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Fighting tons of RF & Misc Interferences after Antenna Upgrade

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BigEvil

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First off all,
thanks in advance for any help, I really appreciate it.

I've got two HTs a Yaesu VX8DR and a FT-60R(I usually keep the latter in the car). I had been using a Daimond SRH 320A & SRH77CA on the two HTs for slightly better performance in my house but finally decided to make the move and put up an antenna on my roof to better operate 2M, 200 & 400. Anyway, I bought a Diamond X3200a and mounted it high atop my house (which is up in the hills of Sherman Oaks CA), used high quality coax and ran it directly to my little shack in the house and eagerly awaited the performance increase I was hoping for........Unfortunately, to my disappointment the increase in range and clarity(which has been significant) has been overshadowed by harsh RF across the whole radio. I've tried many different frequencies, bands, even various operating power modes but the interference and noise is everywhere I go. I tried adjusted the squelch thresholds to the maximum but that did nothing. My friends at Ham Radio Outlet say I am likely picking up all the extra "junk" in the air now since I'm so high up in the hills and using a good antenna. I'm just wondering if/how I can eliminate this noise, at present it really makes using it nearly impossible since its just nonstop stabs(every second or two) of random transmissions, static, noise and other stuff(I'm getting all sorts of TV, VHF FD, and other hams as well as radio stations). Will using CTCSS and tone squelch(or whatever advice you guys give me) sacrifice my ability to TX/RX in other ways?

Thanks again, I can't wait for the help!
KJ6BUR
 

N2MWE

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Wow..you might actually need band pass filters. Try looking and seeing if your portables have an attenuation setting...you might need to lower the front end sensitivity. If not, band pass filters might be in your future. Also, since these are multi band radios, their adjacent channel rejection is not the greatest since they're broadbanded.
 

BigEvil

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I'll look into that right now, I appreciate it. I didn't even realize band pass filters would be something that could help me in this situation, I will need to get more information on that cause they don't seem too cheap! That being said I'm happy to make the investment if it'll help my rectify the problems.
 

BigEvil

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In the meantime I've been messing with the front end attenuator on the HT which has been proving to be relatively successful. Its far from perfect but could get me by until I find a permanent solution.
 

N4KVE

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For the price of a dualband bandpass filter, you could get a dualband mobile radio which would be better than a HT. Since a HT uses a rubber duck antenna which actually has a gain loss, when you connect the HT to a good antenna with some height, the HT becomes a RF sponge & gets tons of intermod. I would suggest going to Eham.net & read reviews of various dual band mobiles to see which are better at rejecting intermod than others. The Yaesu 8800 comes to mind. Or, for rock solid intermod rejection try to pick up some Motorola radios which can be found very cheaply as the narrowbandind deadline approaches. Either way, a HT connected to a gain antenna high up will drive you to drinking with all the noise. GARY N4KVE
 

BigEvil

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Thanks Gary,
Thats the general consensus I'm getting from my various inquiries out there.
I think I'm going to get by with the front end attenuator until I decide my best option for some various dual bander mobiles at the house.

Thanks again
 

VA3XDJ

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I've had the same problem since I put up a Diamond X30 at about 30 ft high using 50 ft of LMR-400 into a Yaesu FT7900 dual bander.

I'm in line of sight of at least a half dozen commercial sites including a VHF paging transmitter a few hundred feet from me.

The problem here is I use the radio for scanning which implies wide band receive and the front end gets overloaded to the point of blacking out weaker signals when that paging transmitter kicks in.

I've discussed the situation with local hams and there's really nothing to be done other than installing commercial rigs on a switch or duplexer.

If you put band pass/band reject cavities or filters you will lose your ability to scan outside of the band pass and you'll also be limited to transmitting inside that band. You could use a switch with two sets of cavities but that would be expensive and you'd lose your ability to scan.

Like previous posters, including yourself have mentionned, you can use an attenuator but it defeats the purpose of having a gain antenna with height to improve your transmit and receive.
 
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BigEvil

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Mike,
what scares me is that you're experiencing these problems with a FT7900 which is a wonderful mobile unit and not a HT. That being said I do not need scanning capability out of band because I have a separate scanner unit that I keep scanning full time and the only real need/hope for my home ham capabilities is to talk to hams on the various repeaters/simples (which inherently will always be within the band limits). Given that information I'm hoping that switching getting a good mobile 2M/440 and mobile 220 rig with better front end will solve my issues. If not then I'll just be scratching my head at the point of ever having great antennas for UHF/VHF since the downsides seem to outweigh the upsides.

