• To anyone looking to acquire commercial radio programming software:

    Please do not make requests for copies of radio programming software which is sold (or was sold) by the manufacturer for any monetary value. All requests will be deleted and a forum infraction issued. Making a request such as this is attempting to engage in software piracy and this forum cannot be involved or associated with this activity. The same goes for any private transaction via Private Message. Even if you attempt to engage in this activity in PM's we will still enforce the forum rules. Your PM's are not private and the administration has the right to read them if there's a hint to criminal activity.

    If you are having trouble legally obtaining software please state so. We do not want any hurt feelings when your vague post is mistaken for a free request. It is YOUR responsibility to properly word your request.

    To obtain Motorola software see the Sticky in the Motorola forum.

    The various other vendors often permit their dealers to sell the software online (i.e., Kenwood). Please use Google or some other search engine to find a dealer that sells the software. Typically each series or individual radio requires its own software package. Often the Kenwood software is less than $100 so don't be a cheapskate; just purchase it.

    For M/A Com/Harris/GE, etc: there are two software packages that program all current and past radios. One package is for conventional programming and the other for trunked programming. The trunked package is in upwards of $2,500. The conventional package is more reasonable though is still several hundred dollars. The benefit is you do not need multiple versions for each radio (unlike Motorola).

    This is a large and very visible forum. We cannot jeopardize the ability to provide the RadioReference services by allowing this activity to occur. Please respect this.

UHF tunable notch filter/trap to block receiver interference

Status
Not open for further replies.
V

videobruce

Member
Premium Subscriber
Joined
Jan 5, 2004
Messages
402
Location
Buffalo NY
I need a narrow band, preferable tunable UHF notch filter. 424-425MHz is the offending frequencies. They are very strong data signals that create havoc on the general UHF business band (450-470 MHz).

This is receive only.

I know tunable notch traps are expensive. I would like it as narrow as possible without getting to expensive.
Other than Tin Lee in Toronto, which are expensive, anyone know a source of custom, narrow band, tunable traps?
 
D

dsalomon

Member
Premium Subscriber
Joined
May 6, 2003
Messages
210
Location
Brooks, GA
Fairview Microwave is known for their custom filters, but they cost a fortune. Here's a tunable band reject from 250 - 500Mhz: http://www.fairviewmicrowave.com/tunable-band-reject-filter-n-female-250mhz-500mhz-sbrf-0250-0500-01-n-p.aspx.

Here's a band reject filter I just found on eBay. It looks like exactly what you want and the price is reasonable (for a tunable filter :).

You'll find a lot doing a Google search for 'tunable band reject filter".

Are you certain the interference is external? Have you looked up and down the band for the same type of interference at regular intervals? You haven't given any information about the radio, antenna setup, QTH information, etc., so it's impossible to help you determine if this might be something internal Vs external. Maybe this is a known birdie for your radio?

73 - David, AG4F
 
V

videobruce

Member
Premium Subscriber
Joined
Jan 5, 2004
Messages
402
Location
Buffalo NY
Forget Fairview, that's utterly ridiculous. That other one would be interesting except for it's size and where it is located (from Greece ).

BNC connectors would be preferred. Even 'F' fittings could work. Actually something like a in-line 'can' type that is used in the CATV industry would be ideal.

I'm more than certain where (the frequencies) are coming from. They are data bursts (5 to 10 secs), impossible to mistaken due the the gross audio level they are at.:mad:
 
C

chief21

Member
Premium Subscriber
Joined
Mar 2, 2004
Messages
1,800
Location
Summer - Western NC; Winter - Tampa Bay FL
videobruce said:
I need a narrow band, preferable tunable UHF notch filter. 424-425MHz is the offending frequencies. They are very strong data signals that create havoc on the general UHF business band (450-470 MHz).

This is receive only.

I know tunable notch traps are expensive. I would like it as narrow as possible without getting to expensive.
Other than Tin Lee in Toronto, which are expensive, anyone know a source of custom, narrow band, tunable traps?
Click to expand...

Give these guys a try. Send them an email and they will quote you a price. If you're not sure exactly what you need, they are very helpful and will recommend the best solution.

PAR Electronics | Filters for the commercial 2 way market, MATV, FM broadcast, laboratory, marine industry, amateur radio, scanner and short wave listening enthusiasts

Not affiliated... just a past customer (they also make antennas).

Good luck,

John AC4JK
 
F

freddaniel

Member
Joined
May 6, 2011
Messages
118
Location
Newport Beach, CA
If you are handy with a service monitor, or spectrum analyzer & signal generator, you might try one of these solutions:
- Build in a small box [1 x 1 x 2] with male and female connectors a simple series resonate trap notch filter to ground. One circuit will provide 25 to 30 dB notch.
- Find a UHF cavity and place a coaxial "T" adapter on only one loop, tuned to the notch frequency. Adjust the loop and cavity for best results.
- Buy on Ebay one of the many channel deletion filters made by Microwave Filter Company, which have 8 adjustable cavities to delete a 6 MHz TV channel. Remove one and retune. Verify frequency range on factory spec sheet.
 
Status
Not open for further replies.

Similar threads

C
  • Locked
A UHF Milair Search Problem Solved!
Replies
13
Views
4K
WartHog
W
Top