Intruder on two meters - New Braunfels


WN4VCH
 

02/01/2007

QTH: Mobile, on Hwy 46 east of the intersection of 46 and FM1863 near
an area of construction.

Frequency: 146.520

Monitored conversation between two truck drivers regarding their
trucks, trailers and the manner in which the were being loaded.
No callsigns. Clearly not hams. I was passing through the area and
did not have to time drive around and try to find where they were working.

Russell (WN4VCH)


Pat Knight AD5BR <ad5br@...>
 

Russell,

Thanks! I've forwarded this to two New Braunfels hams I know. Thanks!

73,
Pat AD5BR

02/01/2007

QTH: Mobile, on Hwy 46 east of the intersection of 46 and FM1863 near
an area of construction.

Frequency: 146.520

Monitored conversation between two truck drivers regarding their
trucks, trailers and the manner in which the were being loaded.
No callsigns. Clearly not hams. I was passing through the area and
did not have to time drive around and try to find where they were working.

Russell (WN4VCH)


WN4VCH
 

The tranmissions were in FM.

-----Original Message-----
From: W5SC@yahoogroups.com [mailto:W5SC@yahoogroups.com] On Behalf Of Shane
O'Neal NS5D
Sent: Thursday, February 01, 2007 4:33 PM
To: W5SC@yahoogroups.com
Subject: Re: [W5SC] Intruder on two meters - New Braunfels

Is it possible that these two fellas were running linear amplifiers on CB
and were close enough to you so as to get into the front end of your radio?

Some of those guys put out a kilowatt or more.


Shane O'Neal NS5D <shane@...>
 

Stubborn and hard-headed as I am, I decided not to take the word of the experts, but to put my second theory below to the test. I could not test the first one without violating the law.

I set my Yaesu VX-6R on 146.520, with a squelch setting of 2. I set my Yaesu FT-757GX to 29.304 Mhz, AM, at 100 watts, with the mike gain turned all the way up. My antenna is a long-wire going into an MFJ roller inductor tuner.

I made some test transmissions on AM on 29.304, with my VX-6R held at arms length away. I was able to hear my voice through the VX-6R. Even though it was very distorted, my transmission was clear enough to be understood, and caused audio feedback. I tuned down to 146.510 and up to 146.530 and did not hear myself.

Then I switched to FM on 29.304 and made some more test transmissions. I was able to hear my voice clearly through the VX-6R, with no distortion. Then I moved the VX-6R across the room from the radio, about 10 feet or so. I was still able to hear my voice clearly while transmitting on 29.304. I was not able to hear anything on 146.510 nor 146.530.

So I stand by the idea that it is theoretically possible to hear two people talking on 29.304 in AM or FM mode, with an FM receiver tuned to 146.520, if you are in close proximity to them and they are running some power. I'm not saying that this is what WN5VCH heard, because it sounds like that was not the case.

The test is easily repeatable if you doubt my results.

I never claimed to be the expert, and I'll be the first one to admit that if I can pass the Extra class test, it is way too easy. Also, I guess I started the mudslinging by insulting the knuckle-heads, so I should have expected no less than an impolite response.

Disclaimer:

Before I get taken out by the sharpshooters, I want to say that I am aware that 29.304 is out of the FM subband on 10 meters, as defined by gentleman's agreement in the ARRL bandplan. However, Part 97 authorizes "phone" in that band and does not specify which flavor. Further, Part 97.305b states that "A station may transmit a test emission on any frequency authorized to the control operator for brief periods for experimental purposes...".

----- Original Message ----
From: Shane O'Neal NS5D <shane@ns5d.com>
To: W5SC@yahoogroups.com
Sent: Thursday, February 1, 2007 10:10:40 PM
Subject: Re: [W5SC] Intruder on two meters - New Braunfels

Again, at the risk of being out-radioed by some more experienced hams...

The fifth harmonic of 27.185 (CB channel 19) is 135.925. Add a power mike and you get splatter. Add a linear and you get powerful splatter. To me that puts these guys in the ballpark even if they were operating on legitimate CB frequencies, especially if you were real close to them.

Another variation on this scenario might be that they are operating some of those truck stop special 10-meter radios (25-30mhz) illegally. The 5th subharmonic of 146.520 is 29.304. A lot of these Galaxy/President/ whatever radios have an FM mode also. This doesn't make it any better than if they were talking on 2 meter radios, but it sounds more plausible to me that a couple of truck drivers would be using these rather than intentionally using 2 meter VHF radios.

Third possibility - these guys actually were hams who just got lazy and didn't give their call signs because they thought no one was listening. I have talked to many OTR drivers with amateur licenses.

Fourth possibility - Gosh, they might actually have two meter radios and be on the national calling frequency, and not have a license. Given some of the conversations I've overheard on 146.520 around here, trash-talking truckers might be an improvement. ;-)

Just trying to make it interesting guys...

----- Original Message ----
From: Mike Check <k5ucq@arrl.net>
To: W5SC@yahoogroups. com
Sent: Thursday, February 1, 2007 8:39:01 PM
Subject: [W5SC] Intruder on two meters - New Braunfels

HF to VHF? What a jump!

Mike Check
Amateur Radio K5UCQ
13 WPM General Class Licensee
-------Original Message----- --

From: Shane O'Neal NS5D
Date: 2/1/2007 4:36:44 PM
To: W5SC@yahoogroups. com
Subject: Re: [W5SC] Intruder on two meters - New Braunfels

Is it possible that these two fellas were running linear amplifiers on CB
and were close enough to you so as to get into the front end of your radio?

Some of those guys put out a kilowatt or more.

----- Original Message ----
From: WN4VCH <wn4vch@gmail. com>
To: W5SC@yahoogroups. com
Sent: Thursday, February 1, 2007 3:20:30 PM
Subject: [W5SC] Intruder on two meters - New Braunfels

02/01/2007

QTH: Mobile, on Hwy 46 east of the intersection of 46 and FM1863 near
an area of construction.

Frequency: 146.520

Monitored conversation between two truck drivers regarding their
trucks, trailers and the manner in which the were being loaded.
No callsigns. Clearly not hams. I was passing through the area and
did not have to time drive around and try to find where they were working.

Russell (WN4VCH)