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| Reviews Summary for PAR SCANNER INTERMOD FILTERS |
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Reviews: 15
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Average rating: 5.0/5
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MSRP: $74 USD
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Description: These scanner filters are used to eliminate interference from high powered pagers and channel "skipping" from other frequencies. The filters are designed to eliminate specific offending frequencies.
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More info: http://www.grove-ent.com/filters.html
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write your own review of the PAR SCANNER INTERMOD FILTERS.
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PA3GTS
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Rating: 5/5
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Oct 20, 2009 06:07
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Ideal no problems more in the airband
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Time owned: 0 to 3 months
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Hello every day problems here with the local radio on 104.7 mhz in the airband vhf, i ordered a fm filter from Dale and in our e-mail contact he asked to give the freq and later received the filter and works great no problem more on my scanner,also the communication with Dale was also perfect !
With friendly greetings from Jelle pa3gts 7s s !
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K8CMI
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Rating: 5/5
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Jun 25, 2009 06:14
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Now I'll keep my scanner
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Time owned: 3 to 6 months
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I was ready to just sell the scanners and give up. I have an FM broadcast antenna located about 2 miles from my house. Their signal was on every vhf channel I scanned. The frontend of the scanner was so overloaded that I had to attenuate everything, including NOAA, just to receive anything.
I found Dale's filters on eHam and gave it a try. The offending signal are GONE! The attenuation is off and I now receive signals that I had previously given up on.
Dale is great to work with. He actually RESPONDS to his emails. Usually within the hour. My offender was at 104.9. Out of the box, the filter has a pretty deep notch near this frequency. Dale offered to tune the filter to put a notch right at 104.9. That's customer service.
Thanks Dale!
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W6LBV
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Rating: 5/5
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Apr 13, 2008 21:47
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A (grief) filter that works
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Time owned: 0 to 3 months
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The Par VHF-FM Notch Filter solved a real and vexing problem for me. The FCC, in its customary institutional laxity, approved license upgrades for two local FM broadcast radio stations that took each of them upwards in power to 50 kilowatts ERP! The transmit antennas for these stations, whose broadcasts are of no interest to me anyway, are located within a metropolitan residential area on a tower that lies just over four miles away in a direct line of sight from my residence. At my dwelling, using a broadband discone receiving antenna located in the clear ten feet above ground and a spectrum analyzer, I measured received signal levels from each station of -16 dBm. When that signal level is developed across a 75 ohm receiver input, it yields more than 43,000 microvolts! (Typically, “S-9" is taken to be 50 microvolts.) These two are the strongest measured off-premises signals at my residence between 0 and 1,000 MHz, and probably in the entire RF spectrum. Few, if any, broadband receiver front ends are going to handle a signal of that magnitude without folding into compression.
That grossly excessive signal level is really needed only for receiving broadcasts on electric toothbrushes! There is no rational purpose in using this great a power level in my area, since VHF signals are always blocked by existing terrain before they can decrease to the noise level at far distances. It’s no wonder that my sensitive monitoring receivers on outdoor antennas curl up and die whenever they are tuned to within a few tens of Mhz of the FM broadcast band. The Par filter, working ahead of a broadband distribution amplifier and the receivers, solved the problem. The receiver blanketing is essentially gone!
On-air testing of the filter using the spectrum analyzer confirmed the published specifications. My several monitoring receivers (30 kHz to 2 Ghz) also expressed their relief at no longer having to work under that crushing load!
There are some (small) niggles with the filter: it would be helpful to have multiple tuneable traps in one filter, since I have two 50 kW FM loudmouths to silence (and two more at the same power level just another mile farther away). And, as expressed by others previously, the filter needs some sort of physical mounting tab arrangement so that it can be permanently fastened to a chassis or rack panel (but industrial Velcro will also work).
The filter is somewhat pricey, but it does the job very effectively and significantly better than most competing products. Dale Parfitt is splendid to work with, as he always has been.
For many years I unquestioningly believed that “bigger outdoor antennas were better antennas.” Finally I measured actual received signal levels. And I discovered that the real problem was far too much RF in the air over my residence, not too little!
