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Transmit pattern

MadisonMod

Member
Jul 16, 2023
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Okay. I just installed the new Browning BR-92-BL antenna on my peterbilt truck. I had to mount it on the back of the cab on existing suport bar using a heavy duty mirror mount. I centered the antenna in the middle of the cab . I grounded the mount and antenna to the truck frame. The coil ended up being close to the roof of the cab. The antenna is 68" long .How does that affect the transmit of the radio? I ordered a 22" Shaft extension which would make the antenna 90" raising the coil above the cab instead of 68" stock length. How would this affect the transmit and swr ? Would you recommend this conversion? I can pos a pic if helpful
 

The higher the coil the better swr and transmit…
I tested the swr on the antenna. It's 1.5
I will definitely add the extension when it gets here. The receive sounds good. I tried a midland field strength meter to try and check the transmit pattern but the meter didn't work for some reason .
 

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Hello . Well I added the 20 inch shaft to the base of antenna and rechecked the swr. it's still 1.5 . The coil is above the cab. I even put a new larger heavy duty stud mount and double check grounding. I tried a top load firestick just to see what happens and match says 1.5 . I put stainless antenna back on. Anyone have other ideas?
 

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After I upgraded from Novice to Conditional amateur license (and yes, that was several decades ago!) I borrowed a friend's SWR bridge just to see what my transmitter was looking at. I'd never failed to make a contact; might have taken two or three tries, but I had worked all states, all continents and had about 80 countries confirmed on 15 meter (21 MHz) cw. My SWR was right around 3.2:1 for the crystals I had. Nothing ever broke or melted, and my 90 watts and triband vertical worked for years.
 
I tried a midland field strength meter to try and check the transmit pattern but the meter didn't work for some reason .
Try putting a longer antenna on the FS meter. My realistic FS/SWR meter wouldn't work with the 4" antenna that came with it, but worked great when I put the whip from a base loaded antenna I have on it.
I parked my pickup in a field, and make a rough 30' diameter circle around it. Keyed up the radio, walked the circle. and wrote down the readings every 30 degrees or so. Printed a circular polar graph paper off of the net, entered the readings, connected them and had a very good representtion of my transmit pattern., which was way more directional front-to-back than I expected

- 399
 
Try putting a longer antenna on the FS meter. My realistic FS/SWR meter wouldn't work with the 4" antenna that came with it, but worked great when I put the whip from a base loaded antenna I have on it.
I parked my pickup in a field, and make a rough 30' diameter circle around it. Keyed up the radio, walked the circle. and wrote down the readings every 30 degrees or so. Printed a circular polar graph paper off of the net, entered the readings, connected them and had a very good representtion of my transmit pattern., which was way more directional front-to-back than I expected

- 399
Get a LARGE meter and a pair of good binoculars. I used a WW2(!!!) surplus milliammeter with some circuitry to make it work with eight D cells for power, testing a ten-meter homebrew yagi. Neighbor agreed to let me put it on top of his plastic mailbox for the few minutes it took to draw the gain circle. Sucker had about 10 dB gain! (That meter is still out in my garage...hope I remembered to take those D cells out !!
 
To Echo the other answers , 1.5 to 1 is good.
This question comes up in lots of radio groups and some people will really get obsessed with minimum swr.

@Beetle
My poor old ft101 worked into some terrible loads in my early ham days.
On 80 meters I thought 3.1 was great......

73
Jeff
Hello everyone. So I learned a few lessons. I purchased the large heavy duty antenna stud because it was recommended. It's trash. The stud pulls right out of the threaded housing. I installed straight heavy duty stud, it's tight. I de sodderd coax end and put new one , no changes in swr. I cut stainless wip several times checking swr each time until Chanel 40 dropped to 1.25 and Chanel 1 at 1.3-5 . I started fine tuning moving wip up 1/16th at a time checking swr until Chanel 1 and 40 are 1.3 . It seems that is the best I'm going to get with this combination and setup. I think the extra power from the 4 pills are causing some of the higher swr . Maybe reflect? I put a brand new stock cobra 29 ltd on and it was at 1.2
 
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Try putting a longer antenna on the FS meter. My realistic FS/SWR meter wouldn't work with the 4" antenna that came with it, but worked great when I put the whip from a base loaded antenna I have on it.
I parked my pickup in a field, and make a rough 30' diameter circle around it. Keyed up the radio, walked the circle. and wrote down the readings every 30 degrees or so. Printed a circular polar graph paper off of the net, entered the readings, connected them and had a very good representtion of my transmit pattern., which was way more directional front-to-back than I expected

- 399
That's a good idea. I'll try that That's what I was trying to do. I appreciate it. I'll let you know what the outcome is. I also ordered a new Nano VNA analyzer. I drove the truck today and was able to hear clearly and speak to people all over the united States.
 

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