Calling all ham radio people HF op in a Scamp? - Page 5 - Fiberglass RV


Reply
 
Thread Tools Search this Thread Display Modes
 
Old 04-17-2020, 07:14 AM   #81
Senior Member
 
Name: Gordon
Trailer: 2015 Scamp (16 Std Layout 4) with '15 Toyota Sienna LE Tug
North Carolina
Posts: 4,353
Quote:
Originally Posted by redbarron55 View Post
..
However in the case of an endfed resonant antenna there is a lot of heat loss in the transformer ans often they still require a matching tuner as well....
This is the SWR claim from the manufacturer of my EF antenna:


My SWR measurements (at the transmitter) are similar - but usually just a little higher. My IC-7300 internal tuner works fine on every band 80-10 except the upper phone portion of 80 (75). And the internal tuner is not even needed on some bands. Its a very versatile antenna but of course will never compare to (or cost more than 1/20th the price of) a tower mounted beam.

Maybe there is some heat loss in the transformer and that is likely where the quality construction makes a difference. All I can tell you is that all things considered I am happy with this as my only HF antenna for nine different bands and I do think I will try the half size version for portable use.
gordon2 is offline   Reply With Quote
Old 04-17-2020, 08:42 AM   #82
Senior Member
 
Name: JD
Trailer: Scamp 16 Modified (BIGLY)
Florida
Posts: 2,016
You are correct on the cost and the matching from the IC7300.
I have a IC7300 as well and the internal matching network will match ~ 4:1 and is handy.
I use an IC-2KL amplifier and the matching IC-AT-500 tuner that will also match about a 4:1 SWR.
My point is that the transformer is fairly lossy as it takes a lot of ferrite cores to transform much power and they need to have ventilation to keep the cores cool enough to keep them from saturation and the SWR going up as you transmit.
With the matching 49:1 matching transformer and the internal matching network (when necessary) both using the transmitter power to heat them up much of the power is not being radiated. Of course this is often the case with any antenna either in ground losses or other losses.
With any unbalanced antenna the ground losses are significant, both on transmitting and receiving, so a radial system pays dividends.
Often with 100 watts we are seeing only ~ 10 watts or so radiated.
I have had good luck with a copy of an AS 2259/GR NVIS antenna with a matching radial system laid out below.
The key to the AS 2259/GR is that the matching network is typically mounted at the base with a very low loss hard line that doubles as a support. Of course the angle of radiation is very high, but then any antenna lower than 1/4 wavelength will have a pretty high angle as well.
In my case I use RG-213 to feed the matching network at the top of the pole and the tuner at the base. Better still would be to just mount an auto match there instead!.
The key in this case is the antenna is non-resonant at any frequency we are interested in so the antenna will stay within the limits of most auto tuners unlike if you accidentally hit a frequency that had and extremely high (or low) impedance like that presented by the endfed antenna popular today.
Losses are probably similar.
I have worked pretty much around the world with the NVIS so it is not that limiting in practice.
The radiating wires act as the guy wires and you still need to be able to arrange them, but the ends are at least attached to the ground.
Your mileage may vary, but whatever gets you on the air is great!
I just have not gotten on the end fed resonant antenna band wagon yet.
We tried one at the winter Field Day here and while we could match it fairly well it did not perform as well as other antennas in our experience.
Of course direction and conditions could account for some of that.
We did do better with the TN07 with radials spread on the ground with an autotuner.
It was easier to setup as well.
Better still was the DX77A we setup on the SCV which is basically a trapped vertical Windom antenna. (It was a problem setting up without that swing up swivel setup, however).
So far I have setup the SCV for 4 field day events using a trapped 80/40 meter dipole at 20 feet center and 10' ends, NVIS, DX77A, and TN07 vertical and they all worked, but not necessarily compared at the same time with A-B switching.
redbarron55 is offline   Reply With Quote
Old 04-17-2020, 01:35 PM   #83
Senior Member
 
Ed Harris's Avatar
 
Name: Ed
Trailer: 1982 Fiber Stream and 2002 Casita Freedom Deluxe,The driveway is a Dark & Lonely Place now!
Missouri
Posts: 1,988
OK so I neglected to stick with replying to the actual spirit of the O.P. about H.F. from a camper with my various comments about VHF/UHF antennas on poles but it also seems obvious that any wire antenna for HF will also be easily deployed from these pushup poles.

On the other hand how many of you guys actually bring 1KW amplifiers and associated stuff when operating from a camper?
Really?

I know we can but.....

I mostly do EMCOMM work in the end and though almost every small antenna clearly has compromises inherent in the design I have used the Buddipole stuff pretty successfully in the field when needed and without needing to get too high on the air either.
Ed Harris is offline   Reply With Quote
Old 04-17-2020, 03:50 PM   #84
Senior Member
 