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AA8IA
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Rating: 5/5
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Apr 6, 2008 19:51
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Great Product, Excellent Service!
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Time owned: 0 to 3 months
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I live at a high elevation in my area, and even though I live out in the country I was hearing severe intermod and significant front end overload on my scanner.
I gave PAR a call, and lo and behold Dale answers the phone and talks to me. I discuss my problem with him. We discussed the likely possibilities and agreed that my local TV Ch 9 was the strongest offender. I ordered a PAR filter to attenuate the 190 mhz region.
When I received the PAR filter, Dale had included a note that stated what he had done in my particular case since the TV signal is actually within a 6 mhz spread, wider than what the typical filter has to attenuate.
I inserted the filter inline and immediately noticed a significant improvement. My initial thoughts were that it significantly lessened the intermod but did not remove it completely. However, I was left with occasional interference across a wide range of VHF that I [erroneously] contributed to remaining TV 9 signal still affecting some areas. Further investigation revealed that the remaining interference I was hearing was due to my local cable company having significant leakage in teh area of my old house, which was affecting certain areas of VHF from the Aero band all the way up to 170 mhz. I hadn't noticed the cable leakage before because of the other problems [which the PAR filter cured].
I then moved to a new place a mile away. I fired up the scanner without the PAR filter and the symptoms were back once again. I put the PAR inline and VHF scanning was totally quiet [i.e. normal] - No odd interfering signals popping up anywhere.
In my opinion, the product is commercial grade. It is built tough and with quality components. You can tell that Dale takes pride in what he builds. The filter is small enough and light enough to leave inline on my handheld scanner connected directly to the antenna jack without fear of having the weight of the filter causing problems with the connector base.
It was great to talk to Dale when I called. These days, you're lucky to talk to an American let alone the manufacturer himself. He explained to me what I should get, how it would benefit me. He didn't try to oversell. He was courteous and obviously is an intelligent man.
Every email correspondence I have had with Dale was answered promptly. My satisfaction level could not be any higher.
The bottom line - Dale builds excellent products at reasonable prices and supports his products, should you need support. If somebody were to ask me to describe Dale, I would describe him as meticulous and a true professional.
Mike
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73383
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Rating: 5/5
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Dec 30, 2007 14:52
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Very Good Product
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Time owned: 0 to 3 months
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I purchased a new Yaesu VR-5000 wideband receiver and was immediately disappointed in the quality of the receiver front-end. I presently use it to monitor the aviation VHF and UHF bands of 118-137 MHz and 225-400 MHz.
Whereas all my other receivers work fine with my outdoor Diamond D130JN discone antenna, the VR-5000 receiver had serious overload and intermodulation problems from FM stations. I was receiving local FM stations all over the VHF and UHF bands. The resultant noise was so bad that I could not squelch it without using the receiver's built-in ATTENUATOR. Of course, this ruined desired signal reception.
This problem led me to PAR Electronics and I purchased one of their VHF-FM Broadband 88-108 MHz filters. Prior to ordering, I checked the FCC's FM Radio Database Query site at http://www.fcc.gov/mb/audio/fmq.html using the "Stations Within a Radius" query form. This searches for stations within a specified distance of your specified coordinates. The query response lists all licensed FM stations and their distance and azimuth. The closest and most powerful station was at 101.3 MHz, 2 miles away.
I ordered the filter and specified the notch to be set at 101.3 MHz. This is a nice feature of the PAR Electronics filter - you can ask that it be tuned to specific frequencies (within technical limits) at no extra charge.
When I received the filter, it included a brief specification sheet and a stopband response printout. This filter actually has three notches in the FM band. In my case, the notches were 90, 98.0 and 101.3 MHz; the notch at 101.3 was about -49 dB with respect to response at 120 MHz.
I installed the filter and it solved the interference problem. I can now set the squelch normally and receive aeronautical stations quite well. I occasionally hear interference on a few frequencies but it seems to come and go, and the frequencies in question do not seem to be active in my area.
