11/14/18 19:33:02 UTC
266.600 MHz
BETHLEHEM, PA
Pilot talking about descent to airport
 
11/14/18 17:58:49 UTC
234.55 MHz
TACOMA, WA
Bluetail working with west group
 
11/14/18 17:57:13 UTC
271.000 MHz
TACOMA, WA
Looking for TFR Center
 
11/14/18 17:56:12 UTC
234.55 MHz
TACOMA, WA
Bullseye. Hostile
 
11/14/18 15:10:42 UTC
248.65 MHz
CHILLICOTHE, OH
Ops in Buckeye/Brush Creek MOA
 

11/14/18 16:39:09 UTC
308.700 MHz
KGYH - ARNG OPS PTD - 41.3 308.7 REMARKS: ARNG OPS C803-299-5214 (GREENVILLE OPS) -AJ
 
11/14/18 16:19:06 UTC
39.950 MHz
per KFBG NOTAM: L0729/18 - AERODROME - FLIGHT STRIP 2 (PU895947) 3RD BN 82ND AVN REG WILL PROVIDE AIR TRAFFIC SERVICES FOR AIRCRAFT OPERATING IN THE VICINITY OF FLIGHT STRIP 2. UNIT WILL SET UP AN/TSQ-198B, TACTICAL TERMINAL CONTROL SYSTEM. ATC SERVICES WILL BE PROVIDED FROM 0800 TO 2200 LCL EACH DAY. OPERATIONAL FREQUENCIES WILL BE 336.500 (UHF) , 141.425 (VHF) AND 64.775 AND 39.950 (FM). ALL AIRCRAFT ARE PERMITTED AND ENCOURAGED TO USE FLIGHT STRIP 2, HOWEVER A MAXIMUM OF TWO AIRCRAFT AT A TIME ARE PERMITTED IN THE AREA. CREWS ARE TO BE VIGILANT DUE TO AN INCREASE IN PERSONNEL ON THE FLIGHT STRIP. 14 NOV 13:00 2018 UNTIL 16 NOV 03:00 2018. CREATED: 13 NOV 21:58 2018 -AJ
 
11/14/18 16:18:14 UTC
336.500 MHz
per KFBG NOTAM: L0729/18 - AERODROME - FLIGHT STRIP 2 (PU895947) 3RD BN 82ND AVN REG WILL PROVIDE AIR TRAFFIC SERVICES FOR AIRCRAFT OPERATING IN THE VICINITY OF FLIGHT STRIP 2. UNIT WILL SET UP AN/TSQ-198B, TACTICAL TERMINAL CONTROL SYSTEM. ATC SERVICES WILL BE PROVIDED FROM 0800 TO 2200 LCL EACH DAY. OPERATIONAL FREQUENCIES WILL BE 336.500 (UHF) , 141.425 (VHF) AND 64.775 AND 39.950 (FM). ALL AIRCRAFT ARE PERMITTED AND ENCOURAGED TO USE FLIGHT STRIP 2, HOWEVER A MAXIMUM OF TWO AIRCRAFT AT A TIME ARE PERMITTED IN THE AREA. CREWS ARE TO BE VIGILANT DUE TO AN INCREASE IN PERSONNEL ON THE FLIGHT STRIP. 14 NOV 13:00 2018 UNTIL 16 NOV 03:00 2018. CREATED: 13 NOV 21:58 2018 -AJ
 
11/07/18 22:30:58 UTC
284.550 MHz
?
 
11/07/18 22:11:53 UTC
399.850 MHz
?
 
11/07/18 21:53:22 UTC
377.100 MHz
la center?
 
11/07/18 21:51:49 UTC
357.150 MHz
?
 



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My Experience with the Radio Shack
Antenna Mounted Amplifer

I know that from time to time many people on various newsgroups and email lists ask the question "what pre-amp will improve my scanners reception?". The typical answer is "they don't work, they'll overload your radio". And usually these comment were from people who have NEVER tried one in their life.

I too have asked the question and after getting either no response or negative comments without any specific information on what was tried I figured I'd experiment myself regardless of what the nay-sayers kept harping. After searching the net I couldn't find any pre-amps specifically for the frequencies which were of interest to me. That would be 108-136, 138-144, and 225-400 MHz ranges. So I went the next best route. Buying an antenna mounted TV amp. Radio Shack as two antenna mounted amps, model # 15-1108 and model #15-1109. Warning: Radio Shack also has inline TV signal amps and distribution amps, however these will not work as well for scanning as they will amplify noise picked-up along your coax as well as the signal.

radio shack antenna mounted amplifier 15-1108
Radio Shack 15-1108
radio shack antenna mounted amplifier 15-1109
Radio Shack 15-1109


At the time of this writing the #15-1108 is $41.99 and provides (according to RadioShacks own specs) 20 dB gain UHF-TV and 25 dB gain VHF-TV. It has a 10 dB adjustment to help prevent overload and also is equipped with a FM trap which can be switched off. The #15-1109 is $64.99. RadioShack's specs simply say "up to 30 dB gain, VHF-TV, VHF-FM, UHF-TV". For the purpose of my experiment I purchased the #15-1108 amp.

