M104C Project

[linearone]

M104C assembly done. Family stuff the rest of the day so measurement/alignment tweaking and tuning time with the beam and V58 above it tomorrow. It's getting into the upper 80s and humid here today, plus air quality advisory due to the smoke from the Canadian wildfires so my motivation for outdoor work is slim to none.

View attachment 64574View attachment 64575

You'll probably find the best tune with the gamma all the way closed and with the bracket where they tell you to put it.
Don't chase 1.0 .50 ohms. When you do that to being gets too now to be usable. If you get it down like one one or one two in the middle and it's one three to one five on the ends, you're perfect. I've also noticed that the SWR doesn't really change when it goes up, but I've noticed that it typically winds up being at a higher frequency than where you tuned it for. For so I tend to tune in now for like channel 10 or 12 to be centered on 20

 

[TimmyTheTorch]

All of the guy wire anchors have now been mounted on the roof. Overall I did a good job hitting the rafter after using the little rafter locating tool I picked up. Hopefully the roof sealant I used will keep us nice and dry inside. So far, so good with that.

I also have five of the guy wires measured, cut and thimbles installed. I think I am going to end up with eight guy wires and possibly ten. I am reconsidering the location of two of the anchors because it'd be nice to be able to take the antenna down without having to go on the roof at all. I am relatively certain that if I do have trouble and have to take it down it will be in the winter. I will not be climbing up our steeply pitched roof to disconnect two of the guy wires from their anchors when it's cold out. I could try to cut them from the ground with some 9mm ammo but I am pretty sure that's not exactly legal where I live. Nor am I that good a shot.

I have two chokes and I had planned on using one on the M104C right at the feedpoint on the antenna and the second one at the V58's feedpoint. I hadn't really considered the rather hefty nature of these chokes and I am trying not to put any more weight up high than is absolutely necessary. I am considering using one choke at the M104C's feedpoint and the second one as close to 36' down from that choke as I can get so it's at the base of the mast. I need to have a coax junction anyway so I can do it there. I'd end up with both on the M104C and go without a choke on the V58. I doubt I'll be using the V58 for much DX regardless. Anyone have an opinion on this idea? If it's not a good one, it should be okay up high for the V58. If winds do take down an antenna / heavy-duty mast being held in place by eight 1/8" 7x7 strand guy wires, two wall mounts, a 1000+ pound concrete base with a 1/4" plate steel mount and 5/8" anchors, well, that's the way it goes.

 

[linearone]

All of the guy wire anchors have now been mounted on the roof. Overall I did a good job hitting the rafter after using the little rafter locating tool I picked up. Hopefully the roof sealant I used will keep us nice and dry inside. So far, so good with that.

I also have five of the guy wires measured, cut and thimbles installed. I think I am going to end up with eight guy wires and possibly ten. I am reconsidering the location of two of the anchors because it'd be nice to be able to take the antenna down without having to go on the roof at all. I am relatively certain that if I do have trouble and have to take it down it will be in the winter. I will not be climbing up our steeply pitched roof to disconnect two of the guy wires from their anchors when it's cold out. I could try to cut them from the ground with some 9mm ammo but I am pretty sure that's not exactly legal where I live. Nor am I that good a shot.

I have two chokes and I had planned on using one on the M104C right at the feedpoint on the antenna and the second one at the V58's feedpoint. I hadn't really considered the rather hefty nature of these chokes and I am trying not to put any more weight up high than is absolutely necessary. I am considering using one choke at the M104C's feedpoint and the second one as close to 36' down from that choke as I can get so it's at the base of the mast. I need to have a coax junction anyway so I can do it there. I'd end up with both on the M104C and go without a choke on the V58. I doubt I'll be using the V58 for much DX regardless. Anyone have an opinion on this idea? If it's not a good one, it should be okay up high for the V58. If winds do take down an antenna / heavy-duty mast being held in place by eight 1/8" 7x7 strand guy wires, two wall mounts, a 1000+ pound concrete base with a 1/4" plate steel mount and 5/8" anchors, well, that's the way it goes.

View attachment 64818

There's base stations with 100kw that don't use chokes

 

[TimmyTheTorch]

I had a bit of spare time this morning so I started tuning the M104C. It is currently horizontally mounted on a mast and is about 7' off the ground. The best I could get it to was 1.3 on channel 1, 1.1 on channel 20 and 1.4 on channel 40. Next I will stick the V58 above it on the same mast and see what happens.

One thing I thought was odd is that the SO-239 connector on the M104C does not have any little notches for the PL-259 end to grab on to. I'm sure there is some engineering reason like decreasing torque on the antenna feed in high winds or the like. Also, the hole in the SO-239 is a very, very tight fit for all the PL-259 connectors I tried, so much so that I actually ruined the end of a 35 foot length of RG213 coax I was using for tuning. Hopefully I can replace the connector it myself and have it function as new.

