What happend to 40 meters #makeitradio


Doug KM4LKC
 

During our April 24th emergency communications exercise, we were very surprised with the difficulty we experienced communicating on 40 meters.  Was it the antenna, was it the time of day we were using 40 meters, was the band just garbage??

Dave, K3FHP gave the link to the Eglin Airforce Base Ionograms - https://lgdc.uml.edu/common/DIDBYearListForStation?ursiCode=EG931
This is a tool to see the NVIS propagation in our area.   

Here is an example of a specific report:



So what did 40 meters look like at 10:45 am on April 24th??



The Band looks terrible to me.  What's your conclusion?



--

Doug KM4LKC
Having fun promoting amateur radio technology


Doug KM4LKC
 

If you want to understand the Inongrams and Eglin AFB soundings, check out this youtube video to better understand these tools.



https://www.youtube.com/watch?v=oTFKNCo3Cl8&ab_channel=BootstrapWorkbench


Rod K4BGU
 

KM4LKC Doug,
On exercise day I gave up trying to participate even though I had believed my 40 meter capability was good. Then, when we (you and I) tried 40 in the JS8call you walked me through, it seems there was very poor signals again. Could it be the conditions were just that bad?
Rod K4BGU 


On May 1, 2021, at 9:39 AM, Doug KM4LKC via groups.io <sunburned_fl@...> wrote:

During our April 24th emergency communications exercise, we were very surprised with the difficulty we experienced communicating on 40 meters.  Was it the antenna, was it the time of day we were using 40 meters, was the band just garbage??

Dave, K3FHP gave the link to the Eglin Airforce Base Ionograms - https://lgdc.uml.edu/common/DIDBYearListForStation?ursiCode=EG931
This is a tool to see the NVIS propagation in our area.   

Here is an example of a specific report:

<ionogramp1.png>


So what did 40 meters look like at 10:45 am on April 24th??

<ionogramp2.png>


The Band looks terrible to me.  What's your conclusion?



--

Doug KM4LKC
Having fun promoting amateur radio technology


David NC4CC
 

I believe that is the signature of a solar burst, either that or a nuke went off somewhere close. J

 

 

From: main@CARS-FL.groups.io [mailto:main@CARS-FL.groups.io] On Behalf Of Doug KM4LKC via groups.io
Sent: Saturday, May 1, 2021 9:39 AM
To: main@CARS-FL.groups.io
Subject: [CARS-FL] What happend to 40 meters #makeitradio

 

During our April 24th emergency communications exercise, we were very surprised with the difficulty we experienced communicating on 40 meters.  Was it the antenna, was it the time of day we were using 40 meters, was the band just garbage??

Dave, K3FHP gave the link to the Eglin Airforce Base Ionograms - https://lgdc.uml.edu/common/DIDBYearListForStation?ursiCode=EG931
This is a tool to see the NVIS propagation in our area.   

Here is an example of a specific report:



So what did 40 meters look like at 10:45 am on April 24th??



The Band looks terrible to me.  What's your conclusion?



--

Doug KM4LKC
Having fun promoting amateur radio technology


Doug KM4LKC
 

After reviewing the Ionograms, I am coming to the conclusion that for NVIS 80 meters is best for 7:00 am -11:00 am +/- (11:00 - 15:00 UTC) and we should be working 40 meters in the afternoon from say 2:00 pm to 6:00 pm (18:00 - 22:00 UTC).