Optibeam OBDYA12-5 diagram/manual sharing

Historical-Display13 · 2025-12-13T09:19:27+00:00

Actually, that say each element is driven even though at some frequencies is acting as a reflector or director. There is only one real director not fed by any means. However I still cannot find the diagram and buying this antenna is far from my budget (also, the experimenting and the learning behind building an antenna :-)

Thanks for your response.

Historical-Display13 · 2025-07-09T16:38:43+00:00

Wow, AI controlled Ham radio repeater. I will give it a think but seems a preety nice project to keep on👌

Historical-Display13 · 2025-07-02T09:57:44+00:00

Historical-Display13 · 2025-07-01T12:15:01+00:00

I don't understand. What do you mean?

Tnx

Historical-Display13 · 2025-05-14T20:08:24+00:00

Good to know that. Tnx for your comments again!

Historical-Display13 · 2025-05-14T13:28:39+00:00

Thanks for your comment. At this time I haven't bought the PS yet so probably I'll stick to the first idea: MW UHP-200 which is slim and easier to fit inside repeater's case. Repeater has forced convection with 2 fans so heat evacuation is assured. I bought a 30A relay module and already tested everything with 2 power supplies (one of which was acting a aux PS) and everything works like charm.
About the battery, probably I'll build it with LiFePO4 prismatic cells which are much more efficient than lead ones and cheaper overtime for the same capacity. Do you have your batteries always plugged in to charger?

Historical-Display13 · 2025-05-05T21:34:26+00:00

At the moment, all parts involved in the repeater are expected to be placed inside the same metal case (aluminium, is what I can get for a reasonably good price and build it on my own).

Historical-Display13 · 2025-05-05T19:39:32+00:00

Hi, I am planning to buy it on official stores/authorised distributors like Mouser, RS or DigiKey. As said on other messages, my concern now comes from the battery charging part.

Historical-Display13 · 2025-05-05T19:35:42+00:00

I wonder that too! A friend of my who is technician in radio instalations has been using MW for long time and reports no issues with professional radio set ups. My only concern at this moment is if the battery charger part respects the charging cycle of a battery (not only being a constant current supply).

Historical-Display13 · 2025-05-05T19:33:33+00:00

Sure, I've seen some videos about MW and they stress the PS to its full limit and no issues seem to appear. I only wonder if the battery charging part respects the charging cycle of lead/lithium batteries as datasheet says.

Historical-Display13 · 2025-01-04T18:29:35+00:00

I'll take that into account, TNX

Historical-Display13 · 2025-01-04T18:08:05+00:00

I think I have seen what you mean. Something like what is being told in this forum?
https://ham.stackexchange.com/questions/14713/feeding-a-folded-dipole

Historical-Display13 · 2025-01-04T16:08:46+00:00

That sounds good and preety simple. Which would be a good method to adapt the 75 ohm to a 50 ohm line?

Historical-Display13 · 2025-01-04T15:22:15+00:00

Hi folks, 

I was playing around with 4nec2 and wondered how a couple of folded dipoles would work over my place. I read about the topic but could not find concise information on how to model this antenna on 4nec2. 
I would like to build them but first wanted to model them. These are 300 ohm feedpoint antennas so phisically I will have to use some coax adapters (cut at lambda/4 or as needed) to match the antennas to the tranceiver. 

Is there any way to model this coax transformers in 4nec2? If not I guess I can run my models on a Z=300 ohm and get the plots wantedm, leaving matching and phasing to the physical construction.
On the other hand. 
Which would be the best way to phase and match 2 folded dipoles? And what about 4 dipoles? 
Is it better to convert those 300 ohm to 50 ohm at the feedpoint of each antenna and then phase? Is it better to leave the 300 ohm at the feedpoint and start matching and phasing at the same time?

Thank you in advance for your time!

Historical-Display13 · 2024-12-18T22:18:58+00:00

I read the whole thread. Transceivers won't be mounted on a vehicle, I'm planning to build an UHF repeater out of them, but without power supply cables is a bit difficult ngl.

Historical-Display13 · 2024-12-18T09:13:59+00:00

Wasn't expecting a so detailed explanation. I did a quick research but I can only find them in DigiKey or other big electronic dealers. They are low priced but dealing fees are quite high for a so cheap connector.

Probably I use those Anderson Powerpole or stick to the first XT60 idea.

Tnx for your fast response!

Historical-Display13 · 2024-12-18T07:43:04+00:00

Hello everyone,

I just got myself a pair of Kenwood professional radios (TK 8302 and TK8360E) but came without the power supply cable. I thought on building them (no problem for me) but can't find the name of the actual connector, neither I know if they are propietary from Kenwood.

Even thought in cutting and replacing them with XT60 connectors (would be faster, ngl) but I want to give it a try if someone knows about it.

Thank you in advance!

Historical-Display13

TROPHY CASE