This is what I have:



These are the notches I am surprised are not there.



But now, it's time to enjoy the rest of my last day of vacation before going back to work tomorrow. Hello, British Open, or to them, just "The" Open.

 

[linearone]

I had a bit of spare time this morning so I started tuning the M104C. It is currently horizontally mounted on a mast and is about 7' off the ground. The best I could get it to was 1.3 on channel 1, 1.1 on channel 20 and 1.4 on channel 40. Next I will stick the V58 above it on the same mast and see what happens.

One thing I thought was odd is that the SO-239 connector on the M104C does not have any little notches for the PL-259 end to grab on to. I'm sure there is some engineering reason like decreasing torque on the antenna feed in high winds or the like. Also, the hole in the SO-239 is a very, very tight fit for all the PL-259 connectors I tried, so much so that I actually ruined the end of a 35 foot length of RG213 coax I was using for tuning. Hopefully I can replace the connector it myself and have it function as new.

This is what I have:

View attachment 64827

These are the notches I am surprised are not there.

View attachment 64828

But now, it's time to enjoy the rest of my last day of vacation before going back to work tomorrow. Hello, British Open, or to them, just "The" Open.

Stop tuning
The antenna is tuned. Did you wind up with the gamma all the way closed?
Also, when you stick the vertical above it sometimes you can take the ground radials off the beam will act as the ground radials

 

[TimmyTheTorch]

Stop tuning
The antenna is tuned. Did you wind up with the gamma all the way closed?
Also, when you stick the vertical above it sometimes you can take the ground radials off the beam will act as the ground radials

I started out at 4" on the capacitor adjust and 24" on the slider adjust and ended up at 2.75" on the capacitor and 19" on the slider. But now I am curious as to what my reading will be if I try with the capacitor adjust set to 0".

 

[TimmyTheTorch]

So, this is either the best way to fit a new PL-259 connector to my RG213 coax or the worst way, depending on which comment you read.

 

[Xracerx13]

Its the lesser of the smarter ways to do it. I've seen cheaper methods with no soldered tip either.
The tip and braid should both be soldered.

 

[linearone]

So, this is either the best way to fit a new PL-259 connector to my RG213 coax or the worst way, depending on which comment you read.

Coax Prep tool kit from DX engineering . You will not be disappointed

 

[snippits75]

I bought a DX Engineering coax stripper for .405 coaxial cables. Then bought a used RFC Industry crimp tool from Ebay for $20 shipped.

The coax strip tool works great. I have used the strip tool on LMR-400 and 8U with good success.

https://www.dxengineering.com/parts/dxe-ut-405c-p1

 

[linearone]

I started out at 4" on the capacitor adjust and 24" on the slider adjust and ended up at 2.75" on the capacitor and 19" on the slider. But now I am curious as to what my reading will be if I try with the capacitor adjust set to 0".

View attachment 64829

You won't get the antenna any broader than that

 

[TimmyTheTorch]

I bought a few new PL-259 connectors and fixed the end of the coax section. SWR still seems good post-repair.

I now have the V58 mounted above the M104C, hope to be able to tune it either tonight or tomorrow night. I also finished creating the rest of the eight guy wires I am going to use to try to hold this thing up. Also installed the Yaeusu rotor and 12 foot aluminum mast with thrust bearing on the two mounting plates, then aligned to mast from the rotor through the thrust bearing.

Next up after that is drilling the hole to run the two RG213 cables and rotor cables into the basement through two inch PVC pipe. Then move the beam and V58 to the aluminum mast, attach the chokes and run the coax down the mast.

Then, I think, raise the antenna, attach/adjust the guy wires and run the cables in through the conduit access point in the wall and into the radio shack (i.e. my basement office).

 

[2AF409]

Looking good Tim. Curious did you ever get your Anytone repaired and what was the problem?

 

[TimmyTheTorch]

Looking good Tim. Curious did you ever get your Anytone repaired and what was the problem?

I ended up sending it to a repair facility that has a lot of experience with this type of radio. It turns out that the one new mosfet I installed was out of spec or otherwise not working as it should. They replaced it, checked/tweaked the bias and it was good as new. I really learned the importance of having a good PEP meter! So far the Daiwa CN-901 I bought has been keeping my gear safe and out of trouble.

 

[TimmyTheTorch]

The V58 mounted above the M104C seems to be working well. I had to do a bit of minor adjusting and ended up with the following.


I hope it's good enough when I get it up on the mast.