Jump to content
  • 0

Question

Posted

I've got a GMRS handheld radio (Wouxun KG-805G), which I'm licensed for, and a BaoFeng UV-82HP dual band (for listening only). Have been watching some vids tonight on RFI interference, and I'm guessing my home office is not a good place for listening (see attached picture - sorry no pic, tried, tried, and tried again, but no).

 

To put it lightly! Yikes! Not ony do I have this jumble of power chords, multiple external drives, printer and LED light, but there are computers on both sides of this with multiple monitors each. I'm beginning to wonder if I should be wearing shielded clothing! LoL

What are your suggestions for getting good reception for my handhelds?

10 answers to this question

Recommended Posts

  • 0
Posted

Reynolds Wrap Heavy Duty aluminum foil.   :rolleyes:

 

Ok, seriously, simple a/c cords do not usually present an RFI problem unless you have some devices that require a ground, but that are not grounded.  Motors can be a source of noise. But, at the signal levels you are looking for, the frequencies you are listening to (uhf) and the use of FM rather than AM, your local environment is not likely to have a significant impact on your reception.  The case where you might find problems would be trying to receive very weak “short wave” signals on a small radio with the built-in antenna.

 

If you want better reception, the best thing you could do would be to setup an outdoor antenna, and the higher, the better. You do not need anything fancy or expensive, even a DIY 1/4 wave dipole would make a huge difference. (google for build a uhf antenna)

  • 0
Posted

Welcome to the world of GMRS David.

 

Berkinet gives good advice. If it is at all possible, setup your antenna outside, and as high as you can practically get it, even when using a hand-held indoors.

 

I personally have and regularly use an Ed-Fong roll-up J-Pole antenna with my HT while indoors. I use it mainly when I know I will be talking, rather than in listen-only mode. This antenna is easy to move and gives me the flexibility to move from room to room. In each room I have a hook immediately in front of the window on which to readily hang the antenna. The hook is always there but is merely a heavy duty tie-wrap (actually off a bag of coffee) in the shape of an S-hook that slips over the curtain rod.

 

I do have an outdoor antenna as well, which is dedicated to the base radio. But since the base is not portable, the HT with that Ed-Fong continues to see daily use. I even take it out to the garage.

 

I do experience elevated noise pickup from different radios when they are located on the computer desk and I am using only the rubber duck antenna. However, when I set the radio on the window sill or switch to the Ed-Fong the offending noise goes away.

 

Regards

 

 

Michael

WRHS965

KE8PLM

  • 0
Posted

I agree with both previous responses.  If you have the wireless modem in there and also have Bluetooth switched on that might have a small  impact, but it would be your radio interfering with them :).

 

Double pane windows with metallic solar coatings. if you have those they are not going to help either.  I have 180 MPH hurricane windows and sliding doors on my home. All of them double glass with metallic solar coatings (they look like green mirrors from the outside).  I can be out on the patio all happy with my HT listening to everyone, and if I walk inside and close the sliding door it's like turning the power off on the HT! Instant silence.

  • 0
Posted

 

 

Double pane windows with metallic solar coatings. if you have those they are not going to help either.  I have 180 MPH hurricane windows and sliding doors on my home. All of them double glass with metallic solar coatings (they look like green mirrors from the outside).  I can be out on the patio all happy with my HT listening to everyone, and if I walk inside and close the sliding door it's like turning the power off on the HT! Instant silence.

Well you'll likely EMP proof in that case as long as you're indoors.

  • 0
Posted

The easiest and quickest improvement would be a better HT antenna, look at the 771G from buytwowayradio.com.

https://www.buytwowayradios.com/nagoya-na-771g.html

Its tuned for GMRS and its almost twice as long as the stock antenna.

I tried it on the 805G and a 82HP.

 

the next step up would be looking at an external antenna.

I use a mag mount on a metal desk indoors, some use a pizza pan as a ground plain.

I'm also the trying out the Ed Fong GMRS tuned 3ft PVC pipe antenna.

I also also have his roll-up dual band.

 

 

good luck and 73

  • 0
Posted

Well you'll likely EMP proof in that case as long as you're indoors.

 

Not quite but close. GMRS HTs will still receive the strongest signals when placed a couple of feet from the glass, Cell drops 2 bars, and 5G WiFi dies 3 feet down the driveway.....

 

Best,

 

JAS

  • 0
Posted

Yeah, outdoors away from everything would be best. I'm using 100' of RG58 out to a Mobile Antenna on a jig that includes a ground plane kit up on a repurposed flagpole, maybe 25 feet up, well away from the house and power lines, etc. Even if you could get the antenna out on a windowsill would be better...

  • 0
Posted

If you set up a base station antenna, you will benefit from using LOW LOSS coaxial cable as feed line. Using RG-58 or RG-8 cable will kill your signal, and when you are only xmitting 2-5 watts to begin with, you want every milliwatt possible to reach your antenna. LMR-400 would be the minimum cable that I would recommend. If the run is over 50 feet, you may want to go up to LMR600. 1/2 heliax would also be a good choice

  • 0
Posted

Yeah, outdoors away from everything would be best. I'm using 100' of RG58 out to a Mobile Antenna on a jig that includes a ground plane kit up on a repurposed flagpole, maybe 25 feet up, well away from the house and power lines, etc. Even if you could get the antenna out on a windowsill would be better...

Really that much RG-58 coax! Depending on which table I consult the losses at 450 MHz, just a bit below the GMRS frequencies, for 100 feet of coax is 11db. That translates into a 98 percent power loss! That coax run is about the next best thing to dummy load. I'll also bet the match is darn near 1:1 too since almost all of the reflected power is wasted in the coax. You could disconnect the antenna end of the cable and still see a near perfect match.

 

I've had people tell me they have used a spool of RG-58 coax with nothing on the end as an effective dummy load on UHF for testing transmitter power, power meter on radio output and the coax spool on the load side of the power meter.

  • 0
Posted

PC's are terrible producers of EMI/RFI interference.

It's just not an easy job to get all that stuff down.

 

As an engineer I've spent many (miserable) hours getting products to pass EMI standards.

We made products that connect to a PC - so they had to be EMI tested while connected to a PC.

We had a heck of a time finding a PC that actually passed EMI just by itself.

Dell and hp were usually pretty good. 

 

Even if the PC is legitimate and passes EMI you need to get your radio at least a few feet away.

There will still be some interference.

I do pretty well just getting my radio 5-6 feet away.

When I hear something I can walk to another room.

 

You can put ferrites on your USB cables and that will almost certainly help some.

Digikey sells "clamp on" ferrites and probably Ham Radio Outlet does too.

Most EMI is radiated by common mode which means the whole cable is an antenna.

Shielding does not do a lot of good unless the whole system is within the shield with NO wires exiting.

 

Another easy thing to do is simply take up the slack in your cables, making a flat bundle with the slack.

Don't make a loop keep it flat like a hot dog shaped bundle. 

This is what the EMI test rules allow to make the test reasonable.

It really can make a difference.  I've seen 3-6dB improvements doing this.

 

As you can see it's a little bit of this and that.

 

Vince

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Answer this question...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use and Guidelines.