Bonjour.
A tester, mais je dirais que ce serait mieux avec un fil de masse sur la carrosserie. Sinon, c'est la tresse du cable coax qui fera le deuxième quart d'onde de l'antenne, mais bon, la carrosserie c'est mieux...
Gil.

Bonjour à tous,

Je viens d'installer une antenne mobile (comme celle visible sur la photo ci-jointe) sur mon véhicule, mais je me pose des questions sur le plan de masse et la mise à la terre :

1. Comment m'assurer que l'antenne dispose d'un plan de masse correct ?

Mon antenne est fixée sur un support métallique qui lui n'est pas raccordé à la carrosserie du véhicule.

Je sais que le plan de masse est important pour optimiser les performances (SWR, rayonnement, etc.), mais je ne sais pas si mon montage est suffisant.



2. Dois-je connecter un fil de mise à la terre supplémentaire ? Si oui, comment et où le fixer sur le véhicule ? Faut t'il souder un câble sur le support et le fixer a une masse du véhicule ? Ou c'est la partie extérieur de câble relié à la radio qui est elle même relié à la batterie qui se charge du travail ?

Si je pose cette question la, autre la partie technique intéressante c'est que au niveau de la réception sur le 70cm c'est vraiment très faible, mon retevis ra89 capte bien mieux que mon antenne mobile....


Mon antenne et une version chinoise de la diamond CR-8900, cela vient peut être de l'antenne ? J'ai trouvé que la qualité est vraiment bien pour le prix..
Voici mon installation : https://ibb.co/2nr129S


Je veux être sûr que mon installation est correcte pour éviter de perdre en performance ou d'endommager mon émetteur (j'utilise un TYT TH-9800)


Merci d'avance pour vos conseils et votre expertise !

73,

The previous post is very good advice to people living in the United States.

In my country, Norway, there have been similar weather emergencies this year, affecting thousands of people.

Unfortunately, AM and FM have been discarded, and replaced with a new concept: DAB and DAB+:

https://en.wikipedia.org/wiki/Digital_Audio_Broadcasting. Unfortunately, IMHO:

QuoteAs of 2023, Norway is the first country to have implemented a national FM radio switch-off ...

I can't access your website

AS you know, the United States recently had two major hurricane strike and particularly hard hit were regions of western North Carolina.  That region is mountainous, with steep slopes and deep valleys: which resulted in at least 1400 land slides, and flood waters in the valleys, filled with trees, boulders and ten meter tall walls of mud, rock and trees moving at highway speeds. The resulting loss of electrical power, cell phones and internet left many people disoriented. My thoughts here focus on how to help non-radio family members during a black-out.

However, a few people posted their experiences and some things were food for thought:

1.  Some people remembered "...an old battery [ AM/FM] radio" they had stored - somewhere. Some noted that theirs was a hand crank "Emergency radio" they had bought on Amazon, just-in-case.

2. In a total information black-out, having even limited  AM/FM news and music was found to be very helpful.  Remember, many people woke-up to no electrical power, no phones and etc. and had zero idea WHY this happened and when it might be fixed. Radio stations provided some of this information.

3. The feeling of NOT being isolated was a factor for many.  To old people like me, the phone is a handy hindrance - at best. However, to many people, they live their lives throught their phones.  Stepping back a generation in technology, yes it's not immediate connection with the outside world, but it IS 'a connection' and having a source of news and music that runs on handcrank recharged batteries or even JUST batteries was seen as very handy, regardless of generation.

4. Some of there radio have a small 'reading light' which was noted as being handy.  My favorite little 'just in case radio, also had a single LED light and frankly, it is always in my daypack when I am away from home. It is not a handcrank radio, but it is rated to operate the radio at 40% volume for 150 hours on 2x AA batteries and I always carry spares. On earbuds it runs longer.

Radio Preppers is primarily an emergency 2 way radio communication website and most of us have ham radio equipment, BUT do you have at least one 'little plastic radio' as part of your emergency equipment?  I do, and here is why; in an emergency like these just experienced, our non-hams are going to be a bit nervous, and while I would NOT put them onto my ham station, because it's too expensive and easy to misuse and damage. However, I can put a simple 'little plastic radio' into their hands, with a pencil and paper to listen to news, weather and etc.  This would be useful to keep them occupied and for the group/family to gather news and information for us to ponder and discuss.

So, do you have a little plastic radio, perhaps a handcranked one? Does your family know how to operate it if you are not there?

Here in the USA, AM/FM are probable the minimum, I add shortwave and NOAA weather radio to basic requirements, if possible.  However, the abasic AM/FM are most likely to be used by the average person for news and music.


de RadioRay  ..._ ._

Hello.
Thanks Ray for posting!
If anyone has information from Sarasota Florida, please post it here, I have many friends there...
Gil.

For those out of this region ( U.S. South/East) the recent INLAND hurricane strike has made a real mess of things, huge floods destroying entire towns, millions without electrical power, most in the area lacking fresh water and food. Despite what 'The Experts' on many forums told us, yes, indeed, the power grid and cellphones failed across large swaths of the impacted area, leaving many without a homek water, food and hope.  No 911.

 
Low tech, independent, survivable communications systems using ham radio is a great solution , particularly on the ALREADY EXISTING 'traffic networks' on the ham radio bands.  I am roughly 400 miles from the center on this impacted region, but easily heard hams in there, both organized ( The Tarheel Emergency Network ) and unorganized , individual hams.  A few lessons come away from this:

1. Be part of a network of hams.  The hams you talk to today are likely the hams you'll pass emergency radio traffic with tomorrow.  If you're not doing it today, you'll likely not be doing it tomorrow. Radio is at least 'two way' communication.

2. WINLINK is amazing in these situations and the network is automated, always waiting for your call.

3. SSB voice and Morse code ( CW ) are the modes I hear most, passing traffic and giving a little morale break.  The various CW traffic nets have been doing a GREAT job, handling radiograms during this emergency: no computer required to send a telegram to friends and family.  Remember, there is a HUGE swath of GRID DOWN states so energy efficiency is hugely important.  Morse code ( CW ) QRP rigs are in use for those with only limited battery power. 4.  This has been going on for a week.  Can YOU operate your radio station for a week For printed copies of messages and pencil and scrap of paper perform well.


4. This grid down began a week ago.  Can YOU operate you ham radio station for a week without commercial power ? Can you live without grid water, sewage and etc. ?  If not, why not?  Fix it while you can.

Food for thought,

73 de Ray  ..._ ._

I was listening to a few hams on HF, who were taking a break by having a small roundtable chat from inside the destroyed area, HF radios, battery power, reduced outputs ( one station was 5 Watts SSB, weak readable here in Virginia). They mentioned recharging batteries "later" and one guy mentioned that had a place he could walk to that had power to recharge his batteries. One CLASSIC "food for thought" comment went like this:

" Well, I was listenin to my A.M. radio and
they told me that if I needed some help to just
call this number or send an e-mail to
some address or visit such-&-such a website .
That'd be just dandy, IF I HAD phone or internet!
What the #%^ are they thinking?"

OTOH, 40m and 80m radio is working rather well.
Of special mention the Tarheel Emergency Net
, Net Control Operators are doing yeoman service.

73 de Ray ..._ ._

Oh yes, just because you keep line-of-sight...
Gil.

I was curious why plane receiver/controller combos are able to get a further range than ground based rc controllers and receivers. I know that rc plane controllers often use a higher frequency, but I was curious if that was the reason for the further range? I've tried looking around online but haven't gotten a good answer. I appreciate any input!