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

[thisguyneedsabeer]

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
  • https://a.co/d/0iisQNOC
• 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
  • https://a.co/d/06XiBrKX

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!

[JoCoBrian]

Is your Surecom meter rated for UHF???

[thisguyneedsabeer]

6 minutes ago, JoCoBrian said:

Is your Surecom meter rated for UHF???

Yes, VHF/UHF. Mcbazel Surecom SW-102 Digital VHF/UHF 125-525Mhz Antenna Power & SWR Meter (https://a.co/d/00tIGLvZ)

[WSAM454]

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?

[thisguyneedsabeer]

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.

[Socalgmrs]

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.  

[nokones]

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.

[WRDJ205]

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.  

[thisguyneedsabeer]

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!

[WRDJ205]

Good luck and let us know how it goes.