Simple Rohn 25 Radio Tower Setup And Things.
ฝัง
- เผยแพร่เมื่อ 25 ส.ค. 2019
- Installation of a simple 3 section Rohn 25 Tower/mast.
tags:
shtf wrol prepper preppers prepping survivalist simplex repeater comm comms communication communications ham amateur radio survivalism disaster EMCOMM preparedness
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Nice to see you back. You run one of my favorite channels.
Agreed we need more guerrillacomm videos love learning from you.
Great to see you back!
Interesting video as always.
Thankyou!
Thanks for the vid. I always look forward to your uploads.
Many thanks great to see you back.
Great to see a new video from you. That discone performance is as expected. The discone itself has a lower corner frequency of about 100MHz. The tunable whip and loading coil is what gets you your low-band coverage. They're often rated for only 10-20W at low-band due to the puny size of that loading coil.
Good to see you back!
I have to put up a rohn 25 stick here in the next few weeks. I have been using the same old stainless radio shack discone for over 25 years that has made 3 moves and is still plugging along. I need to squeeze the old Micor cabinet in the new house :) Hope the new place is treating you well. Great to see you putting out content and thanks for sharing !
I enjoyed your video. I am a former ROHN Engineer and I have designed many of their towers all over the world and my specialy was the poles. I also used to monitor an old web reflector web site for ham operators and their antennas.
One of my biggest complaints about ROHN was their bad information for their 25G wall mounting. The sales people took a drawing for a one particular project and published it for use for every application. Also the ROHN foundation details you mentioned may have been for a free standing guyed ROHN 25G. The base attachment looks like it is on a sidewalk but I can’t tell. Sidewalks are flatwork and are not structural elements so they could never be endorsed. The good news is you only have axial compression and a small shear load at the base. The failure point on your 25G is just above the wall attachment point and most likly in the tower braces. With that said, limit the heigth above the attachment point and the area of the antenna.
There are county wind loading requirements that listed in the EIA-TIA-222 that should be part of the local building code. Normally people get a building permit to install a tower especially on a building. The permit would cost more than the tower because of the required structural analysis by an engineer. So now you have issues with a noncompliant tower without a permit and a your insurance does not know about the tower.. What’s the next video going to be about?
The legend is back!
Good to see you posting again! FWIW: You may get a better response out of the discone with a metal mounting mast; but I can understand using the stationmaster shells (i've done it myself!) Be safe!
Hey your back great to see you.
Diggin the groove, bro...!
The 1 cubic yard base in your spec sheet is referring to a freestanding at up to 50'. For your setup with the eve bracket you are still good to 50'. A 24x24x12 pad would have been my preference but you're still good to go.
That 3920 brings back memories...of dislike of Aeroflex monitors. 753 MHz would most likely be something in Band 14. Part 90 starts at 764 MHz.
Some first net action for sure
Ditto good to see you back Ed mate, please keep the vids coming! I like to use my colinear for 144 and 435 Mhz but I have a Discone ready to erect for general receive, nice and wide band!
I would love to see more videos from you, it has been a while.
Welcome back!
In dealing with Hurricane Dorian this past week here on the south carolina coast, I'm wondering can you do a presentation or video for emergency HF or VHF/UHF antennas that are either self supporting or that can hang from an existing or remaining structure. By the way, I've got the "RADO" and "COMT" currently on my Red Card. Please keep up the good work.
Just found one of those towers laying behind one of our stations. Missing the bottom plate. But looks like it's never been used
You're back!
I think a set of radials need adjustment in length and angle for .1 thru 1000 mhz function, and tweak vertical element length .
Was wondering how you been.
I think you are confused regarding the signal strength readings you see on the spectrum analyzer. It is not showing return loss. The minus dB scale is showing dB below the reference point. A -13 dB signal is 3 dB weaker than a -10 dB signal. Since 3 dB equates to double the power level, a -10 dB signal is twice the received power than a -13 signal. If you notice, the tower mounted antenna is approximately 3 dB stronger than the roof mounted antenna. So, it is performing much better.
Discone antennas are DC grounded, so a metal mast would have been better than a fiberglass one both for better lightning protection and to reduce the noise floor. Without the DC ground to the mast and tower, the coax cable shield becomes part of the antenna and will cause an increase in common mode noise heard at the receiver.
To determine return loss during transmit, you would need a vector network analyzer to measure the impedance of the antenna and feedline at the transmit frequency. A mismatch between the transmitter output impedance and the antenna system will result in reflected power loss.