My only complaint about the filter is there is no convenient way to fix-mount it to a panel. The filter is designed to plug right into the BNC-F connector on the receiver. The filter comes with a BNC-M on one side and BNC-F on the other - this makes it easy to cascade more than one filter if necessary. While this is somewhat convenient, it does mechanically stress the receiver connector. I asked Dale Parfitt at PAR if I could drill and tap the filter body but he indicated that the material was a relatively thin brass extrusion and not really suitable for that. He said that on future filters he could accommodate any mounting pattern I need. This is another nice thing about PAR - the personalized service and quick response you get, something missing from many companies these days.
It's too bad the VR-5000 receiver designers did not build a good front-end, but it's good that PAR Electronics makes a filter to compensate for it.
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MACKAN
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Rating: 5/5
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Dec 7, 2007 03:57
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Another happy customer!
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Time owned: 0 to 3 months
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Enlish is not my first language, so this review is a bit short!
I needed a notch filter to attenuate a very strong signal at 167 MHz. The signal was over 9+40db.
I found the PAR website after a few searches on google, and after a few emails I placed my order.
I ordererd a notch filter for this particular frequency, and also a FM-broadcast filter.
Dale was very helpful, and replied fast to my many questions by email.
Shipping to Sweden (Europe) was pretty fast, I got my filters after 10 business days.
As for the 9+40 signal, it is totally blocked now. The signal meter is not even moving.
Thumbs up for Dale and PAR filters!
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K6SAT
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Rating: 5/5
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Nov 13, 2007 22:30
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High quality and cost effective filters.
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Time owned: 0 to 3 months
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I moved recently into an area that has nearby strong FM broadcast transmitters as well as pager towers. My reception on my scanner was horrible until I installed a VHFSYM158HT to get rid of a pager frequency and a VHF-FM to rid myself of the FM broadcast signals. What a difference, now everything is clear with no interference.
I ordered mine with N connectors and got them within 1 week.
Construction is high quality - you won't be disappointed.
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OCEANS777
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Rating: 5/5
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Aug 29, 2007 14:36
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Outstanding performance and service
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Time owned: 0 to 3 months
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My purchase last week of a PAR Electronics VHFSYM162HT filter is easily the best and most rewarding money I have spent for monitoring in a long time. It has turned out to be as important as my antenna and has provided the largest performance gain.
I live only a few miles from a NOAA broadcast tower and all of my receivers/scanners were picking up 162.550 all through VHF and UHF. Searching was essentially useless as was any scanning of air bands and UHF in particular was a mess.
I called PAR and had the pleasure of speaking with Dale about the problem and after listening to my details and questions he explained the effects of the signal on the receivers and suggested a VHFSYM162HT notched at 162.550.
It arrived quickly and I was very impressed with the build quality and appreciated the performance chart that came with it. These filters have the feel of a professional test instrument and are rock solid without being bulky or heavy.
The performance is absolutely outstanding. It has completely eliminated the problem without any degraded performance anywhere else. I can finally hear even distant ATIS frequencies that were not there or just NOAA weather before.
A spectrum sweep shows the true sharpness of the VHFSYM162HT filter in attenuating the offending 162.550 and this is the true beauty of these professional-grade filters; they are sharp enough to defeat the unwanted signals without dragging down desired adjacent signals too.
I am so impressed I ordered the VHFSYM152 and 158 filters today to deal with paging.
You won't beat the performance and pure quality of these filters at anything within hundreds of dollars of the price. (If you could even find anything) Add the ability to specify the frequency you need notched and Dales expertise - it's the last of the true bargains.
In my case it has allowed me to regain the full performance of a discone mounted up high in tough RF environment without suffering the intermod that frequently cripples and 'deafens' the receivers.
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N8905W
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Rating: 5/5
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Apr 12, 2007 10:40
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Excellent Performance!
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Time owned: 0 to 3 months
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This is a review of Par Electronics and their VHF-FM Scanner Filter.
