[SFDXA] Fwd: FW: 144.2 interference from 72.1 MHz PRIMEX clock system

Fri Apr 23 10:59:34 EDT 2021

I forgot to mention their business is wall clock

https://gtrbusinesssystems.com/wp-content/uploads/2018/03/Primex_XR_brochure_v4_F_LR_web_1.pdf

Hi Ed

Thanks you very much for you comments. Here some comments

*	The power is 60W and 45w EIRP. ¼ vertical roof top over 100 ft high. The license is for .7 KM or .43 miles. My QTH is 4.3 miles away. 
*	It is not only me, several friends with vertical antenna and FM radio has the same issue, not possible to keep a QSO on 144.2
*	My antenna has 12 dBd horizontal, no preamplifier and 200 ft of LMR600 – IC 9100
*	You can see a video with the interference here on 144.2>> recorded at N4IS, 4.3 miles north of the hospital
*	https://www.youtube.com/watch?v=IumTaCjLUtk
*	The Hospital need to send unit back to manufacture to change the frequency but the problem will be the same
*	A simple LPF can provide additional -50db on 144 and they can fix the problem with U$100 70 MHZ Low-Pass Filter- FedEx Fast Ship - SV1AFN shop
*	https://www.ebay.com/itm/202528167936?hash=item2f279e9800:g:meIAAOSwZK1eRZTq
*	I am 4.3 miles and no overload on my front end , several hams in the area are having the same problem, why they need 60w and external antenna to cover .43 miles?
*	We Are appointing Davie Cupper city Radio Club Fred Perkin as point of contact.
*	But there is today several other hospital can College campus in Florida and other states with exactly the  same problem
*	The relationship with the hospital here; is good but irresponsive, I did call twice. In Polka county the ham is fighting for one year long with his local Hospital

Thank once again , we will follow your recommendations and contact Paul W1VLF

Memorial Hospital West

703 North Flamingo Road

Pembroke Pines, FL 33028

ATTN Luis Rodreguez

P:(954)844-7143

73

JC

N4IS

From: Hare, Ed, W1RFI <w1rfi at arrl.org> 

Sent: Friday, April 23, 2021 7:37 AM

To: Jose_Carlos <N4IS at COMCAST.NET>

Cc: Siwiak, Kai, KE4PT <k.siwiak at ieee.org>; 'n2cei' <n2cei at downeastmicrowave.com>; Cianciolo, Paul, W1VLF <pcianciolo at arrl.org>; Baker, Mickey, N4MB (Dir, SE) <fishflorida at gmail.com>

Subject: Re: [Florida Weak Signal Society] CW beacon on 144.2 solved

Hello, Jose,

This one is going to be a challenge, for a number of reasons.

I went to the FCC database and found a number of FCC certifications for Primex Wireless. I also went to their web site and found a model number similar to the model number listed in the FCC certification database.  They would be allowed to change a model number any time or make "cosmetic" changes to the products without impacting the status of the product as being FCC certificated. 

If this is a 30-watt system, they are using a transmitter with an amplifier. More than likely they are using an external antenna. At the 30-watt level, their spurious emissions must be suppressed by 58 dB.  This is similar to the suppression required of Part 97 VHF operation.

The FCC database includes links to test reports.  The certification database includes links to test reports that show harmonic supression well below the limits, so unless actual field-strength measurement were made on-site, FCC would almost certainly accept the premisse thet the equipment meets the rules for spurious emissions.  Keep in miind that Part 97 transmitters do put out similar power on their harmonics, so the system really is pretty much state-of-the-art.  It is even possible that some external non-linearity is creating harmonics that may not actually be coming out the transmitter.  

These external harmonics can even be being generated at the 144.2 MHz receiver input stages. It would be well worth having a station close to one of these systems insert 10 dB of attenuation in front of the 2-meter preamp (not post-preamp in from if the receiver) to see if the harmonic drops by more than 10 dB. 

Now comes the tricky part, and it may not be good news.  If they meet the emissions limits, the operator of the device is still reponsible for "harmful inteference."  That is very much in the eye of the beholder, but the eye that counts will that of the FCC.   In ARRL's long experience with FCC, they are very much apt to think that interference from a transmitter that is more than 20 dB better than the rules require , according to the test reports filed with the FCC is "S5" on one frequency to an amateur station using a high-gain antenna pointed right at the transmitter, connected to a high-gain preamplifier is not "harmful interference" as defined by its rules. 

