Sidebar Sidebar
  • You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.

MFJ 915 INSTALLED AT THE ANTENNA'S FEED POINT

In your opinion should i install the MFJ 915 at the time of the antenna install or should i install the antenna without it. If it can only help and do no damage Im guessing go ahead and install it. This is advice I deffinetly need. I'm assuming it can only help. Am I correct? If not. Please exsplan what adverse effects be can cause if any. Thanks my friends i
wavrider said:
Exactly as Binrat posted as short as possible.

Ensure you have enough room to mount the line isolator securely to the mast pipe, hose clamps or nylon zip ties
Click to expand...
 
Yes, install it. As long as the unit isn't damaged then it should work as intended. Install it!! It will help with CMC, and RFI for sure. Not sure of the pep wattage listed but don't push too much through it. JMHO.
 
I'm fairly sure it's rated at 1500.
The largest amp I'll be using is the ten tube phantom.
I tune it for max smoke with 11/2 watts and see around 300 dead key 850 pep and on ssb with 12-15 I see a bit more than a kw but those readings were taken in the pep mode on a workman meter
so I'm sure thoses readings are over inflated..Not to mention the 50-70% efficiency rating of most all theses early sweep tube amps I'd say those readings i listed are probubly 50 to 60% at best. So I think I'm safe. I purchased an MFj 868 with the digital features of the 826b and a seprate cross needle meter all in one.
And I'm hoping and assuming since it's a true pep reading meter has to do a better job then a workman but wont know until the install. 2015-07-04 02.05.22.png Thanks p.s. i don't drive tes sonar fs2340 with the phantom. I don't use the phantom with this fs 2340 as audio clipper limited has been deleted and with a demco modulator in line and stock D104 it actually has over 25 watts pep and don't want to abuse the phantom so i use a Palomar 500 elite 4 X 1446's. I don't want to abuse the phantom. The Palomars on the bottom shelf and can't be seen.
222DBFL said:
Yes, install it. long as the unit isn't damaged then it should work as intended. Install it!! It will help with CMC, and RFI for sure. Not sure of the pep wattage listed but don't push too much through it. JMHO.
Click to expand...
 
Last edited:
Stella the line isolator will help as previously posted.

If you want to experiment then install the antenna with out any choke straight coax, check vswr on 1 then 20 then 40.

then if you want wrap an rf choke coax type then check your vswr
THEN install the line isolator and re check VSWR again

A lot of time involved but then YOU WILL KNOW how a rf choke vs line isolator vs no choke effects your antenna system.

Stella you are on your way to becoming and antenna enthusiast(y)

Next you will be wanting to build your own home brew antenna, and hanging wires for full wave loops and delta loops, dipoles etc.:D
 
  • Like
Reactions: 222DBFL
I would love to do exactly that but it's juust no feasible. I definitely would like to see if there's a difference and if so what and how much the readings chsnge with or without but since the concensus seems to be if it's gonna do anything it will be positive and shouldn't affect the performance adververly so unfortunately it's gonna have to be attached at the time of the insall. Sux because I'd really like l to see the difference if any.
wavrider said:
Stella the line isolator will help as previously posted.

If you want to experiment then install the antenna with out any choke straight coax, check vswr on 1 then 20 then 40.

then if you want wrap an rf choke coax type then check your vswr
THEN install the line isolator and re check VSWR again

A lot of time involved but then YOU WILL KNOW how a rf choke vs line isolator vs no choke effects your antenna system.

Stella you are on your way to becoming and antenna enthusiast(y)

Next you will be wanting to build your own home brew antenna, and hanging wires for full wave loops and delta loops, dipoles etc.:D
Click to expand...
 
Last edited:
I hear that wavrider. Working on a new antenna now. Not sure what I will build. Am going to try a few different things. Using just my new horz dipole for now. Looking into the delta loop or something similar.
 
222DBFL said:
I hear that wavrider. Working on a new antenna now. Not sure what I will build. Am going to try a few different things. Using just my new horz dipole for now. Looking into the delta loop or something similar.
Click to expand...

A Moxon if you've never done one. Simple to do, loads of gain, great front to back. If you use the online calculators remember the dimensions are for bare wire. If using insulated reduce them by 4-5%. I made that basic error when building one for 10m and trying to work out why the lengths for 28.500 made an antenna resonant at 27.100 when I built it using scrap speaker wire.
 
  • Like
Reactions: 222DBFL
I have thought about the moxon as well. I have a dipole that works well F/B, and is facing N/S, but it's just that, a 1/2 wave dipole. It works, don't get me wrong, but I think I am ready to step up now and build something a bit better. Will have to do a bit of shopping today for needed parts. May end up with moxon, thanks M0GVZ for the thought. It had crossed my mind but now I think I will go a bit further and get some dimensions and wire lenghts and such. I'll be busy all weekend I suppose, trying to master the art of antenna building lol. Thanks for the inspiration!! To the poster, take a que from me and learn how to get your build on, it will save you a lot of unnecessary money in the end!!!
 