I'm using a return loss bridge not shown. the feed line 1/2 inch superflex outer copper cladding is grounded to the tower at the antenna feedpoint with a grounding kit, just before the fiberglass transition. I was too lazy to convert the return loss reading for signal strength, I would of have to re calibrate my zero reference. I just kept it at the return loss setting and visually seen the difference compared to the live read. Network analyzer would of been nice but I don't have access to one. Would like one to see the connection losses and so forth. I don't get too deep in the details with these videos.
I would have liked to see you hookup a Digital TV and do a scan to see what you get... just out of curiosity.
I got one of these towers, but it has no bracket attached to the house, who could I hire to fix this? (roofer, sidding installers, electrician, etc.)
Looking at LTE Upper 700 MHz Band C transmitter on Channel 5259; 753.600 MHz near you. Familiar mask- Good to see you again (!!)
Long time no see.
Do you think that the newer antenna looks a little worse in some areas is because of less loss in the better coax?
(don't ask him those type questions - he'll get all nervous)
Despite the building bracket, that ground mount is scarily inadequate. Maybe hang some sandbags off the tower a few feet above the ground. What did you use to get the tower and antenna up there -- cherry picker?
Yeah - a cherry picker, used yer daughter up at the top.
Wish i had two towers like that
Make 1 good one
Thanks for the video I enjoyed it, is there a way to reach out to you? Thanks for using a service monitor on your videos I find it really helpful, we have a 8920a at our shop.
thanks for the vid man! what are you doing this weekend? camping ??? same spot as last time?
Hey, Thanks man. This year I' getting my house ready for sale, been busy swinging a hammer round here.. Moving north about an hour away.
base of tower should have a lightning ground to a buried rod.
Its there after this video. Will mention it on a follow up update when I placed the air vent antenna on its own out rigger on the tower.
What kind of band spectrum analyzer are you using ?
Its an Aeroflex 3920. Not mine.
Don’t they say lightning arrestors should be grounded outside the house/shack and not inside?
You were saying you can listen to 4 different radios at the same time. But are all 4 able to transmit at the same time?
The quad/tri plexers I think have a 100 watt max power rating. Theoretically if you could tune all those radio to add up below that rating, quite possibly you're able to. Perhaps tune the radios for 20 watts max. I myself have not tried it myself. More detail to come in future videos, I have 3 models of triplexers to showcase.
What are the connectors used for lightning protection?
This is what we use depending on requirements.
www.polyphaser.com/search?Category=RF+Surge+Protectors&sort=y&view_type=grid
@@GUERRILLACOMM Great unit =)
Mounting it on the fiberglass, as opposed to the air vent. Wouldn't have been an electrical ground issue, hence the overall loss?
The discone can be insulated from a grounded support structure with no real impact on return loss (I've hung them from trees for temporary use). In a lightning strike things get interesting however.
@@survivalcomms thanks for the clarification, GC!
No hinged base plates? Ouch..what you have will work.
30' w/ building bracing is OK. I'd put a better antenna on it, though. Also good thing you didn't add guide-wires to it - Always insist on the Guy-Wires.
Does California still use lowband vhf?
Yes, rare, but they're out there.
No lock washers on those bolts? Gotta keep an eye on them. Over time your nuts could vibrate loose.
Good eye, I'll rectify that on the next go around. Thanks.
@@GUERRILLACOMM Glad to see ya back on the TH-cams!
@@RESlusher Stainless steel ones like the bolts =) Good job all the way through for the height of the tower and antenna =)
what kind of watch are you wearing?
Looks like a marathon TSAR.
Marathon Medium size diver watch. I think they renamed it Search and Rescue, Mechanical.
GUERRILLACOMM Oh it was the mechanical, it looked a lot bigger than 36mm in the video.
@@daa3417 Diameter is 36 mm, but its pretty tall, something like 4 mm give or take, makes it look bigger. That's just my only gripe with it. Guess they had to make the dial deep to accommodate the tritium vials on the hands.
GUERRILLACOMM I also think that dial depth is marathon’s thing with their divers, check out Ball watches for what I believe is the brand that does tritium the best out of anyone. I do like the marathon SAR though I’m a big fan of mid size divers if you’ve ever thought about buying an skx013 you should do so now as they’ve been officially discontinued.
I lost my rohn 25g tower a month ago 100foot tower in trees
Ouch, That hurts to hear about. 100 footer is scary to think about toppling over.
@GUERRILLACOMM my uncle Johnny Campos was in the Marine Corps also you might have known him anyways hit me up sometime if you have an email address or something send it to me need to get in touch with you ASAP!!!!!!!!!
“It’s totally wrong but I am going with it”. Geez, mate, that is no disclaimer it’s an admission of negligence.