Jump to content
  • 0

Newbie question, high SWR on indoor antenna, even worse with "cookie sheet" ground plane.


thisguyneedsabeer

Question

I recently picked up this "Bingfu Mobile Ham Radio Antenna Dual Band VHF UHF 136-174MHz 400-520MHz Amateur Radio Antenna Magnetic Base PL259 Male Antenna for BTECH ICOM Kenwood Midland Yaesu TYT AnyTone Mobile Ham Radio" (https://a.co/d/027MJKKi). I have it on top of a book case next to my XTL2500 base station.

I haven't been experiencing any reception problems, but as I am learning more and more about this hobby I decided to check my SWR with the popular Surecom SWR meter that everyone seems to use.

I was getting about 5.5. I think that's about 45% loss? When I used the "cookie sheet" method as a ground plane, it shot up to 8.5%. Is this the wrong type of antenna for this application? I wanted something indoor, but am starting to think I might need to do a Yagi on the roof and feed the coax into my office. If that's the next best step, I was thinking about this setup:

  • TWAYRDIO Yagi Antenna UHF 400-470Mhz,High Gain Outdoor GMRS Vertical Base Antenna,7dBi Receiver Directional Yagi for Ham Radio,Repeater System,433mhz Device,Fm Scanner
  • UHF CB Coax Cable, 100ft KMR400 PL259 Male to Male Coaxial Cable Low Loss UHF Cable CB Coax Cable for HAM Radio, VHF Radio, SWR Meter, Antenna Analyzer

I'm not opposed to spending more money where necessary, but I am trying to keep costs down. I'm trying to make a targeted communication to a buddy ~3 miles away through the city of Philadelphia. 

Appreciate any feedback you might have. Thanks!

Link to comment
Share on other sites

9 answers to this question

Recommended Posts

  • 0

If it is on top of a bookcase, is it near a wall or ceiling?   Possibly try it in a different location, even if it is a bit lower, and see if that makes any change (for the better!)

Any chance you have a window/wall airconditioner, and can put the mag mount base on it, which would also get the antenna outdoors, possibly more in the clear?

Link to comment
Share on other sites

  • 0

The book antenna's location on the book case was high and in a corner close to the ceiling. If I move it toward a window, the SWR stayed the says the same. I lowered the Antenna to be right on my desk, and the SWR was 4.2. If I touch the base, while keying up, the SWR drops to about 1.99. 

 

Edit: Not sure if it's important, but I do have a mini-UHF to SO239 adapter on the back of my XTL2500 to attach the antenna. I could not find an antenna I "liked" with a mini UHF connector.

Link to comment
Share on other sites

  • 0

3 miles in the city with a small indoor antenna probably will not work well at all at any swr.   If at all possible id put the antenna out side and as high as possible.   I don’t think a yagi is needed but a basic antenna up as high as possible to get over the other homes and buildings. Maybe a 2’ with ground plane arials, or if budget and space allows a 10’ 9dbgain with arials will do even better.     Remember 460.xxx is extremely line of site.  Out in the open dessert my 20w $300 total system (radio, antenna, lmr400) does 200miles but that same system in the city might not get 2 miles.  

Link to comment
Share on other sites

  • 0

Your antenna is the problem, scrap it and don't usd it for GMRS. Try a Midland MXTA 26 GMRS antenna and that should resolve your problem. Another good antenna is a Laird B4502 antenna but it will need to be tuned/trimmed.

Link to comment
Share on other sites

  • 0
5 hours ago, thisguyneedsabeer said:

The book antenna's location on the book case was high and in a corner close to the ceiling. If I move it toward a window, the SWR stayed the says the same.

Can you take it to the park and try it outside with less obstructions?   It seems to make a big difference.  

Link to comment
Share on other sites

  • 0
On 6/22/2024 at 5:50 PM, WRXP381 said:

3 miles in the city with a small indoor antenna probably will not work well at all at any swr.   If at all possible id put the antenna out side and as high as possible.   I don’t think a yagi is needed but a basic antenna up as high as possible to get over the other homes and buildings. Maybe a 2’ with ground plane arials, or if budget and space allows a 10’ 9dbgain with arials will do even better.     Remember 460.xxx is extremely line of site.  Out in the open dessert my 20w $300 total system (radio, antenna, lmr400) does 200miles but that same system in the city might not get 2 miles.  

Yeah that'll be my next step, going to try a temporary mount using an old projector tripod and if I get better results, I will affix the antenna to the roof permanently with some PVC piping. 

On 6/22/2024 at 8:58 PM, nokones said:

Your antenna is the problem, scrap it and don't usd it for GMRS. Try a Midland MXTA 26 GMRS antenna and that should resolve your problem. Another good antenna is a Laird B4502 antenna but it will need to be tuned/trimmed.

I looked at the Midland antenna, but I need something that will cover 450-470 as I have some other frequencies in that realm licensed and I'd like to only have to maintain one base station instead of two. So I think the Laird antenna would do better and might be more suited for my vehicle than as an indoor antenna. 

On 6/22/2024 at 9:55 PM, WRDJ205 said:

Can you take it to the park and try it outside with less obstructions?   It seems to make a big difference.  

For some reason the the thought of testing outside hadn't really crossed my mind and I feel rather foolish. I probably can sometime this week. Good call!

Link to comment
Share on other sites

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.