Stella did you get the antenna installed, to busy making DX contacts to post results maybe?(y)
 
Wondering the same Wavrider. Much good info was given here just in this thread. Hopefully it gets used and not wasted.
 
I'm hoping to install it by the weekend. My LMR 400 and pl 259 double connector (for the mfj 915) hasn't arrived yet. I'm looking forward to not only the install but I'm kinda nervously anticipating the moments right after the antenna's up, all the cables are hooked up then the moment when I key the mic and watch my no calibrate swr meter emedietly jump to the swr reading.. Is it gonna be 1.1;1 or close? I dont know but I repaired and replaced everything that could've posibly been causing the original problems. I will absolutely report the out come minutes after my mfj 828 shows me the readings QUOTE="wavrider, post: 527283, member: 9893"]Stella did you get the antenna installed, to busy making DX contacts to post results maybe?(y)[/QUOTE]
 
222DBFL said:
I have thought about the moxon as well. I have a dipole that works well F/B, and is facing N/S, but it's just that, a 1/2 wave dipole. It works, don't get me wrong, but I think I am ready to step up now and build something a bit better. Will have to do a bit of shopping today for needed parts. May end up with moxon, thanks M0GVZ for the thought. It had crossed my mind but now I think I will go a bit further and get some dimensions and wire lenghts and such. I'll be busy all weekend I suppose, trying to master the art of antenna building lol. Thanks for the inspiration!! To the poster, take a que from me and learn how to get your build on, it will save you a lot of unnecessary money in the end!!!
Click to expand...

222 I like the Delta loops, they work well, I co phased a pair of them for 10/11 meters and they screamed,

Also deep nulls on the sides.

Moxon work well easy to build.

I built mine out of 1/2" EMT conduit, little heavy but worked well
 
  • Like
Reactions: 222DBFL
well stellasstillarat,

i looked through the entire thread, and was surprised that no one picked up something.

the fact that you will be installing this "choke balun" on an A99 antenna.

you see, the antron 99 is a half over a quarter wave mutual transductance tuned antenna, as stated in the adverts.

what they dont tell you that that the "quarter wave" part of the antenna is the first 9 feet of your coax.

thats right, the A99 actually uses the shield of your coax as part of its radiating element.

so, do not put the choke right at the feedpoint.

put it 102" down from the feedpoint.

if you put it at the feedpoint, you will notice your SWR jump way up.

im surprised no one else here mentioned this.
LC
 
I'd like to let everyone who's helped me know why the antennas not in the air yet. I have a a very bad back. when i say bad think about the worst back injury someone could have then times that by ten. I need help with the install and if I could've done it myself it would've be in the air weeks ago.
Now. If this is fact I'm going to have to make a 110 " jumper. Correct? Well if this is the fact. This will be the catalyst for putting the brand new 2000 instead of the a99. I mentioned it in an earlier post that the only reason for sticking with the a99 was the fact i received not a singal rfi complaint and didn't want to push my luck. I'm done putting my station together as my cousin stopped by yesterday and the setup is ready to go. It's the neatest wiring job that a station i owned ever had. No cobwebin . So neat i cant beleve it mysrlf. Ill take a few pics tomorrow. Antennas going up on Wednesday rain day Thursday. Like I said if this is fact the 2000"s going up. All I needed was an excuse for either grabbing the box with the a99 or 2000 in it and thismaybe it..
loosecannon said:
well stellasstillarat,

i looked through the entire thread, and was surprised that no one picked up something.

the fact that you will be installing this "choke balun" on an A99 antenna.

you see, the antron 99 is a half over a quarter wave mutual transductance tuned antenna, as stated in the adverts.

what they dont tell you that that the "quarter wave" part of the antenna is the first 9 feet of your coax.

thats right, the A99 actually uses the shield of your coax as part of its radiating element.

so, do not put the choke right at the feedpoint.

put it 102" down from the feedpoint.

if you put it at the feedpoint, you will notice your SWR jump way up.

im surprised no one else here mentioned this.
LC
Click to expand...
loosecannon said:
well stellasstillarat,

i looked through the entire thread, and was surprised that no one picked up something.

the fact that you will be installing this "choke balun" on an A99 antenna.

you see, the antron 99 is a half over a quarter wave mutual transductance tuned antenna, as stated in the adverts.

what they dont tell you that that the "quarter wave" part of the antenna is the first 9 feet of your coax.

thats right, the A99 actually uses the shield of your coax as part of its radiating element.

so, do not put the choke right at the feedpoint.

put it 102" down from the feedpoint.

if you put it at the feedpoint, you will notice your SWR jump way up.

im surprised no one else here mentioned this.
LC
Click to expand...
 

dxChat
Help Users
  • No one is chatting at the moment.


      Top Bottom
      Back