Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

   Home   Help Search  
Pages: [1]   Go Down
  Print  
Author Topic: FM VHF QRP DX  (Read 1619 times)
WP4NXA
Member

Posts: 48




Ignore
« on: April 13, 2009, 07:42:32 PM »

Is DXing even possible on VHF FM during sporadic e with only 5W?

I'm asking this because all I have is a VX-7R handheld and the Arrow Antenna (used for satellite contacts).

Thanks
Logged
N9DG
Member

Posts: 315




Ignore
« Reply #1 on: April 13, 2009, 08:06:55 PM »

Yes, definitely. When you do encounter 2M Es it is usually quite intense and usually short lived. Openings rarely last more than 1/2 hour though longer is not unheard of.

However you are much more likely to find tropospheric ducting than Es on 2M. And I'm not talking about the 100-150 mile enhancement stuff either, but instead some honest to goodness 200-300+ mile DX.

But in either case you really do want to be in a high location with clear views and be using a low loss feedline. That 5W through 100 feet of RG-58 or even RG-8 will hurt performance a lot, not just for TX, but for RX as well. So a real short feedline, or something like LMR-400 (or equivalent/better) to 100 feet or so will work decent.
Logged
WP4NXA
Member

Posts: 48




Ignore
« Reply #2 on: April 13, 2009, 09:19:59 PM »

Thanks.

Since I'm only using my FM handheld with a portable antenna, the feedline is only 3 feet long!
Smiley
Logged
K9KJM
Member

Posts: 2415




Ignore
« Reply #3 on: April 14, 2009, 12:34:55 AM »

Yes, I agree.   I have done well over 200 miles with a hand held with the stock rubber duck!

But dont stop at two meters, When conditions are right, UHF can be even better!   Call CQ on 446 simplex every now and then too!

For really good info about two meters see:
http://www.mountainlake.k12.mn.us/ham/aprs/path.cgi?map=na

(Note that is a "real time" map, What is going on right now. Not a forecast.  It is good for two meters and may or may not reflect UHF, 446 conditions.)

Logged
WA3SKN
Member

Posts: 5496




Ignore
« Reply #4 on: April 14, 2009, 04:34:27 AM »

Not so much as sporadic E, but you can expect "ducting" in the spring and fall, usually around dawn and dusk hours.  It can happen a lot around waterways where inversions happen.
Years ago, I talked to a ham with a 1 watt HT in Newfoundland form Maryland on 2 meters.  Yes, it was spring.
But FM is not the best "weak signal" mode for VHF activities!  It is better for repeater operations and local work.
Justification for more radios!
73s.

-Mike.
Logged
WB2WIK
Member

Posts: 20611




Ignore
« Reply #5 on: April 14, 2009, 08:15:11 AM »

Usually sporadic-E on two meters is short-lived, very spotty and pretty weak.  I've absolutely never heard a two meter FM sporadic-E signal in my life, after 43 years in ham radio and being a VHF enthusiast for most of that time.

Sporadic-E almost always gives out about 100 MHz and doesn't happen above that.  There are some exceptions, but they're pretty rare.

Tropo ducting, on the other hand, is pretty common during the warm weather months and as others have said, often "gets better and better" as you go to the higher and higher frequency bands.  I've worked ducts on 2m, then switched to 70cm and signals were stronger still, and on 23cm just as strong, and even 13cm just as strong or stronger, etc.  The ducts often work up into the microwave region; the critical part is your location, as it's easy to "miss" a duct by being too high, too low or just off to the side of it, since ducts are like waveguides and have a defined floor, ceiling and walls.

If you hear "others" working a duct that you can't hear, sometimes just driving to a location a little higher (or even a little lower) helps.

WB2WIK/6
Logged
TANAKASAN
Member

Posts: 933




Ignore
« Reply #6 on: April 14, 2009, 10:13:11 AM »

Yes it is possible, but in thirty years of ham radio I have only done it once. During a sporadic E even I worked from Birmingham UK to a station just outside Paris, a distance of about 314 miles. I was using 10W from an Icom IC245 into a four element quad.

I wanted that QSL card so much I mailed him direct using registered mail, it arrived two weeks later.

Tanakasan
Logged
N9DG
Member

Posts: 315




Ignore
« Reply #7 on: April 14, 2009, 10:47:27 AM »

"I've absolutely never heard a two meter FM sporadic-E signal in my life, after 43 years in ham radio and being a VHF enthusiast for most of that time."

A few years ago I was driving home from work in the afternoon and was scanning the 2M band. About halfway home I suddenly started hearing DX on some of the repeater outputs. The FM BC band was also full of DX as well. I could tell right away that it was Es and not tropo. I then heard a couple ops on 146.46 FM from ~1000 miles away. I dropped my call in there and they acknowledged my call, but I lost them as I drove a bit further down the road. I think losing them was a combination of them not realizing that it was an Es openning, and the spotty nature of 2M Es. I was just running 65W to 5/8 vertical on the truck cab. That particular 2M Es openning was one of the unusual ones that lasted a total of 1-1.5 hrs. I managed to get home in time to catch the last 30 minutes or so of it from the "weaksignal station".
Logged
TANAKASAN
Member

Posts: 933




Ignore
« Reply #8 on: April 15, 2009, 09:07:05 AM »

Well, out of curiosity I dug out my old logbook and found the contact. This VHF DX was the 141st entry in my first logbook and at the time I wouldn't have known Sporadic E from moonshine. However the signals travelled they got there anyway and I was a happy camper.

Tanakasan
Logged
Pages: [1]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!