There are a few solutions that I can envision. The frequency of the transmitter can be changed, but with a Part 90 license, they can only use the frequency(ies) authorized to them. That can be changed, but the operator of the device would have to initiate this with the FCC and they would probably have to pay a communications attorney to do it and they are going to be very reluctant to spend the money.

A bandpass filter could be installed on the output of the amplifier, but again, the company may reluctant to pay for the filter and its installation.

It is not clear to me what level of communication and cooperation has taken place between local amateurs and the involved hospital.  I recommend that the local amateurs appoint a single point of contact for that communication, to ensure continuity and a consistent message.  Amateurs tend to be very passionate about amateur radio, and that passion sometimes results in communication that sounds threatening and confrontational.  The hospital admiistrator will not understand why a unit that is FCC approved is causing a problem, so finding that understanding is the best practical way to proceed. 

The approach I usually find to be most likely to be effective is to take the mindset that local solutions to local problems are best.  Hams don't want the FCC to decide that this is not harmful interference and thus no action is required and the hospital does not want to risk the FCC mandating changes that may be more than what is needed, or possibly mandating expensive testing that the hospital would need to pay for.  Not making that "official harmful interference" call allows the two parties involved to help each other as their primary goal.

What I recommend is that all possible communication take place, document that communication then, contact Paul Cianciolo, W1VLF, ARRL's RFI engineer by email, providing all the case history and a summary of efforts to date.  Provide a phone number and time of day to call back.  He just did a presentation on RFI that engendered a lot of emails, so expect a few days delay for a while.

That's my best advice so far.  Keep Paul informed about how it works out and if there is resolution, let him know.

Ed Hare, W1RFI

ARRL Laboratory Manager

________________________________________

From: Jose_Carlos <N4IS at COMCAST.NET>

Sent: Tuesday, April 20, 2021 11:53 AM

To: Hare, Ed, W1RFI <w1rfi at arrl.org>

Cc: Siwiak, Kai, KE4PT <k.siwiak at ieee.org>; 'n2cei' <n2cei at downeastmicrowave.com>

Subject: FW: [Florida Weak Signal Society] CW beacon on 144.2 solved 

Hi Ed

I hope all doing well, I’m Jose Carlos N4IS, Fort Lauderdale Florida,  and I would like to ask for you help to understand what to do.

Recently I notices a beacon on 144.200 quite strong, south of me. The ID WQAU710  and the TX equipment is from PRIMEX. 30W into a quarter wave vertical on the roof top.

The signal is s5 on my 2m bean, I am 5  miles away.  

There was some push for clock sinconization due COVID vaccination. I see this situation as growing problem. 72 MHz clocks second harmonic on . 144.2. 144.360. 144.520 and 144.800

Would you help me with some advices what to do? See the email bellow with more information about the clocks.

73’s

JC

N4IS 

Sent from Mail for Windows 10

From: Jose_Carlos

Sent: Tuesday, April 20, 2021 11:25 AM

To: Florida Weak Signal Society

Cc: Buddy Morgan

Subject: RE: [Florida Weak Signal Society] CW beacon on 144.2 solved

Hi Buddy

I called the Memorial Hospital again and this time talked with a guy but not the guy responsible for the service. Searching more deep I found a petitinomn to FCC and a complain about TV station interference.

The company selling this clock on 72 MHz is PRIMEX in WI

https://www.primexinc.com/classicsync-products/72mhz-analog-clocks

That could be a problem every were with poor beacons with 2nd harmonic . 72.100, 72.180, 72.260 and 72.400. I don’t think they are using a decent low pass filter to avoid 144.200 2nd harmonic.

PRIMEX sells 1W, 5 W and 30 W

https://www.primexinc.com/classicsync-products/transmitters

Not sure about antenna polarization, but the 2nd hormonic is s5 here with my 10 elements yagi horizontal pol. If they are using vertical antenna, the signal could be more than 20 db stronger.

We need to watch this space.

73

JC

N4IS

Sent from Mail for Windows 10

From: Buddy Morgan via FLWSS

Sent: Monday, April 19, 2021 10:10 PM

To: flwss at flwss.net

Cc: Buddy Morgan

Subject: Re: [Florida Weak Signal Society] CW beacon on 144.2 solved

It has been a few months ago, but the identical same problem was traced to a clock synchronize system, at, I think it was Polk State College? Don't remember the resolution. 

