and equipment operating over multiple railroads will probably mean that the road channels will remain unencrypted digital, or--if they are encrypted--it will be with an encryption key common to all of the railroads. Unencrypted digital will knock out about 90% of the current railfan radio listening community, encryption would raise that number to about 99.9%.

The TH-K20A will not do 2.5KHz frequency steps, and some of the new splinter channels require that.

Also for a receiver to be truly narrow band, it requires a 2nd set of filters. That means additional cost and I would assume 95% of the time you will not get that in an amateur transceiver they only reduce the TX deviation and add a bit of gain in the audio stage on the RX end. I can not say that is what Kenwood is doing here, they have all of the technical info labeled as confidential on the FCC site.

What does the above mean for a railfan, not much most of the time, as long as you don't need to monitor one of the splinter channels, or even if you do the RX front end is still wide enough to capture some of the traffic with a good S/N ratio.

AAR wanted all of the RR's to switch over to narrow band by July 1st 2010, I don't know if that is the case but a lot of the stuff around here is narrow.

Jim

Jim,

Since I haven't had my hands on a TH-K20A, I'm going by what is in the operating manual, quoted here:

"The transceiver operates in normal FM deviation (±5 kHz) mode for both
transmitting and receiving. You can also operate the transceiver in narrow band
FM deviation (±2.5 kHz) mode."

So, from that might I infer that the radio will narrow-band on receive on the 97 AAR channels, but can not be programmed with the splinter channels. And I wonder if the TM-281 mobile is the same?

Neither radio is an issue for me, since I already have commercial analog radios that will narrow-band, plus andNXDN mobile in my my vehicle and a handheld NXDN. Still, I like the option of carrying a field programmable amateur radio for that use that also would "splinter" frequency receive on the 2.5 kHz deviation for the AAR channels. From what you say, it doesn't sound like the Kenwood amateurs will.

Appreciate all the great info on the K20A.
I might give one a try. Thanks.