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Are there any Alternatives to Packet Radio for sending digital data?

Recently, I asked a question about using an Arduino to send packet radio. I noticed that the top record speed for packet radio is 1 megabit/second, on a modified radio. Someone mention on stack overflow that the normal speed is around 120…
itisyeetimetoday
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How different is Q-factor of SMD inductor from regular one?

I am trying to figure out if it is possible to replace inductors like this wound by 0.1mm (diameter) copper wire with multilayer 0805 SMD inductors. Those are supposed to be used inside band-pass filters. Right now there are 2 coils but I am…
k1zmt
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For air coax calculation, what is correct diameter metric vis-à-vis tube stock thickness?

I am interested in creating a square outer-conductor with round inner-conductor air coax post for a hex beam antenna. I found the extremely useful information at: How do I design a round or square coaxial transmission line to have a specific…
photosynthesis
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Using a Deceased Club Member's Call Sign for Field Day

The Secretary of our club passed away unexpectedly last week. With Field Day rapidly approaching in the U.S., the board is wondering if there is any legitimate way for the club to use the deceased member's call sign for Field Day operations. We can…
Lance
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Will stainless steel bolts work with my copper antenna?

My antenna is copper, elements and the beam. I would like to bolt them together where they cross. Would stainless bolts work? Just sweating them together lets them twist and move some in high winds.
arkieguide
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Are Americans the only hams with four-letter callsigns?

Some American hams are lucky enough to have four letter call signs such as: K1JT Are American hams the only ones with the possibility of a four letter call sign? Is there another country that grants four letter call signs to individuals on a regular…
RoboKaren
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Help understanding the information field in an APRS-IS message

I'm looking at the raw packet data from http://aprs.fi. I see packets such as these: ROSLDG>APN390,HEBOWX,OR2*,qAR,MKSRDG:@015805z4501.34NF12351.41W_000/000g000t053r000p000P000h92b......U2k W7KKE-9>TTRSUT,NEWPRT*,OR2-1,qAR,W7GC-3:'4].…
watkipet
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Weak signal digital modes and clock synchronization

Why to some weak signal digital modes (jt9, jt65, etc.) require knowing a clock time? Does knowing this clock time provide any gain in signal detection ability? (lower required S/N?) What clock synchronization accuracy to what master clock source…
hotpaw2
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What are the implications of pulling LMR400 through EMT conduit with several 90 degree conduit body fittings

In order to route my antenna feedlines out of my house, I have to pass through a wall, into the garage and through another wall. All of this involves four 90 degree turns. I am wondering what the possible issues would be with using 2 inch electrical…
ghendricks
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Long callsigns in WSJT-X?

During the month of May (2018) a lot of Belgian club stations can use callsigns in the format OT70xxx. (The xxx is always 3 letters, for example our club station uses OT70TRA.) In WSJT-X it seems impossible to set this call as 'mycall'; the call…
ON5MF Jurgen
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SSB filtering in the frequency domain?

I'm not sure whether it's more appropriate to ask this question here, or in the dsp.stackexchange. But I'll try here first. There seems to be a lot of information available on the filtering and demodulation of SSB signals in the analog or…
hotpaw2
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Antenna Efficiency

Intuitively, we all understand that an antenna at fractional wavelengths will not radiate well even with perfect impedance matching systems. From what I understand the efficiency of antenna has a few factors: Conduction losses (due to finite…
Skyler 440
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Doppler shift compensation without using predictive modelling

Doppler shift mitigation has been studied extensively in the literature. In my implementations of satellite receivers (using GNU Radio), I use predicted Doppler shift from a software (GPredict) to compensate for Doppler shift. After that, I use a…
Moses Browne Mwakyanjala
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Is there such a thing as a phase modulation voice signal?

Wikipedia indicates that in the digital domain ASK, FSK, and PSK are common. It seems that only AM and FM are used for analog forms of communication. Why don't we use Phase Modulation techniques, and stick mostly to variants of AM and FM?
Adam Davis
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What is this connector?

It is the size of a BNC but has threads. For an RF output. I need to adapt it to SO-239. ---------------------------------------------- Tip o' The Hat to Glenn and Scott. TNC it is. This cable works great: TNC Male to SO-239 pigtail (eBay)
SDsolar
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