Buddy 

-----Original Message-----

From: JOSE CARLOS via FLWSS <flwss at flwss.net>

To: 'Florida Weak Signal Society' <flwss at flwss.net>

Cc: n4is at comcast.net

Sent: Mon, Apr 19, 2021 4:40 pm

Subject: [Florida Weak Signal Society] CW beacon on 144.2 solved

Hi Guys

I found the problem about the CW beacon on 144.200. It is a GPS/clock

related digital signal, Licensed service on 72.100 MHz as WQAU710 Memorial

West Hospital, Pembroke pines city  4 miles south of me. The second

harmonic signal is s3 to s5  with the antenna on their direction. I called

the number on the FCC license for a voice mail.

I have on my notes that FCC allow maximum 13dBm spur above 1 GHz, is it the

same on other VHF frequencies?

73's

JC

N4IS

From: Randy Shirley <wil9926 at bellsouth.net> 
Sent: Friday, April 23, 2021 10:53 AM
To: Carlos <n4is at comcast.net>; sfDXa <SFDXA at mailman.qth.net>
Subject: Fwd: Fwd: FW: 144.2 interference from 72.1 MHz PRIMEX clock system

-------- Forwarded Message -------- 

Subject: 

Fwd: FW: 144.2 interference from 72.1 MHz PRIMEX clock system

Date: 

Fri, 23 Apr 2021 10:49:10 -0400

From: 

Randy Shirley  <mailto:wil9926 at bellsouth.net> <wil9926 at bellsouth.net>

To: 

Mickey Baker  <mailto:n4mb at arrl.net> <n4mb at arrl.net>

Hi Mickey,

This is a real problem here in South Florida. This company looks like they don't care if they are not compliant and destroying the 2 meter band.  Please take a look at the video.  

Please forward this to anyone that you think can help.

Thanks and very 73,

Randy N4QV

President SFDXA

-------- Forwarded Message -------- 

Subject: 

FW: 144.2 interference from 72.1 MHz PRIMEX clock system

Date: 

Wed, 21 Apr 2021 11:44:41 -0400

From: 

n4is at comcast.net <mailto:n4is at comcast.net> 

To: 

'Randy Shirley'  <mailto:wil9926 at bellsouth.net> <wil9926 at bellsouth.net>

From: Jose_Carlos  <mailto:N4IS at COMCAST.NET> <N4IS at COMCAST.NET> 
Sent: Tuesday, April 20, 2021 5:30 PM
To: 'sfdxa mailman'  <mailto:sfdxa at mailman.qth.net> <sfdxa at mailman.qth.net>; 'Florida Weak Signal Society'  <mailto:flwss at flwss.net> <flwss at flwss.net>; Joe Ruggieri via Microwave  <mailto:microwave at mailmanlists.us> <microwave at mailmanlists.us>; gandral at mhs.net <mailto:gandral at mhs.net> 
Subject: 144.2 interference from 72.1 MHz PRIMEX clock system

Hi

The company PRIMEX is selling a clock service based on 72.1 MHz 30 w transmitter, The second harmonic I making very hard to work weak signals on 144.2

Here high it sounds like

 <https://www.youtube.com/watch?v=IumTaCjLUtk> https://www.youtube.com/watch?v=IumTaCjLUtk

The company selling this clock on 72 MHz is PRIMEX in WI

 <https://www.primexinc.com/classicsync-products/72mhz-analog-clocks> https://www.primexinc.com/classicsync-products/72mhz-analog-clocks

That could be a problem every were with poor beacons with 2nd harmonic . 72.100, 72.180, 72.260 and 72.400. I don’t think they are using a decent low pass filter to avoid 144.200 2nd harmonic.

PRIMEX sells 1W, 5 W and 30 W

 <https://www.primexinc.com/classicsync-products/transmitters> https://www.primexinc.com/classicsync-products/transmitters

The signal here is s5 all day long, I am 4,5 miles away from the 30W transmitter on 72.1 MHz WQAU710.

I need some help to fix this issue, but I think it is growing problem due recent investments on 72 MHz clocks,  

73

JC

N4IS

Sent from Mail <https://go.microsoft.com/fwlink/?LinkId=550986>  for Windows 10

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/sfdxa/attachments/20210423/34ea22c1/attachment-0001.html>