How costly is installing commercial rigs w/ duplexers etc... doesn't seem like a fun solution.
 

VA3XDJ

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Well, thats the downside of living in or near a major city.

Combined with the fact that the VHF paging transmitter is at high altitude with lots of power, gain and proximity to my station its inevitable.

It just proves that my antenna, coax and radio are sensitive but that being a wide band rig the front end gets knocked out on VHF when that transmitter kicks in.

I wish they'd force them to get rid of VHF paging and stick with 900MHz FLEX paging.

Also add the fact that digital trunking systems such as P25 and Nexedge transmit their control channels continuously makes for a very hostile RF environment on VHF for me.

Where I am, paging and P25 is located above and below the edges of the 2 meter band...

If the tone squelch on the FT7900 was faster I wouldn't be blasted with POCSAG paging signalling audio out of nowhere.

But yeah, your best bet is a switch with cavities and duplexer but its not a cheap solution unfortunately.

Otherwise Motorola and Midland make great radios with solid front ends. Not a fan of Kenwood or Icom but thats another story...
 
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BigEvil

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Hmm..... I'm going to have to start researching the motorola and midland solutions. I had my eye on a Kenwood and Yaesu dual band mobiles that would hopefully provide some increased front end and be more stable but if you have some thoughts please do share. Also I'm thinking a Alinco for 220 could be fun & cheap.

I have noticed some really excellent results simply turning the front end attenuator on for the whole radio on all bands. I've been using it all day with wonderful results.
 

VA3XDJ

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I'm personally a fan of Motorola. I've connected a VHF Radius M206 to my X30 and have had no problems so far. You can find tons of cheap cables and a lot of Motorolas are ending up in auctions, online classifieds and hamfests. Models such as the Maxtrac and Radius series are your best bet as they are the easiest to work with and are synthesized. You can usually pickup a Motorola for anywhere from 50 to 200$ depending on its condition but you have to be careful with the model number to make sure you get one for the right "band split" (for example, my M206 does 146-174 but goes down to 144 without a problem. If you get an SM50 or SM120 the splits are tighter and might require some "hacking" and recalibrating to operate in the ham bands.)

Of course, they aren't "frequency or tone agile" meaning that once its programmed - thats it, thats all. And getting them programmed at a shop can sometimes be costly. You can find the software online but I won't get into that because Motorola likes to keep a tight grip on it.

As far as Kenwood and Icom I personally have no experience with them but haven't heard much good about them except for the D700/710 from Kenwood.

As far as 220 is concerned I think Alinco and Jetstream have models out there and there's always the made-in-China Anytone mobiles or Puxing/Quansheng/Wouxun/etc for portables but as they are cheap they perform as cheap and are built as cheap.

For example, the Puxing PX888 has a muddy/canny audio, even with speakermic (the PX777 doesn't have this problem) and the Quansheng doesn't do DTMF. The Wouxun programming is a bit tricky but a good bang for the buck and they have a dual bander.

As far as Yaesu/Vertex you definitely can't go wrong with price and quality, features and build in the later models.
 

prcguy

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I experience the same thing with many amateur handhelds with the most recent being a Yaesu VX3, VX7 and VX8. Even with a gain type mobile antenna these handhelds get overloaded in some areas I drive in and with a large base antenna at my office its really bad.

My Wouxon 2m/220 and 2m/440 handhelds seem to work fine under the same conditions as do most amateur mobiles including the Yaesu FT-8900.

In the early 1990s I had several Icom handhelds that were unusable in my area even with the stock rubber duck antenna. If you live in a high level RF area you don't really know what will work until you try it or check with other local hamsters to see what they are using.
prcguy
 
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BigEvil

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Thanks, seems like a trip to HRO is coming where I'll just buy a solid mobile to try out and see what happens.
 

VA3XDJ

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It seems I had forgotten about the Kenwood LTR radios I worked with recently, the TK480 and TK980. Both look solid and well made. Can't say much about performance because I didn't put them thru testing but I would probably say if the prices were lower for the UHF models I'd get them.
 

BigEvil

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skidplate, you'll have to elaborate on what seems to be a very well articulated (and well punctuated) sentence. Perhaps one of the other forum users who are lending there hand in helping newcomers to the hobby (a hobby that is generally supposed to encourage people learning) will be able to help you with your question.
 
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