Name: JD
Trailer: Scamp 16 Modified (BIGLY)
Florida
Posts: 2,016
During the last winter field day I thought I would try taking the IC-2KL amp and just see if it was worthwhile.
It would seem that it is since it is fairly small (of course the power supply is pretty heavy). If you have a generator it would help when making scheduled comms on the NFL emergency net on 40 and 80 meters. 6 dB is still 6 dB.
For just hobby work from the camper I would not bother with it.
In the case of emergency response the Air Force found out they they were not ready and their Communications guys had become more IT techs.
I had the opportunity to work with a few at Hurlburt and refresh their skills on antennas and HF communications and get their PRC-150s out of the cases and find out all of their back up batteries were bad and their ALE programs were lost. There has since been a major push to get back up to speed and work on interoperability with other services.
Since my rig includes a van with more room for supplies and equipment and our deployments will most likely not include long distance high speed highway work I have set up totes with the necessary antennas and equipment along with food and water.
In that space I would probably take my IC-2KL along with the generator and extra fuel.
Normal operations just for fun, not so much as I would just keep it simple and quick.
We found during Michael most comms were VHF/UHF to repeaters away from the coast. The problem was that that hurricane was so powerful that the nearest repeater towers were blown away and the fiber networks were down as well. Oddly the fiber was lost when trees blew down, uprooting the buried fiber. Anything relying on those networks was down as well and that included the new digital trunked emergency communications for the sheriff, fire, and police. To make connection to those distant repeaters required some experimentation and trial and error. It is also hard to hang an antenna from a tree when all of the trees are missing.
We learned a good bit from Michael as did the military. Currently they are working to get back up to speed on HF after getting spoiled by the Starwars systems.
redbarron55 is offline   Reply With Quote
Old 04-17-2020, 04:08 PM   #85
Senior Member
 
Ed Harris's Avatar
 
Name: Ed
Trailer: 1982 Fiber Stream and 2002 Casita Freedom Deluxe,The driveway is a Dark & Lonely Place now!
Missouri
Posts: 1,988
Yeah I have vivid memories of lugging cinder blocks up 9 flights of stairs to an abandoned repeater site in Joplin a few days after the Tornado there in our typical 100% Humidity early summer heat!
We were told that FEMA would have power turned on if we could get the non penetrating rooftop mount working to deploy a portable tower for local comms.
Phone service of all kinds was mostly destroyed throughout the city.

Its amazing in this day and age how little they seem to have learned in practical terms from the teachings of Mr. Murphy.

When all else fails......



Quote:
Originally Posted by redbarron55 View Post
During the last winter field day I thought I would try taking the IC-2KL amp and just see if it was worthwhile.
It would seem that it is since it is fairly small (of course the power supply is pretty heavy). If you have a generator it would help when making scheduled comms on the NFL emergency net on 40 and 80 meters. 6 dB is still 6 dB.
For just hobby work from the camper I would not bother with it.
In the case of emergency response the Air Force found out they they were not ready and their Communications guys had become more IT techs.
I had the opportunity to work with a few at Hurlburt and refresh their skills on antennas and HF communications and get their PRC-150s out of the cases and find out all of their back up batteries were bad and their ALE programs were lost. There has since been a major push to get back up to speed and work on interoperability with other services.
Since my rig includes a van with more room for supplies and equipment and our deployments will most likely not include long distance high speed highway work I have set up totes with the necessary antennas and equipment along with food and water.
In that space I would probably take my IC-2KL along with the generator and extra fuel.
Normal operations just for fun, not so much as I would just keep it simple and quick.
We found during Michael most comms were VHF/UHF to repeaters away from the coast. The problem was that that hurricane was so powerful that the nearest repeater towers were blown away and the fiber networks were down as well. Oddly the fiber was lost when trees blew down, uprooting the buried fiber. Anything relying on those networks was down as well and that included the new digital trunked emergency communications for the sheriff, fire, and police. To make connection to those distant repeaters required some experimentation and trial and error. It is also hard to hang an antenna from a tree when all of the trees are missing.
We learned a good bit from Michael as did the military. Currently they are working to get back up to speed on HF after getting spoiled by the Starwars systems.
Ed Harris is offline   Reply With Quote
Old 04-17-2020, 04:55 PM   #86
Senior Member
 
Name: Gordon
Trailer: 2015 Scamp (16 Std Layout 4) with '15 Toyota Sienna LE Tug
North Carolina
Posts: 4,353
Quote:
Originally Posted by Ed Harris View Post
OK so I neglected to stick with replying to the actual spirit of the O.P. about H.F. from a camper with my various comments about VHF/UHF antennas on poles but it also seems obvious that any wire antenna for HF will also be easily deployed from these pushup poles.

On the other hand how many of you guys actually bring 1KW amplifiers and associated stuff when operating from a camper?
Really?

I know we can but......
Thank you for understanding my point.. an End Fed wire on a short push up pole with short run of coax and strung to a tree 70 or so feet away is about as quick and simple as it gets. And if its not quick and simple, I'm not operating from my campsite.

Add to that multi-band coverage with a 3:1 max SWR tuner, light weight, easy to store...

But I am keeping my 20M BuddiePole for use at the beach where there are no trees.
gordon2 is offline   Reply With Quote
Old 04-25-2020, 04:24 PM   #87
Junior Member
 
Name: Andy
Trailer: Scamp 16'
North Carolina
Posts: 25
Scamp antenna base

Here is what I use for fixed ops. A 20' painter's pole fits it great.
Derswede
Attached Thumbnails
Antenna base.jpg   Antennascamp.jpg  

Derswede is offline   Reply With Quote
Reply

Tags
scamp


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
HAM Radio in a 16' Scamp Deluxe frankcfx Problem Solving | Owners Helping Owners 6 03-16-2014 06:40 PM
Ham Radio Al POGUE Hobbies & Passions 103 10-22-2013 01:11 AM
CQ CQ Ham Radio Scampers... Bob H General Chat 4 06-15-2012 07:48 AM
Ham radio Scamp for sale on QRZ.com Mike Taylor Classified Archives 0 06-29-2009 05:47 PM

» Upcoming Events
No events scheduled in
the next 465 days.
» Featured Campgrounds

Reviews provided by


All times are GMT -6. The time now is 01:54 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, vBulletin Solutions Inc.