I had need for a FM filter when I discovered my new scanner(Pro-97)
was receiving 92.9 FM in the airband frequencies. I researched and found
that Par Electronics, among others, was manufacturing such a filter.
It was within that research that I found Eham.net and the positive reviews
on Dale Parfitt and his company, Par Electronics. Those
positive reviews influenced me to contact Dale for my solution.
I am very glad I chose Par Electronics.
Dale is a professional who embodies the passion of electronics
and amateur radio. This passion extends into his products and
is evidenced by the impeccable workmanship and precision tolerances
that went into building my VHF-FM Filter.
The VHF-FM filter was promptly built and promptly shipped in a sturdy box
with careful and well thought out packaging that insulated the filter
from shipping damage.
Inside the box was my filter, invoice and the plot graphing the
actual tested and measured performance of my filter. Terrific!
The filter itself was impeccably constructed using hardy and durable
materials. A real showcase of workmanship in finish and order.
The filter attached to my scanner easily and looked good as well !
I turned the scanner on and immediately started reaping the benefits
of my decision and Dale's work.
There for all to hear were the once impossible lower airband freqs.
There was a large, noticeable improvement in the audio clarity of
all frequencies that I monitor including Milcom, Police, Fire, Ems.
Weak signals now broke squelch and were received with clarity.
As important as anything else, the irritating squelch tail was gone!
I got more benefits than I expected, and Par Electronics got a
second order from me.
If you have need for a radio filter, give Dale and Par Electronics
your strong consideration.
Thank You, Eham.net and Thank You previous reviewers for encouraging
me to seek out Par Electronics!
Mike
n8905w
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WB1AFC
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Rating: 5/5
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Mar 23, 2005 20:09
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FM Broacast Band Filter - VHF-FM and UHF 471.25 Custom Filter
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Time owned: 0 to 3 months
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WOW… These PAR filters work GREAT!
I recently purchased 4 Radio Shack PRO-2052 scanners to use with my computer controlled scanning setup. The 2052 has RS-232 control with a DB15 on the back panel making it ideal for computer controlled scanning. It is an older model (on close-out pricing) and can be purchased on sale now for $150.
The problem is that the front end is wide open and is subject to significant intermod interference problems, especially after I connected to a discone antenna mounted on my roof at about 40 foot high.
When I connected the discone to my old HP141 Spectrum Analyzer it was easy to see what the problem was:
1. TV Channel 14 is blasting at 471.25 MHZ – Loudest signal I can see from 0-1250MHZ
2. FM Braodcast Band – Second Loudest
3. Pagers at 150 something MHZ
4. Pagers at 462 MHZ
I googled on notch filters and after searching through lots of sites listing very expensive solutions I finally found what looked to be a good solution at a company called PAR Electronics. (http://www.parelectronics.com/) I talked with Dale W4OP at PAR and explained my problem. He immediately understood my problem and made some recommendations as to how a PAR filter could help.
First he recommended starting with a custom filter tuned at the 471.25 frequency to knock out the loudest signal which was causing problems for me on the public service 462MHZ band. Second their off the shelf VHF-FM filter could help with the poor reception I was getting on the 118-136MHZ air band. I am a pilot and this is the band I tune around most.
Both filters arrived in a couple of days after ordering (PAR takes PAYPAL payments making it very easy to do business on-line with them).
The first thing I did was to put the filters in-line and plug my discone back into the spectrum analyzer, and had a look at 440-480MHZ. All I can say is WOW. The TV channel was gone while the police frequencies at 460MHZ were just as loud as ever.
Next I took a look at the 88-108MHZ FM band with and without the filter. Again, the signals all but disappear from the spectrum analyzer. I then fired up my scanner and gave it a try on the air band. Incredible! What a difference! The radio is all but unusable without the filter. When I put it in line I can hear signals that I coulden’t even hear with out it. The FM broadcast band was overloading the front end so much that it was blocking all but the loudest signals.
I will update this review after I have had a chance to test the filters with other radios and in a mobile configuration.
More to come…
Jim
WB1AFC
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