I installed this amp on an Antennawarehouse ScannerBeam. This amp consists of three parts, the antenna mounted amp and the control/power unit. One plus here is that it has a real 120 Volt Plug, NO WALLWART that takes up 2 electrical outlets! That's a big plus in my book as I have over 20 wallwarts for all my radio equipment! The control/power unit has TV F type connectors so I did buy some BNC/F adapters from RadioShack to make coax connections easier.

As a compairison I used the ScannerBeam/Amp setup against a Create Log Periodic mounted at 30' (the ScannerBeam was only at 18'. The Create (non amplified) was feeding a BC 780 scanner and the ScannerBeam (amplified) was feeding another BC 780 so I could do side by side tests.

My first test was in the VHF and UHF TV ranges, as that was what the amp was designed for. I figured if I couldn't see an improvement here there was no use in continuing. Well with both the Create and ScannerBeam pointed in the same direction I let the BC 780's search the entire TV band (both VHF and UHF). On every channel the non-amplified antenna picked up the same station the amplified antenna picked up and was at least 1 (sometimes 2) s-meter bars higher in strength. The audio quality was as good if not slightly better as well. The amplified antenna also picked up 3 other stations which the non amplified antenna couldn't receive. Remember that the non-amplified antenna was mounted 12 feet higher! For these test I left the FM trap on. If I tuned the BC 780 to a VHF TV frequency and opened the squelch I could hear the scratchy sound of an FM station. So without question there was a slight amount of FM overload as a result of the amp which even its own FM trap couldn't attenuate fully. It wasn't enough to cause ill effects to frequencies which there were true signals, even weak sigs (which the Create antenna couldn't receive) The addition of a quality FM trap or bandpass filter for the bands you're interested in might eliminate this problem. I've ordered some filters from Stridesberg which I'll experiment with later.

Click on any image for full sized image


Click Here to see the rest of the
shack and antennas.


The next experiment was the 2 meter ham band. Again, every repeater the non-amplified antenna received the amplified antenna received as well and in most cases better. There was one repeater (not sure if it location) which the non-amplified antenna could not receive where the amplified antenna was able to receive a readable signal.

After testing the 2 meter band I went to the Civil Air Band. A good test case I used here is the Sanford, FL tower on 120.3000. This tower is located about 30 miles away. Before adding the amp to the ScannerBeam the ScannerBeam could not receive the ground side of comms on this freq. The Create usually can (remember the Create is mounted 12' higher). With the amplifier turned on I pointed both beam antennas at the tower. Both antennas now could receive the ground side of the tower comms! Both were receiving it with equal quality. There is one strange think I must note here. On the BC 780 connected to the amplifed antenna, the S-meter would be at between 3 bar and full scale even without anyone transmitting on the monitored frequency. I would open the squelch and only hear the normal amount of static, so it didn't appear to be overload from a FM station. It will be interesting to see if this goes away once I add a commercial quality FM trap. This "full-scale s-meter" situation also occurred in the 225-400 MHz MilAir Band. It didn't appear to effect scanning, the squelch acted normally regardless of the full-scale s-meter deflection.

As my final test I monitored many military air freqs. It seemed that in every case the amplified antenna once again preformed as well as the other antenna. Again remember the other antenna (non amplified). is mounted 12' higher, 12' makes a world of difference for MilAir monitoring. Also the non-amplified Create Log Periodic is advertised to have 11-13 dB gain where as the ScannerBeam only 6 dB gain in the tested frequency ranges.

The amplified antenna setup isn't perfect. You're going to get some FM Overload and some Intermodulation problems (mixing of other signals). I do have some intermod problems do to some paging systems in my area. I believe that the addition of a commercial grade filters will reduce if not eliminate this problem. Even before trying intermod filters I've found the problem to be manageable and not be nearly as bad as we are lead to believe by many people on the various newsgroups. Again you need to remember the people making this comments are usually people who have never tried this themselves!

As a side note you'll see in one of my pictures it appears I'm using a "roof mount antenna tripod" as a temporary antenna stand. I've found that the "EASY-UP" Antenna Tripods make great antenna stands when using 10-20' of antenna mast. As you can see I just have these setting on the concrete patio around our inground pool. On each of the three legs I have 2 concrete patio stones to hold the stand in place during wind. The ScanTenna has seen wind gusts over 40 MPH and hasn't moved. So far the ScannerBeam has seen 20 MPH winds with no ill effects. When we get storms during the hurricane season its very easy to lay these antennas on the ground until after the storm passes. Unless there are forecasts for 60+ MPH winds I have no plans on laying down these antennas. My main antenna, the Create Log Periodic, is mounted on a 30' telescoping mast and is attached to a cement block chimney. Even in 40 MPH winds it stays rock solid. After running out of room on the chimney for more antennas I had to come up with another idea. The EASY-UP Tripods was my solution. They are available from AES-Ham.com and other sources in the net.